How to Plant Fava Beans for Free Fertilizer

You might be familiar with fava beans as an edible crop, but this legume is more than just that: It's also a natural, organic fertilizer (called a green manure) that fixes nitrogen in the soil for other plants to use.

By planting fava beans in your garden, you can improve soil fertility at the same time without needing to add other fertilizers and amendments.

Here's how you do it.

How to use fava beans as green manure

In mild climates, the seeds can be sown as early as late January. Fava beans grow best in daytime temperatures of 60°F to 65°F, so time your plantings accordingly in either season.

Cut down the plants at soil level while they’re in peak bloom. Dig them under a bit and spread a layer of mulch over the bed to maximize nitrogen retention.

(Note that leaving the decomposing plants near the surface provides slow-release nitrogen to new plants, while breaking them up and burying them several inches deep adds a quicker dose of nitrogen.)

Do the chop-and-drop about two to three weeks before you want to plant in the same spot. When your new seedlings are ready, you can just push the mulch aside to transplant.

Live in a mild climate? Fava beans can be sown year-round in areas with Mediterranean-like weather (such as the California coast) where winters are warmer and summers typically don’t go above 75°F. (Between May and August, it’s best if your fava crop has some morning fog or afternoon shade.)

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