Frost Dates for Ottawa, OH 45875
Last spring frost April 30 · First fall frost October 11 · 164 frost-free days · USDA Zone 6a
ZIP 45875 has about 11,500 people.
Moderate season: 164 frost-free days. Spring frost risk spans April 17–May 12 (25 days). Fall frost risk spans September 27–October 26 (29 days).
Frost probability for 45875
| Frost | 10% | 50% | 90% |
|---|---|---|---|
| Spring (last frost) | May 12 | April 30 | April 17 |
| Fall (first frost) | September 27 | October 11 | October 26 |
Dates come from NOAA 1971–2000 freeze probabilities at PANDORA (11.9 km away); the 50% date is the median year.
Which crops fit a 164-day season in Ottawa
In Ottawa (164 frost-free days, a moderate season), 31 of 56 planner crops fit outright, 24 get two plantings, 1 crop is perennial.
| Crop | Start indoors | Plant out / sow | Days you have | Verdict | Last sow date |
|---|---|---|---|---|---|
| Tomato | Mar 26 | May 14–May 21 | 122 | fits: 80 days to maturity, 122 available after May 14. | Jun 11 |
| Pepper | Mar 19 | May 14–May 21 | 122 | fits: 75 days to maturity, 122 available after May 14. | Jun 16 |
| Lettuce | Mar 5 | Apr 2–Apr 9 | 199 | two-plantings: Plant Apr 2 and again by Aug 20; both mature before Oct 18. | Aug 20 |
| Carrots | — | Apr 9–Apr 16 | 206 | fits: 70 days to maturity, 206 available after Apr 9. | Aug 9 |
| Cucumber | Apr 9 | May 14–May 21 | 136 | two-plantings: Plant May 14 and again by Jul 15; both mature before Sep 27. | Jul 15 |
| Beans | — | May 7–May 21 | 150 | two-plantings: Plant May 7 and again by Jul 22; both mature before Oct 4. | Jul 22 |
| Peas | — | Mar 5–May 14 | 227 | fits: 65 days to maturity, 227 available after Mar 5. | Jul 31 |
| Zucchini | Apr 16 | May 14–May 21 | 136 | two-plantings: Plant May 14 and again by Jul 20; both mature before Sep 27. | Jul 20 |
| Onion | Feb 5 | Apr 2–Apr 16 | 199 | fits: 100 days to maturity, 199 available after Apr 2. | — |
| Spinach | — | Mar 5–Apr 23 | 241 | two-plantings: Plant Mar 5 and again by Sep 8; both mature before Nov 1. | Sep 8 |
| Kale | Feb 19 | Apr 2–Apr 16 | 213 | two-plantings: Plant Apr 2 and again by Aug 24; both mature before Nov 1. | Aug 24 |
| Broccoli | Mar 5 | Apr 2–Apr 16 | 199 | fits: 80 days to maturity, 199 available after Apr 2. | Jul 16 |
| Cabbage | Mar 5 | Apr 2–Apr 16 | 213 | fits: 70 days to maturity, 213 available after Apr 2. | Aug 9 |
| Radish | — | Mar 5–May 28 | 227 | two-plantings: Plant Mar 5 and again by Sep 9; both mature before Oct 18. | Sep 9 |
| Beets | — | Mar 5–May 28 | 227 | two-plantings: Plant Mar 5 and again by Aug 10; both mature before Oct 18. | Aug 10 |
| Potatoes | — | Apr 16–Apr 23 | 185 | fits: 90 days to maturity, 185 available after Apr 16. | — |
| Garlic | — | Oct 11 | 269 | overwinter: Plant Oct 11 to Nov 1; harvest the following summer. | Nov 1 |
| Strawberry | — | Mar 26–May 21 | 220 | perennial: A perennial: plant Mar 26; it fruits from the following year and keeps producing for several years. | — |
| Corn | Apr 2 | May 7–May 14 | 136 | fits: 75 days to maturity, 136 available after May 7. | Jun 23 |
| Pumpkin | Apr 16 | May 14–May 14 | 129 | fits: 100 days to maturity, 129 available after May 14. | May 29 |
| Cauliflower | Mar 19 | Apr 23–May 7 | 178 | fits: 75 days to maturity, 178 available after Apr 23. | Jul 21 |
| Swiss Chard | Mar 5 | Apr 16–Apr 16 | 185 | two-plantings: Plant Apr 16 and again by Aug 10; both mature before Oct 18. | Aug 10 |
| Arugula | — | Mar 5–May 28 | 241 | two-plantings: Plant Mar 5 and again by Sep 8; both mature before Nov 1. | Sep 8 |
| Brussel Sprouts | Mar 5 | Apr 2–Apr 16 | 213 | fits: 100 days to maturity, 213 available after Apr 2. | Jul 10 |
| Butternut Squash | Apr 16 | May 14–May 21 | 129 | fits: 100 days to maturity, 129 available after May 14. | May 29 |
