Corn and soybeans – together at last

June 30, 2008 | By | Comments (1)

by Johanna Silver, Sunset Test Garden Coordinator

Intercropping is my next favorite thing to building chicken tractors. It saves space (a recurring theme in the test garden), cuts down on weeds, prevents erosion by having more ground cover, and can even provide the necessary growth requirements for a plant such as shade or trellising.

So, an experiment:


I planted edamame in between the sweet corn approximately two weeks after the corn germinated. This was to give the corn a head start since beans are typically very fast growers. Now, edamame are bush beans, meaning they won’t trellis the corn as pole beans would, but I am hoping they still get along just fine. The idea is that the long, slender shape of the corn won’t over-shade the beans, and the beans, bushing low to the ground, won’t impede the corn’s growth. I’m also hoping that their root systems are compatible and won’t over-compete for nutrients and water. Here is a neat shot that compares their roots as small plants. Think it will work?

I’ve heard a few people stroll through the test garden and remark that this is also a good idea because beans are nitrogen fixers. Now it is true that Edamame, legumes that they are, will also fix nitrogen and put it back into the soil. BUT it must be noted that nitrogen fixing only happens PRIOR TO the beans produce their seed pods. Before this happens nitrogen is stored in nodules on the roots, so farmers will cut off the green part to kill the plants and till the roots (and crop if they want additional green manure) back into the ground. Here is a photo of those nodules. But the deal is done once the beans are produced and they will no longer act as nitrogen fixers. We are growing our beans for eating so our intercropping has nothing to do with putting nitrogen back into the ground. It is simply an experiment to see how these crops grow together (and because it makes the garden coordinator happy).


  1. Sheila

    I do so want to learn how to plant a nitrogen-fixing cover crop this winter. Please consider a post telling us how to do that (and when to start). My trouble is I always want to keep growing things in fall/winter!

    July 12, 2008 at 4:56 am

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