What Do Plants Crave?

February 27, 2024

More Info

Ben Phillips, vegetable extension specialist with MSU Extension works with growers on the sandy soils of Southwest Michigan, and used to work with growers on the clay soils of East Michigan. The soils in each place played into how crops were managed. In this talk we will discuss fertility and moisture management for high quality and high quantity vegetables across this spectrum, including high organic matter soils like muck and pot/bag culture using greenhouse media.

The 2024 MI Ag Ideas to Grow With conference was held virtually, February 19-March 1, 2024. This two-week program encompasses many aspects of the agricultural industry and offers a full array of educational sessions for farmers and homeowners interested in food production and other agricultural endeavors. While there is no cost to participate, attendees must register to receive the necessary zoom links. Registrants can attend as many sessions as they would like and are also able to jump around between tracks. RUP and CCA credits will be offered for several of the sessions. More information can be found at: https://www.canr.msu.edu/miagideas/ 

Video Transcript

Ben is talking today on a topic called What do Plants Crave? In this talk, we will discuss fertility and moisture management for high quality and high quantity vegetables across the spectrum, including high organic matter, soils like, and pot bag culture using greenhouse media. I'd like to remind everyone that this is all open to everyone here. Everyone's welcome to receive this information. Let's get into it then. What do plants, what do plants crave? That's a good question that most people ask. Midsummer, or when they're starting their transplants and things are looking crummy. I stole this title from a movie called Idiocracy. In the movie Idiocracy, there's a plot point where you eventually learn that crops are being fertilized basically a gatorade drink called Brawndo. Here's a screenshot from that movie where they're out there looking at the crops and this fellow has taken a drink right from the overhead pivot because there's Brawndo in there. It's just basically Gatorade. The little tag line they keep throwing in. It's got what plants crave, it's got electrolytes. Today I'm going to talk a little bit about what all that means, maybe they're not so far off. in that movie. So, where we're going in this presentation is discussion of what is fertilizer, how do plants eat it? We all understand that fertilizer is something that should be considered when growing all plants. But we're going to focus on some general things here today and a little bit on some specific vegetable things. But I think the general gist is going to be good. What are the factors that affect fertilizer availability? And we'll get into some soil type here and irrigation talk as well. And then some philosophies on feeding plants. I couldn't really talk about light very much in terms of what plants crave. We're talking here, we're talking fertilizer, water and like a soil substrate and light of all those things, the thing you probably have the least control over is light. So we're not going to spend a whole lot of time talking about the light that plants crave. What is fertilizer really? It comes in basically two forms. There are composts and manures, also decaying vegetative matter. What happens with the raw materials is they are mineralized by microorganisms. That means they're converted into a different form, into these individual elements. And they're often an ion. An ion means it's a molecule that is positively charged or negatively charged. That is the form in which plants take them up. In these ion, the ions are soluble in water. When you put these ions in water, the plants can suck them up like a straw. Conventional fertilizers that you would get that are like big balls, these little like salt prills, those are formulated already as ionic salts. It's an approximation of the natural process that would happen in the soil by microorganisms that are breaking down larger things like manures and plants and things. But they all reach the same final conclusion, and that is that you have soluble in water. What are electrolytes? Going back to that movie, it has what plants crave, it has electrolytes. Electrolytes are also ions. They're charged molecules. They're either positive or negative. The most common electrolytes are salts, acids and bases. We use those in all processes. Most of our fertilizers are salts. We also use acids and bases. And modifying ph in soils we're using electrolytes. The other thing that is key to an electrolyte is that it conducts electricity. That's what the electroal part comes from in the name, when you have these positively charged and negatively charged elements, you can pass electricity through them when they're dissolved in water. Does fertilizer pass electricity and water? Yes, it does. Water itself passes electricity. And then when you have these ions that are dissolved in it, it just modifies the way electricity passes through water. We use various tools to measure this, to tell us all sorts of information. The meter here on the left is an EC meter, that's electrical conductivity. It tells you how much electricity is passing through the water. We've got ph meters, which are another way of measuring electronically the electrical activity associated with certain ions. Hydrogen ion. Then we have these water moisture meters, which are essentially measuring the resistance in the soil column. Let's go through a few of these and how we use electricity, and ions and soil to figure out what we need to do to give plants what they crave. We have soil moisture sensors. They rely on a fundamental principle that when soils are wet, meaning they have a lot of water in them, they don't resist electricity as much. The water conducts electricity, and the more water there is, the better it conducts that electricity. There's a lot of tools out there that are based on this idea. You bury them or you drill a hole and you stick them in that way. What they'll do is they'll send out a small electrical pulse and they'll measure how much of it comes back to give you an idea of how much water is there. And that's converted into something we call volumetric water content, which is a simple percentage really, of how much water is in the soil. Once you know how much water is in the soil, you have a better idea of what you can do with ions. Water greases the wheels for everything else, and without the proper water management, you're not