Downers Grove, Illinois planting calendar and frost dates
Downers Grove is in USDA hardiness zone 6a. The last spring frost typically comes around April 27 and the first fall frost around October 17, giving about 173 frost-free days a year.
- Typical last frost
- April 27
- Typical first frost
- October 17
- Frost-free season
- 173 days
Frost dates in Downers Grove
Last spring frost
- April 12Risky: frost later than this in 9 years out of 10
- April 27Typical: a later frost in half of years
- May 14Safe: a later frost only 1 year in 10
First fall frost
- October 1Risky: frost earlier than this 1 year in 10
- October 17Typical: an earlier frost in half of years
- November 2Late: frost before this in 9 years out of 10
The growing season between the typical last and first frosts is about 173 days. Frost here means a low of 32°F at the weather station. A hard freeze (28°F), which damages most hardy crops too, typically ends around April 16 and returns around October 29.
NOAA U.S. Climate Normals 1991-2020 for Wheaton 3 Se, 2.5 miles W of the city center. Low-lying and rural spots often frost later in spring and earlier in fall than airports and city centers.
What to plant each month in Downers Grove
January
Start indoors: onions
February
Start indoors: broccoli, cabbages, cauliflower, collard greens, kale, leeks, onions, oregano, parsley, peppers, petunias, ranunculus, rosemary, snapdragons
March
Start indoors: basil, black-eyed susans, broccoli, cabbages, cauliflower, celery, chives, cilantro, collard greens, eggplants, ginger, leeks, lettuce, marigolds, nasturtiums, oregano, parsley, peppers, petunias, ranunculus, rosemary, sage, snapdragons, spinach, swiss chard, tomatoes
Plant or sow outdoors: beets, black-eyed susans, blackberries, blueberries, broccoli, cauliflower, chives, cilantro, collard greens, figs, garlic, gladioli, grapes, grass seed, hollyhocks, kale, leeks, onions, peas, poppies, radishes, ranunculus, raspberries, rhubarb, roses, spinach, strawberries, swiss chard, turnips, wildflowers
April
Start indoors: basil, cantaloupes, cosmos, cucumbers, okra, pumpkins, ranunculus, tomatoes, watermelons, winter squash, zucchini
Plant or sow outdoors: asparagus, beets, black-eyed susans, blackberries, broccoli, cabbages, carrots, cauliflower, chives, cilantro, collard greens, dahlias, dill, figs, garden mums, gladioli, grapes, green onions, kentucky bluegrass, lavenders, leeks, lettuce, lilies, marigolds, mints, nasturtiums, onions, oregano, parsley, perennial ryegrass, petunias, potatoes, radishes, ranunculus, rosemary, roses, sage, snapdragons, spinach, sunflowers, sweet corn, sweet peas, swiss chard, tall fescue, thyme, turnips
May
Start indoors: cosmos, okra, zinnias
Plant or sow outdoors: asparagus, basil, cantaloupes, celery, chives, cilantro, cosmos, cucumbers, dahlias, dill, eggplants, garden mums, ginger, gladioli, grapes, green beans, green onions, kentucky bluegrass, lavenders, lettuce, lilies, marigolds, mints, nasturtiums, okra, oregano, parsley, peanuts, peppers, perennial ryegrass, petunias, pumpkins, ranunculus, rosemary, sage, spinach, sunflowers, sweet corn, sweet peas, sweet potatoes, swiss chard, tall fescue, thyme, tomatoes, watermelons, winter squash, zucchini
June
Plant or sow outdoors: bermudagrass, celery, centipedegrass, cosmos, green onions, okra, peanuts, st. augustinegrass, sweet potatoes, zinnias, zoysiagrass
July
Plant or sow outdoors: bermudagrass, centipedegrass, st. augustinegrass, zoysiagrass
Plant for fall: bearded irises, brussels sprouts, carrots, collard greens, lettuce, peas, snapdragons, swiss chard
August
Plant for fall: azaleas, bearded irises, beets, broccoli, cabbages, carrots, cauliflower, clematis, collard greens, coneflowers, daylilies, hostas, hydrangeas, kale, lettuce, peas, radishes, roses, saffron, snapdragons, spinach, swiss chard, turnips
September
Plant for fall: azaleas, bearded irises, cabbages, cauliflower, clematis, coneflowers, crocuses, daffodils, daylilies, grass seed, hostas, hyacinths, hydrangeas, kale, kentucky bluegrass, lilies, ornamental alliums, peonies, perennial ryegrass, radishes, roses, saffron, spinach, tall fescue, tulips
October
Plant for fall: crocuses, daffodils, garlic, hyacinths, lilies, ornamental alliums, peonies, tulips
Frost dates and zones by ZIP code in Downers Grove
All 2 of Downers Grove's main ZIP codes take their frost dates from Wheaton 3 Se, so the dates on this page apply across the city. The hardiness zone is 5b in 60516, and 6a in 60515.
