Pennsylvania’s distinct seasons favor early spring planting as soon as the ground thaws, plus a late summer sowing. Knowing the **best time to plant kale in Pennsylvania** is key to getting two full harvests each year, because kale thrives in cool weather and actually tastes sweeter after a light frost.
Kale is one of the easiest greens to grow in the Keystone State. It handles cold better than lettuce or spinach, and it can survive snow if it’s well-established. The trick is timing your planting so the plants mature during the cooler parts of spring and fall, not during the heat of July.
Best Time To Plant Kale In Pennsylvania
For most of Pennsylvania, you have two main planting windows. The first is in early spring, about 3 to 5 weeks before the last expected frost. The second is in late summer, about 6 to 8 weeks before the first expected frost in fall.
Spring planting gives you a harvest from late May through June. Fall planting gives you kale from October through November, and sometimes into December if you use row covers.
Spring Planting Window
In Pennsylvania, the last frost date varies by region:
- Southeastern PA (Philadelphia area): around April 10-15
- Central PA (Harrisburg, State College): around April 20-30
- Northern PA (Scranton, Erie): around May 5-15
- Higher elevations (Poconos, Alleghenies): around May 15-25
Count backward 3 to 5 weeks from your local last frost date. That’s when you can direct sow seeds or transplant seedlings outside. For example, if your last frost is April 20, you can plant seeds around March 20 to April 1.
Kale seeds germinate in soil as cold as 40°F, but they do best when soil temps are between 45°F and 75°F. If you plant too early and the ground is frozen or waterlogged, seeds may rot. Wait until the soil is workable—not muddy, just moist and crumbly.
Using Transplants For Spring
If you start seeds indoors 4 to 6 weeks before your planting date, you can set out transplants 2 to 3 weeks before the last frost. Transplants give you a head start, but they need hardening off. Put them outside for a few hours each day for a week before planting.
Hardening off is simple: set the trays in a shady spot for 2 hours, then bring them in. Increase time and sunlight each day. This prevents transplant shock and leaf burn.
Fall Planting Window
Fall kale is often better than spring kale. Cool nights and shorter days keep the leaves tender and sweet. The first frost in Pennsylvania ranges from:
- Northern PA: around September 20 to October 5
- Central PA: around October 5 to 15
- Southeastern PA: around October 15 to 30
Count backward 6 to 8 weeks from your first frost date. For central PA with a first frost around October 10, plant seeds around August 15 to September 1. For southeastern PA with a first frost around October 25, plant seeds around September 1 to 15.
Fall planting is more forgiving than spring because the soil is warm and germination is fast. The main challenge is keeping seedlings cool and watered during late summer heat. Plant in a spot that gets afternoon shade, or use shade cloth for the first two weeks.
Succession Planting For Continuous Harvest
Instead of planting all your kale at once, try succession planting. Plant a row every 2 to 3 weeks during both windows. This gives you a steady supply instead of a glut that all matures at the same time.
For spring, plant one batch 5 weeks before last frost, another 3 weeks before, and a third on the frost date. For fall, plant one batch 8 weeks before first frost, another 6 weeks before, and a third 4 weeks before.
Choosing The Right Kale Variety For Pennsylvania
Not all kale varieties handle Pennsylvania’s climate the same way. Some bolt (go to seed) quickly in heat, while others stay sweet longer into winter.
Best Varieties For Spring
- Dwarf Siberian: cold-hardy, fast-growing, good for early spring
- Red Russian: tender leaves, mild flavor, handles light frost well
- Vates Blue Curled: compact, slow to bolt, good for small gardens
Best Varieties For Fall And Winter
- Winterbor: very cold-hardy, survives down to 10°F with protection
- Lacinato (Dinosaur): traditional Italian variety, sweet after frost
- Redbor: ornamental and edible, stays purple in cold weather
If you want one variety that works for both seasons, try Winterbor or Lacinato. They are reliable in Pennsylvania’s zone 5 to 7 climates.
Soil Preparation For Kale
Kale grows best in rich, well-drained soil with a pH between 6.0 and 7.5. Test your soil pH before planting. Pennsylvania soils are often acidic, especially in the western part of the state. If your pH is below 6.0, add lime a few weeks before planting.
Work in 2 to 3 inches of compost or well-rotted manure into the top 8 inches of soil. Kale is a heavy feeder, so it needs plenty of nitrogen. You can also side-dress with fish emulsion or blood meal when the plants are about 6 inches tall.
How To Plant Kale Seeds
- Prepare the soil by removing rocks and weeds.
- Sow seeds 1/4 to 1/2 inch deep.
- Space seeds 1 inch apart in rows 18 to 24 inches apart.
- Cover lightly with soil and water gently.
- Thin seedlings to 12 to 18 inches apart when they have 2 true leaves.
If you are planting transplants, dig holes slightly larger than the root ball. Space them 12 to 18 inches apart. Water them in well and add a layer of mulch to keep the soil cool and moist.
Caring For Kale Through The Season
Kale needs consistent moisture, especially during the first few weeks after planting. Give it about 1 to 1.5 inches of water per week, either from rain or irrigation. Water at the base of the plants to avoid wetting the leaves, which can lead to fungal diseases.
Mulch around the plants with straw, shredded leaves, or grass clippings. This keeps the soil temperature stable, reduces weeds, and retains moisture. In summer, mulch is critical to keep the roots cool.