really going to get a good fertility management. Here's a chart, this might be one of those screenshot moments for you all. Going on the bottom, all these different soil types, going up and down, it shows you the volumetric water content in percent. It only goes to 50 because soil is composed of three things, air, water, and then the hard parts of dirt. The soil, the individual little soil pieces. You can't have 100% water because there's also air and soil in there. But what you can see here is that in different soils you have these different trigger points for irrigation. And it's all related to how well soil holds water when you have these sandy soils over here on the left, when you're at a 4% volumetric water content, that means plants are going to be sad and you're going to have to start irrigating to get up to around 10% It doesn't hold a lot of water. Sand can't hold a lot of water because it drains too fast. The percent ranges are fairly small. When you move over to a sandy clay loam or all the way over to like a straight clay, they hold water really well. They often have much larger ranges for volumetric soil content. We can also see in this chart is that clay soils have the ability to hold more water. That's just something that is inherently possible with a clay soil, you irrigate them differently and we'll talk more about that later. We're going to dive into the irrigation closer to the end. The other thing you can measure in the soil with electricity is what they call electrical conductivity. And this is a process that's more commonly used in greenhouse media. This is with pearlite, sphagnum, peat moss, and things like that. In compost, they're mixed up. They're often called soil list mixes. If you're raising plants exclusively in this structure, you need to be paying attention to your EC. The EC is a basic measurement of how many ions are in the water. If you want to measure this yourself, you would take one part soil or potting mix or whatever, have you have, mix that with two parts distilled water or if you're doing hyotroponically, you would just take whatever your fertilizer solution is, just that your water and your fertilizer put together. Then you stir it up, wait 15 minutes for it to settle, and then you stick in your EC meter and you measure what is the electrical conductivity that's happening here. The range is pretty small. The optimal range is quite small. It's 1-2 0.5 millisemens. There's a lot of ways you can measure this though, with different units. And it gets really confusing when you start googling this because you get people who always want to report in parts per million. The approximate equivalent to one to 2.5 millisemens is 640 to 1,600 parts per million of salt. This doesn't tell you the exact nutrient content. This just tells you how many ions are in the water. If you have water that you're pulling out of a well, it's hard water. That means it already has a lot of ions in it. And if you put your EC meter in there, you'll get a reading and it'll show you that it has ions in it. And then if you add fertilizer to that, you want to find the difference between the base level of EC and what you've added to get some idea of how much fertilizer you've added. That's why in this testing procedure, it asks for distilled water, which is also called de ionized water, and it has no ions in it. It'll give you the truest reading of what your soil has in it. For hydroponic folks this can get fairly tedious and rather prescriptive. Here's just an example of a fruiting vegetable and some basic recommendations for EC over the period of growth. What you're starting with are tiny plants who don't need a lot of fertilizer. You use your EC meter and you measure your water every week with your fertilizer in it. And you want it to be only around 0.8 If it's too high, you'll burn the little roots and they don't need that much. You're going to waste some too, going into some vegetation period, you're going to maintain an EC of about 0.8 Then after you start flowering and blooming and you're putting all this fruit load on a big plant, you start to increase the EC or increase the fertilizer you're adding to that mix. And you just measure every time you add to see that you're hitting that EC level and you don't really want to go much higher than two in this case, 1.3 is as high as it goes. The recommendation, that's one way to measure fertility content in a hydroponic style arrangement or even with soil mix. But in any case, you're giving the plants almost everything they need through soluble fertilizer. Another thing you can measure with electrical components in the soil is ph. It's measuring the activity of hydrogen ions which are positively charged. The more hydrogen ions that are active in the soil and moving around, the more acidic that solution is. In this little part, hydrogen ions are in red, You've got a lot of those. Then when you get into a more basic solution, you have far fewer of them. And you have more of a different ion called hydroxide. But ph is measuring the ion of just hydrogen. Plus you can use the same procedure for measuring that in a soilless media, where you have one part, two distilled water. You put in your probe and you get a reading. You can do that just exactly the same. You can do that with field soil too. If you're going outside in the soil and you want to have some idea of what your ph is, you can go shovel up soil from the ground, mix it in a one to two ratio with distilled water. Put in a ph meter and you can read, so you can get your soil ph that way. In a greenhouse, it's often recommended that a more acidic soil is good. There's some reasons for that. A lot of the water that we have here in Michigan that we use for irrigating is basic when you're relying on water coming from the water table. The plants only getting that they're not getting rain because you might be growing in a greenhouse or something. Then it has the tendency to creep up and up, and up and up. The ph just gets higher and higher. It's helpful to either acidify that water or maintain a low ph. In the media itself, a lot of it already comes that way, like sphagnum. Peat moss comes from bogs and things, and those are already acidic. You have a fair amount of acidity in that soil already, and you just want to keep it from getting up and out of control once you're out in the field and you're fertilizing with more conventional fertilizers and they're getting rain fed, then keeping a ph 6-7 for field production. Soil is generally right in the money if you're not in those