Frost Dates for Harrisburg, PA 17112
Last spring frost April 28 · First fall frost October 15 · 170 frost-free days · USDA Zone 7a
ZIP 17112 has about 38,500 people, the largest of 10 ZIP codes in Harrisburg.
Moderate season: 170 frost-free days. Spring frost risk spans April 14–May 11 (27 days). Fall frost risk spans October 1–October 28 (27 days).
Frost probability for 17112
| Frost | 10% | 50% | 90% |
|---|---|---|---|
| Spring (last frost) | May 11 | April 28 | April 14 |
| Fall (first frost) | October 1 | October 15 | October 28 |
Dates come from NOAA 1971–2000 freeze probabilities at LANDISVILLE 2 NW (40.8 km away); the 50% date is the median year.
Frost dates by ZIP code in Harrisburg, PA
| ZIP | Last spring frost (50%) | First fall frost (50%) | Zone |
|---|---|---|---|
| 17112 | April 28 | October 15 | 7a |
| 17111 | April 28 | October 13 | 7a |
| 17109 | April 28 | October 13 | 7a |
| 17110 | April 29 | October 15 | 7a |
| 17104 | April 28 | October 13 | 7a |
| 17103 | April 28 | October 13 | 7a |
| 17113 | April 28 | October 13 | 7a |
| 17102 | April 27 | October 15 | 7a |
| 17101 | April 27 | October 15 | 7a |
| 17120 | April 28 | October 13 | 7a |
Which crops fit a 170-day season in Harrisburg
In Harrisburg (170 frost-free days, a moderate season), 30 of 56 planner crops fit outright, 25 get two plantings, 1 crop is perennial.
| Crop | Start indoors | Plant out / sow | Days you have | Verdict | Last sow date |
|---|---|---|---|---|---|
| Tomato | Mar 24 | May 12–May 19 | 128 | fits: 80 days to maturity, 128 available after May 12. | Jun 15 |
| Pepper | Mar 17 | May 12–May 19 | 128 | fits: 75 days to maturity, 128 available after May 12. | Jun 20 |
| Lettuce | Mar 3 | Mar 31–Apr 7 | 205 | two-plantings: Plant Mar 31 and again by Aug 24; both mature before Oct 22. | Aug 24 |
| Carrots | — | Apr 7–Apr 14 | 212 | fits: 70 days to maturity, 212 available after Apr 7. | Aug 13 |
| Cucumber | Apr 7 | May 12–May 19 | 142 | two-plantings: Plant May 12 and again by Jul 19; both mature before Oct 1. | Jul 19 |
| Beans | — | May 5–May 19 | 156 | two-plantings: Plant May 5 and again by Jul 26; both mature before Oct 8. | Jul 26 |
| Peas | — | Mar 3–May 12 | 233 | fits: 65 days to maturity, 233 available after Mar 3. | Aug 4 |
| Zucchini | Apr 14 | May 12–May 19 | 142 | two-plantings: Plant May 12 and again by Jul 24; both mature before Oct 1. | Jul 24 |
| Onion | Feb 3 | Mar 31–Apr 14 | 205 | fits: 100 days to maturity, 205 available after Mar 31. | — |
| Spinach | — | Mar 3–Apr 21 | 247 | two-plantings: Plant Mar 3 and again by Sep 12; both mature before Nov 5. | Sep 12 |
| Kale | Feb 17 | Mar 31–Apr 14 | 219 | two-plantings: Plant Mar 31 and again by Aug 28; both mature before Nov 5. | Aug 28 |
| Broccoli | Mar 3 | Mar 31–Apr 14 | 205 | fits: 80 days to maturity, 205 available after Mar 31. | Jul 20 |
| Cabbage | Mar 3 | Mar 31–Apr 14 | 219 | fits: 70 days to maturity, 219 available after Mar 31. | Aug 13 |
| Radish | — | Mar 3–May 26 | 233 | two-plantings: Plant Mar 3 and again by Sep 13; both mature before Oct 22. | Sep 13 |
