Frost Dates for Oskaloosa, IA 52577
Last spring frost April 21 · First fall frost October 9 · 171 frost-free days · USDA Zone 5b
ZIP 52577 has about 14,600 people.
Moderate season: 171 frost-free days. Spring frost risk spans April 9–May 2 (23 days). Fall frost risk spans September 24–October 26 (32 days).
Frost probability for 52577
| Frost | 10% | 50% | 90% |
|---|---|---|---|
| Spring (last frost) | May 2 | April 21 | April 9 |
| Fall (first frost) | September 24 | October 9 | October 26 |
Dates come from NOAA 1971–2000 freeze probabilities at ALBIA 3 NNE (25.3 km away); the 50% date is the median year.
Which crops fit a 171-day season in Oskaloosa
In Oskaloosa (171 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 17 | May 5–May 12 | 129 | fits: 80 days to maturity, 129 available after May 5. | Jun 9 |
| Pepper | Mar 10 | May 5–May 12 | 129 | fits: 75 days to maturity, 129 available after May 5. | Jun 14 |
| Lettuce | Feb 24 | Mar 24–Mar 31 | 206 | two-plantings: Plant Mar 24 and again by Aug 18; both mature before Oct 16. | Aug 18 |
| Carrots | — | Mar 31–Apr 7 | 213 | fits: 70 days to maturity, 213 available after Mar 31. | Aug 7 |
| Cucumber | Mar 31 | May 5–May 12 | 143 | two-plantings: Plant May 5 and again by Jul 13; both mature before Sep 25. | Jul 13 |
| Beans | — | Apr 28–May 12 | 157 | two-plantings: Plant Apr 28 and again by Jul 20; both mature before Oct 2. | Jul 20 |
| Peas | — | Feb 24–May 5 | 234 | fits: 65 days to maturity, 234 available after Feb 24. | Jul 29 |
| Zucchini | Apr 7 | May 5–May 12 | 143 | two-plantings: Plant May 5 and again by Jul 18; both mature before Sep 25. | Jul 18 |
| Onion | Jan 27 | Mar 24–Apr 7 | 206 | fits: 100 days to maturity, 206 available after Mar 24. | — |
| Spinach | — | Feb 24–Apr 14 | 248 | two-plantings: Plant Feb 24 and again by Sep 6; both mature before Oct 30. | Sep 6 |
| Kale | Feb 10 | Mar 24–Apr 7 | 220 | two-plantings: Plant Mar 24 and again by Aug 22; both mature before Oct 30. | Aug 22 |
| Broccoli | Feb 24 | Mar 24–Apr 7 | 206 | fits: 80 days to maturity, 206 available after Mar 24. | Jul 14 |
| Cabbage | Feb 24 | Mar 24–Apr 7 | 220 | fits: 70 days to maturity, 220 available after Mar 24. | Aug 7 |
| Radish | — | Feb 24–May 19 | 234 | two-plantings: Plant Feb 24 and again by Sep 7; both mature before Oct 16. | Sep 7 |
| Beets | — | Feb 24–May 19 | 234 | two-plantings: Plant Feb 24 and again by Aug 8; both mature before Oct 16. | Aug 8 |
| Potatoes | — | Apr 7–Apr 14 | 192 | fits: 90 days to maturity, 192 available after Apr 7. | — |
| Garlic | — | Oct 9 | 276 | overwinter: Plant Oct 9 to Oct 30; harvest the following summer. | Oct 30 |
| Strawberry | — | Mar 17–May 12 | 227 | perennial: A perennial: plant Mar 17; it fruits from the following year and keeps producing for several years. | — |
| Corn | Mar 24 | Apr 28–May 5 | 143 | fits: 75 days to maturity, 143 available after Apr 28. | Jun 21 |
| Pumpkin | Apr 7 | May 5–May 5 | 136 | fits: 100 days to maturity, 136 available after May 5. | May 27 |
| Cauliflower | Mar 10 | Apr 14–Apr 28 | 185 | fits: 75 days to maturity, 185 available after Apr 14. | Jul 19 |
| Swiss Chard | Feb 24 | Apr 7–Apr 7 | 192 | two-plantings: Plant Apr 7 and again by Aug 8; both mature before Oct 16. | Aug 8 |
| Arugula | — | Feb 24–May 19 | 248 | two-plantings: Plant Feb 24 and again by Sep 6; both mature before Oct 30. | Sep 6 |
| Brussel Sprouts | Feb 24 | Mar 24–Apr 7 | 220 | fits: 100 days to maturity, 220 available after Mar 24. | Jul 8 |
| Butternut Squash | Apr 7 | May 5–May 12 | 136 | fits: 100 days to maturity, 136 available after May 5. | May 27 |
| Eggplant | Mar 3 | May 5–May 12 | 129 | fits: 70 days to maturity, 129 available after May 5. | Jun 19 |
