When to Plant in Allentown, PA

Allentown, Pennsylvania, is characterized by a climate that features a median last spring frost date of May 2 and a median first fall frost date of October 9, providing approximately 160 frost-free days each year. This growing season allows gardeners ample time to cultivate a variety of fruits, vegetables, and flowers, making the most of the unique conditions presented by the local climate.

The humid temperate climate of Allentown features four distinct seasons, which greatly influences the types of plants that flourish. Crops such as tomatoes, peppers, and cucumbers thrive due to the warm summers and ample rainfall, while cooler season crops like spinach and kale can be planted in early spring. Conversely, crops such as melons and sweet potatoes may struggle due to insufficient heat accumulation or shorter growing seasons.

What to plant now in Allentown

Spring: Start planting cool-season crops like peas and radishes as soon as the ground can be worked in early March. After the last frost on May 2, transition to warm-season crops like tomatoes and peppers.
Summer: In June, plant succession crops and continue sowing beans and corn. As the risk of frost diminishes, ensure to maintain soil moisture for summer crops as temperatures rise.
Fall: Begin planting fall crops like garlic and shallots in late September. Harvest summer crops before the expected first frost date of October 9, and prepare for winter gardening.
Winter: Utilize this quiet season to plan for next year. Consider starting seeds indoors for early spring planting or explore winter gardening with cold frames for hardy vegetables.

In Allentown (160 frost-free days, a moderate season), 32 of 56 planner crops fit outright, 23 get two plantings, 1 crop is perennial.

Month by month in Allentown

Month	What to do
January	In January, gardening is at a standstill. Use this time to plan your spring garden layout and order seeds. Reflect on last year’s successes and failures.
February	February can still be cold and windy. Prepare tools for spring planting and consider starting seeds indoors for early transplants. Assess soil health in preparation for the forthcoming season.
March	With the arrival of March, focus on starting cool-season crops like peas, kale, and radishes outdoors as soon as the soil thaws. Prepare beds for planting and amend soil as needed.
April	April brings milder weather. Continue sowing cool-season crops, and by mid to late April, prepare for the shift towards planting warm-season crops in anticipation of the last frost on May 2.
May	As the last frost date arrives on May 2, it's time to plant warm-season crops like tomatoes, peppers, and cucumbers. Ensure to monitor weather forecasts for any unexpected cold snaps.
June	June marks the height of growing season. Continue planting successions of warm-season crops, and ensure regular watering and mulching to maintain moisture during the warmer months.
July	July typically brings heat, so keep crops well-watered. Focus on harvesting mature crops, and consider planting a second round of beans or summer squash for continuous yield.
August	In August, begin to prepare for the fall harvest. Start planting fall crops like beets and carrots. Afternoons might be hot, so consider evening watering to minimize evaporation.
September	September signals the transition to fall gardening. Plant garlic and shallots for overwintering before the first frost date on October 9 approaches. Harvest any late summer crops as needed.
October	October is crucial for wrapping up the harvest before the first fall frost on October 9. Protect late crops with row covers or blankets as temperatures drop.
November	November is time for cleanup and preparation for winter. Clear out spent plants and consider planting cover crops to improve soil health. Organize tools for winter storage.
December	December is a quiet month for gardening. Reflect on the past year’s yields and successes. Consider what new crops you would like to experiment with in the coming season.

Frost dates for Allentown ZIP codes

ZIP	Last spring frost (50%)	First fall frost (50%)	Zone
18102	May 2	October 9	7a

FAQ

When is the last frost in Allentown?

The last frost in Allentown typically occurs on May 2, making it essential to plan your planting schedule around this date.

What vegetables grow best in Allentown?

Vegetables such as tomatoes, peppers, and cucumbers thrive in Allentown's climate, benefiting from the warm summers and sufficient rainfall.

When should I plant tomatoes in Allentown?

Tomatoes should be planted outdoors after the last frost on May 2, when soil temperatures have warmed sufficiently.

Can I garden year-round in Allentown?

Year-round gardening is challenging due to cold winters, but you can start seedlings indoors and use cold frames for hardy vegetables.

How does Plan My Garden help Allentown gardeners?

Plan My Garden provides tailored advice based on local climate conditions, helping gardeners make informed choices about what and when to plant.