| Eggplant | Mar 12 | May 14–May 21 | 122 | fits: 70 days to maturity, 122 available after May 14. | Jun 21 |
| Okra | Apr 2 | May 7–May 14 | 143 | two-plantings: Plant May 7 and again by Jul 20; both mature before Sep 27. | Jul 20 |
| Basil | Mar 26 | May 21–May 21 | 129 | fits: 60 days to maturity, 129 available after May 21. | Jul 15 |
| Cilantro | — | Apr 2–Apr 23 | 199 | two-plantings: Plant Apr 2 and again by Aug 15; both mature before Oct 18. | Aug 15 |
| Parsley | Feb 19 | May 7–May 14 | 164 | fits: 70 days to maturity, 164 available after May 7. | Jul 26 |
| Celery | Feb 19 | May 7–May 21 | 164 | fits: 120 days to maturity, 164 available after May 7. | Jun 6 |
| Scallions | Feb 19 | Apr 2–Apr 16 | 213 | two-plantings: Plant Apr 2 and again by Aug 19; both mature before Nov 1. | Aug 19 |
| Turnip | — | Apr 2–Apr 16 | 213 | two-plantings: Plant Apr 2 and again by Aug 29; both mature before Nov 1. | Aug 29 |
| Kohlrabi | — | Mar 19–Apr 2 | 227 | two-plantings: Plant Mar 19 and again by Aug 24; both mature before Nov 1. | Aug 24 |
| Bok Choy | Apr 2 | Apr 23–Apr 30 | 178 | two-plantings: Plant Apr 23 and again by Aug 20; both mature before Oct 18. | Aug 20 |
| Collards | Feb 19 | Apr 2–Apr 16 | 213 | two-plantings: Plant Apr 2 and again by Aug 19; both mature before Nov 1. | Aug 19 |
| Cantaloupe | Apr 16 | May 14–May 21 | 122 | fits: 85 days to maturity, 122 available after May 14. | Jun 6 |
| Chives | Feb 5 | May 7–May 14 | 178 | fits: 90 days to maturity, 178 available after May 7. | — |
| Dill | — | Mar 5–May 28 | 227 | two-plantings: Plant Mar 5 and again by Aug 10; both mature before Oct 18. | Aug 10 |
| Oregano | Feb 19 | May 7–May 14 | 178 | fits: 80 days to maturity, 178 available after May 7. | — |
| Rosemary | Feb 5 | May 7–May 14 | 164 | fits: 80 days to maturity, 164 available after May 7. | — |
| Sage | Mar 5 | May 7–May 14 | 178 | fits: 75 days to maturity, 178 available after May 7. | — |
| Thyme | Feb 19 | May 7–May 14 | 178 | fits: 90 days to maturity, 178 available after May 7. | — |
| Calendula | Mar 19 | Apr 16–Apr 30 | 185 | two-plantings: Plant Apr 16 and again by Aug 15; both mature before Oct 18. | Aug 15 |
| Cosmos | Apr 2 | Apr 30–May 14 | 150 | two-plantings: Plant Apr 30 and again by Jul 15; both mature before Sep 27. | Jul 15 |
| Lavender | Feb 5 | Apr 30–May 14 | 185 | fits: 90 days to maturity, 185 available after Apr 30. | — |
| Marigolds | Mar 19 | Apr 30–May 7 | 150 | two-plantings: Plant Apr 30 and again by Jul 25; both mature before Sep 27. | Jul 25 |
| Melons | Apr 16 | May 14–May 21 | 122 | fits: 85 days to maturity, 122 available after May 14. | Jun 6 |
| Mint | — | Apr 30–May 14 | 185 | fits: 90 days to maturity, 185 available after Apr 30. | — |
| Nasturtiums | Apr 2 | Apr 30–May 7 | 150 | two-plantings: Plant Apr 30 and again by Jul 20; both mature before Sep 27. | Jul 20 |
| Pole Beans | — | May 7–May 21 | 143 | fits: 65 days to maturity, 143 available after May 7. | Jul 10 |
| Spaghetti Squash | Apr 16 | May 14–May 21 | 129 | fits: 90 days to maturity, 129 available after May 14. | Jun 8 |
| Sunflowers | — | Apr 30–May 14 | 150 | fits: 70 days to maturity, 150 available after Apr 30. | Jul 5 |
| Tomatillos | Mar 5 | May 7–May 14 | 129 | fits: 75 days to maturity, 129 available after May 7. | Jun 16 |
| Watermelon | Apr 16 | May 7–May 14 | 129 | fits: 80 days to maturity, 129 available after May 7. | Jun 11 |
| Yellow Squash | Apr 16 | May 14–May 21 | 136 | two-plantings: Plant May 14 and again by Jul 20; both mature before Sep 27. | Jul 20 |
| Zinnias | Apr 2 | Apr 30–May 14 | 150 | two-plantings: Plant Apr 30 and again by Jul 15; both mature before Sep 27. | Jul 15 |
Month by month in Ottawa
| Month | What to do |
|---|---|