| Okra | Mar 24 | Apr 28–May 5 | 150 | two-plantings: Plant Apr 28 and again by Jul 18; both mature before Sep 25. | Jul 18 |
| Basil | Mar 17 | May 12–May 12 | 136 | two-plantings: Plant May 12 and again by Jul 13; both mature before Sep 25. | Jul 13 |
| Cilantro | — | Mar 24–Apr 14 | 206 | two-plantings: Plant Mar 24 and again by Aug 13; both mature before Oct 16. | Aug 13 |
| Parsley | Feb 10 | Apr 28–May 5 | 171 | fits: 70 days to maturity, 171 available after Apr 28. | Jul 24 |
| Celery | Feb 10 | Apr 28–May 12 | 171 | fits: 120 days to maturity, 171 available after Apr 28. | Jun 4 |
| Scallions | Feb 10 | Mar 24–Apr 7 | 220 | two-plantings: Plant Mar 24 and again by Aug 17; both mature before Oct 30. | Aug 17 |
| Turnip | — | Mar 24–Apr 7 | 220 | two-plantings: Plant Mar 24 and again by Aug 27; both mature before Oct 30. | Aug 27 |
| Kohlrabi | — | Mar 10–Mar 24 | 234 | two-plantings: Plant Mar 10 and again by Aug 22; both mature before Oct 30. | Aug 22 |
| Bok Choy | Mar 24 | Apr 14–Apr 21 | 185 | two-plantings: Plant Apr 14 and again by Aug 18; both mature before Oct 16. | Aug 18 |
| Collards | Feb 10 | Mar 24–Apr 7 | 220 | two-plantings: Plant Mar 24 and again by Aug 17; both mature before Oct 30. | Aug 17 |
| Cantaloupe | Apr 7 | May 5–May 12 | 129 | fits: 85 days to maturity, 129 available after May 5. | Jun 4 |
| Chives | Jan 27 | Apr 28–May 5 | 185 | fits: 90 days to maturity, 185 available after Apr 28. | — |
| Dill | — | Feb 24–May 19 | 234 | two-plantings: Plant Feb 24 and again by Aug 8; both mature before Oct 16. | Aug 8 |
| Oregano | Feb 10 | Apr 28–May 5 | 185 | fits: 80 days to maturity, 185 available after Apr 28. | — |
| Rosemary | Jan 27 | Apr 28–May 5 | 171 | fits: 80 days to maturity, 171 available after Apr 28. | — |
| Sage | Feb 24 | Apr 28–May 5 | 185 | fits: 75 days to maturity, 185 available after Apr 28. | — |
| Thyme | Feb 10 | Apr 28–May 5 | 185 | fits: 90 days to maturity, 185 available after Apr 28. | — |
| Calendula | Mar 10 | Apr 7–Apr 21 | 192 | two-plantings: Plant Apr 7 and again by Aug 13; both mature before Oct 16. | Aug 13 |
| Cosmos | Mar 24 | Apr 21–May 5 | 157 | two-plantings: Plant Apr 21 and again by Jul 13; both mature before Sep 25. | Jul 13 |
| Lavender | Jan 27 | Apr 21–May 5 | 192 | fits: 90 days to maturity, 192 available after Apr 21. | — |
| Marigolds | Mar 10 | Apr 21–Apr 28 | 157 | two-plantings: Plant Apr 21 and again by Jul 23; both mature before Sep 25. | Jul 23 |
| Melons | Apr 7 | May 5–May 12 | 129 | fits: 85 days to maturity, 129 available after May 5. | Jun 4 |
| Mint | — | Apr 21–May 5 | 192 | fits: 90 days to maturity, 192 available after Apr 21. | — |
| Nasturtiums | Mar 24 | Apr 21–Apr 28 | 157 | two-plantings: Plant Apr 21 and again by Jul 18; both mature before Sep 25. | Jul 18 |
| Pole Beans | — | Apr 28–May 12 | 150 | fits: 65 days to maturity, 150 available after Apr 28. | Jul 8 |
| Spaghetti Squash | Apr 7 | May 5–May 12 | 136 | fits: 90 days to maturity, 136 available after May 5. | Jun 6 |
| Sunflowers | — | Apr 21–May 5 | 157 | fits: 70 days to maturity, 157 available after Apr 21. | Jul 3 |
| Tomatillos | Feb 24 | Apr 28–May 5 | 136 | fits: 75 days to maturity, 136 available after Apr 28. | Jun 14 |
| Watermelon | Apr 7 | Apr 28–May 5 | 136 | fits: 80 days to maturity, 136 available after Apr 28. | Jun 9 |
| Yellow Squash | Apr 7 | May 5–May 12 | 143 | two-plantings: Plant May 5 and again by Jul 18; both mature before Sep 25. | Jul 18 |
| Zinnias | Mar 24 | Apr 21–May 5 | 157 | two-plantings: Plant Apr 21 and again by Jul 13; both mature before Sep 25. | Jul 13 |
Month by month in Oskaloosa
