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Raise, Grow, Harvest, Eat, Repeat

A blog for growers, consumers, and backyard gardeners to grow, eat, and connect in the local food system.

Cover Crops Week: Day 3- Leguminous


Today's topic is leguminous cover crops. Unlike the nonleguminous cover crops, these will actually sequester nitrogen into the soil. They are a great tool as they can be used in place of nitrogen fertilizers. These cover crops will also sometimes be used in conjunction with the fertilizer. For instance, white clover can add between 80-200 lbs of total N per acre. Knowing that and then factoring in our spacing, we may be able to project how much nitrogen will be added to the soil and can then balance out our fertility plan. Many of the leguminous cover crops are also more suited for the green manures (tilling under and breaking down in the soil) as they are shorter in height than many of the grasses. Some of these leguminous cover crops can become fairly "wild" and spread throughout the garden. One of the most notorious ones that tends to spread is hairy vetch. It does still have many qualities that are good such as keeping moisture in, blocking out weed species, and adding Nitrogen to the soil but it's important to be forewarned on this negative characteristic that it has.

Cowpea cover crop

Within the legume family, there are cowpeas, crimson clover, hairy vetch, red clover, sweet clovers, and white clovers. There are many numerous ones out there as well but we'll talk about some of the main ones that we commonly see and those that you can easily find. I've already mentioned hairy vetch so let's talk about some others. Cowpea is a warm season legume and the best qualities that it has are erosion and weed fighting. It isn't as good for nitrogen scavenging. It does have a nice flowering characteristic which is useful for attracting pollinators. Most of the clovers mentioned above have similar characteristics most notable that all of them are very good for grazing. But there is some variation. Sweetclovers are one of the best clovers for soil building. Crimson clover is very good for erosion and weed fighting but not as good as others for quick growth. Red clover tends to also not be as good for quick growth. White clover works well for erosion and weed control but is not good for nitrogen scavenging and quick growth. Choosing one clover over the other will typically be tied to how much nitrogen they will add to the soil and also when they can be planted as some are more appropriate for early spring or fall.

Crimson Clover

So as a recap then:

Best leguminous cover crop(s) for early spring- Red and Sweet Clover

Best leguminous cover crop(s) for late spring to mid-summer- Cowpea

Best leguminous cover crop for erosion and weed clover- Cowpea

Best clover for soil building- Sweet Clover

Best clover for weed control- Sweet, Red, Crimson, and White (even across the board)

Join us tomorrow for the Exit Strategies.



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