| January | Plan your garden layout and order seeds. Research varieties suited to your frost dates. |
| February | Start indoors: Chives (Feb 5), Lavender (Feb 5), Onion (Feb 5), Rosemary (Feb 5), Celery (Feb 19), Collards (Feb 19), +5 more. |
| March | Start indoors: Broccoli (Mar 5), Brussel Sprouts (Mar 5), Cabbage (Mar 5), Lettuce (Mar 5), Sage (Mar 5), Swiss Chard (Mar 5), +8 more. Direct sow from: Arugula (Mar 5), Beets (Mar 5), Dill (Mar 5), Peas (Mar 5), Radish (Mar 5), Spinach (Mar 5), +1 more. Plant: Strawberry (Mar 26). |
| April | Start indoors: Bok Choy (Apr 2), Corn (Apr 2), Cosmos (Apr 2), Nasturtiums (Apr 2), Okra (Apr 2), Zinnias (Apr 2), +9 more. Direct sow from: Cilantro (Apr 2), Turnip (Apr 2), Carrots (Apr 9), Potatoes (Apr 16), Sunflowers (Apr 30). Transplant from: Broccoli (Apr 2), Brussel Sprouts (Apr 2), Cabbage (Apr 2), Collards (Apr 2), Kale (Apr 2), Lettuce (Apr 2), +12 more. Last frost around April 30. |
| May | Direct sow from: Beans (May 7), Pole Beans (May 7). Transplant from: Celery (May 7), Chives (May 7), Corn (May 7), Okra (May 7), Oregano (May 7), Parsley (May 7), +17 more. Last sowing dates: Butternut Squash (May 29), Pumpkin (May 29). |
| June | Last sowing dates: Cantaloupe (Jun 6), Celery (Jun 6), Melons (Jun 6), Spaghetti Squash (Jun 8), Tomato (Jun 11), Watermelon (Jun 11), +4 more. |
| July | Last sowing dates: Sunflowers (Jul 5), Brussel Sprouts (Jul 10), Pole Beans (Jul 10), Basil (Jul 15), Cosmos (Jul 15), Cucumber (Jul 15), +11 more. |
| August | Last sowing dates: Cabbage (Aug 9), Carrots (Aug 9), Beets (Aug 10), Dill (Aug 10), Swiss Chard (Aug 10), Calendula (Aug 15), +8 more. |
| September | Last sowing dates: Arugula (Sep 8), Spinach (Sep 8), Radish (Sep 9). |
| October | Direct sow from: Garlic (Oct 11). First frost around October 11. |
| November | Last sowing dates: Garlic (Nov 1). |
| 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 Ottawa, OH (ZIP 45875)?
The median last spring frost date for Ottawa, OH (ZIP code 45875) is around April 30. 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 17; one in ten it runs past May 12.
What is the first fall frost date in Ottawa, OH?
The median first fall frost date for Ottawa, OH is around October 11. 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 27 in the earliest one-in-ten years, so cover tomatoes and peppers from then.
How long is the growing season in Ottawa, OH?
The frost-free growing season in Ottawa is about 164 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 Ottawa (164 frost-free days, a moderate season), 31 of 56 planner crops fit outright, 24 get two plantings, 1 crop is perennial.
What USDA hardiness zone is Ottawa, OH?
Ottawa, OH 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 Ottawa, OH?
Start tomatoes indoors Mar 26 and plant out May 14 in Ottawa. The planner uses the local median last frost and this crop's indoor-start and transplant offsets.
How many plantings of lettuce fit in Ottawa?
Two: plant Apr 2 and again by Aug 20; both mature before Oct 18.
When do I plant garlic in Ottawa?
Oct 11 to Nov 1; it overwinters and is ready the following summer.
Which nearby ZIP has a longer season?
Delphos (ZIP 45833) has 171 frost-free days, 7 more than Ottawa (ZIP 45875). See Delphos ZIP 45833 frost dates
Nearby and related
- Frost dates for Delphos, OH 45833 (20 mi)
- Frost dates for Lima, OH 45805 (20.9 mi)
- Frost dates for Findlay, OH 45840 (21.4 mi)
- Frost dates for Defiance, OH 43512 (24.8 mi)
- Frost dates for Napoleon, OH 43545 (25.7 mi)
- When to plant in OH
- When to plant Peppers in OH
- When to plant Cucumbers in OH
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- When to plant Basil in OH
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- Look up another ZIP