Harrisburg, Pennsylvania planting calendar and frost dates
Harrisburg is in USDA hardiness zone 7a. The last spring frost typically comes around April 15 and the first fall frost around October 23, giving about 189 frost-free days a year.
- Hardiness zone
- Zone 7a
- Typical last frost
- April 15
- Typical first frost
- October 23
- Frost-free season
- 189 days
Frost dates in Harrisburg
Last spring frost
- April 1Risky: frost later than this in 9 years out of 10
- April 15Typical: a later frost in half of years
- May 2Safe: a later frost only 1 year in 10
First fall frost
- October 7Risky: frost earlier than this 1 year in 10
- October 23Typical: an earlier frost in half of years
- November 7Late: frost before this in 9 years out of 10
The growing season between the typical last and first frosts is about 189 days. Frost here means a low of 32°F at the weather station. A hard freeze (28°F), which damages most hardy crops too, typically ends around April 3 and returns around November 5.
NOAA U.S. Climate Normals 1991-2020 for Harrisburg 1 Ne, 3 miles SSE of the city center. Low-lying and rural spots often frost later in spring and earlier in fall than airports and city centers.
What to plant each month in Harrisburg
January
Start indoors: broccoli, cauliflower, collard greens, kale, leeks, onions, petunias, ranunculus
February
Start indoors: black-eyed susans, broccoli, cabbages, cauliflower, chives, collard greens, ginger, kale, leeks, lettuce, marigolds, onions, oregano, parsley, peppers, petunias, ranunculus, rosemary, sage, snapdragons
March
Start indoors: basil, black-eyed susans, cabbages, celery, chives, cilantro, collard greens, eggplants, ginger, lettuce, marigolds, nasturtiums, peppers, ranunculus, sage, snapdragons, spinach, swiss chard, tomatoes
Plant or sow outdoors: beets, black-eyed susans, blackberries, blueberries, broccoli, cabbages, carrots, cauliflower, chives, cilantro, collard greens, figs, garlic, gladioli, grapes, grass seed, hollyhocks, kale, leeks, lettuce, onions, parsley, peas, poppies, radishes, ranunculus, raspberries, rhubarb, roses, spinach, strawberries, swiss chard, turnips, wildflowers
April
Start indoors: basil, cantaloupes, cosmos, cucumbers, okra, pumpkins, ranunculus, tomatoes, watermelons, winter squash, zucchini
Plant or sow outdoors: asparagus, beets, black-eyed susans, blackberries, broccoli, cabbages, carrots, cauliflower, chives, cilantro, dahlias, dill, figs, garden mums, ginger, gladioli, grapes, green onions, kentucky bluegrass, lavenders, leeks, lettuce, lilies, marigolds, mints, nasturtiums, onions, oregano, parsley, perennial ryegrass, petunias, potatoes, radishes, ranunculus, rosemary, roses, sage, snapdragons, spinach, sunflowers, sweet corn, sweet peas, swiss chard, tall fescue, thyme, turnips
May
Start indoors: cosmos, okra, zinnias
Plant or sow outdoors: asparagus, basil, bermudagrass, cantaloupes, celery, centipedegrass, cosmos, cucumbers, eggplants, garden mums, ginger, green beans, green onions, kentucky bluegrass, okra, peanuts, peppers, perennial ryegrass, pumpkins, st. augustinegrass, sunflowers, sweet peas, sweet potatoes, tall fescue, tomatoes, watermelons, winter squash, zoysiagrass, zucchini
June
Plant or sow outdoors: bermudagrass, celery, centipedegrass, cosmos, green onions, okra, peanuts, st. augustinegrass, sweet potatoes, zinnias, zoysiagrass
July
Plant or sow outdoors: bermudagrass, centipedegrass, zoysiagrass
Plant for fall: bearded irises, brussels sprouts, carrots, collard greens, lettuce, peas, snapdragons, swiss chard
August
Plant for fall: azaleas, bearded irises, beets, broccoli, cabbages, carrots, cauliflower, clematis, collard greens, coneflowers, daylilies, hostas, hydrangeas, kale, lettuce, peas, radishes, roses, saffron, snapdragons, spinach, swiss chard, turnips
September
Plant for fall: azaleas, bearded irises, beets, broccoli, cabbages, cauliflower, clematis, coneflowers, crocuses, daffodils, daylilies, grass seed, hostas, hyacinths, hydrangeas, kale, kentucky bluegrass, lilies, ornamental alliums, peonies, perennial ryegrass, radishes, roses, saffron, spinach, tall fescue, tulips, turnips
October
Plant for fall: crocuses, daffodils, daylilies, garlic, hyacinths, lilies, ornamental alliums, peonies, tulips
November
Plant for fall: crocuses, garlic, hyacinths, ornamental alliums, tulips
December
Start indoors: onions
Frost dates and zones by ZIP code in Harrisburg
Harrisburg's 5 main ZIP codes take their frost dates from 2 different NOAA stations: the typical last frost ranges from April 9 in 17101 to April 15 in 17110. Every one of them is in zone 7a.
