Sam’s Spade: The talented legume
I recently gathered some fresh sugar snap peas from the garden as an easy appetizer for dinner. The plants are fun to watch grow, as they stretch out tendrils that latch onto anything nearby and quickly climb up the trellis. Peas are part of an ancient family of plants called legumes, a family that has a rich history with mankind. For thousands of years we have benefited from these vigorous plants, namely their high protein content and value as a green manure. Other than peas, some common legumes are clover, lupines, beans, and alfalfa.
Legumes are a fascinating line of plants particularly because their roots can absorb nitrogen straight out of the atmosphere with the aid of a bacteria, called rhizobia, found already in the soil. Other vegetables have to search for usable nitrogen in the soil itself, and a lot of times there's simply not enough for plants to flourish. Since the atmosphere is 78 percent nitrogen, our peas have little trouble finding the nutrient that is so important to vegetative growth.
Now here's a trick you can use to get a bunch of big juicy peas:
Legumes can also take advantage of a whole different type of microorganism, a special type of fungus that many plants (not just legumes) utilize: mycorrhizae. You have probably heard of mycorrhizae, or at least someone trying to pronounce it, and wondered what it was. Mycorrhizae is another type of fungus which plants can have a symbiotic relationship with. However, where rhizobia works inside the root of the pea plant, mycorrhizae attaches to the outside of the root and gains access to the nutrients and water in the soil. Thus, mycorrhizae basically serve as additional plant roots, only they are better at absorbing nutrients than roots, get longer than roots, and can fit in smaller places than roots—think of the advantages!
At the beginning of the season I treated my peas with Epsoma "Bio-Tone Starter Plus," a fertilizer containing mycorrhizae. This product specifically lists “endomycorrhizal fungi” on the label which is what you want for peas and other vegetables. After two weeks I had little doubt that the fungi had become established in my garden: it seemed as though the peas' metabolism had doubled and they responded by accelerating towards the sky!
So if your peas were lacking this year or you simply want to witness the potential of some legumes, supplement them with mycorrhizae, which can be found in some shape or form at local gardening centers. Mycorrhizae can actually benefit a variety of plants in your garden, ranging from cucumber to squash, however there are some, including kale and broccoli, that simply don't profit. A more complete list of plants that benefit (and don't benefit) from mycorrhizae can be found here: http://www.mycorrhizae.com/mycocyclopedia/