| Beets | — | Mar 3–May 26 | 233 | two-plantings: Plant Mar 3 and again by Aug 14; both mature before Oct 22. | Aug 14 |
| Potatoes | — | Apr 14–Apr 21 | 191 | fits: 90 days to maturity, 191 available after Apr 14. | — |
| Garlic | — | Oct 15 | 275 | overwinter: Plant Oct 15 to Nov 5; harvest the following summer. | Nov 5 |
| Strawberry | — | Mar 24–May 19 | 226 | perennial: A perennial: plant Mar 24; it fruits from the following year and keeps producing for several years. | — |
| Corn | Mar 31 | May 5–May 12 | 142 | fits: 75 days to maturity, 142 available after May 5. | Jun 27 |
| Pumpkin | Apr 14 | May 12–May 12 | 135 | fits: 100 days to maturity, 135 available after May 12. | Jun 2 |
| Cauliflower | Mar 17 | Apr 21–May 5 | 184 | fits: 75 days to maturity, 184 available after Apr 21. | Jul 25 |
| Swiss Chard | Mar 3 | Apr 14–Apr 14 | 191 | two-plantings: Plant Apr 14 and again by Aug 14; both mature before Oct 22. | Aug 14 |
| Arugula | — | Mar 3–May 26 | 247 | two-plantings: Plant Mar 3 and again by Sep 12; both mature before Nov 5. | Sep 12 |
| Brussel Sprouts | Mar 3 | Mar 31–Apr 14 | 219 | fits: 100 days to maturity, 219 available after Mar 31. | Jul 14 |
| Butternut Squash | Apr 14 | May 12–May 19 | 135 | fits: 100 days to maturity, 135 available after May 12. | Jun 2 |
| Eggplant | Mar 10 | May 12–May 19 | 128 | fits: 70 days to maturity, 128 available after May 12. | Jun 25 |
| Okra | Mar 31 | May 5–May 12 | 149 | two-plantings: Plant May 5 and again by Jul 24; both mature before Oct 1. | Jul 24 |
| Basil | Mar 24 | May 19–May 19 | 135 | two-plantings: Plant May 19 and again by Jul 19; both mature before Oct 1. | Jul 19 |
| Cilantro | — | Mar 31–Apr 21 | 205 | two-plantings: Plant Mar 31 and again by Aug 19; both mature before Oct 22. | Aug 19 |
| Parsley | Feb 17 | May 5–May 12 | 170 | fits: 70 days to maturity, 170 available after May 5. | Jul 30 |
| Celery | Feb 17 | May 5–May 19 | 170 | fits: 120 days to maturity, 170 available after May 5. | Jun 10 |
| Scallions | Feb 17 | Mar 31–Apr 14 | 219 | two-plantings: Plant Mar 31 and again by Aug 23; both mature before Nov 5. | Aug 23 |
| Turnip | — | Mar 31–Apr 14 | 219 | two-plantings: Plant Mar 31 and again by Sep 2; both mature before Nov 5. | Sep 2 |
| Kohlrabi | — | Mar 17–Mar 31 | 233 | two-plantings: Plant Mar 17 and again by Aug 28; both mature before Nov 5. | Aug 28 |
| Bok Choy | Mar 31 | Apr 21–Apr 28 | 184 | two-plantings: Plant Apr 21 and again by Aug 24; both mature before Oct 22. | Aug 24 |
| Collards | Feb 17 | Mar 31–Apr 14 | 219 | two-plantings: Plant Mar 31 and again by Aug 23; both mature before Nov 5. | Aug 23 |
| Cantaloupe | Apr 14 | May 12–May 19 | 128 | fits: 85 days to maturity, 128 available after May 12. | Jun 10 |
| Chives | Feb 3 | May 5–May 12 | 184 | fits: 90 days to maturity, 184 available after May 5. | — |
| Dill | — | Mar 3–May 26 | 233 | two-plantings: Plant Mar 3 and again by Aug 14; both mature before Oct 22. | Aug 14 |
| Oregano | Feb 17 | May 5–May 12 | 184 | fits: 80 days to maturity, 184 available after May 5. | — |
