In zone 6, sow or transplant zucchini outside around May 15, about two weeks after your last spring frost, once the soil is about 70 °F. Expect your first zucchini from about June 24. For a longer harvest, sow a second batch about three weeks later.
Zucchini dates for your ZIP code
Planting times based on university extension guidance (UNH, Cornell, Purdue, Minnesota, Nebraska and UMass Extension). Frost dates from NOAA 1991–2020 U.S. Climate Normals, nearest weather station. Zones derived from the 2023 USDA Plant Hardiness Zone Map data (PRISM Climate Group, Oregon State University). This is not the official USDA Plant Hardiness Zone Map.
Zucchini timing in zone 6
| Task | When |
|---|---|
| Start indoors (optional) | April 17 – April 24 |
| Plant outside | May 15 |
| First harvest | June 24 – July 9 |
| Second sowing | About 3 weeks after the first |
| Check stems for vine borers | From early summer |
| Pick | Every day or two, while the fruit is small |
Most of zone 6 sees its last spring frost between April 25 and May 8, with a typical date of May 1. Zucchini is killed by frost and needs warm soil to sprout, so wait until the soil is about 70 °F two inches down. The tool above uses the weather station closest to your ZIP code.
Why zucchini waits for warm soil
Zucchini and other summer squash are tender, warm-season plants. Frost kills them, and their seeds need warm soil, about 70 °F two inches deep, to sprout well. That is usually about two weeks after the last spring frost.
Best zucchini and summer squash for zone 6
Any zucchini or summer squash grows well in zone 6. Most bear in 40–55 days.
- Zucchini: green or golden types.
- Other summer squash: crookneck, straightneck and patty pan.
- If squash vine borers wreck your plants, try butternut-type squash (Cucurbita moschata), the least susceptible group, as a winter squash alternative.
How to plant zucchini
- Sow seeds about ½ inch deep directly in the garden, or set out transplants started indoors three to four weeks earlier.
- Space plants out: in hills, 3–4 seeds per hill with 5–6 feet between hills; in rows, thin to 8–12 inches apart. Bush types need 2–3 feet between rows.
- Use row covers on cold nights early on, and remove them once flowers open.
- Water deeply and keep the soil evenly moist.
- Sow a second batch about three weeks later for a longer harvest.
Zone 6 zucchini tips
- Plant twice. A second sowing about three weeks after the first keeps you picking after the first plants decline.
- Watch for squash vine borers. A plant that suddenly wilts in midsummer, with sawdust-like frass at the base of the stem, has borers inside. Start checking in early summer.
- Plant later to dodge them. A later sowing of fast zucchini can miss the borers’ peak egg-laying.
- Watch for squash bugs and powdery mildew. Squash bugs gather in groups and leave leaves ragged; mildew shows as white powdery spots.
Harvesting zucchini
Pick zucchini small, before the fruit gets oversized, with large seeds and hard skin. Small fruit is the most tender. Check the plants every day or two in summer, because zucchini grows fast. The flowers are edible too: pick them the day they open. Taking male flowers doesn’t reduce your harvest.
Zucchini planting dates in nearby zones
See dates for every zone on the zucchini planting guide, or build a full schedule with the planting calendar.
Frequently asked questions
Is it too late to plant zucchini in zone 6 in June?
No. Zucchini bears in 40–55 days, so a June sowing has time before your first frost around October 13, and it may avoid the worst of the vine borers.
What kills zucchini plants in midsummer?
Most often squash vine borers. Their larvae tunnel into the stem, and the plant wilts suddenly. Look for an entry hole and yellow, sawdust-like frass at the base.
Can I plant zucchini before the last frost?
No. Frost kills zucchini, and seeds don’t sprout well until the soil is about 70 °F. Plant about two weeks after your last frost.
How many zucchini plants do I need?
Fewer than you think. One or two plants feed most households, because each plant produces for weeks.
Why are my zucchini flowers falling off?
The first flowers are usually male and drop naturally. Fruit comes from the female flowers, which have a small squash at their base.
Sources. Planting dates use the median frost dates of each USDA zone, calculated from NOAA climate data for every ZIP code in the zone.