Vegetable Family: Legumes (Leguminosae)

The legumes are one awesome vegetable family (Leguminosae).  Really, they are!  Legumes are essential to any crop rotation plan because of one major trait: legumes are nitrogen fixers!  What does that mean?  It means that legumes have an amazing ability to take nitrogen from the air and change it into a form usable by plants.  But it’s not really the legumes that do all the work.  Little tiny microorganisms live in a symbiotic relationship with the legumes.  These microorganisms hang out around the plant roots feeding off the plant and converting the nitrogen into something the plant can use.

Legumes in Crop Rotation

Legumes are great to plant after a heavy feeding plant like tomatoes or corn to replenish the soil.  As the legumes grow and die the remains will put nitrogen back into the soil in a form that has already been converted for other plants to use.  Remember that it is a good thing to let the legumes die and turn them back into the soil.  Clearing legume remains out of your garden will remove much of the benefit.

What Plants are Legumes?

Beans and peas are what most people think of when thinking about legumes but clover is too.  Clover is a legume that is very good as a cover crop that will fix nitrogen into the soil and help to make the bed more fertile.

Peanuts are also legumes as are many varieties of trees like redbud and locust.

Legume Issues

Legumes can suffer from health issues like anthracnose, blight, rusts, downy mildew, and mosaic viruses. Various insects will feed on bean plants like bean beetles, cucumber beetles, and aphids.  Some of these will spread disease from plant to plant so good insect control is always important.