Allentown, PA · zone 6b · ~186 frost-free days
When to plant a garden in Allentown.
In Allentown, the typical last spring frost lands around Apr 20 and the first fall frost around Oct 23, giving you about 186 frost-free days. Cool-season crops go out before the last frost; warm-season crops wait until after it.
The 2026 windows
Sow dates for Allentown, keyed to your frost.
| Crop | Start indoors | Spring sow / set out | Fall sow |
|---|---|---|---|
| Tomato, slicing | Mar 16 to May 16 | Apr 27 to Jun 27 | — |
| Lettuce, leaf | — | Mar 13 to Apr 27 | Aug 9 to Oct 8 |
| Carrot | — | Mar 13 to Apr 15 | Jul 28 to Aug 23 |
| Bush Bean | — | Apr 20 to Jun 10 | Jul 9 to Aug 11 |
| Cucumber, slicing | — | Apr 27 to Jul 27 | Jun 22 to Jul 23 |
| Pepper, bell | Mar 25 to May 16 | May 6 to Jun 27 | — |
| Kale | Jan 30 to Feb 27 | Mar 13 to Apr 10 | Jul 23 to Sep 7 |
| Spinach | — | Feb 27 to Apr 10 | Aug 9 to Sep 27 |
Allentown sits in Zone 6b, but two gardens in the same city can be a week or two apart. The planner works from your ZIP code's frost dates, not the zone, so the dates land right for your block, not the metro average.
Build your Allentown garden plan.
Tell the free planner what you want to eat and who you're feeding. It returns plant counts, spacing, and frost-safe sow dates for ZIP 18101 in about 60 seconds.