Few vegetables are as welcome as spring edible podded peas after a long cold winter. Sweet snap peas and flat snow peas are delicious when grown in the cool season in the warmer Western zones. Later sowing can be troublesome here because peas aren’t fond of drier, hotter seasons. Plant them early that way flowers and pods are forming while it’s still relatively cool and moist.
Timing is one thing, but there’s another trick to making these crops really produce. It’s because they are legumes, a group of plants that have a unique ability to grow in nitrogen poor soils because they take nitrogen in from the atmosphere via their leaves. The nutrient is transferred to the roots where a tiny fungus called mycorrhizae lives symbiotically inside the tissues.
When a pea seed is planted, it has no internal mycorrhizae, so it must find it with roots and take it up from your garden soil. Once in the plant the relationship is symbiotic. If not myco is present in your ground, the plants won’t have optimal myco content early on. It builds up gradually during the growing season. Unfortunately in hot zones, the heat comes too early for an extended benefit from the mycorrhizae. But if you can inoculate your seed with myco at planting, this buildup begins at germination, reaching optimal levels much earlier.
Mycorrhizae must be the right species to inoculate your peas and beans if this symbiosis to occur properly. Farmers use it every year so that strain of myco becomes more populous in the soil microbe community overall. It’ll build up in your beds and gardens, too.
Most catalogs offer packaged inoculant for peas and beans in conjunction with their seeds. A more recent improvement demanded by organic farmers is OMRI-approved myco products you can buy with your seeds from the same sources. It comes dry in a pouch and is often moistened with water in solution to better coat seeds. Each brand will have its own instructions for this process on the package.
At the end of the season, you can pull up your pea plants to inspect the roots. Your myco live in small root nodules you’ll see at the end of life. When you till those roots right back in they release all that nitrogen and myco back into the soil as nodules and the rest of the plant decompose.
This tilling-in of spent legumes is key to why they are so favored as cover crops by organic farmers. In the fall legumes are sown and cover the field, then all of it is tilled in for organic matter and nitrogen enhancement in spring when preparing to plant. Cover crop seed can also be enhanced with these same inoculants to enhance soil nutritional benefits over a shorter growing season.
There are more edible podded varieties of peas than ever before, many of them now grown as spreading plants rather than on treillage to allow row cover protection on cold nights. In general, since snow peas have been around a lot longer, they may prove more resilient over time. Super sweet snap peas are a 20th century vegetable introduction that has difficulty dealing with heat and very low humidity.
Experienced gardeners know the secrets of symbiotic mycorrhizae and how to use them for soil improvement and a more abundant harvest. This practice turns all of us into soil scientists who utilize the natural relationship of fungi to plants to produce more food. It’s an invisible thing, by and large, but a very important aspect of modern organic gardening.
To learn more about this amazing relationship in the wild and in your garden, check out author Jeff Lowenfels’ January release, “Teaming with Fungi: The Organic Growers Guide to Mycorrhizae.” This is the third great microbe title of Lowenfels’ organic gardener’s earthy trilogy, all widely available online or in bookstores.
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Maureen Gilmer is an author, horticulturist and landscape designer. Learn more at www.MoPlants.com
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