Collard greens thrive when set out in the garden several weeks before your region’s average last frost date. Knowing exactly When To Plant Collard Greens can mean the difference between a bumper crop and a sad, bolted mess. This guide walks you through everything you need, from soil temp to regional timing, so you get it right the first time.
Think of collards as the tough, reliable cousin of kale and cabbage. They love cool weather and actually taste sweeter after a light frost. That makes timing your planting pretty straightforward, but a few details matter a lot.
Let’s break it down step by step, so you can get those greens in the ground at the perfect moment.
When To Plant Collard Greens
The short answer is: plant them in early spring for a summer harvest, and again in late summer for a fall and winter harvest. But the exact dates depend on where you live and your local frost dates.
Collards are biennials, meaning they grow leaves in their first year and flower in their second. If you plant too late in spring, the heat will trigger bolting (going to seed) and the leaves turn bitter. Plant too early in fall, and the heat might stunt them. So timing is everything.
Understanding Your Growing Zone And Frost Dates
Your first step is to find your USDA hardiness zone and your area’s average last spring frost date and first fall frost date. You can look this up online with a quick search for your city or county.
- Last spring frost date: This is the average date when the danger of frost has passed in your area.
- First fall frost date: This is the average date when the first frost usually hits in autumn.
Collards can handle a light frost (down to about 26°F) but not a hard freeze. They actually taste better after a frost because the cold converts starches into sugars.
Spring Planting: Getting A Head Start
For a spring crop, you want to plant collards so they mature before the summer heat sets in. Here’s the rule of thumb:
- Start seeds indoors: 6 to 8 weeks before your average last frost date.
- Transplant seedlings outdoors: 3 to 4 weeks before your average last frost date.
- Direct sow seeds outdoors: 2 to 4 weeks before your average last frost date.
This gives the plants a cool, slow start. They’ll grow steadily as the weather warms, and you can start harvesting leaves by late spring or early summer.
If you live in a region with a short spring, like the northern states, aim for the earlier end of that window. In warmer climates (zones 8 and above), you can plant even earlier, as early as February in some places.
Fall Planting: For A Winter Harvest
Fall planting is actually easier and often more productive. The cool weather keeps the leaves tender and sweet, and you can harvest well into winter if you protect the plants.
For a fall crop, count backward from your first fall frost date:
- Direct sow seeds outdoors: 6 to 8 weeks before your first fall frost date.
- Transplant seedlings: 4 to 6 weeks before your first fall frost date.
This timing lets the plants establish themselves in the warm late-summer soil, then grow through the cool autumn. You can start harvesting leaves about 60 to 80 days after planting, depending on the variety.
In mild winter areas (zones 8–10), you can plant collards in late summer and harvest all winter long. They’ll keep producing until the weather gets really cold.
Soil Temperature Matters Too
Collard seeds germinate best when the soil temperature is between 45°F and 85°F. The sweet spot is around 70°F. If the soil is too cold (below 40°F), seeds may rot. If it’s too hot (above 85°F), germination drops off.
Use a soil thermometer to check. In spring, wait until the soil has warmed to at least 45°F before direct sowing. In fall, you can plant when the soil is still warm, but the air is cooling down.
Regional Planting Guides
Here’s a quick breakdown for different parts of the U.S. These are general guidelines, so adjust based on your local weather patterns.
Northern States (Zones 3–5)
- Spring: Start seeds indoors in March. Transplant outdoors in late April or early May, after the last hard frost.
- Fall: Direct sow seeds in late July or early August. Harvest from October through November.
Central States (Zones 6–7)
- Spring: Start seeds indoors in February or March. Transplant outdoors in March or early April.
- Fall: Direct sow seeds in August. Harvest from October through December.
Southern States (Zones 8–10)
- Spring: Plant in February or March. You can also direct sow in January in the warmest areas.
- Fall: Plant in September or October. Harvest through winter and into early spring.
Coastal And Mountain Regions
If you live near the coast, the mild temperatures let you plant collards almost year-round. In mountain areas, the growing season is short, so stick to spring and early fall plantings.
Step-By-Step Planting Instructions
Once you know your timing, here’s how to actually get those collards in the ground.
1. Prepare The Soil
Collards like rich, well-draining soil with a pH between 6.0 and 7.5. Work in plenty of compost or aged manure a few weeks before planting. They are heavy feeders, so good soil prep pays off.
