For zone 7, timing kale planting for early spring or late summer ensures a long growing season. Knowing the best time to plant kale in hardiness zone 7 is the key to harvesting sweet, tender leaves from spring through fall and even into winter. This guide breaks down exactly when to sow seeds and set out transplants for a continuous supply.
Understanding Hardiness Zone 7 And Kale
Zone 7 includes areas with average minimum winter temperatures between 0°F and 10°F. This moderate climate gives you two distinct planting windows for kale. Kale thrives in cool weather and actually tastes better after a light frost.
Planting at the wrong time leads to bolting, bitter leaves, or poor germination. The trick is to avoid the heat of midsummer while giving the plants enough time to mature before extreme cold or heat arrives.
Best Time To Plant Kale In Hardiness Zone 7
The best time to plant kale in hardiness zone 7 falls into two main seasons: early spring and late summer. For spring planting, aim for 3 to 4 weeks before your last expected frost date. In zone 7, that typically means late February to mid-March. For a fall harvest, plant in late July through early September.
Kale seeds germinate in soil temperatures as low as 40°F, but they do best between 60°F and 70°F. Transplants handle light frosts well, so you can set them out earlier than many other vegetables.
Spring Planting Window For Zone 7
Start seeds indoors 4 to 6 weeks before your last frost date. For zone 7, that usually means starting seeds in January or February. Harden off seedlings gradually before transplanting outdoors.
Direct sowing in the garden works too. Sow seeds outdoors as soon as the soil can be worked in early spring. Cover them with a light layer of soil or row cover if a hard freeze threatens.
- Last frost date range: March 15 to April 15 (check your local extension)
- Indoor seed starting: January 15 to February 15
- Transplant outdoors: February 20 to March 20
- Direct sow outdoors: February 15 to March 15
Fall Planting Window For Zone 7
Fall planting often produces the sweetest kale because frost converts starches to sugars. Count back 8 to 10 weeks from your first expected fall frost date. In zone 7, first frost typically occurs between October 15 and November 15.
Plant fall kale so it matures during cooler weather. Direct sow seeds in late July or early August. Transplants can go in during August. The plants will grow slowly as days shorten, but they keep producing well into December.
- First fall frost date: October 15 to November 15
- Direct sow outdoors: July 20 to August 20
- Set out transplants: August 1 to September 1
- Harvest window: October through December (or longer with protection)
Factors That Affect Planting Timing
Several variables shift the exact dates. Your specific microclimate, soil temperature, and kale variety all play a role. Pay attention to your garden’s conditions rather than relying solely on a calendar.
Soil Temperature
Kale seeds germinate best when soil is between 60°F and 70°F. Use a soil thermometer to check. If the soil is too cold, seeds may rot. If too hot, germination drops off sharply above 85°F.
For spring planting, soil warms slowly. Black plastic or row covers can help warm the soil a few degrees. For fall planting, soil is often too warm in August. Shade cloth or planting in a slightly shaded spot helps.
Kale Variety Selection
Different kale varieties handle temperature extremes differently. Choose varieties suited to your planting season for best results.
- Winterbor: Very cold hardy, good for fall and winter harvest
- Red Russian: Tolerates heat better, good for spring and early fall
- Lacinato (Dinosaur): Prefers cool weather, excellent for spring and fall
- Vates: Dwarf variety, good for containers and small spaces
- Scarlet: Ornamental and edible, handles light frost well
Microclimate Considerations
Your garden may be warmer or cooler than the general zone 7 average. South-facing slopes warm up faster in spring. Low spots collect cold air and frost. Urban areas often stay warmer than rural ones.
Observe your garden for frost pockets and warm spots. Plant early spring kale in the warmest area. For fall, choose a spot that gets some afternoon shade to keep soil cooler.
Step-By-Step Planting Guide For Zone 7
Follow these steps for successful kale planting in zone 7. Adjust timing based on your specific location within the zone.
Step 1: Prepare The Soil
Kale grows best in rich, well-draining soil with a pH between 6.0 and 7.5. Test your soil and amend as needed. Work in 2 to 4 inches of compost or aged manure before planting.
Remove weeds and rocks. Kale has shallow roots, so loose soil helps them spread. Add a balanced fertilizer according to package directions.
Step 2: Start Seeds Or Buy Transplants
Starting seeds indoors gives you more variety options. Use seed starting mix and keep it moist. Provide bright light once seedlings emerge. Harden off over a week before transplanting.
Buying transplants from a nursery is easier for beginners. Look for stocky plants with dark green leaves. Avoid leggy or yellowed transplants.
Step 3: Plant At The Right Depth
Sow seeds 1/4 to 1/2 inch deep. Space seeds 1 inch apart in rows 18 to 24 inches apart. Thin seedlings to 12 to 18 inches apart once they have two sets of true leaves.
For transplants, dig a hole slightly larger than the root ball. Set the plant at the same depth it was growing in the pot. Water well after planting.
