Zone 6a planting schedule
Zone 6a covers places where the coldest night of an average winter falls between -10 to -5 °F. Here is what that means for frost dates and planting, month by month.
- Average winter low
- -10 to -5 °F
- Typical first frost
- Oct 20
- Last frost, most towns
- Apr 19 to May 1
- Frost-free season
- about 178 days
Middle values among the 393 towns of 10,000 people or more in zone 6a (our calculation, NOAA 1991-2020).
Where zone 6a is
Zone 6a towns are most common in Illinois, Indiana, Michigan, Ohio, Colorado, Wisconsin, Massachusetts and New York. Its biggest cities include Chicago, IL; Denver, CO; Milwaukee, WI; Colorado Springs, CO; Aurora, CO. Because a zone is set only by winter cold, towns in it can have quite different springs: the middle half of them have their last frost between Apr 19 and May 1. Use your own town's dates when you can.
| City | Last frost | First frost | Season |
|---|---|---|---|
| Chicago, IL | Apr 11 | Oct 31 | 201 d |
| Denver, CO | May 4 | Oct 8 | 156 d |
| Milwaukee, WI | Apr 19 | Oct 29 | 192 d |
| Colorado Springs, CO | May 3 | Oct 8 | 158 d |
| Aurora, CO | May 4 | Oct 8 | 156 d |
| Fort Wayne, IN | Apr 24 | Oct 21 | 178 d |
| Grand Rapids, MI | Apr 29 | Oct 20 | 174 d |
| Fort Collins, CO | May 2 | Oct 7 | 157 d |
| Lakewood, CO | May 3 | Oct 7 | 155 d |
| Springfield, MA | May 3 | Oct 8 | 158 d |
| Joliet, IL | Apr 19 | Oct 25 | 188 d |
| Thornton, CO | May 2 | Oct 11 | 160 d |
Zone 6a planting calendar, month by month
Counted from the zone's typical frost dates. March is the busiest month for planting outside, with 29 crops going in. Each crop name links to its own page with the dates for your exact town.
| Month | Start indoors | Plant or sow outside | First harvest |
|---|---|---|---|
| January | Onions, Leeks, Celery, Parsley | ||
| February | Marigolds, Herbs, Tomatoes, Peppers, Broccoli, Kale, Cabbage, Cauliflower, Brussels Sprouts, Eggplant | Roses, Fruit Trees, Apple Trees, Cherry Trees | |
| March | Zinnias, Lettuce, Cucumbers, Zucchini (Summer Squash), Winter Squash, Pumpkins, Watermelon, Cantaloupe, Swiss Chard, Okra, Basil | Strawberries, Wildflowers, Blueberries, Raspberries, Asparagus, Rhubarb, Lilies, Hostas, Herbs, Trees, Hydrangeas, Potatoes, Onions, Peas, Broccoli, Lettuce, Carrots, Radishes, Beets, Spinach, Kale, Cabbage, Cauliflower, Brussels Sprouts, Collard Greens, Swiss Chard, Bok Choy, Turnips, Leeks | Radishes |
| April | Sunflowers, Dahlias, Gladiolus, Summer Bulbs, Zinnias, Marigolds, Tomatoes, Peppers, Cucumbers, Zucchini (Summer Squash), Winter Squash, Cantaloupe, Sweet Corn, Green Beans, Cauliflower, Swiss Chard, Celery, Basil, Dill, Parsley | Spinach, Collard Greens, Turnips | |
| May | Winter Squash, Pumpkins, Watermelon, Cantaloupe, Eggplant, Okra, Sweet Potatoes | Potatoes, Peas, Broccoli, Lettuce, Carrots, Beets, Kale, Cabbage, Cauliflower, Bok Choy, Basil | |
| June | Tomatoes, Peppers, Onions, Cucumbers, Zucchini (Summer Squash), Sweet Corn, Green Beans, Brussels Sprouts, Swiss Chard, Leeks, Eggplant, Okra | ||
| July | Irises, Broccoli, Lettuce, Cucumbers, Zucchini (Summer Squash), Green Beans, Carrots, Radishes, Kale, Cabbage, Cauliflower, Brussels Sprouts, Collard Greens, Bok Choy | Winter Squash, Pumpkins, Watermelon, Cantaloupe, Sweet Potatoes | |
| August | Strawberries, Wildflowers, Hostas, Herbs, Trees, Hydrangeas, Peas, Beets, Spinach, Swiss Chard, Arugula, Turnips | ||
| September | Daffodils, Tulips, Blueberries, Lilies, Peonies, Hyacinths, Crocus, Ornamental Alliums, Garlic, Shallots | ||
| October | Rhubarb, Fruit Trees, Apple Trees, Crape Myrtles | ||
| November | |||
| December |
Fall plantings are listed with the month they go in. Ranges for each crop are on its page.
What grows well in zone 6a
A season of about 178 days fits nearly every garden crop. Cool-season crops get a spring and a fall planting; warm-season crops such as tomatoes, peppers, squash and beans have a long, steady summer.
Zone and frost dates: our own calculation from NOAA NCEI records (Global Summary of the Year, U.S. Climate Normals 1991-2020); not the official USDA Plant Hardiness Zone Map. Crop timing: university extension guides, listed on each crop page.