Frost Dates for Marshalltown, IA 50158
Last spring frost April 29 · First fall frost October 3 · 157 frost-free days · USDA Zone 5a
ZIP 50158 has about 31,400 people.
Moderate season: 157 frost-free days. Spring frost risk spans April 15–May 12 (27 days). Fall frost risk spans September 20–October 16 (26 days).
Frost probability for 50158
| Frost | 10% | 50% | 90% |
|---|---|---|---|
| Spring (last frost) | May 12 | April 29 | April 15 |
| Fall (first frost) | September 20 | October 3 | October 16 |
Dates come from NOAA 1971–2000 freeze probabilities at TOLEDO 3N (26.5 km away); the 50% date is the median year.
Which crops fit a 157-day season in Marshalltown
In Marshalltown (157 frost-free days, a moderate season), 32 of 56 planner crops fit outright, 23 get two plantings, 1 crop is perennial.
| Crop | Start indoors | Plant out / sow | Days you have | Verdict | Last sow date |
|---|---|---|---|---|---|
| Tomato | Mar 25 | May 13–May 20 | 115 | fits: 80 days to maturity, 115 available after May 13. | Jun 3 |
| Pepper | Mar 18 | May 13–May 20 | 115 | fits: 75 days to maturity, 115 available after May 13. | Jun 8 |
| Lettuce | Mar 4 | Apr 1–Apr 8 | 192 | two-plantings: Plant Apr 1 and again by Aug 12; both mature before Oct 10. | Aug 12 |
| Carrots | — | Apr 8–Apr 15 | 199 | fits: 70 days to maturity, 199 available after Apr 8. | Aug 1 |
| Cucumber | Apr 8 | May 13–May 20 | 129 | fits: 60 days to maturity, 129 available after May 13. | Jul 7 |
| Beans | — | May 6–May 20 | 143 | two-plantings: Plant May 6 and again by Jul 14; both mature before Sep 26. | Jul 14 |
| Peas | — | Mar 4–May 13 | 220 | fits: 65 days to maturity, 220 available after Mar 4. | Jul 23 |
| Zucchini | Apr 15 | May 13–May 20 | 129 | two-plantings: Plant May 13 and again by Jul 12; both mature before Sep 19. | Jul 12 |
| Onion | Feb 4 | Apr 1–Apr 15 | 192 | fits: 100 days to maturity, 192 available after Apr 1. | — |
| Spinach | — | Mar 4–Apr 22 | 234 | two-plantings: Plant Mar 4 and again by Aug 31; both mature before Oct 24. | Aug 31 |
| Kale | Feb 18 | Apr 1–Apr 15 | 206 | two-plantings: Plant Apr 1 and again by Aug 16; both mature before Oct 24. | Aug 16 |
| Broccoli | Mar 4 | Apr 1–Apr 15 | 192 | fits: 80 days to maturity, 192 available after Apr 1. | Jul 8 |
| Cabbage | Mar 4 | Apr 1–Apr 15 | 206 | fits: 70 days to maturity, 206 available after Apr 1. | Aug 1 |
| Radish | — | Mar 4–May 27 | 220 | two-plantings: Plant Mar 4 and again by Sep 1; both mature before Oct 10. | Sep 1 |
| Beets | — | Mar 4–May 27 | 220 | two-plantings: Plant Mar 4 and again by Aug 2; both mature before Oct 10. | Aug 2 |
| Potatoes | — | Apr 15–Apr 22 | 178 | fits: 90 days to maturity, 178 available after Apr 15. | — |
| Garlic | — | Oct 3 | 262 | overwinter: Plant Oct 3 to Oct 24; harvest the following summer. | Oct 24 |
| Strawberry | — | Mar 25–May 20 | 213 | perennial: A perennial: plant Mar 25; it fruits from the following year and keeps producing for several years. | — |
| Corn | Apr 1 | May 6–May 13 | 129 | fits: 75 days to maturity, 129 available after May 6. | Jun 15 |
| Pumpkin | Apr 15 | May 13–May 13 | 122 | fits: 100 days to maturity, 122 available after May 13. | May 21 |
| Cauliflower | Mar 18 | Apr 22–May 6 | 171 | fits: 75 days to maturity, 171 available after Apr 22. | Jul 13 |
| Swiss Chard | Mar 4 | Apr 15–Apr 15 | 178 | two-plantings: Plant Apr 15 and again by Aug 2; both mature before Oct 10. | Aug 2 |
| Arugula | — | Mar 4–May 27 | 234 | two-plantings: Plant Mar 4 and again by Aug 31; both mature before Oct 24. | Aug 31 |
| Brussel Sprouts | Mar 4 | Apr 1–Apr 15 | 206 | fits: 100 days to maturity, 206 available after Apr 1. | Jul 2 |