ranges. There are ways to change that if you're working with field soil and you're outside about six months to really actually initiate a change. It takes some time and it takes a high volume of material, depending on how much you want to change. It's a log rhythmic scale. It's not just like a one to one thing. The larger your differences between where you are and where you want to be, you have to add a whole lot of acidifier or Something that changes it. To be more basic, most people here in Michigan find themselves using lime on a fairly regular basis. Because in a field setting, a lot of nitrogen fertilizers and animal manures slowly acidify and they can get your soil range below six. Folks will add lime every few years to try to boost it back up to that 65 to seven range. There are some situations though where soils are a little too basic, especially in hoop houses within soil production. In those cases, acidifying the soil is helpful every few years Using something like sulfur. And some nitrogen fertilizers, like I said before, will acidify as well. But sometimes you need just a big slug, just bring it down. And putting in elemental sulfur is one of the better ways to do that. This chart here shows the availability of different nutrients in the presence of different ph environments. How you look at this is it's not the quantity of each of those nutrients that are present, but how available they are. For example, if you had soil with a, where's my mouse? I can't find my mouth. There it is. If you had a soil that was over 7.5 and you put a bunch of phosphorus on, that phosphorus wouldn't actually be available even though you added a bunch to the soil. Because what happens in a high ph environment is it gets locked up and it combines with calcium. When it's combined with calcium, it's no longer available to plants. The same thing happens when you're in a low ph scenario where it gets linked up with aluminum and iron. And even if you have a load of phosphorus, it doesn't actually become available to plants in that ph environment. A third thing we can measure, this is the last big measurable thing where we're talking electricity and soils and electrolytes. But the third big thing is cation exchange capacity. It's one of the most important things. One of the most important things, cation exchange capacity is essentially the degree to which a soil can exchange these positively charged ions. Essentially, it's an indication of your soil surface area. In these pictures below, we can see soil particles at different sizes. We've got clays over here on the left which are essentially like plates. And they get all piled together, almost like pages in a book. In between all of those pages of the book is a surface where cat ions can bind to, it can hold a lot of cat ions. Over on the left we have sand, which you don't need a microscope to see how big those soil particles are. There's fewer of them in the same volume, and there's less area for cations to exchange with and to bind to that makes it a little less available for certain nutrients. The cat ion exchange capacity, it affects, it gives you an idea of your soil, the ability to hold water and to hold nutrients. It also gives you an idea of the timeline it would take to change ph. Herbicide activity as well is affected by the soil soil particle size. In this chart below, you can see the cation exchange capacity that the range you may expect in different soil types. In sands, you get a lower reading, 112 in loams, ten to 15 silt loams a little higher. Clays get up to 50, and organic muck soils can get really nuts, up to 100. The higher that number is, the better it holds water, the better it holds nutrients, the better it holds herbicides. If you're using herbicides, you need to use a lower rate on some of these soils. In fact, I think for herbicide activity, it's for sandy soils, you need to use a lower rate because it stays in solution between the soil particles longer then the timeline to change. The ph also changes when you have a high CEC, that means it takes a lot more of an acidifier or a base fire to actually change the ph. So why are cat ions so important? Why do we have a cat ion exchange capacity? And why does that get all the attention and not something with anions which are the negatively charged things? Well, it's basically because the world is negatively charged. If you ever feeling down, just remember the world is negatively charged. Maybe you already knew this. It's, everything is negatively charged. The soil is basically all negatively charged, and plants that are growing in it are negatively charged. What that means is that when you have ions that have a positive charge, they get stuck to that negatively charged surface that facilitates them getting used in the plant. In this chart here, I've got a whole series of elements that are commonly taken up by plants and then the form they're taken up on, you can see a lot of the ones with a plus sign, meaning they're positive, they're cat ions. They're either not very mobile in the soil or they're not mobile at all. That's because they're stuck to stuff, they're stuck to soil particles, or they're stuck to the root. They're not mobile. Plants influence this electrical gradient. All right? They've got H plus, which is the ion that we use to measure acidity. It's a super active ion. It zoos around, gets linked to stuff in order to maintain equilibrium. If hydrogen gets bound to something, something else that's positive has to come off to keep the equilibrium in place. Hydrogen is often used as like the money that gets exchanged in the soil system to pull nutrients off of soil particles. Plants will do this in different ways. Some plants will actually pump hydrogen ions out of themselves into the soil, Just so that it'll bind to a soil particle and kick off another nutrient like in this case potassium. It's like a one to one exchange, give hydrogen to the soil particle. The soil particle releases potassium, it goes to the root. Other times, plants will release acids and those acids will break down and they'll make more H plus, which then does the same thing. At that point, it will move hydrogen onto a solar particle and it'll pick off another element that the root then absorbs. Another way plants will influence this gradient is by giving sugar to microbes. Then the microbes make the hydrogen, and then the hydrogen kicks off the nutrient that goes to the plant. The plants will handle this in lots of different ways. It all happens in water. It has to be in water. And hydrogen plays a