“Cool” vegetables for you to grow this spring

Start your gardening season earlier by planting cool season vegetables, which prefer lower temperatures for seed germination and plant growth. Some crops can be seeded together.

Companion planting of garlic among Swiss chard. Photo credit: Rebecca Finneran, MSU Extension
Companion planting of garlic among Swiss chard. Photo credit: Rebecca Finneran, MSU Extension

Smart Gardeners know they don’t have to wait for those sunny and 70-degree days to get started planting in the vegetable garden. There are some “cool” vegetables that prefer the lower temperatures of spring for seed germination and plant growth. Known as “cool season” vegetables, you can get started as early as the ground can be worked in late March to April, depending upon your Michigan location, to take full advantage and extend your gardening season. Make use of this smart practice to reap the rewards of fresh greens, root crops and cole crops earlier.

Once soil temperatures reach 50 degrees, you can seed a variety of cool season vegetables. Cool season vegetables prefer and sometimes require the cooler soil temperatures to germinate. These include leaf lettuce, onions, parsnips, mustard greens, beets, peas, carrots, turnips, cabbage, spinach, kohlrabi, cauliflower, radish, celery, Swiss chard, kale and collards. Measure the soil temperature using a soil probe or use a kitchen thermometer that measures hot and cold.

It’s important to prepare your soil for planting. Water-logged soils will cause seeds to rot before they make their way into the world. Take care that your soil is not too moist before planting. Also, any cultivation or disturbance of the soil when it is too wet will destroy the soil structure and be detrimental to the microbial life that lends to a healthy soil. Soils should be lightly tilled or broken apart to deposit seed not cultivated repeatedly.

This is also a great time to make plans for companion planting and different layers of your vegetable garden. Seed radishes and beets along with your lettuce. The shallow-rooted lettuce will grow near the soil’s surface while the radishes and beets will push down into the soil. These root crops will naturally break up the soil, adding air and water space. Plant roots will provide a place for necessary soil microbes to live. Place onion sets among your greens for the same effect. If your greens die back or bolt, you can reseed another crop while allowing the root crop to fully mature.

Take advantage of the vining habit of peas to plant them amidst a ground cover of greens. Provide upright support for your peas via a trellis while lettuce or spinach help to shade and cool the roots of the peas and ward off weed seeds. Pea seeds can even be planted in a spring porch container along with cold-loving pansies or snapdragons.

Peas and pansies in a container
Container with edible peas on a trellis for support and pansies to provide color and a living mulch. Pansies are also edible flowers. Photo credit: Rebecca Finneran, MSU Extension

Consider incorporating some perennial vegetables such as asparagus and rhubarb. These crops will take more room and a permanent location, but once established and successfully managed, they will continue to provide fresh asparagus spears and rhubarb stalks. Choose a well-drained location for each and mix in organic matter such as compost to prepare the soil. Once plants are established, adding composted material annually around the base of the plants will continue to be a smart practice to build healthy soils.

Smart Gardeners can also work to incorporate season extenders such as low tunnels or cold frames, which will aid in heating up spring soils quicker and thus assist with germination for cool season crops. The sun’s natural enegy allows these covered beds to heat up as the sunlight becomes more prominent in our spring sky. Also providing protection from late-season frosts, these season extenders can boost your production dramatically.

Smart Gardeners can plan ahead to reseed a mid- to late summer, “cool” vegetable crop for fall harvest as well. For instance, plant greens even into late August for fall harvest.

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