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When to plant zucchini

Squash family, Cucurbita pepo

Spacing
36″ apart
Per sq ft
1 per 4
To harvest
45–60 days
Frost
Tender

Companion plants for zucchini

What to grow next to zucchini, what to keep away, and what is only tradition. Every pairing says how strong the evidence is.

Grow together 4

Helps, or shares the bed well.

Keep apart 1

Shared pests, disease or competition.

  • Cucumber Practical They don’t cross-pollinate into strange fruit (a common myth), but they share cucumber beetles, mildew and bacterial wilt. Spread them out if you can.

    Cucumber guide

Tradition only 2

On many charts, with little or no evidence.

  • Radish Tradition Said to help Radishes are said to repel cucumber beetles. Studies have not shown it.

    Radish guide

  • Potato Tradition Said to harm Often listed as bad neighbors, supposedly encouraging blight. There is no shared-disease link; the real problem is that both sprawl.

    Potato guide

Studied Field or lab research shows an effect, at least under some conditions.
Mixed Some studies find an effect, others don’t, or it only works in a narrow way.
Practical Explained by light, space, timing, support or a shared pest or disease.
Tradition Widely repeated, but with little or no evidence behind it.

See every pairing side by side in the companion planting chart, or try them in a bed with the garden planner.

When to plant zucchini by city

Start zucchini indoors 3–4 weeks before your last frost, plant them out 1–3 weeks after your last frost, or sow seed outdoors 1–4 weeks after your last frost, once the soil is at least 65°F. Here is what that means for 2027 in cities across the US, using each city’s average frost dates and the date its normal daily temperature reaches 65°F, so cool-spring places like Seattle wait for real warmth (NOAA 1991–2020). Pick the city with the climate most like yours, or enter your ZIP code above.

City Last frost Start indoors Plant out Sow outdoors
Seattle, WA (9a) Mar 13 May 26 – Jun 2 Jun 30 – Jul 14 Jun 30 – Jul 21
Portland, OR (8b) Feb 25 May 21–28 Jun 25 – Jul 9 Jun 25 – Jul 16
Sacramento, CA (9b) Jan 12 Mar 28 – Apr 4 May 2–16 May 2–23
Phoenix, AZ (10a) Jan 5 Feb 2–9 Mar 9–23 Mar 9–30
Salt Lake City, UT (7b) Mar 31 Apr 19–26 May 24 – Jun 7 May 24 – Jun 14
Denver, CO (6a) Apr 30 Apr 25 – May 2 May 30 – Jun 13 May 30 – Jun 20
Dallas, TX (8b) Mar 2 Mar 2–9 Apr 6–20 Apr 6–27
Minneapolis, MN (5a) Apr 23 Apr 29 – May 6 Jun 3–17 Jun 3–24
Kansas City, MO (6b) Apr 4 Apr 5–12 May 10–24 May 10–31
Chicago, IL (6b) Apr 10 May 2–9 Jun 6–20 Jun 6–27
Columbus, OH (6b) Apr 20 Apr 18–25 May 23 – Jun 6 May 23 – Jun 13
Nashville, TN (7b) Apr 1 Mar 31 – Apr 7 May 5–19 May 5–26
Atlanta, GA (8a) Mar 24 Mar 23–30 Apr 27 – May 11 Apr 27 – May 18
Raleigh, NC (8a) Mar 28 Mar 27 – Apr 3 May 1–15 May 1–22
Philadelphia, PA (7b) Mar 30 Apr 7–14 May 12–26 May 12 – Jun 2
Boston, MA (7a) Apr 4 May 1–8 Jun 5–19 Jun 5–26

In frost-free parts of Florida, southern California and the Gulf Coast, timing is about heat instead: plant zucchini in late winter or early spring and again in late summer.

Don’t go by the calendar alone. Zucchini planted into cold soil sit still for weeks; wait until the soil 4 inches down is at least 65°F and nights stay above 50°F.

Zucchini spacing

In a square-foot bed, plant one plant per 4 square feet (a 2 × 2 ft block). In traditional rows, space plants about 36 inches apart with 48 inches between rows.

One or two plants feed a family. Pick fruit at 6–8 inches.

One square foot planted with zucchini, as drawn in the planner.

How to grow zucchini

Zucchini is famously productive: one or two plants are enough for most households. Bush varieties stay put but spread 3–4 feet across, so give them room.

Sun and soil

Full sun and rich, well-drained soil with compost worked in, pH about 6.0–6.5. Water deeply, 1–2 inches a week, keeping moisture steady during fruiting.

Planting

  1. Direct-sow 1 inch deep 1–4 weeks after the last frost, once soil is 65°F. Sow 2–3 seeds per spot and thin to the strongest.
  2. Or transplant 3–4-week-old seedlings 1–3 weeks after the last frost.
  3. Allow 36 inches between plants and 48 inches between rows; in a square-foot bed, one plant takes a 2×2 block.

Care

  • Water at the base in the morning so leaves dry before night.
  • Side-dress with nitrogen when flowering starts; excess grows leaves instead of fruit.
  • Check stem bases weekly for holes and sawdust-like frass, the first sign of squash vine borer.
  • A second sowing a few weeks later replaces early plants lost to borers or mildew.

Harvest

Pick at 6–8 inches, while the skin is glossy and tender. Check daily in summer; fruit grows fast and overgrown zucchini slows the plant. Cut with a knife. Male flowers are good to eat.

Common problems

  • Squash vine borer: Plants wilt suddenly at midday. Use row cover until bloom. If larvae are inside, slit the stem, remove them, and bury the stem section so it reroots.
  • Squash bugs: Crush bronze egg clusters under leaves, hand-pick bugs, and trap adults under boards overnight.
  • Powdery mildew: White patches on older leaves by midsummer. Choose resistant varieties and give plants space.
  • Small fruit that shrivels: Poor pollination. Avoid insecticides during bloom, or brush pollen from a male flower onto a female one.

Varieties to try

  • 'Black Beauty' — dark green, classic
  • 'Spineless Beauty' — less prickly, easier picking
  • 'Eight Ball' — round fruit for stuffing
  • 'Costata Romanesco' — ribbed Italian heirloom, nutty flavor

Crop rotation

Zucchini belong to the squash family (Cucurbitaceae). Heavy feeders. Cucumber beetles and powdery mildew carry over between years. Relatives that count as the same family for rotation: cucumber, yellow squash, winter squash, pumpkin, cantaloupe, watermelon.

Frequently asked questions

When should I plant zucchini?
Start zucchini indoors 3–4 weeks before your last frost, plant them out 1–3 weeks after your last frost, or sow seed outdoors 1–4 weeks after your last frost, once the soil is at least 65°F. Type your ZIP code above for exact dates, or see the city table.
What grows well with zucchini?
Good neighbors for zucchini include nasturtium, marigold, calendula and zinnia. Each one is listed above with the reason and how strong the evidence is.
What should not be planted with zucchini?
Keep zucchini apart from cucumber. They don’t cross-pollinate into strange fruit (a common myth), but they share cucumber beetles, mildew and bacterial wilt. Spread them out if you can.
How far apart should I plant zucchini?
In rows, space zucchini about 36 inches apart with rows 48 inches apart. In a square-foot bed, plant one plant per 4 square feet (a 2 × 2 ft block).
How long do zucchini take to grow?
About 45–60 days from sowing to first harvest, depending on the variety and the weather.
Can zucchini handle frost?
No. Zucchini are killed by frost and sulk in cold soil, so wait until after your last frost and until the soil reaches about 65°F.

Sources

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When to plant

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