| ZIP code | Zone | Weather station | Typical last frost | Typical first frost |
|---|---|---|---|---|
| 17101 | 7a | Middletown Harrisburg International Airport, 8.2 mi ESE | Apr 9 | Nov 2 |
| 17102 | 7a | Middletown Harrisburg International Airport, 9 mi SE | Apr 9 | Nov 2 |
| 17103 | 7a | Harrisburg 1 Ne, 0.6 mi NW | Apr 15 | Oct 23 |
| 17104 | 7a | Middletown Harrisburg International Airport, 6.9 mi SE | Apr 9 | Nov 2 |
| 17110 | 7a | Harrisburg 1 Ne, 3 mi SSE | Apr 15 | Oct 23 |
Planting dates for popular crops in Harrisburg
| Plant | Start indoors | Plant or sow outdoors | Fall planting |
|---|---|---|---|
| Tomatoes | Mar 18 to Apr 1 | May 13 to 27 | — |
| Strawberries | — | Mar 4 to 18 | — |
| Lettuce | Feb 18 to Mar 4 | Apr 8 to 22 | Jul 24 to Aug 28 |
| Cilantro | Mar 4 to 18 | Apr 15 to 22 | — |
| Basil | Mar 25 to Apr 8 | May 13 to 20 | — |
| Potatoes | — | Apr 14 to 21 | — |
| Garlic | — | Mar 4 to 18 | Oct 23 to Nov 6 |
| Onions | Dec 24 to Feb 4 | Mar 18 to Apr 1 | — |
| Cucumbers | Apr 15 to 29 | May 13 to 27 | — |
| Pumpkins | Apr 15 to 29 | May 13 to 27 | — |
| Peppers | Feb 25 to Mar 25 | May 13 to 27 | — |
| Carrots | — | Mar 25 to Apr 15 | Jul 31 to Aug 21 |
| Sweet Potatoes | — | May 29 to Jun 5 | — |
| Watermelons | Apr 8 to 22 | May 13 to 27 | — |
| Sweet Corn | — | Apr 15 to 29 | — |
| Green Beans | — | May 13 to 27 | — |
| Zucchini | Apr 15 to 29 | May 13 to 27 | — |
| Broccoli | Jan 28 to Feb 18 | Mar 18 to Apr 1 | Aug 7 to Sep 4 |
| Peas | — | Mar 4 to 18 | Jul 31 to Aug 14 |
| Spinach | Mar 4 to 11 | Apr 8 to 22 | Aug 14 to Sep 18 |
| Sunflowers | — | Apr 15 to May 6 | — |
| Zinnias | May 17 to 24 | Jun 14 to 28 | — |
| Tulips | — | — | Sep 11 to Nov 6 |
| Daffodils | — | — | Sep 11 to Oct 23 |
| Grass Seed | — | Mar 4 to 18 | Sep 11 to 25 |
Nearby cities
- Lancaster, PA zone 7a, last frost Apr 19
- Reading, PA zone 7a, last frost Apr 14
- Frederick, MD zone 7a, last frost Apr 2
- Baltimore, MD zone 8a, last frost Mar 24
- Allentown, PA zone 7a, last frost Apr 20
- Gaithersburg, MD zone 7b, last frost Apr 2
Planting in PennsylvaniaAbout zone 7aPrintable calendar for Harrisburg
Questions
When is the last frost in Harrisburg?
Around April 15 in a typical year, based on NOAA's 1991-2020 records for Harrisburg 1 Ne. There is still a 1 in 10 chance of frost after May 2.
What planting zone is Harrisburg in?
USDA hardiness zone 7a (2023 map). The zone tells you which perennials survive the winter; planting dates depend on frost dates instead.
When should I plant tomatoes in Harrisburg?
Start seeds indoors March 18 to April 1 and set plants out May 13 to 27.
When is the first frost in Harrisburg?
Around October 23 in a typical year, and before October 7 about 1 year in 10.