USDA Zone 5a Planting Calendar (2026)
Zone 5a (-20 to -15°F) has an average last spring frost on Apr 30 and first fall frost on Oct 5 — about 158 growing days. Typical areas: Chicago IL, Des Moines IA.
How to use the zone 5a planting calendar
Every planting date on this page is calculated from zone 5a's average frost dates. Because your last spring frost lands around Apr 30 and your first fall frost around Oct 5, you have roughly 158 frost-free days to work with — a moderate growing season. The table below lists, for each of 20 common vegetables, when to start seeds indoors, when to sow or transplant outdoors, and when you can expect your first harvest.
Frost dates are averages, not guarantees. In a cold year the last frost can arrive 1-2 weeks later, so keep row covers handy for tender seedlings in Apr. Click any vegetable name to open a detailed zone 5a guide with spacing, companions, container tips and troubleshooting.
Cool-season crops for zone 5a
These tolerate light frost and go out first, 2-4 weeks before your Apr 30 last frost, and again in late summer for a fall crop: lettuce, carrot, broccoli, spinach, kale, onion, garlic, potato, peas, radish, beet, cabbage, cauliflower.
Warm-season crops for zone 5a
These need warm soil and frost-free weather, so plant them after Apr 30: tomato, pepper, cucumber, corn, bush beans, summer squash, zucchini. In a moderate season, start the slowest ones indoors to be sure they ripen before Oct.
| Vegetable | Start Indoors | Sow / Transplant | Harvest From |
|---|---|---|---|
| Beet | — | Apr 2 | May 27 |
| 🥦 Broccoli | Mar 26 | Apr 16 | Jun 20 |
| 🫘 Bush Beans | — | May 7 | Jul 1 |
| 🥬 Cabbage | Mar 19 | Apr 16 | Jul 5 |
| 🥕 Carrot | — | Apr 9 | Jun 18 |
| 🥦 Cauliflower | Mar 19 | Apr 16 | Jun 30 |
| 🌽 Corn | — | May 14 | Aug 2 |
| 🥒 Cucumber | Apr 9 | May 14 | Jul 8 |
| 🧄 Garlic | — | Oct 15 | Jun 12 |
| 🥬 Kale | Mar 26 | Apr 9 | Jun 3 |
| 🥬 Lettuce | Apr 2 | Apr 9 | May 24 |
| 🧅 Onion | Feb 19 | Apr 2 | Jul 11 |
| 🟢 Peas | — | Mar 19 | May 18 |
| 🫑 Pepper | Mar 5 | May 14 | Jul 23 |
| 🥔 Potato | — | Apr 16 | Jul 15 |
| 🌶️ Radish | — | Apr 2 | Apr 30 |
| 🍃 Spinach | — | Mar 26 | May 5 |
| 🎃 Summer Squash | Apr 9 | May 7 | Jun 26 |
| 🍅 Tomato | Mar 19 | May 7 | Jul 21 |
| 🥒 Zucchini | Apr 9 | May 7 | Jun 26 |
Spring, summer and fall planting in zone 5a
Spring (Apr): As soon as the soil can be worked, direct sow hardy cool-season crops and set out frost-tolerant transplants. This is your window for peas, lettuce, spinach and the brassicas before summer heat arrives.
Early summer (after Apr 30): Once frost danger passes and soil warms past 60°F, transplant tomatoes, peppers and squash and direct sow beans and cucumbers. This is the heart of the zone 5a growing season.
Late summer to fall (before Oct 5):Sow a second round of quick cool-season crops for a fall harvest. Count back each crop's days-to-harvest from Oct 5 to find the latest safe sowing date, and use row covers to stretch the season a few extra weeks.
Zone 5a planting FAQ
What planting zone is Chicago IL?
Areas like Chicago IL, Des Moines IA fall in USDA hardiness zone 5a, defined by an average annual minimum temperature of -20 to -15°F. Your average last spring frost is around Apr 30 and your first fall frost around Oct 5.
When is the last frost in zone 5a?
The average last spring frost in zone 5a is around Apr 30. Wait until after this date before transplanting warm-season crops like tomatoes, peppers and squash. Cool-season crops can go out 2-4 weeks earlier because they tolerate light frost.
How long is the growing season in zone 5a?
Zone 5a has roughly 158 frost-free days between the last spring frost (Apr 30) and first fall frost (Oct 5). That is a moderate season — enough time for most vegetables plus some succession planting.
What vegetables grow best in zone 5a?
Reliable choices for zone 5a include cool-season crops such as lettuce, carrot, broccoli, spinach planted in early spring, and warm-season crops such as tomato, pepper, cucumber, corn planted after the last frost. See the full table below for exact dates.
Can I grow a fall garden in zone 5a?
Yes. With a first frost around Oct 5, you can plant a second round of quick cool-season crops in mid to late summer. Count back the days-to-harvest from Oct 5 to find your fall planting date.
When should I start seeds indoors in zone 5a?
Most warm-season seedlings are started indoors 6-8 weeks before the last frost — that means roughly Apr for zone 5a. Tomatoes, peppers and eggplant benefit most from an indoor head start in this zone.