Mount Prospect, Illinois planting calendar and frost dates
Mount Prospect is in USDA hardiness zone 6a. The last spring frost typically comes around April 16 and the first fall frost around October 28, giving about 193 frost-free days a year.
- Hardiness zone
- Zone 6a
- Typical last frost
- April 16
- Typical first frost
- October 28
- Frost-free season
- 193 days
Frost dates in Mount Prospect
Last spring frost
- April 3Risky: frost later than this in 9 years out of 10
- April 16Typical: a later frost in half of years
- May 1Safe: a later frost only 1 year in 10
First fall frost
- October 15Risky: frost earlier than this 1 year in 10
- October 28Typical: an earlier frost in half of years
- November 11Late: frost before this in 9 years out of 10
The growing season between the typical last and first frosts is about 193 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 5 and returns around November 7.
NOAA U.S. Climate Normals 1991-2020 for Chicago Ohare International Airport, 4.9 miles S of the city center. Low-lying and rural spots often frost later in spring and earlier in fall than airports and city centers. Mount Prospect shares this station with Des Plaines, so the two cities have the same frost dates and planting calendar.
What to plant each month in Mount Prospect
January
Start indoors: broccoli, cauliflower, collard greens, kale, leeks, onions, petunias, ranunculus
February
Start indoors: black-eyed susans, broccoli, cabbages, cauliflower, chives, collard greens, ginger, kale, leeks, lettuce, marigolds, onions, oregano, parsley, peppers, petunias, ranunculus, rosemary, sage, snapdragons
March
Start indoors: basil, black-eyed susans, cabbages, celery, chives, cilantro, collard greens, eggplants, ginger, lettuce, marigolds, nasturtiums, peppers, ranunculus, sage, snapdragons, spinach, swiss chard, tomatoes
Plant or sow outdoors: beets, black-eyed susans, blackberries, blueberries, broccoli, cabbages, carrots, cauliflower, chives, cilantro, collard greens, figs, garlic, gladioli, grapes, grass seed, hollyhocks, kale, leeks, lettuce, onions, parsley, 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, dahlias, dill, figs, garden mums, ginger, 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, cucumbers, okra, pumpkins, winter squash, zinnias, zucchini
Plant or sow outdoors: asparagus, basil, bermudagrass, cantaloupes, celery, centipedegrass, cosmos, cucumbers, eggplants, garden mums, ginger, green beans, green onions, kentucky bluegrass, okra, peanuts, peppers, perennial ryegrass, pumpkins, st. augustinegrass, sunflowers, sweet corn, sweet peas, sweet potatoes, tall fescue, tomatoes, watermelons, winter squash, zoysiagrass, 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, zoysiagrass
Plant for fall: brussels sprouts, collard greens, lettuce, swiss chard
August
Plant for fall: bearded irises, beets, broccoli, cabbages, carrots, cauliflower, collard greens, daylilies, kale, lettuce, peas, radishes, snapdragons, spinach, swiss chard, turnips
September
Plant for fall: azaleas, bearded irises, beets, broccoli, cabbages, cauliflower, clematis, coneflowers, crocuses, daffodils, daylilies, grass seed, hostas, hyacinths, hydrangeas, kale, kentucky bluegrass, lettuce, lilies, ornamental alliums, peonies, perennial ryegrass, radishes, roses, saffron, snapdragons, spinach, tall fescue, tulips, turnips
October
Plant for fall: crocuses, daffodils, daylilies, garlic, hyacinths, lilies, ornamental alliums, peonies, tulips
November
Plant for fall: crocuses, garlic, hyacinths, ornamental alliums, tulips
December
Start indoors: onions
Frost dates and zones by ZIP code in Mount Prospect
All 2 of Mount Prospect's main ZIP codes take their frost dates from Chicago Ohare International Airport, so the dates on this page apply across the city. Every one of them is in zone 6a.
| ZIP code | Zone | Weather station | Typical last frost | Typical first frost |
|---|---|---|---|---|
| 60005 | 6a | Chicago Ohare International Airport, 5.5 mi SSE | Apr 16 | Oct 28 |
| 60056 | 6a | Chicago Ohare International Airport, 4.9 mi S | Apr 16 | Oct 28 |
Chicago Ohare International Airport also supplies the frost dates for Schaumburg, Palatine, Des Plaines and Oak Park, so their planting calendars match Mount Prospect's.
Planting dates for popular crops in Mount Prospect
| Plant | Start indoors | Plant or sow outdoors | Fall planting |
|---|---|---|---|
| Tomatoes | Mar 20 to Apr 3 | May 15 to 29 | — |
| Strawberries | — | Mar 5 to 19 | — |
| Lettuce | Feb 19 to Mar 5 | Apr 9 to 23 | Jul 29 to Sep 2 |
| Cilantro | Mar 5 to 19 | Apr 16 to 23 | — |
| Basil | Mar 27 to Apr 10 | May 15 to 22 | — |
| Potatoes | — | Apr 17 to 24 | — |
| Garlic | — | Mar 5 to 19 | Oct 28 to Nov 11 |
| Onions | Dec 25 to Feb 5 | Mar 19 to Apr 2 | — |
| Cucumbers | Apr 17 to May 1 | May 15 to 29 | — |
| Pumpkins | Apr 17 to May 1 | May 15 to 29 | — |
| Peppers | Feb 27 to Mar 27 | May 15 to 29 | — |
| Carrots | — | Mar 26 to Apr 16 | Aug 5 to 26 |
| Sweet Potatoes | — | May 30 to Jun 6 | — |
| Watermelons | Apr 10 to 24 | May 15 to 29 | — |
| Sweet Corn | — | Apr 17 to May 1 | — |
| Green Beans | — | May 15 to 29 | — |
| Zucchini | Apr 17 to May 1 | May 15 to 29 | — |
| Broccoli | Jan 29 to Feb 19 | Mar 19 to Apr 2 | Aug 12 to Sep 9 |
| Peas | — | Mar 5 to 19 | Aug 5 to 19 |
| Spinach | Mar 5 to 12 | Apr 9 to 23 | Aug 19 to Sep 23 |
| Sunflowers | — | Apr 17 to May 8 | — |
| Zinnias | May 16 to 23 | Jun 13 to 27 | — |
| Tulips | — | — | Sep 16 to Nov 11 |
| Daffodils | — | — | Sep 16 to Oct 28 |
| Grass Seed | — | Mar 5 to 19 | Sep 16 to 30 |
Nearby cities
- Des Plaines, IL zone 6a, last frost Apr 16
- Arlington Heights, IL zone 6a, last frost Apr 19
- Palatine, IL zone 5b, last frost Apr 16
- Schaumburg, IL zone 5b, last frost Apr 16
- Skokie, IL zone 6a, last frost Apr 26
- Hoffman Estates, IL zone 5b, last frost Apr 26
Planting in IllinoisAbout zone 6aPrintable calendar for Mount Prospect
Questions
When is the last frost in Mount Prospect?
Around April 16 in a typical year, based on NOAA's 1991-2020 records for Chicago Ohare International Airport. There is still a 1 in 10 chance of frost after May 1.
What planting zone is Mount Prospect in?
USDA hardiness zone 6a (2023 map). The zone tells you which perennials survive the winter; planting dates depend on frost dates instead.
When should I plant tomatoes in Mount Prospect?
Start seeds indoors March 20 to April 3 and set plants out May 15 to 29.
When is the first frost in Mount Prospect?
Around October 28 in a typical year, and before October 15 about 1 year in 10.