| Butternut Squash | Apr 15 | May 13–May 20 | 122 | fits: 100 days to maturity, 122 available after May 13. | May 21 |
| Eggplant | Mar 11 | May 13–May 20 | 115 | fits: 70 days to maturity, 115 available after May 13. | Jun 13 |
| Okra | Apr 1 | May 6–May 13 | 136 | two-plantings: Plant May 6 and again by Jul 12; both mature before Sep 19. | Jul 12 |
| Basil | Mar 25 | May 20–May 20 | 122 | fits: 60 days to maturity, 122 available after May 20. | Jul 7 |
| Cilantro | — | Apr 1–Apr 22 | 192 | two-plantings: Plant Apr 1 and again by Aug 7; both mature before Oct 10. | Aug 7 |
| Parsley | Feb 18 | May 6–May 13 | 157 | fits: 70 days to maturity, 157 available after May 6. | Jul 18 |
| Celery | Feb 18 | May 6–May 20 | 157 | fits: 120 days to maturity, 157 available after May 6. | May 29 |
| Scallions | Feb 18 | Apr 1–Apr 15 | 206 | two-plantings: Plant Apr 1 and again by Aug 11; both mature before Oct 24. | Aug 11 |
| Turnip | — | Apr 1–Apr 15 | 206 | two-plantings: Plant Apr 1 and again by Aug 21; both mature before Oct 24. | Aug 21 |
| Kohlrabi | — | Mar 18–Apr 1 | 220 | two-plantings: Plant Mar 18 and again by Aug 16; both mature before Oct 24. | Aug 16 |
| Bok Choy | Apr 1 | Apr 22–Apr 29 | 171 | two-plantings: Plant Apr 22 and again by Aug 12; both mature before Oct 10. | Aug 12 |
| Collards | Feb 18 | Apr 1–Apr 15 | 206 | two-plantings: Plant Apr 1 and again by Aug 11; both mature before Oct 24. | Aug 11 |
| Cantaloupe | Apr 15 | May 13–May 20 | 115 | fits: 85 days to maturity, 115 available after May 13. | May 29 |
| Chives | Feb 4 | May 6–May 13 | 171 | fits: 90 days to maturity, 171 available after May 6. | — |
| Dill | — | Mar 4–May 27 | 220 | two-plantings: Plant Mar 4 and again by Aug 2; both mature before Oct 10. | Aug 2 |
| Oregano | Feb 18 | May 6–May 13 | 171 | fits: 80 days to maturity, 171 available after May 6. | — |
| Rosemary | Feb 4 | May 6–May 13 | 157 | fits: 80 days to maturity, 157 available after May 6. | — |
| Sage | Mar 4 | May 6–May 13 | 171 | fits: 75 days to maturity, 171 available after May 6. | — |
| Thyme | Feb 18 | May 6–May 13 | 171 | fits: 90 days to maturity, 171 available after May 6. | — |
| Calendula | Mar 18 | Apr 15–Apr 29 | 178 | two-plantings: Plant Apr 15 and again by Aug 7; both mature before Oct 10. | Aug 7 |
| Cosmos | Apr 1 | Apr 29–May 13 | 143 | two-plantings: Plant Apr 29 and again by Jul 7; both mature before Sep 19. | Jul 7 |
| Lavender | Feb 4 | Apr 29–May 13 | 178 | fits: 90 days to maturity, 178 available after Apr 29. | — |
| Marigolds | Mar 18 | Apr 29–May 6 | 143 | two-plantings: Plant Apr 29 and again by Jul 17; both mature before Sep 19. | Jul 17 |
| Melons | Apr 15 | May 13–May 20 | 115 | fits: 85 days to maturity, 115 available after May 13. | May 29 |
| Mint | — | Apr 29–May 13 | 178 | fits: 90 days to maturity, 178 available after Apr 29. | — |
| Nasturtiums | Apr 1 | Apr 29–May 6 | 143 | two-plantings: Plant Apr 29 and again by Jul 12; both mature before Sep 19. | Jul 12 |
| Pole Beans | — | May 6–May 20 | 136 | fits: 65 days to maturity, 136 available after May 6. | Jul 2 |
| Spaghetti Squash | Apr 15 | May 13–May 20 | 122 | fits: 90 days to maturity, 122 available after May 13. | May 31 |
| Sunflowers | — | Apr 29–May 13 | 143 | fits: 70 days to maturity, 143 available after Apr 29. | Jun 27 |
| Tomatillos | Mar 4 | May 6–May 13 | 122 | fits: 75 days to maturity, 122 available after May 6. | Jun 8 |
| Watermelon | Apr 15 | May 6–May 13 | 122 | fits: 80 days to maturity, 122 available after May 6. | Jun 3 |
| Yellow Squash | Apr 15 | May 13–May 20 | 129 | two-plantings: Plant May 13 and again by Jul 12; both mature before Sep 19. | Jul 12 |
