Zucchini in zone 6 go out in May and crop until the October frost

Zucchini go into zone 6 gardens in May. Sow seed straight into the ground from early May to early June, or plant out transplants from early to late May. Either way, you’ll be picking by late June or July.

They’re one of the easiest summer crops and one of the most generous. Two plants keep most households in zucchini until the first frost around mid-October.

Seed or transplant

Direct sowing is simplest. Zucchini grow fast, germinate well in warm soil and don’t like having their roots disturbed. Sow two seeds about 1 inch deep at each spot from early May, and thin to the stronger one.

Starting indoors gives a couple of weeks’ head start. Sow one seed per 3- or 4-inch pot from late March to late April and keep them warm. They grow quickly, so don’t start too early or they’ll be root-bound before May.

Zone 6’s average last frost is around April 21, but zucchini are tender and stall in cold soil. Wait until nights are above 50 °F. Zones are set by winter lows, not frost dates, so your own timing may differ by a week or two.

Planting

1. Choose a spot in full sun. Each plant spreads about 3 feet across.
2. Dig in plenty of compost, as zucchini are hungry plants.
3. Space plants about 3 feet apart each way, or give each one four squares in square foot gardening.
4. Water well and mulch once the soil is warm.

Nasturtiums, marigolds and sweet corn make good neighbours. Keep zucchini away from potatoes.

Watering and pollination

Water deeply at the base about twice a week, more in hot weather. Avoid wetting the leaves, which encourages powdery mildew.

Plants produce male flowers first, on thin stems, then female flowers with a tiny zucchini behind them. Bees carry pollen between them. If young fruit shrivel and rot at the tip, they weren’t pollinated: wait for more bees, or transfer pollen yourself with a small brush on a sunny morning.

Picking

Zucchini start cropping about 50 to 65 days from sowing and keep going for around 12 weeks. Pick them at 6 to 8 inches long, every day or two in midsummer. A missed one becomes a giant within days and slows the plant down.

Common problems

Squash vine borer. The biggest zucchini pest in much of the US. A moth lays eggs at the base of the stem in early summer, and the larvae tunnel inside, so the plant suddenly wilts. Cover young plants with row cover until they flower, wrap the lower stem in foil, or sow a second batch in June as a backup.

Powdery mildew. A white coating on leaves from midsummer. Water at the base and remove the worst leaves.

Squash bugs. Grey-brown bugs and clusters of bronze eggs under the leaves. Check regularly and crush eggs and nymphs.

Choose zone 6 on the zucchini page for the full window, and see green beans in zone 6, which are sown at the same time.