major component, the positively charged hydrogen ion. What about ions? The negative ones. In order for an ions to enter a negatively charged environment, they need to be forced into it. It's like holding two negative ends of a magnet together. They just like don't want to connect, right? So it's for that reason that most of the anions in our soil are what they call mobile. They're just always in the, so the water solution and they never stick to anything. These are the ones that are usually most at risk of being run off from high levels of rain or over irrigating. They just move with the water and then they go away. The one exception here is phosphorus. It's not very mobile as an ion. It gets linked up with other molecules like I showed before. At a high ph it gets linked up with calcium. At a low ph, it's linked up with iron and aluminum. It gets linked up with all these other nutrients and it becomes less soluble and it just hangs out on soil particles as these aggregates. And it's also prone to being washed out. It just behaves differently than the other anion. How do the plants deal with these anions if they're always in solution and they're not zipping around on electrical charges? Well, healthy plants, they ask for it. Essentially. That's one way I can think about it. Healthy plants are growing quickly. As they're growing, they're increasing the number of leaves and they're increasing the sizes of those leaves. Through those leaves, they're releasing water through transpiration or evapo, transpiration as it's called as the water is leaving the leaves. They then start a vacuum. Pull of water from the roots, Anything that's dissolved in that water, including anions, gets sucked into the plant with the water. It's like a pump that's called mass flow and it's all driven by a healthy plant that's transpiring into the air through its leaves. If your plants healthy and it's transpiring as it should, then it's pulling up water and it's bringing nutrients with that water. Another way that plants will ask for nutrients, in particular phosphorus, is they'll have special cells in the roots that, that will move an ions across the gradient. It'll bring a negatively charged ion into a negatively charged environment through force. It does this in a couple of ways that I can't spend a lot of time getting into, but there are phosphorous transport cells that just bring phosphorus in against an electrical gradient. What plants need more phosphorus. What they'll do is they'll expand their roots into all these hairy little fibers that are just loaded with these phosphorous transfer areas. They'll also enlist fungal friends to do the same thing. Essentially, there are a whole load of microorganisms that will actually infest roots and then act as additional roots for plants. I think on Thursday, Chris Galbraith, my colleague, is going to talk about a lot of these good guys that do this thing for plants. Those are other ways that plants will get phosphorous in other anions that aren't electrically based coming in through that electrical gradient. I had a question here coming from David Noto about thoughts on potassium or me together he used the word potash slang word for potassium. Then calcium carbonate or calcium carbonate is positively charged. Potassium is positively charged. They're not going to get bound together, usually. I don't think there's any downside to using them at the same time. However, potash is typically a larger size. If you're trying to spread it through like a broadcast spreader. It's going to spread really differently than lime will, which is a finely crushed powder. You may be thinking about using different spreading mechanisms for spreading each of those because they're going to flow differently through a machine. In a, Potassium can sometimes fall out a solution. Calcium can do the same thing if you're trying to do something with like a liquid I'd be in contact with. Actually, that's what this next slide is going to be about. Be in contact with your input suppliers so that you can understand if you're going to be mixing two different liquids together, there's often more ingredients than what's listed. Sometimes if you mix two different liquids together, they can have a chemical reaction and then they'll form a solid that doesn't flow through sprinklers very well. But I wanted to talk about how you may be in a situation where you just have a certain soil and that's just what you have. They're very old. You don't simply change your soil type. You don't turn a clay into a sand or vice versa. You can modify things a little bit, especially something like ph. You can modify organic matter a bit with certain inputs. But by and large, what you're going to be working with is the inherent dynamics of your soil particle sizes, whether they're sands or clays. And you just need to adapt your style of irrigating and your style of fertilizing to fit what that soil can do for you. The vegetables are going to grow quite well in a range of soil types. You just need to learn how to manage the physics and the chemical things that are going on in that soil. Hopefully from what I just talked about and we're going to continue talking about, can help you do that. When you're working within these systems, it can be really helpful to know what is happening in your soil through testing it. There's lots of labs that'll do it. What happens with MSU is we'll ship it to a place in South Bend, Indiana and they do it and then we slap our recommendations on it. You can also send directly to that lab in South Bend, they're called AN L Labs. You can also start investing in tissue testing, which some people subscribe to right away, that they tissue test on a weekly basis and others will use it more as a diagnostics tool. When things start looking weird, then they lose some tissue testing to figure out what is my plant missing here or is it getting too much of something? Once you have some idea of what you're working with, then it's helpful to understand the nutrient contents of your products and calibrating for using them in a way that you're not going to fry your plants or not give them enough. What this often ends up looking like is you're fertilizing like a yes. Let me elaborate on that. There's basically two ways to fertilize plants. There's the baking style and the frying style. The thing about baking is that you get all your materials together and you get it all measured out. You get the oven preheated, you mix it all together, you put it in the oven, and then it's just hands off at that point. With frying