Frost Dates for Slippery Rock, PA 16057
Last spring frost May 16 · First fall frost September 30 · 137 frost-free days · USDA Zone 6a
ZIP 16057 has about 15,700 people.
Moderate season: 137 frost-free days. Spring frost risk spans April 29–June 2 (34 days). Fall frost risk spans September 14–October 18 (34 days).
Frost probability for 16057
| Frost | 10% | 50% | 90% |
|---|---|---|---|
| Spring (last frost) | June 2 | May 16 | April 29 |
| Fall (first frost) | September 14 | September 30 | October 18 |
Dates come from NOAA 1971–2000 freeze probabilities at MERCER (25.9 km away); the 50% date is the median year.
Which crops fit a 137-day season in Slippery Rock
In Slippery Rock (137 frost-free days, a moderate season), 39 of 56 planner crops fit outright, 16 get two plantings, 1 crop is perennial.
| Crop | Start indoors | Plant out / sow | Days you have | Verdict | Last sow date |
|---|---|---|---|---|---|
| Tomato | Apr 11 | May 30–Jun 6 | 95 | fits: 80 days to maturity, 95 available after May 30. | May 31 |
| Pepper | Apr 4 | May 30–Jun 6 | 95 | fits: 75 days to maturity, 95 available after May 30. | Jun 5 |
| Lettuce | Mar 21 | Apr 18–Apr 25 | 172 | two-plantings: Plant Apr 18 and again by Aug 9; both mature before Oct 7. | Aug 9 |
| Carrots | — | Apr 25–May 2 | 179 | fits: 70 days to maturity, 179 available after Apr 25. | Jul 29 |
| Cucumber | Apr 25 | May 30–Jun 6 | 109 | fits: 60 days to maturity, 109 available after May 30. | Jul 4 |
| Beans | — | May 23–Jun 6 | 123 | fits: 60 days to maturity, 123 available after May 23. | Jul 11 |
| Peas | — | Mar 21–May 30 | 200 | fits: 65 days to maturity, 200 available after Mar 21. | Jul 20 |
| Zucchini | May 2 | May 30–Jun 6 | 109 | fits: 55 days to maturity, 109 available after May 30. | Jul 9 |
| Onion | Feb 21 | Apr 18–May 2 | 172 | fits: 100 days to maturity, 172 available after Apr 18. | — |
| Spinach | — | Mar 21–May 9 | 214 | two-plantings: Plant Mar 21 and again by Aug 28; both mature before Oct 21. | Aug 28 |
| Kale | Mar 7 | Apr 18–May 2 | 186 | two-plantings: Plant Apr 18 and again by Aug 13; both mature before Oct 21. | Aug 13 |
| Broccoli | Mar 21 | Apr 18–May 2 | 172 | fits: 80 days to maturity, 172 available after Apr 18. | Jul 5 |
| Cabbage | Mar 21 | Apr 18–May 2 | 186 | fits: 70 days to maturity, 186 available after Apr 18. | Jul 29 |
| Radish | — | Mar 21–Jun 13 | 200 | two-plantings: Plant Mar 21 and again by Aug 29; both mature before Oct 7. | Aug 29 |
| Beets | — | Mar 21–Jun 13 | 200 | two-plantings: Plant Mar 21 and again by Jul 30; both mature before Oct 7. | Jul 30 |
| Potatoes | — | May 2–May 9 | 158 | fits: 90 days to maturity, 158 available after May 2. | — |
| Garlic | — | Sep 30 | 242 | overwinter: Plant Sep 30 to Oct 21; harvest the following summer. | Oct 21 |
| Strawberry | — | Apr 11–Jun 6 | 193 | perennial: A perennial: plant Apr 11; it fruits from the following year and keeps producing for several years. | — |
| Corn | Apr 18 | May 23–May 30 | 109 | fits: 75 days to maturity, 109 available after May 23. | Jun 12 |
| Pumpkin | May 2 | May 30–May 30 | 102 | fits: 100 days to maturity, 102 available after May 30. | — |
| Cauliflower | Apr 4 | May 9–May 23 | 151 | fits: 75 days to maturity, 151 available after May 9. | Jul 10 |
| Swiss Chard | Mar 21 | May 2–May 2 | 158 | two-plantings: Plant May 2 and again by Jul 30; both mature before Oct 7. | Jul 30 |
| Arugula | — | Mar 21–Jun 13 | 214 | two-plantings: Plant Mar 21 and again by Aug 28; both mature before Oct 21. | Aug 28 |
| Brussel Sprouts | Mar 21 | Apr 18–May 2 | 186 | fits: 100 days to maturity, 186 available after Apr 18. | Jun 29 |