Step 4: Water And Mulch
Kale needs consistent moisture, about 1 to 1.5 inches per week. Water deeply at the base to keep leaves dry and prevent disease. Mulch with straw or shredded leaves to retain moisture and regulate soil temperature.
In hot weather, kale may need more frequent watering. Check soil moisture by sticking your finger an inch into the soil. If it feels dry, water.
Step 5: Protect From Pests
Common kale pests include aphids, cabbage worms, and flea beetles. Use row covers for young plants. Handpick caterpillars. Spray aphids off with a strong stream of water.
Companion planting with herbs like dill or cilantro can attract beneficial insects. Rotate crops yearly to reduce soil-borne diseases.
Extending The Harvest Season
With proper timing, you can harvest kale for 8 to 10 months in zone 7. Succession planting and season extension techniques help maximize your yield.
Succession Planting
Plant small batches every 2 to 3 weeks during spring and fall windows. This ensures a continuous supply instead of one big harvest. Stop planting about 6 weeks before your first expected fall frost for the final crop.
For spring, plant a second batch 3 weeks after the first. For fall, plant a second batch in mid-August. This spreads out the harvest and reduces waste.
Using Row Covers And Cold Frames
Extend your fall harvest well into winter with protection. Row covers add 5 to 10 degrees of frost protection. Cold frames can keep kale growing through most of zone 7 winters.
In mild zone 7 winters, kale often survives without protection. A heavy snow cover actually insulates the plants. Harvest leaves even when temperatures drop into the teens.
Overwintering Kale
Kale is biennial, meaning it lives for two years. In zone 7, you can overwinter plants for an early spring harvest. Mulch heavily around the base in late fall. The plants will go dormant but start growing again in late winter.
Remove flower stalks as they appear in spring to keep leaves tender. Once plants bolt, leaves become bitter. Pull them and plant new kale for summer.
Common Mistakes To Avoid
Even experienced gardeners make timing errors. Avoid these common pitfalls for better results.
- Planting too late in spring: Kale bolts quickly when days get long and hot. Plant early enough to harvest before June.
- Planting too early in fall: Hot soil and air temperatures in August can stunt seedlings. Provide shade or wait until soil cools.
- Overcrowding: Crowded plants compete for nutrients and water. Thin seedlings to proper spacing.
- Neglecting water: Kale is 90% water. Inconsistent watering leads to tough, bitter leaves.
- Ignoring pests: Flea beetles love young kale. Use row covers or diatomaceous earth early.
Harvesting Kale At The Right Time
Harvest kale when leaves are about the size of your hand, usually 50 to 75 days from seeding. Pick outer leaves first, leaving the center to continue growing. This method gives you multiple harvests from each plant.
For the sweetest flavor, harvest after a light frost. Cold temperatures trigger the plant to convert starches to sugars. Leaves harvested in November often taste noticeably sweeter than those from September.
Stop harvesting heavily when plants are stressed by extreme heat or cold. Let them recover before taking more leaves. In spring, harvest until flower stalks appear, then pull the plants.
Frequently Asked Questions
Can I plant kale in zone 7 during summer?
Summer planting is not ideal because heat causes bitter leaves and poor germination. If you want summer kale, plant in partial shade and keep soil consistently moist. Harvest young leaves before they get tough.
What is the latest I can plant kale in zone 7 for winter harvest?
Plant kale for winter harvest no later than early September. This gives plants 8 to 10 weeks to mature before hard freezes. With protection, you can harvest through February.
Should I soak kale seeds before planting?
Soaking is not necessary. Kale seeds germinate quickly without pretreatment. Soaking can actually cause seeds to rot if soil is too wet. Just plant them in moist soil.
How do I know if my kale is bolting?
Bolting starts when the center of the plant elongates and forms a flower stalk. Leaves become smaller and more bitter. Once you see this, harvest remaining leaves quickly and replant.
Can I grow kale in containers in zone 7?
Yes, kale grows well in containers at least 12 inches deep. Use quality potting mix and water frequently. Container plants may need more protection from extreme temperatures than in-ground plants.
Final Tips For Zone 7 Kale Success
Keep a garden journal to track your planting dates and results. Note frost dates, soil temperatures, and harvest quality. Over time, you’ll fine-tune your timing for your specific microclimate.
Don’t be afraid to experiment with different varieties and planting dates. Kale is forgiving and tolerates some timing mistakes. Even if you plant a bit late, you’ll likely get a decent harvest.
Share extra kale with neighbors or preserve it by freezing or dehydrating. Kale freezes well without blanching. Just wash, dry, and pack in freezer bags for winter soups and smoothies.
Remember that the best time to plant kale in hardiness zone 7 is a range, not a single date. Watch your garden, check soil temperature, and adjust based on weather patterns. With practice, you’ll have a steady supply of nutritious, homegrown kale for most of the year.