Greenhouse growers: Five things to consider while gearing up for spring 2018

Combine traditional methods with some innovative techniques to help keep your greenhouse operation running smoothly this spring.

Photo 1. Leaf distortion in New Guinea impatiens due to low substrate pH and excessive soluble salts. All photos by Jeremy Jubenville, MSU Extension.
Photo 1. Leaf distortion in New Guinea impatiens due to low substrate pH and excessive soluble salts. All photos by Jeremy Jubenville, MSU Extension.

One of the great things about working in agriculture is that every season is different. Variation abounds in nature! This could be no more evident than to people who work with plants and animals for a living. Even in a greenhouse, where we try to control everything, nature still has plenty of ways to keep us on our toes.

The difficulty in accounting for every possible issue that may surface over the course of a growing season highlights the importance of being adaptable to a changing environment. Some problems are easy to predict: pests will show up, disease will too—it’s just a matter of when and where. Other problems could be tougher to foresee, such as widespread substrate pH problems, area-wide power outages or a polar vortex.

The following is a short list of ideas that may help growers nip some of their predictable problems in the bud so they have more time to focus on any new situations that arise.

1. Verify the quality of your water and substrate.

This may be the single most important task you can accomplish. Few factors have a more profound effect on the quality of finished greenhouse plants than the condition of the irrigation water and the chemical or physical properties of the substrate (Photo 1). Modern technology has made in-house testing a quick and simple process.

One of the best investments you can make is in high-quality pH, EC and alkalinity testing equipment. Create a schedule for testing your water and substrate on a regular basis and record the results in a log book or spreadsheet. Don’t forget to test your bulk media when it first arrives—what you learn could save you a lot of headaches down the road.

2. Mycoinsecticide dips for incoming plant material.

Starting clean is one of the most important factors in a successful pest management program. Nevertheless, when we bring in cuttings and liners from outside sources, there’s a good chance they’ll come with a few insect pests as well. No matter how hard they try, it’s almost impossible for suppliers to ship pest-free plant material.

The Vineland Research and Innovation Centre has developed an innovative technique to help reduce the number of pests that come in on imported plant material. It’s economical, worker-friendly and easy to integrate into the production process. A short demonstration video can be found here: Vineland Research – Cutting Dips.

Interested in trying it out? Run a small trial this season! Contact one of Michigan State University Extension’s educators or outreach specialists on the floriculture team for more details and technical assistance.

3. Create a quarantine area.

When we receive shipments of plugs and liners from a propagator, where do they go? It depends on the operation, but in many greenhouses, the material sits on racks or benches near the production area. In this arrangement, any pest that was hitchhiking on the plant material now has access to all your clean crops. Some growers have found a way to arrange it so incoming material is physically separated from the production area and monitored for a short period of time.

If your receiving area can be closed off from the rest of the facility (i.e., with a door), it can be as simple as placing some sticky traps in the racks and leaving them overnight. Inspect the cards and a few plants in the morning, make a note of what you observe and take pest management action as necessary. This method could work very well in tandem with mycoinsecticide dips.

4. Plant growth regulator dips for tricky planter and basket combinations.

Producing a crop that is uniform in size and shape is an important goal for a greenhouse. Not only does it help you use rack space with maximum efficiency, but it serves as a symbol of consistent product quality. Growers will often employ a combination of chemical, manual and environmental methods to control plant height or stem elongation. Plant growth regulators (PGR) are usually the most efficient method and are often applied as sprays or drenches. A more difficult challenge arises when several different plant species are combined within the same container, often resulting in a dissonant collection of conflicting growth habits and incompatible PGR requirements (Photo 2).

Basket combination

Photo 2. The petunia in this combination basket has almost swallowed the geranium.

PGR liner dipping is a method that could help provide consistent and predictable results for single-species crops and combo planters. While this method may require some logistical adjustments on the transplant line, the strategic application of PGRs to certain species before they’re transplanted in the finish containers can be an elegant way to rein in vigorous varieties without retarding less aggressive species.

Information on this subject is abundant, but here are a few links to start:

Contact a member of the MSU Extension Floriculture Team for more details and technical assistance.

5. Staying informed on new Worker Protection Standards.

The EPA Worker Protection Standard (WPS) was originally created in 1992 and designed to reduce the risk of pesticide accidents with workers in agriculture. Major revisions to these regulations occurred in 2015, but many of the new requirements weren’t scheduled to go into effect until 2017 and 2018.

Even though these regulations can be complicated and confusing, employers are still obligated to meet the newest requirements. The MSU Extension Floriculture Team has arranged for several experts to come talk to you and answer any questions you may have regarding the Worker Protection Standard, respirators and regulatory inspections.

Programs are open to all and scheduled at three locations in January. Join us on one of the following dates:

WPS compliance is very important. If you cannot make it to one of the programs and you have questions about the requirements, do not hesitate to contact a member of the MSU Extension Floriculture Team. Be sure to check back for future articles on the subject.

Did you find this article useful?