Frost Dates for Ionia, MI 48846
Last spring frost May 11 · First fall frost October 4 · 146 frost-free days · USDA Zone 6a
Frost probability for 48846
| Frost | 10% | 50% | 90% |
|---|---|---|---|
| Spring (last frost) | May 28 | May 11 | April 24 |
| Fall (first frost) | September 18 | October 4 | October 17 |
Dates come from NOAA 1971–2000 freeze probabilities at the nearest reporting station (42.6 km away); the 50% date is the median year.
Month by month in Ionia
| Month | What to do |
|---|---|
| January | Plan your garden layout and order seeds. Research varieties suited to your frost dates. |
| February | Start the slowest-growing crops indoors: onions, leeks, and celery (10–12 weeks before last frost). |
| March | Start peppers and eggplant indoors 8–10 weeks before your last frost (around May 11). Start tomatoes about two weeks later, 6–8 weeks before last frost. |
| April | Start herbs, basil, and squash indoors (4–6 weeks before frost). Direct sow peas, spinach, and lettuce if soil is workable. |
| May | Last frost around May 11. Transplant cold-hardy crops (broccoli, kale, cabbage). Harden off tomato and pepper seedlings. |
| June | Frost has passed. Transplant tomatoes, peppers, and basil outdoors. Direct sow beans, cucumbers, squash, and zucchini. |
| July | Succession plant lettuce and greens. Keep beds weeded and watered consistently. |
| August | Harvest regularly to encourage production. Monitor for pests and disease. |
| September | First fall frost approaching (around October 4). Transplant fall brassicas. Sow spinach, arugula, and radishes. |
| October | First frost around October 4. Harvest tomatoes and peppers before frost. Cover cold-hardy crops with row covers to extend the season. |
| 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. |
What grows in a 146-day season
Frequently Asked Questions
What is the last frost date for Ionia, MI (ZIP 48846)?
The median last spring frost date for Ionia, MI (ZIP code 48846) is around May 11. 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.
What is the first fall frost date in Ionia, MI?
The median first fall frost date for Ionia, MI is around October 4. Plan to harvest or protect frost-sensitive crops like tomatoes and peppers at least a week before this date to avoid losses.
How long is the growing season in Ionia, MI?
The frost-free growing season in Ionia is about 146 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.
What USDA hardiness zone is Ionia, MI?
Based on frost date patterns, Ionia falls approximately in 6a. USDA hardiness zones are determined by average annual minimum winter temperatures and guide both plant selection and planting timing for your location.
When should I start tomatoes indoors in Ionia, MI?
Start tomato seeds indoors 6–8 weeks before your last frost date (around May 11). For Ionia, that's roughly March 16 to March 30. Transplant outdoors 1–2 weeks after your last frost.
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