| Butternut Squash | May 2 | May 30–Jun 6 | 102 | fits: 100 days to maturity, 102 available after May 30. | — |
| Eggplant | Mar 28 | May 30–Jun 6 | 95 | fits: 70 days to maturity, 95 available after May 30. | Jun 10 |
| Okra | Apr 18 | May 23–May 30 | 116 | fits: 55 days to maturity, 116 available after May 23. | Jul 9 |
| Basil | Apr 11 | Jun 6–Jun 6 | 102 | fits: 60 days to maturity, 102 available after Jun 6. | Jul 4 |
| Cilantro | — | Apr 18–May 9 | 172 | two-plantings: Plant Apr 18 and again by Aug 4; both mature before Oct 7. | Aug 4 |
| Parsley | Mar 7 | May 23–May 30 | 137 | fits: 70 days to maturity, 137 available after May 23. | Jul 15 |
| Celery | Mar 7 | May 23–Jun 6 | 137 | fits: 120 days to maturity, 137 available after May 23. | May 26 |
| Scallions | Mar 7 | Apr 18–May 2 | 186 | two-plantings: Plant Apr 18 and again by Aug 8; both mature before Oct 21. | Aug 8 |
| Turnip | — | Apr 18–May 2 | 186 | two-plantings: Plant Apr 18 and again by Aug 18; both mature before Oct 21. | Aug 18 |
| Kohlrabi | — | Apr 4–Apr 18 | 200 | two-plantings: Plant Apr 4 and again by Aug 13; both mature before Oct 21. | Aug 13 |
| Bok Choy | Apr 18 | May 9–May 16 | 151 | two-plantings: Plant May 9 and again by Aug 9; both mature before Oct 7. | Aug 9 |
| Collards | Mar 7 | Apr 18–May 2 | 186 | two-plantings: Plant Apr 18 and again by Aug 8; both mature before Oct 21. | Aug 8 |
| Cantaloupe | May 2 | May 30–Jun 6 | 95 | fits: 85 days to maturity, 95 available after May 30. | — |
| Chives | Feb 21 | May 23–May 30 | 151 | fits: 90 days to maturity, 151 available after May 23. | — |
| Dill | — | Mar 21–Jun 13 | 200 | two-plantings: Plant Mar 21 and again by Jul 30; both mature before Oct 7. | Jul 30 |
| Oregano | Mar 7 | May 23–May 30 | 151 | fits: 80 days to maturity, 151 available after May 23. | — |
| Rosemary | Feb 21 | May 23–May 30 | 137 | fits: 80 days to maturity, 137 available after May 23. | — |
| Sage | Mar 21 | May 23–May 30 | 151 | fits: 75 days to maturity, 151 available after May 23. | — |
| Thyme | Mar 7 | May 23–May 30 | 151 | fits: 90 days to maturity, 151 available after May 23. | — |
| Calendula | Apr 4 | May 2–May 16 | 158 | two-plantings: Plant May 2 and again by Aug 4; both mature before Oct 7. | Aug 4 |
| Cosmos | Apr 18 | May 16–May 30 | 123 | fits: 60 days to maturity, 123 available after May 16. | Jul 4 |
| Lavender | Feb 21 | May 16–May 30 | 158 | fits: 90 days to maturity, 158 available after May 16. | — |
| Marigolds | Apr 4 | May 16–May 23 | 123 | two-plantings: Plant May 16 and again by Jul 14; both mature before Sep 16. | Jul 14 |
| Melons | May 2 | May 30–Jun 6 | 95 | fits: 85 days to maturity, 95 available after May 30. | — |
| Mint | — | May 16–May 30 | 158 | fits: 90 days to maturity, 158 available after May 16. | — |
| Nasturtiums | Apr 18 | May 16–May 23 | 123 | fits: 55 days to maturity, 123 available after May 16. | Jul 9 |
| Pole Beans | — | May 23–Jun 6 | 116 | fits: 65 days to maturity, 116 available after May 23. | Jun 29 |
| Spaghetti Squash | May 2 | May 30–Jun 6 | 102 | fits: 90 days to maturity, 102 available after May 30. | — |
| Sunflowers | — | May 16–May 30 | 123 | fits: 70 days to maturity, 123 available after May 16. | Jun 24 |
| Tomatillos | Mar 21 | May 23–May 30 | 102 | fits: 75 days to maturity, 102 available after May 23. | Jun 5 |
| Watermelon | May 2 | May 23–May 30 | 102 | fits: 80 days to maturity, 102 available after May 23. | May 31 |
| Yellow Squash | May 2 | May 30–Jun 6 | 109 | fits: 55 days to maturity, 109 available after May 30. | Jul 9 |
| Zinnias | Apr 18 | May 16–May 30 | 123 | fits: 60 days to maturity, 123 available after May 16. | Jul 4 |
Month by month in Slippery Rock
| Month | What to do |
|---|---|
