When to plant summer squash by city
Start summer squash 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 summer squash in late winter or early spring and again in late summer.
Don’t go by the calendar alone. Summer squash 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.
Yellow squash 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.
Same care as zucchini. Pick young and often.
How to grow summer squash
Yellow squash, crookneck or straightneck, grows exactly like zucchini and is just as generous. Its thin skin bruises easily and turns tough and warty if left too long, so pick it young and often.
Sun and soil
Full sun and fertile, well-drained soil, pH 6.0–6.5. Keep soil moist to about 6 inches deep, especially during flowering and fruit set.
Planting
- Sow 1 inch deep 1–4 weeks after the last frost, once soil is at least 65°F.
- Plant 2–3 seeds per hill and thin to one, or set out transplants 1–3 weeks after the last frost.
- Give each plant 36 inches, with 48 inches between rows.
Care
- Water deeply once or twice a week and keep water off the leaves.
- Mulch with 2–3 inches of straw once soil is warm to hold moisture and keep fruit clean.
- If you must spray for pests, do it in the evening after flowers close to protect bees.
Harvest
Pick straight- and crooknecks at 1½–2 inches thick while the skin is bright and smooth; pattypans at 3–4 inches across. Pick every day or two and handle gently. Fruit keeps about a week refrigerated.
Common problems
- Squash bugs: Crush bronze egg clusters under leaves and trap adults under a board, destroying them each morning.
- Mosaic viruses: Mottled leaves and green-streaked or bumpy fruit, spread by aphids. Pull infected plants and choose virus-resistant varieties.
- Blossom-end rot: Dark, dry rot at the flower end. Keep watering steady and mulch.
Varieties to try
- 'Early Prolific Straightneck' — dependable, high-yielding
- 'Early Summer Crookneck' — classic buttery crookneck
- 'Zephyr' — straightneck with a green tip
- 'Sunburst' — yellow pattypan
Crop rotation
Summer squash 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, zucchini, winter squash, pumpkin, cantaloupe, watermelon.
Frequently asked questions
When should I plant summer squash?
What grows well with summer squash?
How far apart should I plant summer squash?
How long do summer squash take to grow?
Can summer squash handle frost?
Sources
- Frost dates: NOAA National Centers for Environmental Information, U.S. Climate Normals 1991–2020.
- Hardiness zones: 2023 USDA Plant Hardiness Zone Map, USDA-ARS and PRISM Climate Group, Oregon State University.
- Planting windows and spacing: Vegetable Planting Guide (GardenNotes #720), Colorado State University Extension, and other land-grant extension guides.
- Trap cropping: a review of the state of the art, Sarkar et al., 2018 (open-access review)
- Summer Squash — Clemson Cooperative Extension (HGIC)
- Summer and Winter Squash in the Garden — Utah State University Extension