| Month | What to do |
|---|---|
| January | Start indoors: Chives (Jan 27), Lavender (Jan 27), Onion (Jan 27), Rosemary (Jan 27). |
| February | Start indoors: Celery (Feb 10), Collards (Feb 10), Kale (Feb 10), Oregano (Feb 10), Parsley (Feb 10), Scallions (Feb 10), +8 more. Direct sow from: Arugula (Feb 24), Beets (Feb 24), Dill (Feb 24), Peas (Feb 24), Radish (Feb 24), Spinach (Feb 24). |
| March | Start indoors: Eggplant (Mar 3), Calendula (Mar 10), Cauliflower (Mar 10), Marigolds (Mar 10), Pepper (Mar 10), Basil (Mar 17), +8 more. Direct sow from: Kohlrabi (Mar 10), Cilantro (Mar 24), Turnip (Mar 24), Carrots (Mar 31). Transplant from: Broccoli (Mar 24), Brussel Sprouts (Mar 24), Cabbage (Mar 24), Collards (Mar 24), Kale (Mar 24), Lettuce (Mar 24), +2 more. Plant: Strawberry (Mar 17). |
| April | Start indoors: Butternut Squash (Apr 7), Cantaloupe (Apr 7), Melons (Apr 7), Pumpkin (Apr 7), Spaghetti Squash (Apr 7), Watermelon (Apr 7), +2 more. Direct sow from: Potatoes (Apr 7), Sunflowers (Apr 21), Beans (Apr 28), Pole Beans (Apr 28). Transplant from: Calendula (Apr 7), Swiss Chard (Apr 7), Bok Choy (Apr 14), Cauliflower (Apr 14), Cosmos (Apr 21), Lavender (Apr 21), +15 more. Last frost around April 21. |
| May | Transplant from: Butternut Squash (May 5), Cantaloupe (May 5), Cucumber (May 5), Eggplant (May 5), Melons (May 5), Pepper (May 5), +6 more. Last sowing dates: Butternut Squash (May 27), Pumpkin (May 27). |
| June | Last sowing dates: Cantaloupe (Jun 4), Celery (Jun 4), Melons (Jun 4), Spaghetti Squash (Jun 6), Tomato (Jun 9), Watermelon (Jun 9), +4 more. |
| July | Last sowing dates: Sunflowers (Jul 3), Brussel Sprouts (Jul 8), Pole Beans (Jul 8), Basil (Jul 13), Cosmos (Jul 13), Cucumber (Jul 13), +11 more. |
| August | Last sowing dates: Cabbage (Aug 7), Carrots (Aug 7), Beets (Aug 8), Dill (Aug 8), Swiss Chard (Aug 8), Calendula (Aug 13), +8 more. |
| September | Last sowing dates: Arugula (Sep 6), Spinach (Sep 6), Radish (Sep 7). |
| October | Direct sow from: Garlic (Oct 9). First frost around October 9. Last sowing dates: Garlic (Oct 30). |
| November | Harvest remaining cold-hardy crops: kale, carrots, and beets. Plant garlic bulbs for next year. |
| 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 Oskaloosa, IA (ZIP 52577)?
The median last spring frost date for Oskaloosa, IA (ZIP code 52577) is around April 21. 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 9; one in ten it runs past May 2.
What is the first fall frost date in Oskaloosa, IA?
The median first fall frost date for Oskaloosa, IA is around October 9. 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 24 in the earliest one-in-ten years, so cover tomatoes and peppers from then.
How long is the growing season in Oskaloosa, IA?
The frost-free growing season in Oskaloosa is about 171 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 Oskaloosa (171 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 Oskaloosa, IA?
Oskaloosa, IA is in USDA hardiness zone 5b (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 Oskaloosa, IA?
Start tomatoes indoors Mar 17 and plant out May 5 in Oskaloosa. The planner uses the local median last frost and this crop's indoor-start and transplant offsets.
How many plantings of lettuce fit in Oskaloosa?
Two: plant Mar 24 and again by Aug 18; both mature before Oct 16.
When do I plant garlic in Oskaloosa?
Oct 9 to Oct 30; it overwinters and is ready the following summer.
Which nearby ZIP has a longer season?
Ottumwa (ZIP 52501) has 179 frost-free days, 8 more than Oskaloosa (ZIP 52577). See Ottumwa ZIP 52501 frost dates
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