| January | Plan your garden layout and order seeds. Research varieties suited to your frost dates. |
| February | Start indoors: Chives (Feb 21), Lavender (Feb 21), Onion (Feb 21), Rosemary (Feb 21). |
| March | Start indoors: Celery (Mar 7), Collards (Mar 7), Kale (Mar 7), Oregano (Mar 7), Parsley (Mar 7), Scallions (Mar 7), +9 more. Direct sow from: Arugula (Mar 21), Beets (Mar 21), Dill (Mar 21), Peas (Mar 21), Radish (Mar 21), Spinach (Mar 21). |
| April | Start indoors: Calendula (Apr 4), Cauliflower (Apr 4), Marigolds (Apr 4), Pepper (Apr 4), Basil (Apr 11), Tomato (Apr 11), +7 more. Direct sow from: Kohlrabi (Apr 4), Cilantro (Apr 18), Turnip (Apr 18), Carrots (Apr 25). Transplant from: Broccoli (Apr 18), Brussel Sprouts (Apr 18), Cabbage (Apr 18), Collards (Apr 18), Kale (Apr 18), Lettuce (Apr 18), +2 more. Plant: Strawberry (Apr 11). |
| May | Start indoors: Butternut Squash (May 2), Cantaloupe (May 2), Melons (May 2), Pumpkin (May 2), Spaghetti Squash (May 2), Watermelon (May 2), +2 more. Direct sow from: Potatoes (May 2), Sunflowers (May 16), Beans (May 23), Pole Beans (May 23). Transplant from: Calendula (May 2), Swiss Chard (May 2), Bok Choy (May 9), Cauliflower (May 9), Cosmos (May 16), Lavender (May 16), +26 more. Last frost around May 16. Last sowing dates: Celery (May 26), Tomato (May 31), Watermelon (May 31). |
| June | Transplant from: Basil (Jun 6). Last sowing dates: Pepper (Jun 5), Tomatillos (Jun 5), Eggplant (Jun 10), Corn (Jun 12), Sunflowers (Jun 24), Brussel Sprouts (Jun 29), +1 more. |
| July | Last sowing dates: Basil (Jul 4), Cosmos (Jul 4), Cucumber (Jul 4), Zinnias (Jul 4), Broccoli (Jul 5), Nasturtiums (Jul 9), +13 more. |
| August | Last sowing dates: Calendula (Aug 4), Cilantro (Aug 4), Collards (Aug 8), Scallions (Aug 8), Bok Choy (Aug 9), Lettuce (Aug 9), +6 more. |
| September | Direct sow from: Garlic (Sep 30). First frost around September 30. |
| October | Last sowing dates: Garlic (Oct 21). |
| November | Clean up spent plants. Add compost to beds. Rest, review, and plan next year's garden. |
| 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 Slippery Rock, PA (ZIP 16057)?
The median last spring frost date for Slippery Rock, PA (ZIP code 16057) is around May 16. 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 29; one in ten it runs past June 2.
What is the first fall frost date in Slippery Rock, PA?
The median first fall frost date for Slippery Rock, PA is around September 30. 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 September 14 in the earliest one-in-ten years, so cover tomatoes and peppers from then.
How long is the growing season in Slippery Rock, PA?
The frost-free growing season in Slippery Rock is about 137 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 Slippery Rock (137 frost-free days, a moderate season), 39 of 56 planner crops fit outright, 16 get two plantings, 1 crop is perennial.
What USDA hardiness zone is Slippery Rock, PA?
Slippery Rock, PA is in USDA hardiness zone 6a (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 Slippery Rock, PA?
Start tomatoes indoors Apr 11 and plant out May 30 in Slippery Rock. The planner uses the local median last frost and this crop's indoor-start and transplant offsets.
How many plantings of lettuce fit in Slippery Rock?
Two: plant Apr 18 and again by Aug 9; both mature before Oct 7.
When do I plant garlic in Slippery Rock?
Sep 30 to Oct 21; it overwinters and is ready the following summer.
Which nearby ZIP has a longer season?
Ellwood City (ZIP 16117) has 150 frost-free days, 13 more than Slippery Rock (ZIP 16057). See Ellwood City ZIP 16117 frost dates
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