when you're making a steak, or your sauteing some vegetables, or even making a soup, for example. You've got heat applied to the food that you're going to make and you're testing it and you're tasting it as it's being made, and you're making adjustments continually. You're adding a little salt, you're adding a little basil. You're continually adjusting it in real time. You can do fertilization much the same way with the baking approach. You're using soil tests to guide your inputs before you plant things. You put your ingredients together before you plant. You can use slow release products that will dribble out your fertility over the course of the season. Or you can use more active release products, but then you split up the rate you do in a little bit of frying. Sometimes you do in like a pre plant application, usually about half of your full needs, a particular for nitrogen. Then later on, about six weeks, four to six weeks later, you add the other half and you can split that up more finely. If you're using something like drip tape, then you're getting closer to something like the frying approach I'm talking about, this is where you're adding nutrients almost on a weekly basis. You're spoon feeding, It's not often used alone. This frying approach isn't often used alone, particularly if it's like, if you have like a folia nutrient program. It's almost impossible to get the full nutrient needs to plants solely through their leaves. They can do some absorption through the leaves in certain elements more than others, But it's hard to do the diet that they need 100% through foliar fertilizer. It's often used in conjunction with this pre plant and incorporated model, this baking model, if you want to call it that, more often with the frying method, that the nutrients are in a solble form already and they're immediately available either through, like in vegetable world, it'd be like in a drip tape solution or a foliar solution. It's just immediately available, the plant suck it up right away. These two philosophies, this baking and frying philosophy, they loosely overlap with some more scientific approaches. One is essentially what you're doing is you're feeding the soil, not the plant. It relies on this idea of drawing down nutrients like a bank and then building them up again ahead of the next crop, and getting them what they need for each. Like a bank, you're putting in a deposit and the plants are making a withdrawal. With this philosophy, you're relying on soil tests to tell you what is the most limiting nutrient in your system right now, this multi staved barrel is analogy that is sometimes used in this barrel. Each stave represents a different nutrient. The health and the yield of your plants is dictated by how high you can get that water level. In this case, it looks like potassium is the nutrient that is most limiting to the plants. And therefore, you'd want to be adding more potassium in your soil to bring that up. But once you bring potassium up, there's always going to be a next lower stave and then you have to address that nutrient as well. The soil tests can help you understand the balance as well, which is the next slide. Here, the balance between nutrients is important. This is another electrical based philosophy. Here you've got a bunch of primary nutrients, potassium, magnesium, and calcium mainly, that are all positively charged. And that means they're competing. They're competing. They have negative surfaces, roots that they will bind to. Okay? And hydrogen is in there, kicking them off to go into this electrical gradient that they zap onto plants. But since they're all positive, any one of them could bind to a root. You want to maintain a certain percentage of each of them so that they have better chances of being represented in your plant. If you have a lot of potassium, then they're going to outcompete magnesium and calcium in the soil like ionic environment. You need to balance that out. This chart is confusingly so is that different nutrients will make others more available or they'll compete by and large. Most nutrients compete with each other because most of them are cat ions. Most of them are positively charged and they're bouncing around the soil environment through the electrical gradient, and the positively charged stuff is going to compete with each other. Okay, I wanted to talk a little bit about responding to visual symptoms of nutrient deficiencies. And I'm not going to get too prescriptive here and I'm not going to show all that many pictures. Because tomorrow my colleague Salta, is going to talk a little bit about visual diagnosis of diseases. And some of those aren't from a pathogen, some of them are from something like a nutrient deficiency or toxicity. I'm not going to harp on that too hard. But in general, the symptoms of a nutrient deficiency often include a color change. Yellowing is common, purpling to also some die back and spotting. Sometimes it's hard to find stuff happening in the roots, because unless you're digging things up, I'm not familiar with too many root symptoms. Then sometimes it manifests only in the fruit. This is a helpful chart, helpful graph, that can bring you closer to a diagnosis. There are some nutrients that are really mobile in the plant. What that means is when a plant is growing, it will use itself as a nutrient bank. For an example, on the bottom half of this graph, you'll see nitrogen, phosphorus, potassium, and magnesium in the old tissues. And what that means is that you will see symptoms of their deficiencies in the older tissues. Because when a plant is growing, it will just take those elements from the old leaves and it'll move them to the new leaves. It's mobile, they'll just say, okay, old leaves give me some magnesium. The new leaves need it, send it up. When you see weird symptoms, only on old leaves, that could mean it's one of these nutrients. Now, vice versa, all these elements in the top of the chart, these are not mobile in the plant where they land, they stay. That means they tend to concentrate in the older tissues. When you have new growth, it's not getting it, You'll see a deficiency symptom only in the new growth. That's one quick little tip for helping to diagnose some things. They manifest in a lot of ways. I did put some pictures of tomatoes because a lot of people grow tomatoes and they're like the dog of the vegetable world. They're very expressive of what's going wrong with them. On the top left, here is an example of what a phosphorus deficiency looks like in tomatoes. In many