How to Plant and Grow Collard Greens for a Tasty Cool Season Harvest

Collard greens are a staple in the South, but these hardy, leafy plants are easy and fun to grow in any edible garden. Collard greens or collards (Brassica oleracea var. viridis) grow relatively quickly, usually within a couple of months of planting seeds. Plant these big leafy greens after the last frost in the spring or in the fall well before the first frost, depending on your location. Here’s everything you need to know to successfully grow collard greens.

Where to Plant Collard Greens

Collard greens do best when grown in an area that receives full to partial sun. These leafy greens are part of the Brassica family, which also includes broccoli, Brussels sprouts, cauliflower, and kale. Collard greens can be planted directly in the ground, in raised beds, or in containers. 

It’s best to rotate the placement of these crops each season to ensure there are sufficient nutrients in the soil and to minimize the spread of pests and diseases.

How and When to Plant Collard Greens

Sow collard seeds indoors a month before the last spring frost or, if growing in the fall, sow the seeds directly in the ground two or three months before the first fall frost. In warmer climates, collards are best planted in the fall, so they grow in cooler weather. When exposed to warm or hot weather, they tend to bolt, especially in the hotter months of the summer. 

When starting seeds indoors, sow two seeds per cell or soil block about ¼ inch deep. After they sprout, thin the seedlings to one per cell or soil block so the collard seedlings aren’t competing for resources. 

When sowing seeds directly in the ground, sow them ¼ to ½ inch deep with three to four seeds per hole spaced 24 inches apart. Space rows at least 15 inches apart. After they germinate, thin the seedlings to one per hole. 

Collard Greens Care Tips

Collard greens are easy to grow when they receive the care they need.

Light

Collard greens grow best in full sun. They need to receive six hours of sunlight daily. If you live in a hot climate, growing them in partial shade can protect their leaves from burning, a condition known as sunscald.

Soil and Water

Collards do best in well-draining, nutrient-rich soil. Add compost to the soil before planting to ensure plenty of nutrients are available. Add a layer of mulch between the plants to retain moisture in the soil and prevent weeds. 

Collards do best when the soil is moist but never soggy. After watering, insert your finger about 6 inches deep into the soil to check for moisture. This ensures the soil has sufficient water. Water deeply and less frequently to encourage roots to grow more deeply. Typically, they need around 1 inch of water a week.

Temperature and Humidity

Collard greens are a cool-weather crop that doesn’t fare well when the temperature increases. When the weather gets too warm, collards tend to bolt (flower and go to seed). Collards can handle some frost, and the leaves taste slightly sweeter when exposed to colder temperatures.

Fertilizer

Collard greens should be grown in soil with ample organic amendments, such as compost or manure. When sufficient organic matter is in the soil, fertilizer is typically unnecessary.  

Consider doing a soil test before planting to know which minerals and nutrients are in your soil and what you may need to add via fertilizer or amendments. Soil tests are available through your nearest extension.

Potting and Repotting Collard Greens

Collard greens are easy to grow in containers that are deep and wide. One collard green plant can grow in a 12-inch diameter container, and if you plan to grow multiple plants, double or triple the pot width. For example, if you want to grow three collard greens, use a 36-inch container. Before planting, make sure the pot has ample drainage holes so extra water can flow out. 

Pests and Problems

Collards are affected by pests and diseases that afflict other members of the Brassica family. Pay attention to your plants and watch for cabbage worms, cabbage maggots, flea beetles, and slugs. If you spot any insects or worms, pick them off, spray them off with a strong jet of water, or use insecticidal neem oil.

Alternaria, black rot, and clubroot are common diseases that affect collard greens. Alternaria has leaf spots, while black rot is detected by the yellow triangles on the leaves. Typically, you should harvest what you can of a diseased plant, pull it out, and toss it in the trash; you don’t want to spread diseases in the compost.

One way to minimize diseases is to rotate your crops each year. You should also pull out your crops in the off-season.

How to Propagate Collard Greens

You can propagate collard greens by sowing seeds indoors or directly in the ground. Sow seeds approximately ¼ to ½ inch deep and keep the soil moist. When the seedlings have true leaves, they are ready to transplant. 

If you’re growing directly in the ground, sow seeds in rows with spacing around 18 inches apart to allow plants to have enough space to grow and not compete with each other.

Harvesting Collard Greens

Leaves are tender when they reach around 6-8 inches long, which is a good time to harvest. Snip the leaves with pruners or scissors starting at the bottom of the stalk. Let the smaller leaves grow before harvesting. You can continue harvesting even when there’s frost; the leaves often have a sweeter flavor in cold weather.

Collard greens are usually ready for harvest between 60 to 80 days, depending on the variety and your climate. You can harvest ‘baby’ or smaller leaves earlier and often reap multiple harvests.

Types of Collard Greens

Different varieties of collard greens offer resistance to bolting, diseases, frost, and heat, so it's important to seek out ones that are best suited for your growing conditions.

‘Georgia Cabbage’

A heirloom variety, Brassica oleracea ‘Georgia Cabbage’ has yellowish-green leaves with a flavor profile that reminds some of cabbage and a hint of nuts. It can tolerate temperatures as low as 20°F. Ensure you provide ample space, as it will reach 15-20 inches tall at maturity.

‘Champion’

Brassica oleracea ‘Champion’ is bolt-resistant with darker-hued, bluish-green leaves. It grows quickly, and its leaves don’t tend to turn yellow.

‘Green Glaze’

Brassica oleracea ‘Green Glaze’ is ready to harvest in around 79 days. This variety has dark green-hued, glossy leaves. It's slow to bolt and is ideal for anyone living in extreme climates as it is both frost- and heat-resistant. The leaves are resistant to cabbage worms and loopers. 

Collard Greens Companion Plants

Collards grow well with many other veggies, flowers, and herbs. Here are a few to try.

Marigolds

Marigolds are known to repel multiple types of pests, such as cabbage worms, slugs, thrips, and white flies. These pretty flowers also can act as trap crops because they entice insects to them, distracting them from bothering other plants.

Mint

Mint can deter ants, aphids, flea beetles, and white cabbage moths. Grow mint in a contained area, such as a pot, because it can become unruly and quickly take over your garden space.

Rosemary

Collards and rosemary grow well together because this herb helps repel unwanted insects, including cabbage moths. Rosemary and collards can be grown in containers or directly in the ground.