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- Start indoors
- Sow outdoors
- Plant out
- Plant
- Fall crop
- Today
Historical frost averages plus extension guidance, not a forecast. Check the forecast and soil temperature before planting.
Sow cucumbers outside 1–3 weeks after your last spring frost, once the soil is at least 60°F and nights stay above 50°F. For an earlier start, sow indoors 1–3 weeks before the last frost and plant out 1–3 weeks after it.
- Frost tolerance
- Tender: no frost
- Soil temperature
- Sow at 60°F+, best 65–95°F
- Days to harvest
- 50–65 days from seed
The rule we use
- Start seeds indoors: 1–3 weeks before the last spring frost
- Sow outdoors: 1–3 weeks after the last spring frost
- Plant out: 1–3 weeks after the last spring frost
Warm soil is the key
Cucumber seed rots in cold, wet ground, and seedlings sit still below about 60°F. A soil thermometer saves guessing. Black plastic or landscape fabric laid over the bed a week before planting warms it by several degrees.
Sow 1 inch deep, two or three seeds every 12 inches, then thin to the best seedling. Seeds usually come up in a week in warm soil.
Starting indoors
Cucumbers grow fast and dislike root disturbance, so start them only 2–3 weeks before you plan to plant out, in individual pots. Older seedlings that get root-bound often stall.
Harden them off for a few days and plant without breaking up the root ball. If a cold night comes after planting, cover them.
Growing and picking
Growing cucumbers on a trellis saves space, keeps fruit clean and straight, and lets air dry the leaves, which cuts down on disease. Water deeply and evenly; dry spells make bitter, misshapen fruit.
Pick often, when fruit is still firm and green. Leaving big, yellowing cucumbers on the vine tells the plant to stop producing. For a fall crop, sow a second batch in early summer, at least 10 weeks before your first fall frost.
Seeds and supplies for cucumbers
- Cucumber seeds at True Leaf Market
- Park Seed for seeds and young plants.
- A soil thermometer to check the soil is warm enough before sowing.
- Seedling heat mats keep seed trays warm for fast, even sprouting.
- Garden trellis to grow vines upward.
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Questions about planting cucumbers
When is it warm enough to plant cucumbers?
When soil is at least 60°F and nights stay above 50°F, usually 1–3 weeks after your last frost.
Should I start cucumbers indoors?
It helps in short-season areas. Sow only 2–3 weeks before planting out, in individual pots, and handle the roots gently.
Can I plant cucumbers in July?
In most areas, yes. Cucumbers ripen in about 50–65 days, so check you have that many days plus two weeks before your first fall frost.
Sources
- Vegetable Planting Calendar for Central Maryland (2026), University of Maryland Extension
- Vegetables for Spring and Fall Planting; Vegetables for Summer Planting, University of Maryland Extension Master Gardeners
- Suggested Vegetable Planting Dates for Utah, Utah State University Extension
- Vegetable Planting Guide (CMG GardenNotes #720), Colorado State University Extension
- Soil temperature conditions for vegetable seed germination, Oregon State University Extension
- Extension Gardener Handbook, Ch. 16: Vegetable Gardening, NC State Extension
- Frost dates: NOAA NCEI U.S. Climate Normals 1991–2020 (doi:10.25921/4ek7-fk11)