crops, when phosphorus is low, they'll turn purple. Tomatoes do the same thing, they turn purple. In the middle is a potassium deficiency, which tends to happen on the oldest leaves. When I have seen it, it is typically something that has an edge burn. A little bit of an edge burn, and oftentimes, the symptoms can look quite similar to magnesium deficiency because there's some yellowing that happens between the veins. And you can see that in this picture. And in the bottom right, you can see magnesium with yellowing between the veins of the oldest growth. These are the largest leaves near the base of the plant. Those two can be confusing. Manganese is another one that I see from time to time, mainly in hoop houses that are growing in the soil. And the hoop house has been used for like six years or more. The reason that this happens, it's only in the new growth because it's an immobile nutrient. But manganese is something that becomes more limiting in high ph soils. What happens in a hoop house after about three or four years irrigating from well water, is that the ph just gets higher and higher, and higher, and higher and higher. It's not uncommon to go to a hoop House and look at some soils and find ph over eight. It's in those soils where you start to see manganese deficiencies in the new growth. Then in the bottom left, everybody has probably seen blossom end rot in tomato. But it's how calcium deficiency manifests in this plant. It, calcium deficiency in other plants looks different, but in tomato it manifests as a fruit rot right at the tip of the fruit. You can diagnose plants right there individually, but what can also be helpful is zooming out from individual plants and seeing if there's some pattern going on. Because there's a lot of things that will look like a disease or a fertility problem. But then once you zoom out, you may get some additional information that helps you narrow some things down. Like in this case, it looks like we've just got some low spots syndromes, here, we've got some low spots, and therefore, plants are suffering from any number of different things. Sometimes when you zoom out, you can find other things, straight lines. You see problems only in straight lines. Straight lines don't usually happen in nature, and typically that's a human caused problem and that might be a fertility problem if you're fertilizing or spraying. I just want to broadly describe some fertility approaches here. Conventional fertilizers are typically 18, 60% active ingredient, that means by weight. Let's talk about urea, for example. It's very common. Nitrogen fertilizer, it's 46% nitrogen. It's available to plants almost immediately once it gets dissolved. Organic fertilizers are typically a lower percentage fertility component. There's a lot of bulk material and a lower percentage of active ingredient, if you want to call it that, it's usually no more than 15% It's typically a slower releasing nutrient then there are some benefits to that. If you're using soil in a hoop house, it's generally recommended that if you're doing a soil test and you get some input, recommendations generally recommended you cut those down significantly because in a hoop house environment, you're not getting the same in outs that would push nutrients out of the root zone. Many of the soil recommendations for open field settings are, are factoring in a certain amount of loss through rain, pushing nutrients out of the root zone. But in a hoop house, that's less likely to happen unless you're irrigatting like crazy the other thing, that you'll have more fertility than you really need. The other thing that can happen, you just have these salts that build up over time and you end up with a really salty soil environment, which makes it more of a challenge over time for direct seeding seeds in small little brand new roots don't really like a high salt environment. If we're going back to that EC measurement that's really small, like between 0.8 and 2.5 If you get over 2.5 electrical conductivity in your soil, seedlings don't like it, they really don't like it. If you're boosting a lot of fertility into a hoop house, you're not getting washed through or like winter snows that push things through, you end up with more salts. And then if you're doing direct seeding with like carrots or lettuce or something like that, they can be more affected on the long haul. Another thing, a cover crops. Cover crops that include a legume component, beans and peas. They can fix their own nitrogen and oftentimes they'll create a surplus when you're following a crop. When you're following beans that were as a commercial crop, or you're following a cover crop that included legumes, then you're going to get some nitrogen benefit from that variable. But 30 pounds an acre is a plannable number. Following a 30 pounds is about what you could expect. That would mean when you're thinking about inputting nitrogen yourself, spending money on nitrogen to put in the ground, You might want to subtract 30 pounds an acre from that recipe and save some money. Nutrient forms are often coming in spreadable formats that are like solids, right? We got manures, we got compost, crust rock, salty prills like urea and various other thrill based fertilizers. The more and more we're seeing liquids taking a lot of the market benefits to liquids, but they are heavier and harder to ship. Then they're broadcast in different ways. They broadcast dried, sometimes they're precision placed but still dry with vacuums. I got some pictures of all these. How about I just go to the pictures for drive materials. We've got all sorts of ways of broadcasting it. We've got spreaders that are driven electrically or by the PTO or the tractor. We've got drop spreaders as well that just drop it right underneath. We've got spreaders that spread sloppy stuff too in a way that's more or less like a broadcaster, like on the top right here. It'll spread chunks of stuff. Then the more liquid a manure is, then you've got different technologies being used here to apply more of a liquidy type thing. We've also got side dressing components that precision place fertilizers and they can do this with liquids and dry stuff. There's very old technology like the farm all cup here in the black and white picture and there's very new technology that are fault achieving, essentially the same thing, scratching the soil and then piping in some amount of fertilizer right in the little divot you've created to precision place it so you're not just spreading it all over the place, you're putting it