Cover Cropping Like a Pro

Improving Soil with Cover Crops

Cover crops are an excellent way to build better soil health for both the soil and the plants. This article examines the  advantages and methods of using cover crops, with specific advice for Southern and Northern gardeners.

What is a Cover Crop?

A cover crop is a plant grown primarily to improve soil health rather than to harvest for food. These crops can be used to increase nutrients, improve soil structure, and reduce weeds. The timing and types of cover crops can vary between Southern and Northern regions.

Cover Crops for Southern Gardens

In Southern (or warm weather gardens), the summer heat makes it challenging to grow some of the more traditional crops. However, this season is ideal for cover crops since it protects the soil from the heat and evaporation. Certain cover crops thrive in hot climates.

Examples of Cover Crops That Thrive in Heat:

• Cowpeas (Black-eyed Peas)

• Sweet Potatoes

• Sorghum

• Millet

• Sun Hemp

• Marigolds

Timing for Planting Cover Crops

The ideal time to plant cover crops in Southern gardens is in June or July once spring crops like tomatoes or squash have died out. Cover crops should grow until late September, once nighttime temperatures consistently drop below 70°F.

Cover Crops for Northern Gardens

In Northern (or colder regions), gardeners can take advantage of cooler temperatures to grow cover crops. Usually the primary growing season for traditional vegetables require warmer temperatures but these cover crops are ideal to grow before or after the main growing season.

Types of Cover Crops That Thrive in Cooler Temps:

• Winter Wheat

• Winter Rye

• Field Peas

• Oats 

• Clover

• Hairy Vetch

Timing for Planting Cover Crops

In Northern gardens, cover crops can be planted early in spring before the ground warms up enough for summer crops or after the summer harvests as a fall season crop. Spring cover crops are most beneficial for improved nitrogen while fall cover crops assist with refilling biomass and root or soil structure before winter.

Benefits of Cover Crops in Both Climates:

1. Soil Structure Maintenance: Cover crops maintain soil structure by preventing evaporation and death of microbial soil life during harsh conditions, whether that be the heat of summer or harsher winter. The root structure created by decomposing plants sustain microorganisms and help to naturally aerate the soil.

2. Moisture Retention: The foliage of cover crops acts as a natural mulch, protecting the soil from sun exposure and reducing evaporation. 

3. Biomass Production: Most cover crops produce large amounts of foliage, which can be used to refill garden beds with organic material. This material can also be crimped down to act as a mulch for the future plants.

4. Weed Suppression: Dense cover crops suffocate weeds by blocking sunlight which reduces the need for weeding. By using the cover crop as mulch once it is cut down, can further reduces weeds into the next growing season.

5. Nitrogen Fixation: Legumes like cowpeas, field peas, and sun hemp fix nitrogen in the soil naturally. Legumes develop a relationship with beneficial Rhizobium bacteria in the soil to convert nitrogen in the air into nitrogen that plants can use for nutrition. Cut the cover crop down before they flower and seed to get the maximum nitrogen benefits.

6. Wildlife Habitat: Cover crops provide habitats for beneficial insects and wildlife. The crop provides wildlife with a home and food which promotes biodiversity and natural pest control in the garden.

How to Plant and Cut Cover Crops

Planting Cover Crops:

1. Prepare the Soil: Start by clearing the garden area of any existing plants and debris. Loosen or till the soil to ensure good seed-to-soil contact.

2. Sow the Seeds: Broadcast the seeds evenly over the soil. For larger seeds, like cowpeas and sweet potatoes, you can plant them in rows or specific spots based on planting reccomendations.

3. Cover the Seeds: Lightly rake or spread the soil over the seeds. Ensure that they are not buried too deep, as this can negatively impact germination.

4. Watering: Water the area thoroughly after planting. Keep the soil consistently moist until the seeds germinate then maintain a regular watering schedule for the cover crop.

Cutting Cover Crops:

1. Timing: The ideal time to cut down the cover crops is before they flower and set seed, especially if you are aiming to maximize nitrogen nutrition.

2. Cutting Method: Use a mower, scythe, or garden shears to cut the cover crops down at its base. Leave the roots in the ground to decompose and add even more organic matter.

3. Crimping Method: Another option is to crimp the cover crops by rolling over them with a crimper to break the stems. This method allows the plants to die while leaving a protective mat on the soil surface. Cover the crimped crops with a tarp for 7-10 days to ensure they are fully killed before planting your next crop.

4. Handling the Biomass: The cut or crimped foliage can be broken up to use as mulch, added to compost bins, or left on the soil surface to decompose naturally to enrich the soil.

5. Preparing for Next Crop: After cutting or crimping, you can plant your next crop by making small holes through the cover crop mulch and planting the seeds or transplants.

Cover crops offer tremendous benefits, from improving soil health to reducing weeds and improving nitrogen naturally. By integrating cover crops into gardening practices, gardeners can maintain healthier, more productive soils while limiting the addition of chemical amendments and fertilizers.