| Rosemary | Feb 3 | May 5–May 12 | 170 | fits: 80 days to maturity, 170 available after May 5. | — |
| Sage | Mar 3 | May 5–May 12 | 184 | fits: 75 days to maturity, 184 available after May 5. | — |
| Thyme | Feb 17 | May 5–May 12 | 184 | fits: 90 days to maturity, 184 available after May 5. | — |
| Calendula | Mar 17 | Apr 14–Apr 28 | 191 | two-plantings: Plant Apr 14 and again by Aug 19; both mature before Oct 22. | Aug 19 |
| Cosmos | Mar 31 | Apr 28–May 12 | 156 | two-plantings: Plant Apr 28 and again by Jul 19; both mature before Oct 1. | Jul 19 |
| Lavender | Feb 3 | Apr 28–May 12 | 191 | fits: 90 days to maturity, 191 available after Apr 28. | — |
| Marigolds | Mar 17 | Apr 28–May 5 | 156 | two-plantings: Plant Apr 28 and again by Jul 29; both mature before Oct 1. | Jul 29 |
| Melons | Apr 14 | May 12–May 19 | 128 | fits: 85 days to maturity, 128 available after May 12. | Jun 10 |
| Mint | — | Apr 28–May 12 | 191 | fits: 90 days to maturity, 191 available after Apr 28. | — |
| Nasturtiums | Mar 31 | Apr 28–May 5 | 156 | two-plantings: Plant Apr 28 and again by Jul 24; both mature before Oct 1. | Jul 24 |
| Pole Beans | — | May 5–May 19 | 149 | fits: 65 days to maturity, 149 available after May 5. | Jul 14 |
| Spaghetti Squash | Apr 14 | May 12–May 19 | 135 | fits: 90 days to maturity, 135 available after May 12. | Jun 12 |
| Sunflowers | — | Apr 28–May 12 | 156 | fits: 70 days to maturity, 156 available after Apr 28. | Jul 9 |
| Tomatillos | Mar 3 | May 5–May 12 | 135 | fits: 75 days to maturity, 135 available after May 5. | Jun 20 |
| Watermelon | Apr 14 | May 5–May 12 | 135 | fits: 80 days to maturity, 135 available after May 5. | Jun 15 |
| Yellow Squash | Apr 14 | May 12–May 19 | 142 | two-plantings: Plant May 12 and again by Jul 24; both mature before Oct 1. | Jul 24 |
| Zinnias | Mar 31 | Apr 28–May 12 | 156 | two-plantings: Plant Apr 28 and again by Jul 19; both mature before Oct 1. | Jul 19 |
Month by month in Harrisburg
| Month | What to do |
|---|---|
| January | Plan your garden layout and order seeds. Research varieties suited to your frost dates. |
| February | Start indoors: Chives (Feb 3), Lavender (Feb 3), Onion (Feb 3), Rosemary (Feb 3), Celery (Feb 17), Collards (Feb 17), +5 more. |
| March | Start indoors: Broccoli (Mar 3), Brussel Sprouts (Mar 3), Cabbage (Mar 3), Lettuce (Mar 3), Sage (Mar 3), Swiss Chard (Mar 3), +14 more. Direct sow from: Arugula (Mar 3), Beets (Mar 3), Dill (Mar 3), Peas (Mar 3), Radish (Mar 3), Spinach (Mar 3), +3 more. Transplant from: Broccoli (Mar 31), Brussel Sprouts (Mar 31), Cabbage (Mar 31), Collards (Mar 31), Kale (Mar 31), Lettuce (Mar 31), +2 more. Plant: Strawberry (Mar 24). |
| April | Start indoors: Cucumber (Apr 7), Butternut Squash (Apr 14), Cantaloupe (Apr 14), Melons (Apr 14), Pumpkin (Apr 14), Spaghetti Squash (Apr 14), +3 more. Direct sow from: Carrots (Apr 7), Potatoes (Apr 14), Sunflowers (Apr 28). Transplant from: Calendula (Apr 14), Swiss Chard (Apr 14), Bok Choy (Apr 21), Cauliflower (Apr 21), Cosmos (Apr 28), Lavender (Apr 28), +4 more. Last frost around April 28. |