2. Start Seeds Indoors (Optional)
If you want a head start, sow seeds in seed-starting mix about 6–8 weeks before your last frost. Plant seeds ¼ inch deep. Keep the soil moist and warm (around 70°F). Seedlings emerge in 5–10 days.
Once they have two sets of true leaves, harden them off by putting them outside for a few hours each day for a week. Then transplant.
3. Direct Sow Outdoors
If direct sowing, plant seeds ¼ to ½ inch deep, spaced about 3 inches apart in rows. Cover lightly with soil and water gently. Thin seedlings to 12–18 inches apart once they are a few inches tall. Thinned plants are edible, so use them in salads.
4. Transplant Seedlings
Space transplants 12–18 inches apart in rows that are 2–3 feet apart. Dig a hole slightly bigger than the root ball, place the plant in, and firm the soil around it. Water well.
If you are planting in fall, shade the transplants for a few days if the weather is still hot. A row cover works great.
5. Water And Mulch
Collards need consistent moisture, especially when they are young. Water deeply once or twice a week, depending on rainfall. Mulch around the plants with straw or shredded leaves to keep the soil cool and moist.
Caring For Your Collards Through The Season
Once your collards are in the ground, a little care goes a long way.
Fertilizing
Collards are heavy feeders. Side-dress them with a balanced fertilizer (like 10-10-10) about 3–4 weeks after transplanting. You can also use fish emulsion or compost tea every few weeks.
Pest Control
Aphids, cabbage worms, and flea beetles love collards. Use row covers to keep pests off young plants. If you see bugs, spray with neem oil or insecticidal soap. Hand-pick caterpillars if you only have a few plants.
Harvesting
Start harvesting outer leaves when they are about 8–10 inches long. Leave the inner rosette of leaves to keep growing. You can harvest for weeks or even months this way.
For a full head, wait until the plant is about 2 feet tall and cut the entire stalk at the base. Many varieties will regrow from the stump if you leave a few inches.
Common Mistakes And How To Avoid Them
Even experienced gardeners mess up timing sometimes. Here are the most common errors.
- Planting too late in spring: The heat makes collards bolt and turn bitter. Stick to the early window.
- Planting too early in fall: Hot soil and air can stress young plants. Wait until late summer or early fall.
- Not hardening off seedlings: Sudden sun and wind can shock transplants. Always harden them off for a week.
- Overcrowding: Collards need space to grow big leaves. Thin or space them at least 12 inches apart.
- Ignoring frost protection: While collards handle light frost, a hard freeze (below 25°F) can kill them. Use row covers or cold frames if a deep freeze is coming.
Frequently Asked Questions
Can I plant collard greens in the summer?
It’s not ideal. Summer heat makes collards tough and bitter. If you must, choose a heat-tolerant variety and provide afternoon shade. But spring and fall are much better.
How late can I plant collard greens in the fall?
You can plant as late as 6–8 weeks before your first hard freeze. In mild climates, you can plant even later, as long as the soil is workable. They’ll grow slowly but still produce.
Do collard greens come back every year?
Collards are biennials, so they live for two years. In mild climates, they may survive winter and produce leaves again in spring before bolting. In cold climates, they usually die over winter.
Should I soak collard seeds before planting?
Soaking is not necessary. Collard seeds germinate quickly without it. But if you want to speed things up, soak them in warm water for 4–6 hours before planting.
Can I grow collard greens in containers?
Yes. Use a pot that is at least 12 inches deep and wide. Fill with rich potting soil and water regularly. Dwarf varieties like ‘Vates’ or ‘Champion’ work best in containers.
Final Tips For Success
Collards are one of the easiest greens to grow, as long as you get the timing right. Pay attention to your local frost dates, prep the soil well, and don’t be afraid to plant a fall crop. The sweet, frost-kissed leaves are worth the effort.
If you are new to gardening, start with a spring planting first. It’s more forgiving. Then try a fall planting once you have the hang of it. You’ll be amazed at how much food a few plants can produce.
Remember, collards are forgiving. Even if you plant a week or two off, they usually still do fine. The key is to avoid the extremes of heat and deep cold. Keep an eye on the weather, and adjust as needed.
So check your frost dates, pick a sunny spot, and get those collards in the ground. Your future self—and your dinner plate—will thank you.