Collard greens, a member of the Brassica family alongside cabbage and kale, are a popular and easy-to-grow leafy vegetable. This cool-weather crop is known for its large, dark green, nutrient-dense leaves. Collards do not form a tight head like cabbage; instead, they grow as a loose bouquet of leaves, making them ideal for continuous harvest throughout the growing season. Achieving a successful and flavorful yield depends heavily on precise planting times.
Timing for Spring and Fall Crops
Collards thrive in temperatures between 60 and 75 degrees Fahrenheit and tolerate cold, surviving temperatures as low as 15°F. This cold hardiness allows for two primary planting windows: a spring crop and a fall crop. The fall harvest is often preferred for its superior flavor because the plant’s starches convert to sugars when exposed to light frost, which sweetens the leaves and reduces bitterness.
For a spring harvest, the goal is to allow plants to mature before the intense heat of summer, which can cause them to “bolt,” or flower prematurely, leading to tough and bitter leaves. To get a head start, sow seeds indoors six to eight weeks before the last expected spring frost date. Alternatively, direct sow seeds or transplant seedlings into the garden about two to four weeks before the final frost, once the soil is workable.
The fall crop is considered the most rewarding, as the plants benefit from cooling temperatures and frost exposure. Plant seeds in mid-to-late summer, roughly 60 to 90 days before the first anticipated fall frost. This timing ensures the plants reach maturity just as the first light frosts arrive, maximizing the conversion of starches to sugars for a sweeter taste. In regions with mild winters, collards can be planted in late summer or fall and harvested continuously throughout the winter season.
Starting Collards from Seed or Transplants
Gardeners can start collards from seed or purchase small nursery transplants. Starting seeds indoors is a common practice for spring planting, as it helps bypass the cool, slow-to-warm soil conditions of early spring and gives the plants an earlier start. Seeds should be sown about one-quarter inch deep in seed trays.
Once seedlings develop true leaves, they are ready for the garden. Before permanent placement, young plants must undergo “hardening off,” which involves slowly introducing them to outdoor conditions over a week or two to prevent shock. Direct sowing is often easier for the fall crop; seeds are planted about half an inch deep and then thinned after they sprout. Proper spacing is 18 to 24 inches between mature plants to allow for good air circulation and full leaf development.
Essential Soil and Sun Requirements
Collard greens are heavy feeders, requiring fertile soil rich in nitrogen and organic matter to support rapid leaf growth. Before planting, amend the soil with several inches of aged compost or manure to ensure a steady supply of nutrients. An ideal soil pH is slightly acidic to neutral (6.0 to 7.0), which aids in nutrient uptake and discourages common diseases.
The plants prefer a location that receives full sun (at least six hours of direct sunlight daily), as this promotes the best flavor development. In hotter climates or during late-summer planting, collards benefit from partial afternoon shade, which protects the leaves from scorching and prevents bolting. Consistent moisture is required, needing about one to one and a half inches of water per week during dry periods to keep the leaves tender and prevent bitterness.
To protect the growing plants from common garden threats, preventative measures are necessary. Pests like cabbage worms and aphids target the tender brassica leaves and can quickly damage a crop. Employing physical barriers, such as floating row covers, immediately after planting effectively blocks adult moths and butterflies from laying eggs. Regularly checking the undersides of the leaves for pests or eggs aids in the early management of infestation.
Harvesting Your Collard Greens
Collard greens are ready for harvest between 60 and 75 days after planting, depending on the variety and growing conditions. Leaves are most tender and flavorful when dark green and about 10 inches long. The preferred technique is the “cut-and-come-again” method, which allows for a continuous yield over several weeks or months.
This method involves harvesting the larger, lower, and outer leaves first, leaving the smaller, central leaves and the growing point untouched. Leaving the inner leaves to continue developing ensures the plant keeps producing new growth. Leaves harvested after a light frost will have the sweetest flavor due to cold-induced sugar production. If harvesting the entire plant at once, wait until the plant has a large number of mature leaves, then cut the entire stalk a few inches above the soil line.