How Do I Know When to Plant Vegetables in My Area?

September 7, 2026 · 4 min read

If you've ever put a tomato seedling in the ground too early and watched it shiver through a surprise cold snap, you already know: timing is half the battle in vegetable gardening. The good news is that "when to plant" isn't a mystery — it comes down to two numbers and one simple question.

It All Starts With Your Frost Dates

Every location has an average last frost date in spring and an average first frost date in fall. These two dates define your growing season, and almost every planting decision flows from them.

You can find your frost dates by searching "your zip code frost dates" or checking your USDA hardiness zone — but a rough date only gets you so far. Frost dates are averages, not guarantees. A "last frost" of March 15 just means that, historically, the odds of a freeze after that date drop off — not that it's impossible. Smart gardeners build in a little cushion rather than planting the literal day after.

Cool-Season vs. Warm-Season Crops

Once you know your frost dates, the next question is simple: does this vegetable like the cold, or hate it?

Cool-season crops actually prefer to grow before it gets hot, and many can handle a light frost without issue:

• Lettuce, spinach, kale
• Broccoli, cabbage, cauliflower
• Peas
• Carrots, beets, radishes

These go in the ground before your last frost date, or in late summer for a fall harvest — they're not fans of summer heat and will bolt (go to seed early) if planted too late in spring.

Warm-season crops are the opposite — they're tender, frost-sensitive, and need real warmth to thrive:

• Tomatoes, peppers, eggplant
• Squash, cucumbers, melons
• Beans, corn
• Basil

These wait until after your last frost date, once the soil itself has warmed up — not just the air. A lot of these crops will simply sulk (or die outright) if the soil's still cold, even if the days feel warm enough.

The Part Frost Dates Don't Tell You

Here's the piece that trips people up: soil temperature often matters more than the calendar. Tomatoes, for example, want soil consistently above 60°F to really take off — planting into cold soil "because the frost date passed" just means a slow, stressed start, even if nothing actually freezes.

A simple trick: stick a regular kitchen thermometer a few inches into your garden soil in the morning for a few days in a row. If it's holding steady above the crop's minimum, you're in business.

Don't Forget: You Can Plant Twice

Most home gardeners only think about spring planting, but your fall window is just as real — and often more forgiving, since cool-season crops planted in late summer mature as the weather cools down, avoiding the bolt-inducing heat of a spring finish. Counting backward from your first fall frost date (using a crop's "days to maturity") tells you your fall planting deadline, the same way counting forward from your last spring frost tells you your spring start.

Let Dottie Do the Math

This is exactly the kind of thing that's simple in theory and easy to get wrong in practice — which is why Dottie's Garden builds your USDA zone right into your care calendar. Instead of cross-referencing frost dates and days-to-maturity charts yourself, your reminders are already timed to your specific zone, for both your spring and fall windows.

If you're not sure what's safe to plant this week, just ask Dottie — she already knows your zone, and she won't let you rush the tomatoes.