| ZIP code | Zone | Weather station | Typical last frost | Typical first frost |
|---|---|---|---|---|
| 60515 | 6a | Wheaton 3 Se, 2.5 mi W | Apr 27 | Oct 17 |
| 60516 | 5b | Wheaton 3 Se, 4.7 mi NW | Apr 27 | Oct 17 |
Wheaton 3 Se also supplies the frost dates for Wheaton, so their planting calendars match Downers Grove's.
Planting dates for popular crops in Downers Grove
| Plant | Start indoors | Plant or sow outdoors | Fall planting |
|---|---|---|---|
| Tomatoes | Mar 18 to Apr 1 | May 13 to 27 | — |
| Strawberries | — | Mar 16 to 30 | — |
| Lettuce | Mar 2 to 16 | Apr 20 to May 4 | Jul 18 to Aug 22 |
| Cilantro | Mar 16 to 30 | Apr 27 to May 4 | — |
| Basil | Mar 25 to Apr 8 | May 13 to 20 | — |
| Potatoes | — | Apr 15 to 22 | — |
| Garlic | — | Mar 16 to 30 | Oct 17 to 31 |
| Onions | Jan 5 to Feb 16 | Mar 30 to Apr 13 | — |
| Cucumbers | Apr 15 to 29 | May 13 to 27 | — |
| Pumpkins | Apr 15 to 29 | May 13 to 27 | — |
| Peppers | Feb 25 to Mar 25 | May 13 to 27 | — |
| Carrots | — | Apr 6 to 27 | Jul 25 to Aug 15 |
| Sweet Potatoes | — | May 29 to Jun 5 | — |
| Watermelons | Apr 8 to 22 | May 13 to 27 | — |
| Sweet Corn | — | Apr 27 to May 11 | — |
| Green Beans | — | May 13 to 27 | — |
| Zucchini | Apr 15 to 29 | May 13 to 27 | — |
| Broccoli | Feb 9 to Mar 2 | Mar 30 to Apr 13 | Aug 1 to 29 |
| Peas | — | Mar 16 to 30 | Jul 25 to Aug 8 |
| Spinach | Mar 16 to 23 | Apr 20 to May 4 | Aug 8 to Sep 12 |
| Sunflowers | — | Apr 27 to May 18 | — |
| Zinnias | May 16 to 23 | Jun 13 to 27 | — |
| Tulips | — | — | Sep 5 to Oct 31 |
| Daffodils | — | — | Sep 5 to Oct 17 |
| Grass Seed | — | Mar 16 to 30 | Sep 5 to 19 |
Nearby cities
- Wheaton, IL zone 5b, last frost Apr 27
- Naperville, IL zone 5b, last frost Apr 19
- Bolingbrook, IL zone 6a, last frost Apr 19
- Berwyn, IL zone 6a, last frost Apr 11
- Oak Park, IL zone 6a, last frost Apr 16
- Cicero, IL zone 6a, last frost Apr 11
Planting in IllinoisAbout zone 6aPrintable calendar for Downers Grove
Questions
When is the last frost in Downers Grove?
Around April 27 in a typical year, based on NOAA's 1991-2020 records for Wheaton 3 Se. There is still a 1 in 10 chance of frost after May 14.
What planting zone is Downers Grove in?
USDA hardiness zone 6a (2023 map), with parts of the city in zone 5b. The zone tells you which perennials survive the winter; planting dates depend on frost dates instead.
When should I plant tomatoes in Downers Grove?
Start seeds indoors March 18 to April 1 and set plants out May 13 to 27; the safest date to plant out is after May 14.
When is the first frost in Downers Grove?
Around October 17 in a typical year, and before October 1 about 1 year in 10.