Replenishing the Garden Soil Using Cover Crops

Benefits of Replenishing Garden Soil

To have improved garden soils using cover crops can help replenish the area by increasing organic matter, suppress nematode populations, control weed germination, and improve overall soil tilth. When building up the garden soils you should supply the best cover crop that fulfills the characteristics you are wanting to replenish in the soil and incorporate the needed compounds back into the soil properly to better fulfill the vegetable garden.

Cover Crop: Sunn Hemp

On this week’s episode, Travis is discussing the best cover crop to use when you need to replenish the garden soil. The best warm-season cover crop that adds many benefits to the garden soil is known as Sunn Hemp. This variety is a legume which means it is related to crops like peas and peanuts. This cover crop allows you to add a significant amount of nitrogen, suppress weeds, and quality organic matter into the garden soil. However, compared to other warm-season varieties the Sunn Hemp is the only nitrogen fixer cover crop. As a nitrogen fixer, it is able to grab nitrogen from the atmosphere and convert it into your garden soil. This fixer is important in the garden because when you get rid of the cover crop you will gain lots of available nitrogen for the next vegetable crop you plant in that area. Some recent studies have shown that Sunn Hemp can fix up to 100 pounds of nitrogen per acre which is excellent when planting heavy feeder crops like onions and corn. Sunn Hemp should be planted when soil temperatures are around 65 to 70 degrees Fahrenheit. When planting it can be broadcasted or with a precision planter like the garden seeder. This warm-season cover crop grows extremely fast and typically reaches maturity in 8 to 12 weeks. This cover crop variety is pretty much maintenance-free and does not take a lot of effort to grow in the area. Since it grows so quickly it suppresses weed pressures by outpacing weed germination which is a major benefit in the vegetable garden. Like all cover crops, Sunn Hemp should be cut or mowed before it reaches seed to prevent reseeding issues in the future growing seasons.

Warm Season Cover Crop Varieties

Along with Sunn Hemp, there are three other cover crop varieties that we have available that beneficial characteristics for the garden soil as well. The Brown Top Millet provides ideal ground cover for weed suppression and for adding organic matter back into the soil. This tall bunching grass can reach up to 12 feet high and usually matures within 60 to 70 days. As a millet, this green manure can add a significant amount of organic matter to depleted soils which can improve soil quality and tilth. Next, is Buckwheat which is another fast-growing cover crop that is ideal for planting in small windows between fall and spring plantings. It works best for weed suppression and provides organic matter that helps loosen up the topsoil making it more workable and increases soil drainage for planting. The best warm-season cover crop for reducing nematode populations is Sorghum Sudangrass. As a bunching grass, the sudangrass creates a dense mat of tall vegetation similar to corn, but with smaller leaf blades. When mowing down or decomposing the cover crop vegetation it releases natural compounds that are suppressive to nematode populations. We recommend using the sudangrass as a transition crop between spring and fall planting.

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