How to Plant Cucumber Seeds and Seedlings

Planting cucumbers can be one of the most rewarding parts of the gardening season, and understanding the site, spacing, and soil needs is crucial for a successful harvest. Over the years, I’ve discovered that cucumbers thrive when given plenty of sunlight, rich soil, and adequate space to spread their vines. Whether you’re starting from seeds or seedlings, the right preparation and care at the beginning of the growing season can make all the difference. In this guide, I’ll walk you through the best practices for selecting the perfect location, preparing the soil, and spacing your cucumber plants to ensure they grow strong and healthy, setting you up for a bountiful crop. With my personal experience and trusted tips, you’ll be ready to plant cucumbers that not only grow well but produce delicious fruits all season long.

Table of Contents

Get Started with These Basics

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.
Plant cucumber seeds in the garden 1 to 2 weeks after the last frost, or when the soil is at least 60°F (16°C). Set cucumber seedlings in the garden 2 weeks after the last frost.
Grow cucumbers in humus-rich, well-drained soil. Cucumbers are heavy feeders and need a moderate amount of nitrogen and potassium and a high amount of phosphorus; use an organic fertilizer formulated for tomatoes. Keep the soil evenly moist during flowering and fruit development.

Support cucumbers on trellis, poles, or cages, or plant cucumbers on hills or mounds and let plants trail and sprawl. Cucumbers grow well as a trellised crop; the fruit will grow straighter, cleaner, and healthier. Remove the lateral branches from the bottom 18 inches of the stem for the best fruit production; this strategy will delay the onset of fruits but will result in a greater number of fruits.
In short-season regions with late last frost dates, plant cucumbers as soon as peas and spinach are finished.
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 seedlings grow plant — Cucumber seedlings in the garden

Where to Plant Cucumbers

Cucumbers grow best in full sun but will grow with just 5 hours of sun a day. Cucumbers are very tender vegetables; they need temperatures of 70°F (21ºC) or warmer to grow well. They grow best in growing zones 4–12. If you allow cucumber vines to sprawl on the ground you will need about 9 square feet (2.7 sq m) per plant. You can grow cucumbers vertically; place them next to a fence or a trellis. Cucumbers prefer well-drained sandy loam supplemented with compost or well-rotted manure.

Grow cucumbers in full sun. Cucumbers can tolerate partial shade.
Cucumbers prefer loose, well-drained soil rich in organic matter. Prepare planting beds in advance of planting by adding 2 to 3 inches (5-7cm) of aged compost, commercial organic planting mix, and aged manure to beds. Turn the soil to 12 inches (30cm) deep
Place black plastic sheeting over the planting bed in spring to warm the soil in advance of planting.
Cucumbers prefer a soil pH of 5.5 to 6.8. Cucumbers can tolerate alkaline soil to a pH of 7.6.
Set trellises or supports in place to grow cucumbers up or mound the soil to create a small hill off which cucumber vines can run. Use a trellis 4 to 6 feet (1.2-1.8m) tall. Create a mound at least 16 inches (40cm) across and several inches high; space mounds 4 to 6 feet (1.2-1.8m) apart.

cucumber seedlings for planting — Cucumbers are tender annuals that grow best in temperatures ranging from 60° to 90°F.

Sowing Cucumber Seeds

You can direct sow cucumber seed in spring after all danger of frost has passed and the soil has warmed to 70°F (21°C). The seeds will not germinate at a soil temperature below 50°F (10°C). Sow seed ¾–1 inch (1.9–3.8 cm) deep, thinned to 36 inches (90 cm) apart. Cucumbers require 55–65 frost-free days to mature.

To get a head start on the season, sow cucumbers in peat pots 3–5 weeks before planting out. Transplant cucumbers out into the garden after the soil has warmed and the weather settled. For successive crops, plant cucumbers every 2 weeks until midsummer.

Cucumber seeds will germinate in as little as three days when the soil temperature is 80° to 90°F. Sow cucumber seeds indoors about three weeks before setting seedlings into the garden. Start cucumbers indoors in individual pots so that the roots are not disturbed at transplanting. Set out cucumber starts when the garden soil temperature is 70°F or greater. You can speed garden soil warming by covering the planting area with black plastic mulch or by using mounds or raised rows to grow cucumbers.

Sow cucumber seeds 1 inch (2.5cm) deep.
Sow seeds at the base of the vertical support or on a mound at 6 to 8-inch (15-20cm) intervals.
When seedlings are 3 to 4 inches (7-10cm) tall, thin to the strongest plant spaced 12 to 18 inches (30-45cm) apart for vining cucumbers on vertical supports and 24 to 36 (61-91cm) inches apart for bush varieties.
Cut weak seedlings off at the soil level with scissors to avoid disturbing the roots of the remaining plants.

Sow seed or set out cucumber transplants after all danger of frost has passed and the soil has warmed to 60°F (16°C). Frost can stress cucumbers. If there is a danger of frost once cucumbers are in the garden, protect plants with floating row covers.

Transplanting Cucumber Seedlings Started Indoors

Starting cucumber seeds indoors is a great way to get a jump start on the growing season, especially in regions with shorter summers or cooler climates. To begin, sow cucumber seeds in biodegradable pots or peat pellets about 2–3 weeks before your last expected frost date. This allows the seedlings time to develop strong roots and get a head start. Plant the seeds about ½ inch deep in a warm, sunny location or under grow lights, with temperatures maintained between 70–85°F for optimal germination. Be sure to keep the soil consistently moist, but not soggy, and once the seedlings emerge, provide them with plenty of light to prevent leggy growth. I recommend using a gentle liquid fertilizer once the seedlings have their first true leaves to give them a nutrient boost without overwhelming them.

