Zone 4 Planting Calendar: What to Plant Each Month

Nothing to sow outdoors in January, February, September, October, November, December in zone 4. Crops already in the ground keep growing and keep being harvested. Use the time to plan beds, order seed, build a compost pile, or start long-season crops under a light indoors.

Soil beats calendar. Extension guidance for the hardiest crops is “as soon as the soil can be worked” or “as soon as the soil thaws” — not a fixed date. If you cannot crumble a handful of soil in your fist, wait, whatever the table says. Warm-season crops have a matching rule: beans want 60°F soil, cucumbers and squash 70°F.

This matters most in zone 4. The earliest spring windows above assume the ground has thawed and is workable, and in a late spring it may still be frozen or waterlogged on those dates. A raised bed, which warms 2 to 3 weeks earlier than open ground, is the reliable way to hit the early dates here.

About the bolting warnings. Cool-season crops run to seed and turn bitter in summer heat. The “may bolt in heat” flag above is a rough calendar rule — mid-June to the start of September, the same window across the whole country — because a hardiness zone carries no summer-temperature information at all. In zone 4 treat it as cautious; summers here are mild enough that midsummer sowings often succeed.

Where these dates come from. A USDA hardiness zone describes average annual extreme minimum WINTER temperature — it is a winter-survival rating for perennials, not a frost-date band. The frost dates below are widely-used approximations for each zone, not official USDA figures, and a single zone spans hundreds of miles. Treat them as a default guess and replace them with your own local averages wherever you have them.

You can enter your own frost dates in the interactive calendar and every window on it recalculates from your numbers. Look up your local averages on the NOAA last-spring-freeze map. Note that an “average” frost date is the point where the chance of freezing drops below 50 percent, so for tender crops it is worth waiting a week or two past it.