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Cucumber Seed Starting Tips

Seedling Cucumber
Cucumber seedlings

Cucumbers are a tender, warm-weather crop.

Start cucumbers indoors 6 to 3 weeks before you plan to transplant them into the garden or direct sow seed in the garden 2 to 3 weeks after all danger of frost is past and the soil has warmed.

Support cucumbers on a trellis, poles, or cages, or plant cucumbers on hills or mounds and let plants trail and sprawl.

Cucumbers are very sensitive to frost so time your final planting in summer so that fruits come to harvest a few weeks before the first expected frost.

Cucumbers mature 55 to 65 days after sowing.

Cucumber Sowing and Planting Tips

  • Grow cucumbers from seeds or seedlings.
  • Seed is viable for 5 years.
  • Start cucumbers indoors 6 to 3 weeks before you plan to transplant them into the garden. Direct sow seed in the garden after all danger of frost has passed and the soil has warmed to 65°F (18°C).
  • Sow seed indoors in peat pots filled with seed starting mix. The indoor temperature should be greater than 70°F (21°C) during the day, 60°F (16°C) at night.
  • Sow seed ¾ to1 inch (1.9-3.8 cm) deep.
  • Seeds will germinate in 5 to 7 days at 68°F (20°C) or warmer. Cucumber seeds will not germinate at a soil temperature below 50°F (10°C).
  • Space plants in the garden 12 inches (30 cm) apart in rows 24 inches (60 cm) apart.
  • Put a trellis, cage, or pole in place to train vines up or plant on hills or mounded soil—3 plants to a hill and allow plants to sprawl.
  • Water to keep the soil from drying; fruit development requires uninterrupted moisture.
  • Fertilize with fish emulsion or a soluble complete fertilizer at half strength.
  • Add aged compost to planting beds in advance of transplanting.
  • Cucumbers prefer a soil pH range of 6.5 to 7.5.
  • Grow cucumbers in full sun for best yield.
  • Plant cucumbers every 2 weeks until midsummer for a successive harvest.
  • Sow seeds for the final crop in summer no later than 12 weeks before the first expected frost.
  • Avoid planting cucumbers where melons or squash have grown recently.
  • Common cucumber pest enemies include aphids, cucumber beetles, flea beetles, squash bugs, squash vine borers, slugs, and snails.
  • Common diseases include bacterial wilt, fusarium wilt, downy mildew, powdery mildew, and cucumber mosaic.

Interplanting: Plant cucumbers with bush beans, corn, dill, eggplant, lettuce, melon, squash, and tomatoes.

Container Growing Cucumbers: Choose a container 8 inches (20 cm) wide 12 inches (30 cm) deep. Use a trellis or support to increase yields.

Cucumber Planting Calendar

Starting corn for summer harvest:

  • 6 weeks before the last frost in spring: start seed indoors.
  • 4 weeks before the last frost in spring: warm planting beds where cucumbers will grow by covering with black plastic or covering with a plastic tunnel.
  • 2 weeks before the last frost in spring: transplant seedlings into warmed planting beds and protect them with plastic tunnel; minimum soil temperature should be 60°F.
  • 2 to 3 weeks after the last frost in spring: direct sow seed in the garden or set out transplant unprotected.
  • Every 3 weeks sow succession crops.

Starting corn for fall harvest:

  • 14-12 weeks before the first frost in autumn: direct sow or sow seeds indoors for transplanting out when space opens in the garden. Plants are killed by frost.
Cumber seedlings
Start cucumber seed indoors 3 weeks before the last frost or outdoors 3 weeks after the last frost.
  • Cucumbers for slicing: ‘Marketmore’, ‘Bush Champion’, ‘Salad Bush’, ‘Diva’.
  • Cucumbers for pickling: ‘Pickalot’, ‘Pioneer’, ‘Northern Pickling.’ Others: ‘Suyo Long’, ‘Lemon’, ‘Armenian.’

Botanical Name: Cucumis sativus

Cucumbers are a member of the Cucurbitaceae family; other members squash, watermelon, pumpkins, and some melons.

More tips: How to Grow Cucumbers.

Written by Stephen Albert

Stephen Albert is a horticulturist, master gardener, and certified nurseryman who has taught at the University of California for more than 25 years. He holds graduate degrees from the University of California and the University of Iowa. His books include Vegetable Garden Grower’s Guide, Vegetable Garden Almanac & Planner, Tomato Grower’s Answer Book, and Kitchen Garden Grower’s Guide. His Vegetable Garden Grower’s Masterclass is available online. has more than 10 million visitors each year.


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  1. Our cucumbers were started inside and now have cukes already starting on the plants. Should we cut the cukes off until it is time to put the plants outside?

    • Fruit that sets on young plants can tax the plant’s strength. If new flowers are appearing, you can nip off the young fruits then set the plants in the garden. Give the plants some B-1 vitamin at transplant time to help get past transplant shock.

    • Yes, leggy cucumbers can be planted deeply. Dig a hole deep enough to bury the stem up to the first set of leaves. Press potting soil firmly around the stem; be careful not to injure or break the stem. Keep the soil just moist, not wet. Feed with a dilute solution of fish emulsion every 10 days or so.

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