In zone 9, sow or transplant zucchini outside around March 17, about two weeks after your last spring frost, once the soil is about 70 °F. Expect your first zucchini from about April 26. 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 9
| Task | When |
|---|---|
| Start indoors (optional) | February 17 – February 24 |
| Plant outside | March 17 |
| First harvest | April 26 – May 11 |
| Second sowing | About 3 weeks after the first, or in late summer |
| Check stems for vine borers | From late spring |
| Pick | Every day or two, while the fruit is small |
Most of zone 9 sees its last spring frost between February 16 and March 15, with a typical date of March 3. 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 9
In zone 9, zucchini grows quickly but faces heavy pest pressure, so plant early and replant often.
- Zucchini: green or golden types.
- Other summer squash: crookneck, straightneck and patty pan.
- Butternut-type squash (Cucurbita moschata) is the least susceptible to squash vine borers if they keep killing your plants.
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 9 zucchini tips
- Plant early. Sow as soon as the soil reaches about 70 °F, so you harvest before pests build up.
- Replant instead of rescuing. Zucchini is fast. A new sowing every few weeks, or a late-summer planting for fall, keeps you in squash when older plants fail.
- Check for squash vine borers. Sudden wilting and sawdust-like frass at the stem base mean larvae are inside. Remove and discard infested plants; don’t compost them.
- Watch for squash bugs and powdery mildew, which are common in warm weather.
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
- Zone 8April 14
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 9 in April?
Not necessarily. Your season is long enough for another planting, and a late-summer sowing can produce in fall before your first frost around November 25.
What kills zucchini plants in summer?
Most often squash vine borers. Their larvae tunnel into the stem and the plant collapses. Remove infested plants and sow a new batch.
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.