right where the plants want it. A lot of ways to do it with liquid as well. In plastic culture, vegetable systems, which is a very common way of growing vegetables, especially on sandy soils, you use a drip tape that you cover with plastic mulch. In greenhouse situations where you're growing in bags or pots, then you're also using a lot of liquid piped add tape. In this case, this picture shows tape with, I think, two foot emitter spacings and the fellow just put the bags underneath each of those emitters. You can also use these little stakes that you poke into the main line and then you drive the steak right into the pots. It's a little more control dripping. You can get more creative arrangements in spacing that way. Sprinklers of you can put fertilizer into overhead sprinklers as well. It's basically like spraying it through a sprayer, but you have solid set irrigation, lots of different types of spreading. You've got impact style, which might only half a hemisphere. Or you've got 360 degrees sprayers like some of these other ones here, like the wobbler on the far right. We also have moving sprinklers. We've got a lot of different models, even watering cans, a moving sprinkler because you're on the run and you're doused in water. But the one on the top right called the reel, you pull out the impact sprinkler there on the top right. It unspools that whole mechanism, you turn on the water and then the water movement itself powers the spool that then pulls the irrigation unit back to itself. Those are fairly adaptable. Then we get solid or we have pivot irrigation which are rather permanent installations that travel across huge swap landscape and you can put fertilizer into those systems as well. Then in the hydroponic system, exclusively at the root level that the fertility is applied, It's pumped around through buckets like on the bottom right, also to rails like in the bottom left. Then in float systems, this liquid that you see underneath that Styrofoam board, it's a fertilizer solution. It's all mixed up, it's tested, but it's at the right EC, it's got the right ph and the roots just grow in there without soil. And then those are cycled through a filtering system where you can monitor it and keep up with the nutrient levels. As the plants grow with a lot of these liquid systems, an injector is used. The two main ways of injecting are with what they call a diaphragm injector, which is pictured here. It's a pump essentially that is powered by the movement of water. It sucks up a little bit of a concentrate from another container, Like in this picture, there's a 50 gallon barrel in an apple. In the other picture, it looks like maybe a five gallon barrel on a dolly. Each of them are fairly movable around a farm. You put the concentrate in the barrels, then you at the diaphragm pump with this bottom part here, the twisting mechanism. And it adjusts the rate at which it's pulling up the concentrate and putting it in the water. It's a more expensive way to go, but a lot of people enjoy the adaptability of it. The other way to go is with something called a Venturi injector. The feature few moving parts. It relies on a physical principle where when water is moving through a pipe and you restrict the diameter of that pipe, it drops the pressure. And then you expand this diameter of the pipe directly after that, and it generates this vacuum. You put fertilizer in through that vacuum. The only way you can really adjust the rate that you're applying to this is by adjusting the pressure, these two valves. You adjust the pressure with these two valves instead of just one on the diaphragm pump. Then depending on the throughput of your water, you would need a different size Venti mechanism. You would work through whoever's selling this product to figure out what level is going to be right for your throughput and what diameter of venturi you'd need. As it comes to irrigating and using these systems, the common rule of thumb is to put on an inch of water a week. Such a strange way of measuring a volume of something liquid. But it's a lot easier to see what an inch looks like than it is to see what a gallon looks like. Because gallons can take all sorts of shapes and forms. People say an inch 1 " of water on an acre is 27,154 gallons on 100 square feet, it's 46 gallons. When you're trying to hit a mark of 1 " per week, it's helpful to have those numbers in mind. Then when you are working with a system you might already have or you're looking to buy a system to irrigate with, you need to have some idea of what the gallons per minute or gallon per hour delivery rate is. Then with that number, you can figure out how to reach 46 gallons. How long does it take? How many minutes does it take to get 46 gallons on 100 square feet? Then with that information, you can hit the ground running and figure out how much you can deliver over a certain amount of time. Maybe you do that over several days. It's helpful to keep track of some things though, like rainfall, because why would you irrigate if you got rain that week? It can be really attractive, especially at a gardener level. So you have a timer that just makes it run every day. It can be really attractive to do that, but when you've got rain coming as well, then you may be over watering and just spending money on nothing. Then evapo transpiration. It's harder to find that information. Evaporo, transpiration isn't often something reported in the Daily news. You need to go through some ag, specific venues to find those numbers, but that's essentially how much water is leaving your plants every day through them. Just living, you want to be able to meet that need then plus some more at the root zone. Let me show you a graph that demonstrates what this looks like. This is last year, the amount of rain we got every day from March through October, the end of October. It's basically our vegetable season. All the blue bars is rain and it's accumulated every day. We got rain. It adds to the bar before it, so you can see it grows over the season, and we got about 32 " of rain between March and October. That's a, our average for the whole year, including snow is around that much. We got a lot of rain. Then the red line is essentially the same measurement, but instead of using bars, I used a line so it's easier to see. That's the amount of water in inches that was leaving the plants on each of those same days. What you can see right away is that early in the season between March into the end of May, we were getting more rain than plants were evaporating out of their