When it’s time to transplant your cucumber seedlings into the garden, wait until the soil temperature reaches at least 65°F and all danger of frost has passed. Cucumbers are sensitive to cold and can suffer if exposed to temperatures below 50°F. Before transplanting, harden off the seedlings by gradually exposing them to outdoor conditions for 3–5 days, starting with a few hours of shade and gradually increasing their time in full sun. Once the seedlings are acclimated, dig holes large enough to accommodate the root ball, spacing vining varieties about 12–18 inches apart and bush types around 6–8 inches apart. Gently transplant the seedlings, being careful not to disturb their roots too much, and water them well after planting. With proper care, your seedlings will soon thrive in the garden, setting the stage for a bountiful cucumber harvest.

Spacing Cucumbers

Plant cucumbers in full sun and set bush cucumbers 18 to 24 inches apart and vining varieties at least 24 to 36 inches apart in rows 3 feet apart. Cucumbers like well-drained roots so planting on mounds is a good idea. Set three plants on mounds 3 feet across; space mounds 6 feet apart. Set trellises or pole supports in place before you plant seedlings. To prevent diseases, air circulation around plants is important.

Sow seeds or set out seedlings in raised hills or in rows after all danger of frost has passed in spring and the soil has warmed to at least 60°. Successive crops can follow 4 weeks later. Plant one side of the trellis early and the other side later.

Set a trellis, tripod, or cage in place at planting time if you are growing vining varieties. A 12 to 18-inch (30-45cm) diameter wire cage is ideal for growing vining cucumbers. You can make a cage from a 4 to 5-foot (1.2-1.5m) section of wire fencing or construction mesh.
To grow an early crop, you can start cucumbers indoors 2 to 3 weeks before the last frost in spring then transplant seedlings to the garden 2 to 3 weeks after the last frost.

Avoid bitter-tasting cucumbers with sunlight and regular water

Cucumber Planting Details Summary

Sowing depth: 1/2 inch (12mm) or slightly more
Space between plant after thinning: 12-24 inches (30-60cm)
Days to sprout: 8-12
Days to harvest: 50-70
Storage period: 1-2 weeks
Seeds per 100-row feet: 3/4 ounces
Yield per 100-row feet: 600 fruits
Suggested varieties: Slicers: Marketmore, Bush Champion, Salad Bush, Diva; Picklers: Pickalot, Pioneer, Northern Pickling; Others: Suyo Long, Lemon, Armenian; For containers: Pot Luck, Spacemaster, Salad Bush.

Pro Tips Summary: Cucumber Sowing and Planting

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, and 60°F (16°C) at night.
Sow seed ¾ to 1 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 the 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 and 12 inches (30 cm) deep. Use a trellis or support to increase yields.

Young cucumber plants plant grow — Young cucumber plants

Cucumber Planting Calendar

Starting cucumbers 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 a 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.

Cumber seedlings — Start cucumber seed indoors 3 weeks before the last frost or outdoors 3 weeks after the last frost.

Cucumber Planting Dates

(These dates are for the Northern Hemisphere)

Average date of the last frost	Planting dates
Jan. 30	Feb. 15-Mar. 15
Feb. 8	Feb. 15-Apr. 1
Feb. 18	Feb. 15- Apr. 15
Feb. 28	Mar. 1-Apr. 15
Mar. 10	Mar. 15-Apr. 15
Mar. 20	Apr. 1-May 1
Mar. 30	Apr. 10-May 15
Apr. 10	Apr. 20-June 1
Apr. 20	May 1-June 15
Apr. 30	May 15-June 15
May 10	May 20-June 15
May 20	June 1-15
May 30	June 5-15
June 10	June 10-15

Cucumber Varieties to Grow

Cucumbers are divided into slicing cucumbers for fresh eating and pickling cucumbers. There are dozens of varieties to choose from. In the list below “gyn” denotes gynoecious which produces only female flowers and must be grown near a monoecious plant; others are monoecious, which produce both male and female flowers.

Slicing: Ashley (66 days); Comet II (gyn-60 days); Dasher II (55 days); General Lee (gyn-55 days); Jazzer (48 days); Marketmore (76 days); Poinsett (65 days); Revenue (gyn-48 days); Slice King (49 days); Spacemaster (60 days); Speedway (gyn-56 days); Supersett (53 days); Sweet Slice (62 days); Tasty Green (55 days); Ultra-Slice Early (56 days).
Pickling: Baby Bush (51 days); Calypso (gyn-56 days); Conquest (gyn-50 days); Cross Country (51 days); Edmondson (70 days); Green Spear (gyn-55 days); Pik Rite (gyn-63 days); Salty (53 days); Spear It (gyn-52 days); Sumter (56 days).
Burpless: Comet II (gyn-60 days); Green Knight (60 days); Jazzer (48 days); Perfection (60 days); Sweet Slice (62 days); Tasty Green (55 days).
Greenhouse: Aidas (gyn-65 days); Carmen (gyn-65 days); English Telegraph (65 days).
Container varieties: Patio Pic (50 days); Potluck (50 days); Spacemaster (60 days); Bush Whopper.
Others: Lemon (64 days); Long White (65 days); White Wonder (60 days).

Related Posts:

Ultimate Beginner to Expert Guide to Growing Cucumbers