When To Plant Broccoli In Pa

If you’re planning your Pennsylvania garden, knowing when to plant broccoli in PA is the first step to a successful harvest. Getting the timing right is crucial because broccoli prefers cool weather to develop those tight, flavorful heads before the summer heat arrives.

This guide will walk you through the optimal planting windows for both spring and fall crops across Pennsylvania’s varied climate zones. We’ll cover everything from seed starting dates to transplanting tips, ensuring you get the most from your broccoli patch.

Pennsylvania spans USDA Hardiness Zones 5b through 7a, meaning frost dates can vary by several weeks. Broccoli is a cool-season crop that thrives in temperatures between 60°F and 70°F. It can tolerate a light frost, which actually improves its flavor, but it struggles in prolonged heat.

For most gardeners in the state, you have two main planting opportunities: spring and fall. The fall crop is often more reliable and productive because it matures as temperatures are cooling down, not heating up.

Understanding Your Pennsylvania Growing Zone

First, find your last expected spring frost date. This is your key reference point.

Zone 5b (Northwestern PA, higher elevations): Last frost around May 15.
Zone 6a & 6b (Central PA, including State College, Harrisburg): Last frost between April 30 and May 10.
Zone 7a (Southeastern PA, including Philadelphia, Lancaster): Last frost around April 15 to April 25.

Your first fall frost date is equally important for planning your late-season crop. In Zone 5b, it’s around October 10. In Zone 7a, it’s closer to October 25.

Spring Planting Schedule for Broccoli

The goal for spring is to get broccoli established so it can produce heads before summer heat causes bolting (premature flowering). Starting seeds indoors is highly recommended.

Starting Seeds Indoors

Begin your broccoli seeds inside 6 to 8 weeks before your last spring frost date. Here’s a simple timeline:

Zone 7a: Start seeds indoors in mid to late February.
Zone 6: Start seeds indoors in early to mid-March.
Zone 5b: Start seeds indoors in late March.

Use a seed-starting mix and provide plenty of light. Seedlings need strong light to grow stocky and healthy, a south-facing window often isn’t enough. Keep the soil moist but not soggy.

Transplanting Seedlings Outdoors

Transplant your young broccoli plants into the garden 2 to 4 weeks before your last frost date. They should have 4 to 6 true leaves and be hardened off first.

Hardening Off: This is critical. Over 7-10 days, gradually expose plants to outdoor conditions. Start with a shaded, protected spot for an hour, increasing time and sun exposure each day.
Soil Prep: Broccoli needs fertile, well-draining soil with a pH between 6.0 and 7.0. Work in several inches of compost or aged manure before planting.
Spacing: Set plants 18 to 24 inches apart in rows spaced 3 feet apart. This gives them room to grow good-sized heads.

Fall Planting Schedule for Broccoli

Fall is an excellent time for growing broccoli in Pennsylvania. The crop matures in cooler, often moister weather, leading to sweeter, more tender heads. You’ll work backward from your first fall frost date.

Direct Sowing or Transplanting for Fall

For a fall harvest, you can either start seeds indoors in summer or direct sow in the garden. Starting indoors protects young seedlings from summer’s intense heat.

Calculate your planting date: Count back 85 to 100 days from your first fall frost date. This accounts for growth time.
For Transplants: Start seeds indoors 12 to 14 weeks before the first frost. For Zone 6, this means starting in mid-July.
For Direct Sowing: Sow seeds directly in the garden about 10 to 12 weeks before the first frost. Ensure the seedbed is kept consistently moist for germination.

Transplant your fall seedlings into the garden in late summer, when the worst heat is passing. Provide shade cloth for the first week if its still very hot and sunny.

Essential Care Tips for Pennsylvania Broccoli

Proper care after planting ensures strong growth and big heads.

Watering and Feeding

Broccoli needs consistent moisture, about 1 to 1.5 inches of water per week. Water at the base of the plant to keep leaves dry and prevent disease. A layer of mulch helps retain soil moisture and suppress weeds.

Fertilize when transplanting and again when plants are about 12 inches tall. Use a balanced vegetable fertilizer or side-dress with compost. Too much nitrogen can lead to lots of leaves and small heads, so follow instructions carefully.

Pest and Disease Management

Common Pennsylvania broccoli pests include cabbage worms, aphids, and flea beetles.

Check the undersides of leaves regularly for green cabbage worm eggs and caterpillars.
Use floating row covers immediately after planting to exclude many pests.
For aphids, a strong spray of water from the hose can knock them off.
Practice crop rotation—don’t plant broccoli where cabbage, kale, or cauliflower grew the previous year—to reduce soil-borne diseases.

Harvesting Your Broccoli

Harvest is the rewarding part! Your broccoli head is ready when the central head is tight, firm, and the individual florets are still small and densely packed.

Cut the main head at a slant about 5 to 8 inches down the stem with a sharp knife.
After the main head is harvested, many varieties will produce smaller side shoots for several weeks. Keep watering and you’ll get a continued yield.

Don’t wait to long to harvest. If the florets start to separate or show yellow flowers, the head is past its prime and will taste bitter, though its still edible.

Recommended Broccoli Varieties for PA

Choosing the right variety can make a difference. Look for types with good heat or cold tolerance.

For Spring: ‘Green Magic’, ‘Gypsy’, and ‘Imperial’ are known for good heat tolerance, helping them resist bolting.
For Fall: ‘Belstar’, ‘Arcadia’, and ‘Waltham 29’ are reliable, cold-tolerant varieties that produce well into autumn.
Quick Maturing: ‘De Cicco’ is an heirloom that produces lots of side shoots and matures quickly, which is great for shorter seasons.

FAQs: Planting Broccoli in Pennsylvania

Can I plant broccoli in July in Pennsylvania?

Yes, but only for a fall harvest. Mid-July is the ideal time to start broccoli seeds indoors for a fall crop in most of Pennsylvania. This gives them time to mature in the cooler autumn weather.

What happens if I plant broccoli too early in spring?

Planting hardened-off transplants a few weeks before the last frost is good. But if you plant too early and a hard freeze hits, young plants can be damaged or stunted. Its safer to wait until soil temperatures are at least 45°F.

Can broccoli survive a frost in PA?

Yes! Established broccoli plants can survive light frosts (down to about 28°F). In fact, a light frost can make the flavor sweeter. For fall crops, a hard freeze will end the harvest.

Why did my broccoli form small, loose heads?

This is called “buttoning.” It’s often caused by stress, such as transplanting too-old seedlings, nutrient deficiency, or especially temperature extremes (like a week of hot weather when the plant is young). Consistent care is key.

Is it better to direct sow or transplant broccoli?

For spring, transplanting is almost always better. It gives the plants a head start indoors, away from cold soil and pests. For fall, you can do either, but starting indoors in July heat ensures better germination and protects seedlings.

By following these timing guidelines and care tips, you can enjoy two productive seasons of homegrown broccoli. The key is respecting its preference for cool weather and planning your garden calendar around Pennsylvania’s frost dates. With a little attention to timing, you’ll be harvesting crisp, delicious broccoli from your own backyard.