Fertilizing Kale
Kale grows fast and depletes soil nutrients quickly. Feed it every 3 to 4 weeks with a balanced organic fertilizer like 5-5-5 or a nitrogen-rich one like 10-5-5. You can also use compost tea or fish emulsion.
Stop fertilizing about 3 weeks before you plan to harvest in fall. Too much nitrogen late in the season can make leaves tough and less sweet.
Pest And Disease Management
The most common kale pests in Pennsylvania are cabbage worms, aphids, and flea beetles. Use row covers to keep butterflies from laying eggs on the leaves. If you see small green caterpillars, pick them off by hand or spray with Bt (Bacillus thuringiensis).
Aphids can be washed off with a strong spray of water. Flea beetles leave small holes in the leaves; they are worse in hot, dry weather. Diatomaceous earth or neem oil can help control them.
Diseases like downy mildew and black rot are less common but can occur in wet conditions. Space plants well for air circulation and avoid overhead watering in the evening.
Harvesting Kale At The Right Time
Kale is ready to harvest when the leaves are about the size of your hand, usually 50 to 75 days after planting. Start by picking the oldest, lowest leaves first. Leave the central growing point and the top leaves so the plant keeps producing.
For spring-planted kale, harvest before temperatures regularly hit 80°F. Once it gets hot, the leaves become tough and bitter. If you see flower stalks forming, the plant is bolting—harvest everything immediately.
For fall-planted kale, wait until after a light frost to harvest. The cold converts starches to sugars, making the leaves sweeter. You can keep harvesting into December if you cover the plants with row covers or a cold frame.
How To Store Fresh Kale
Kale stores well in the refrigerator for up to a week. Wash the leaves, dry them thoroughly, and wrap them in a paper towel inside a plastic bag. Do not wash kale until you are ready to use it, as moisture speeds up spoilage.
You can also freeze kale. Blanch the leaves in boiling water for 2 minutes, then plunge them into ice water. Drain, pack into freezer bags, and freeze for up to 6 months. Frozen kale is great for soups and smoothies.
Common Mistakes When Planting Kale In Pennsylvania
Many gardeners make a few predictable errors. Here are the most common ones and how to avoid them.
Planting Too Late In Spring
If you wait until May to plant kale in most of Pennsylvania, the plants will be young when summer heat arrives. They may bolt before you get a good harvest. Stick to the early spring window.
Not Hardening Off Transplants
Putting indoor-grown seedlings straight into the garden shocks them. They may turn purple or white and stop growing. Always harden them off over a week.
Overcrowding
Kale needs space. If you plant seeds too thickly and don’t thin them, the plants compete for light and nutrients. You get small, weak leaves. Thin to at least 12 inches apart.
Forgetting To Mulch
Bare soil around kale plants dries out fast and gets hot. Mulch is not optional—it’s essential for keeping the roots cool and moist, especially in summer.
Extending The Growing Season For Kale
Pennsylvania’s winters are cold, but you can extend your kale harvest well past the first frost with simple protection.
Using Row Covers
Floating row covers add about 5 to 10 degrees of frost protection. Drape them over hoops or directly on the plants. They also keep pests off. Remove them on sunny days above 50°F to prevent overheating.
Building A Cold Frame
A cold frame is a box with a glass or plastic top. It traps heat from the sun and protects plants from wind and snow. You can harvest kale from a cold frame through January in most of Pennsylvania.
Growing In A High Tunnel Or Greenhouse
If you have a high tunnel or unheated greenhouse, you can grow kale all winter. The structure keeps the temperature above freezing on most nights. With a small heater, you can harvest fresh kale every month of the year.
Frequently Asked Questions About Planting Kale In Pennsylvania
Can I Plant Kale In The Summer In Pennsylvania?
Summer planting is not ideal because heat makes kale bitter and tough. If you want a fall harvest, plant in late summer (August to early September) so the plants mature in cool weather.
How Late Can I Plant Kale In Pennsylvania For A Fall Harvest?
You can plant kale as late as 6 weeks before your first expected frost. For central PA, that’s around early September. For southeastern PA, you can plant into mid-September.
Does Kale Need Full Sun In Pennsylvania?
Kale grows best in full sun (6 to 8 hours per day), but it tolerates partial shade. In summer, afternoon shade can actually help prevent bolting and keep leaves tender.
Can I Grow Kale In Containers In Pennsylvania?
Yes, kale grows well in containers that are at least 12 inches deep and wide. Use a high-quality potting mix and fertilize regularly. Containers dry out faster, so water daily in warm weather.
What Is The Best Kale Variety For Beginners In Pennsylvania?
Winterbor is a great choice for beginners. It is very cold-hardy, resists bolting, and produces large, tender leaves. It grows well in both spring and fall plantings.
Final Tips For Success
Kale is forgiving, but timing matters. Mark your calendar with your local frost dates and count backward to find your planting windows. Write them down so you don’t miss the window.
Start small if you are new to gardening. A 10-foot row of kale can feed a family of four for weeks. You can always plant more next season.
Keep a garden journal. Note when you planted, what variety you used, and when you harvested. Over time, you will learn the perfect timing for your specific microclimate in Pennsylvania.
Remember that kale tastes best after a frost. Don’t rush to harvest all your fall kale before the first cold snap. Let it get kissed by frost, then enjoy the sweetest leaves of the year.
With the right timing and a little care, you can enjoy fresh, homegrown kale from spring through winter in Pennsylvania. The **best time to plant kale in pennsylvania** gives you two distinct seasons of abundance—take advantage of both.