What to plant
Growing Cucumbers in Raised Beds
Sow cucumbers 1 to 2 weeks after the last spring frost, once soil reaches 60°F. On a trellis they need only 12 inches between plants, a raised bed 10 to 12 inches deep, and steady water.
| Fact | Detail |
|---|---|
| Seed depth | 1/2 to 1 in |
| Soil temperature to sow | 60°F minimum; 70°F sprouts seed in about a week |
| Trellised spacing | 12 in between plants |
| Bush types | 18–24 in |
| Trellis height | 5–6 ft |
| Bed depth | 10–12 in |
| Days to first harvest | About 50–70 from sowing |
| Last sowing | About 10–12 weeks before first fall frost |
When to plant
Cucumbers are tender. Frost kills them, and cold soil rots the seed. Sow directly in the bed one to two weeks after the last spring frost, once a soil thermometer pushed 2 inches in shows 60°F or higher. A raised bed usually gets there ahead of in-ground rows.
To get a head start, sow in 3- or 4-inch pots indoors three to four weeks before planting out. Cucumbers dislike root disturbance, so slide the whole root ball out gently and plant it without breaking it apart. For a second crop, sow again about a month after the first; the last sowing should go in roughly ten to twelve weeks before your first fall frost.
Spacing and depth
Growing up is the best way to fit cucumbers in a bed. With a trellis, sow two or three seeds every 12 inches along its base and thin to the strongest one. A 4-foot trellis can hold four plants. Left to sprawl, a single vine can cover 15 to 20 square feet, so give ground-grown plants 3 to 4 feet. Compact bush varieties need about 18 to 24 inches.
Plant seed 1/2 to 1 inch deep. Roots spread wide but do most of their work in the top foot, so a bed 10 to 12 inches deep serves them well. Shallower setups are covered in our depth guide.
Soil and feeding
Cucumbers grow fast and feed heavily. Mix 1 to 2 inches of compost into a standard raised bed soil mix before sowing, along with a balanced granular fertilizer at the label rate. Side-dress once when vines begin to run and again at first bloom. Keep the pH between 6.0 and 7.0. Avoid piling on high-nitrogen feeds later in the season, which push leaves at the expense of fruit.
Watering
A cucumber is mostly water, and the plant needs about 1 to 2 inches a week once vines are fruiting, sometimes more in a hot spell. Raised beds drain quickly, so check the soil daily in midsummer: if it is dry an inch down, water deeply. Use drip line or a soaker hose and keep the leaves dry to slow powdery and downy mildew. Mulch 2 to 3 inches deep after the soil is warm. See watering raised garden beds for timer setups.
Crop specifics: trellising, pollination, watering, bitterness
Trellising
Stand the trellis along the bed's northern edge, where its shadow lands on the path, not on other crops. A 5- to 6-foot panel of livestock fencing, a sturdy net between two posts, or a cattle panel bent into an arch between two beds all work. Vines grab on with tendrils, but guide the leaders for the first week or two. Trellised fruit grows straighter, stays cleaner and is easier to spot.
Pollination
Most cucumbers carry separate male and female flowers. Females have a tiny cucumber behind the petals. Male flowers often appear a week or two first, so early blooms that fall off are normal. Bees move pollen between them; if fruit starts and then yellows and shrivels, pollination was poor. Plant a few flowers nearby, avoid spraying in daytime, or transfer pollen with a small brush. Parthenocarpic varieties set fruit without pollination and suit screened areas.
Steady moisture
Skipped waterings show up in the fruit as curved, pinched or hollow cucumbers. A timer on a drip line removes the guesswork.
Bitterness
Bitterness comes from compounds that build up when plants are stressed by heat or drought. It concentrates in the skin and stem end, so peeling and trimming usually help. Varieties sold as burpless or bitter-free carry less of it.
Harvest
Check the vines every day or two once fruit sets, because cucumbers grow quickly. Pick slicers at 6 to 8 inches and pickling types at 2 to 4 inches, while they are firm and evenly green. Cut them with pruners rather than twisting. Never leave yellow, overgrown fruit on the vine; it signals the plant to stop producing. Refrigerate and use within a week.
Cucumbers share a summer bed easily with peppers, and a quick crop of lettuce can grow in the trellis shade. Our guide to choosing crops covers the rest of the bed.
Common problems
Striped or spotted beetles on leaves
Cucumber beetles chew plants and spread bacterial wilt. Cover seedlings with row cover until flowering, then hand-pick.
White powder on leaves
Powdery mildew shows up in midsummer. Improve airflow, water at the base and grow resistant varieties.
Vines wilting suddenly
Bacterial wilt from beetles can collapse a healthy vine in days. Remove infected plants and control beetles early.
Flowers but no cucumbers
Early blooms are often all male. Wait for females, and encourage bees or hand-pollinate.