| Zinnias | Apr 1 | Apr 29–May 13 | 143 | two-plantings: Plant Apr 29 and again by Jul 7; both mature before Sep 19. | Jul 7 |
Month by month in Marshalltown
| Month | What to do |
|---|---|
| January | Plan your garden layout and order seeds. Research varieties suited to your frost dates. |
| February | Start indoors: Chives (Feb 4), Lavender (Feb 4), Onion (Feb 4), Rosemary (Feb 4), Celery (Feb 18), Collards (Feb 18), +5 more. |
| March | Start indoors: Broccoli (Mar 4), Brussel Sprouts (Mar 4), Cabbage (Mar 4), Lettuce (Mar 4), Sage (Mar 4), Swiss Chard (Mar 4), +8 more. Direct sow from: Arugula (Mar 4), Beets (Mar 4), Dill (Mar 4), Peas (Mar 4), Radish (Mar 4), Spinach (Mar 4), +1 more. Plant: Strawberry (Mar 25). |
| April | Start indoors: Bok Choy (Apr 1), Corn (Apr 1), Cosmos (Apr 1), Nasturtiums (Apr 1), Okra (Apr 1), Zinnias (Apr 1), +9 more. Direct sow from: Cilantro (Apr 1), Turnip (Apr 1), Carrots (Apr 8), Potatoes (Apr 15), Sunflowers (Apr 29). Transplant from: Broccoli (Apr 1), Brussel Sprouts (Apr 1), Cabbage (Apr 1), Collards (Apr 1), Kale (Apr 1), Lettuce (Apr 1), +12 more. Last frost around April 29. |
| May | Direct sow from: Beans (May 6), Pole Beans (May 6). Transplant from: Celery (May 6), Chives (May 6), Corn (May 6), Okra (May 6), Oregano (May 6), Parsley (May 6), +17 more. Last sowing dates: Butternut Squash (May 21), Pumpkin (May 21), Cantaloupe (May 29), Celery (May 29), Melons (May 29), Spaghetti Squash (May 31). |
| June | Last sowing dates: Tomato (Jun 3), Watermelon (Jun 3), Pepper (Jun 8), Tomatillos (Jun 8), Eggplant (Jun 13), Corn (Jun 15), +1 more. |
| July | Last sowing dates: Brussel Sprouts (Jul 2), Pole Beans (Jul 2), Basil (Jul 7), Cosmos (Jul 7), Cucumber (Jul 7), Zinnias (Jul 7), +10 more. |
| August | Last sowing dates: Cabbage (Aug 1), Carrots (Aug 1), Beets (Aug 2), Dill (Aug 2), Swiss Chard (Aug 2), Calendula (Aug 7), +10 more. |
| September | Last sowing dates: Radish (Sep 1). |
| October | Direct sow from: Garlic (Oct 3). First frost around October 3. Last sowing dates: Garlic (Oct 24). |
| 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 Marshalltown, IA (ZIP 50158)?
The median last spring frost date for Marshalltown, IA (ZIP code 50158) is around April 29. 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 15; one in ten it runs past May 12.
What is the first fall frost date in Marshalltown, IA?
The median first fall frost date for Marshalltown, IA is around October 3. 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 20 in the earliest one-in-ten years, so cover tomatoes and peppers from then.
How long is the growing season in Marshalltown, IA?
The frost-free growing season in Marshalltown is about 157 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 Marshalltown (157 frost-free days, a moderate season), 32 of 56 planner crops fit outright, 23 get two plantings, 1 crop is perennial.
What USDA hardiness zone is Marshalltown, IA?
Marshalltown, IA is in USDA hardiness zone 5a (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 Marshalltown, IA?
Start tomatoes indoors Mar 25 and plant out May 13 in Marshalltown. The planner uses the local median last frost and this crop's indoor-start and transplant offsets.
How many plantings of lettuce fit in Marshalltown?
Two: plant Apr 1 and again by Aug 12; both mature before Oct 10.
When do I plant garlic in Marshalltown?
Oct 3 to Oct 24; it overwinters and is ready the following summer.
Which nearby ZIP has a longer season?
Bondurant (ZIP 50035) has 164 frost-free days, 7 more than Marshalltown (ZIP 50158). See Bondurant ZIP 50035 frost dates
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