Zone 6 Planting Calendar

What to do

Vegetables sown outdoors go in one of four waves, timed in weeks off your last-frost date rather than a fixed day on the calendar. The table below works those weeks out at both ends of zone 6’s range, so find the column closer to your own last-frost date and read down it — everything in between falls somewhere in the middle.

Wave	Weeks vs. last frost	Early window (~Apr 16 last frost)	Late window (~May 15 last frost)	Crops
Hardy	2–4 weeks before	Mar 19–Apr 2	Apr 17–May 1	broccoli, cabbage, kale, kohlrabi, onions, lettuce, peas, radishes, spinach, turnips
Semi-hardy	0–2 weeks before	Apr 2–16	May 1–15	beets, carrots, cauliflower, parsley, parsnips, potatoes, Swiss chard
Tender	at last frost	Apr 16	May 15	bush beans and trellised pole beans, celery, corn, cucumbers, summer squash
Very tender	2+ weeks after	from Apr 30	from May 29	lima beans, cantaloupe, eggplant, okra, peppers, pumpkin, sweet potatoes, tomatillos, winter squash, tomatoes, watermelon

Those are outdoor dates, sown in the bed or set out as transplants started indoors weeks earlier — indoor trays generally want 4 to 8 weeks under lights before they’re ready to move out, with tomatoes and peppers toward the longer end. In zone 6’s shorter early window especially, that head start is what makes a full-season crop possible: a variety bred for a shorter season buys real insurance if your last frost lands on the late side, and growing tomatoes walks through how to pick one.

Hardy crops keep growing at daytime temperatures as low as 40°F; very tender crops want above 60°F and do best between 70°F and 95°F. A week of daytime temperatures below 55°F can stunt a very tender crop even after its window opens, a real risk in the early half of zone 6, where a mid-April planting date can still meet a cold snap.

Soil temperature is a better signal than any date on this table. Check it around 8 a.m., 4 inches deep for most crops and 6 inches for beans, and plant once the soil holds a crop’s minimum at that reading — lettuce 35°F, tomato and corn 50°F, watermelon 60°F. Save the higher, optimum figure for a seed tray indoors, where you control the temperature; outdoors, aim for the minimum and rising. Vine crops resent root disturbance and do best direct-seeded once soil is warm; started as transplants, keep them to 2–3 weeks before setting out, the tight end of what starting seeds indoors covers.

Running four offsets against two frost dates for a dozen crops is the tedious part. Arbor asks for your zip code when you set up a garden, resolves your zone and pulls that zone’s average frost dates, and counts each crop’s planting week back from them using that crop’s own offset — then adds the resulting tasks to your list when you confirm the plan.

Zone and season notes

The 6a/6b split is worth about two weeks in spring, and it’s the fastest way to narrow the range above: if you know which half of zone 6 you’re in, start from a two-week difference rather than the full month. Elevation explains most of what’s left — a garden at higher elevation or in a low-lying frost pocket sits toward the late edge of the zone 6 range, while a warmer valley or urban microclimate sits toward the early edge. The neighboring zone tells the same story from the other side: one zone cooler runs about two weeks later in spring and two weeks earlier in fall than zone 6’s own warmer half.

Fall is the second season here, and it’s timed backward. Take a crop’s days to maturity — the figure on its seed packet — count back from your first frost date, and that’s its last safe sowing date: a bean whose packet claims 55 days has to be in the ground by about August 11 against an early-October first frost, or August 27 against a late-October one. That math governs frost-tender crops. Hardy crops are the exception worth knowing: they stand light frost and keep growing until a hard freeze, so spinach, kale, and turnips can go in later than the subtraction suggests and still produce past the first frost date. Most fall crops go in from July onward. Once the beds are finished for the year, a cover crop can go in during September or October. Garlic follows neither pattern: either hardneck or softneck works here, planted October through November, ready to lift in June or July.

If your own observed frost dates fall outside this window, trust your dates over the zone — shifts of one to two weeks are normal even within a single state. This calendar draws on eastern and midwestern zone 6 data; the arid and high-elevation stretches of zone 6 in the mountain West run on a different clock and need their own sourcing. For the frost-date math itself, see when to plant vegetables.