| May | Direct sow from: Beans (May 5), Pole Beans (May 5). Transplant from: Celery (May 5), Chives (May 5), Corn (May 5), Okra (May 5), Oregano (May 5), Parsley (May 5), +17 more. |
| June | Last sowing dates: Butternut Squash (Jun 2), Pumpkin (Jun 2), Cantaloupe (Jun 10), Celery (Jun 10), Melons (Jun 10), Spaghetti Squash (Jun 12), +6 more. |
| July | Last sowing dates: Sunflowers (Jul 9), Brussel Sprouts (Jul 14), Pole Beans (Jul 14), Basil (Jul 19), Cosmos (Jul 19), Cucumber (Jul 19), +10 more. |
| August | Last sowing dates: Peas (Aug 4), Cabbage (Aug 13), Carrots (Aug 13), Beets (Aug 14), Dill (Aug 14), Swiss Chard (Aug 14), +8 more. |
| September | Last sowing dates: Turnip (Sep 2), Arugula (Sep 12), Spinach (Sep 12), Radish (Sep 13). |
| October | Direct sow from: Garlic (Oct 15). First frost around October 15. |
| November | Last sowing dates: Garlic (Nov 5). |
| December | Clean up spent plants. Add compost to beds. Rest, review, and plan next year's garden. |
Frequently Asked Questions
What is the last frost date for Harrisburg, PA (ZIP 17112)?
The median last spring frost date for Harrisburg, PA (ZIP code 17112) is around April 28. This is the 50th-percentile date — meaning half of all years see frost end before this date. Use the 10% and 90% dates to understand the full range of risk in your area. One year in ten frost ends before April 14; one in ten it runs past May 11.
What is the first fall frost date in Harrisburg, PA?
The median first fall frost date for Harrisburg, PA is around October 15. Plan to harvest or protect frost-sensitive crops like tomatoes and peppers at least a week before this date to avoid losses. The first frost arrives around October 1 in the earliest one-in-ten years, so cover tomatoes and peppers from then.
How long is the growing season in Harrisburg, PA?
The frost-free growing season in Harrisburg is about 170 days. This window — from your last spring frost to your first fall frost — is when warm-season vegetables thrive. Cold-hardy crops like kale, spinach, and peas can extend your season by weeks on either side. In Harrisburg (170 frost-free days, a moderate season), 30 of 56 planner crops fit outright, 25 get two plantings, 1 crop is perennial.
What USDA hardiness zone is Harrisburg, PA?
Harrisburg, PA is in USDA hardiness zone 7a (2023 USDA Plant Hardiness Zone Map). Zones come from the average coldest winter temperature, so they tell you which perennials survive the winter; the frost dates on this page tell you when to plant.
When should I start tomatoes indoors in Harrisburg, PA?
Start tomatoes indoors Mar 24 and plant out May 12 in Harrisburg. The planner uses the local median last frost and this crop's indoor-start and transplant offsets.
How many plantings of lettuce fit in Harrisburg?
Two: plant Mar 31 and again by Aug 24; both mature before Oct 22.
When do I plant garlic in Harrisburg?
Oct 15 to Nov 5; it overwinters and is ready the following summer.
Nearby and related
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