When to Plant Collard Greens in Allentown, PA
Published: April 24, 2026
Collard Green Planting Dates for Allentown, PA
| Start seeds indoors | February 23–March 2 |
| Last frost (average) | March 30 |
| Transplant outdoors | March 9–19 |
| Direct sow outdoors | March 9–19 |
| Minimum soil temperature | 45°F |
| Expect first harvest | May 8 – May 23 |
| Fall crop planting | August 23–September 2 |
| Fall crop harvest | October 22 |
| First fall frost (average) | November 1 |
⚠ Direct sow or transplant collard greens 3–4 weeks before last frost. Extremely cold hardy — withstands temps to 15°F. Can be grown as a perennial in Zones 8+. Fall planting produces the best-flavored greens.
Best Collard Green Varieties for Allentown, PA
Consult a Allentown-area nursery or your state extension office for collard green varieties proven in Zone 6a.
Growing Collard Greens in Allentown
Allentown sits in Zone 6a, with an average last frost of March 30 and first fall frost around November 1 — giving a 216-day frost-free growing season. Cool-season crops like collard green benefit from Allentown's cooler spring and fall windows, when temperatures stay in the 55–75°F sweet spot that produces the best flavor and least bolting.
Allentown's moderate climate supports collard green on the standard transplant calendar with minimal special accommodation. Succession planting — sowing fresh seeds or setting new transplants every 2–3 weeks through spring — stretches the harvest window and gives you a backup crop if pests hit the first planting.
Allentown's clay-loam soils are productive but benefit from annual compost amendment — 2 to 3 inches worked in before planting improves drainage and nutrient availability for collard green. Consistent watering (1 inches per week) paired with organic mulch maintains the even moisture that clay-loam holds well. Avoid working wet soil in spring, which causes severe compaction in clay-loam blends.
Collard Green Calendar for Allentown
| Month | Task |
|---|---|
| February | Start seeds indoors under grow lights |
| March | Transplant outdoors into warm soil |
| May | Expect first harvest window to open |
| August | Start fall crop — transplants or direct sow |
| November | First fall frost — harvest remaining, end of outdoor season |
Collard Green Tips for Allentown Gardeners
- •Harvest outer leaves continuously once plants reach 10 inches — the central growing point produces for months.
- •In Zones 8+ collard greens often overwinter and produce for 2–3 years as a perennial.
- •Succession plant collard green in Allentown every 2–3 weeks through spring to extend the harvest window into summer.
Common Collard Green Pests in Allentown
- •Cabbage Worm — peaks July in Zone 6a (active May–September); green caterpillars on brassicas; apply Bt spray or use row covers.
- •Aphid — peaks July in Zone 6a (active May–September); monitor closely during peak season and treat early.
- •Flea Beetle — peaks July in Zone 6a (active May–September); tiny black beetles that riddle leaves with holes; row covers protect seedlings.
Check plants every 2–3 days during peak season — early intervention prevents most infestations from becoming serious.
What to Plant with Collard Greens in Allentown
In Allentown's moderate climate, Onion and Garlic are the most beneficial plants to grow alongside collard green. Onion deters carrot fly, aphids, and several root-zone pests through sulfur compounds. Keep collard green away from Tomato — it competes for nutrients or shares pest pressure.
Frequently Asked Questions
When should I plant collard green in Allentown, PA?
In Allentown (Zone 6a), start collard green seeds indoors around February 23–March 2 and transplant outdoors around March 9–19. The city's average last frost of March 30 is the anchor date — count 5 weeks back for seed starting and 3 weeks back for transplanting.
What zone is Allentown, PA for collard green growing?
Allentown is USDA Zone 6a. For collard green, this means a frost-free growing season of roughly 31 weeks running from March 30 to November 1. Cool-season crops like collard green thrive in this zone with both spring and fall planting windows available.
When is collard green harvest season in Allentown?
Expect the first collard green harvest in Allentown around May 8, with harvest continuing through May 23. This is based on 60–75 days from transplant or direct sow. A fall crop planted August 23–September 2 adds a second harvest around October 22.
How long does it take to grow collard green in Allentown, PA?
From transplant or direct sow to first harvest, collard green takes 60–75 days in Allentown's climate. Based on a typical planting date of March 9–19, expect your first harvest around May 8. Allentown's Zone 6a transition-zone climate produces maturity times right in the middle of the stated range.
What soil does collard green need in Allentown?
Allentown's clay-loam soil is productive for collard green but benefits from annual compost amendment. Work 2–3 inches of compost into the top 10 inches before planting. Avoid working wet soil in spring — clay-loam compacts badly when wet. Consistent watering paired with organic mulch maintains the even moisture these soils hold well.