leaves. We had a surplus of water. Then quickly, that shifted into June and July where we had not enough rain to meet the demand that plants were exhausting into the air. That red line was higher than the blue bars. That means during those time periods, it was important to supplement with irrigation so that plants could continue evapo, transparting, continuing bringing nutrients up through the roots and continuing to keep a soil solution of nutrients at the root zone ion dissolved in water. When you're not supplementing in times of need like this, your plants suffer. I wish this information was more readily available through typical news channels, but it often isn't, and you have to seek it out through specialized places in one way. The place where I got this is from MSU Viral Weather, the website with all sorts of weather data pertinent to growing plants. This is the same information displayed, instead of accumulating, it's like every day, just what happened that day. You can see we got some pretty extreme rains going into August. But I find this a little harder to read and accumulation charts a little easier to understand. There's something else to consider with irrigating. It's not just of apple transpiration, it's not just precipitation but your soil type. We've talked about clays and sands and some attributes that are inherent to them. Here's one way to think about these soils and how they move liquid. If any of you have watched the prices, right? You may be familiar with the game of Plinko, where the contestant drops a chip down a board that has lots of pegs in it. Which board do you think would move this Plinko chip faster, the one with fewer pegs or the one with more pegs? I'm curious. You can put it in the chest. Sorry, I haven't been asking you many questions but I'm curious what you think which would move faster, fewer pegs? That's right. Fewer pegs. That Plinko chip is going to move basically straight down. Our soils are like that too. Sandy soils are like the Plinko board on the left. It's got bigger chunks and fewer of them, and water can move down with gravity a lot faster than in a clay soil. Clay soil has way more soil particles all jammed together and the water moves back and forth, left to right, more than it moves down. In this chart, it shows that graphically with soil types and water data. On the left we've got sandy soils. As the water enters the soil column, it essentially moves straight down. And it does so quite rapidly. Within a day, the water is all the way down to 72 " deep. You contrast that with the clay soil. It takes two days to reach that depth. It takes 4 hours to get to two feet, 4 hours to get to two feet. That's like right in the root zone of most of our plants, two feet. There's not many roots beyond that takes 4 hours to get to that level, whereas in the sand it takes less than 40 minutes. You irrigate these two soils quite differently to get plant roots. What they need, by and large, the recipe is for, in a sandy type of soil, you want a high flow because you want that water to go out, not just down, you want a lot of water coming in so that it spreads out laterally more. You don't want to irrigate for a long time because you're mostly just going to push it all. It's going to be a short time and you want to do it more frequently, it's like in spurts. Whereas in a clay soil, you want to lower flow so that you can get it to go out, but not too far out so that it just flows across the surface. You want to irrigate for a longer time and less frequently if any of you have grown in clay soils, you know that more often than not, the problem in a clay soil environment is getting the water out. Especially when we've got situations where we get like 4 " of rain in a week, it takes a while for that soil to actually then drain out again. If you're irrigating clay soils, it's a light touch, low flow, long time, and infrequent in order to change the input volume or uniformity of any of these moisture related things you're working with. Changing your pipe diameters or your sprinkler spacing, or your emitters on a drip tape. If you're using movable units, then your speed affects how much water you're delivering as well. Let's say you've got a watering can and a gallon of water in it. If you're walking fast and you're pouring at a constant rate, then the water isn't being spread over very much area or not. A lot of water is getting in, but if you're walking very slowly or just standing still and dumping that gallon out, you're getting a lot more water into a particular area. You have to modify a few different things to hit the mark you're looking for wrapping up the unified theory here is that we've got charged ions, positive and negative ones that are dissolved in water. And that's what makes this whole thing work. You need the water to make it work. Plants need the right ions, the right nutrients in the proper concentrations with the right, with consistent moisture. That's like the three way mix that these plants really the right proper concentrations, adequate ph and consistent moisture. I guess that's four things. If you're working with the soil system, you are really truly blessed with the fact that plants are an active participant in this. Plants are modifying the soil environment electrically and microbial to get what they want as long as they're healthy. They are asking the soil to give them what they need. A lot of times what your job is, is to make sure the soil has what they need and the plants can essentially take care of themselves. When you're working in a hydroponic environment that is 100% on you, the plants are asking, but there's no microbial associations. There's less of an electrical component, it's all. So there's a lot more attention that you have to pay into a hydroponic system. If you would like to talk more about any of this at greater depth with people at MSU who work with vegetables, these are the folks you could reach out to. I'm the one on the bottom left down in Benton Harbor. My other colleague, also another Ben, is further north of me around Oceana County, Salta Mambetova is based over in the thumb around Franken Mouth. Chris Galbraith is down in southeast Michigan, in Monroe County. We all are happy to help you in any way if you're trying to make the vegetable thing work for you. In conclusion, you could feed your plants gatorade perhaps, but I don't think it would have the right nutrient components for the plants. Who knows what the ph is? I would stick with the data that you can collect and not follow the movie idiocracy.