Vegetable · Cucurbitaceae
Cucumber
Cucumis sativus
Hand it full sun, warm soil, and steady water, and a cucumber vine will reward you with more fruit than you can keep up with.
Full sun
Every 2–4 days
59–95°F · 15–35°C
50–70 days
Overview
Cucumbers are a warm-season vine in the gourd family, cousins to melons and squash, and they get going quickly once the weather finally settles. Hand the seed warm soil and full sun and even a couple of plants will keep your kitchen in slicers all summer long. Most are happy trailing along the ground, yet they will climb a trellis just as willingly, which saves space and keeps the fruit clean.
There are two friendly groups to know. Slicing types grow long and smooth for eating fresh, while pickling types stay short and bumpy and make the best jars. A few newer varieties even set fruit with no bees at all, which is a real comfort under row covers or through a cool, wet spell when pollinators are hard to find.
These vines ask for very little beyond warmth, sun, and even water, so do not worry. Let the soil lurch from bone dry to soaked and you may see bitter, misshapen fruit, but steady moisture quietly does most of the work for you. Keep picking, every day or two at the peak, and the vines will happily set more right up to the first frost.
Care
The short version: give it full sun, warm and fertile soil rich in organic matter, and even moisture of about an inch a week, then pick often and the vines will keep going for you.
Light
Cucumbers want full sun, somewhere around six to eight hours a day, and that light is what powers their quick growth and generous fruiting. They will get by in partial sun, though you will gather fewer cucumbers and invite more disease wherever the leaves sit shaded and damp.
Water
Aim to keep the soil evenly moist, about an inch of water a week between rain and the hose. Water deeply right at the base, and give them a little more while they are flowering and fruiting. The quickest path to bitter, crooked fruit is letting the soil dry out and then drowning it, so try to stay steady.
Soil
Settle them into fertile, well-drained loam full of organic matter, with a pH of 6.0 to 6.5. Because these vines adore warmth, a raised bed or a sheet of plastic mulch to heat the soil early really does pay you back.
Temperature
Cucumbers are a warm-season crop, most content between 59°F and 95°F (15°C to 35°C). The seed will simply refuse to sprout in soil colder than 50°F (10°C), so a cold spring is nothing to push against.
Humidity
Everyday outdoor humidity suits them perfectly, so there is no number to chase. Airflow matters far more than moisture in the air, since crowded, damp leaves are exactly the conditions powdery mildew is hoping for.
Feeding
Mix a balanced fertilizer like 10-10-10 into the bed before you plant. Once the vines begin to run, a nitrogen side-dress helps carry the plant through its long stretch of fruiting.
Pruning
Cucumbers need almost no pruning, which is one less thing to fuss over. On a trellis you can pinch the side shoots to keep growth in check, and it helps to remove diseased or damaged leaves promptly so any foliar disease has a harder time spreading.
Size & spacing
The vines themselves rise only 8 to 18 inches (20 to 46 cm), yet they sprawl 3 to 8 feet (91 to 244 cm) wide across the ground. Give them that room to wander, or a trellis to climb, so air can move through and the fruit stays up off the soil.
When to plant
Cucumbers love warmth and have no patience for frost or chilly soil, so there is no need to rush them. Wait until frost has truly passed and the ground has warmed to at least 60°F (16°C), usually mid to late May, and only then sow seed or set out your transplants. Once they take hold you will be picking fruit from midsummer right up to the first frost.
Northern hemisphere
Southern hemisphere
Typical months for a temperate climate: start earlier in warm zones, later where spring frosts linger.
- Sow: 2-4 weeks before the last frost (late April in northern regions); use peat or paper pots because seedlings resent root disturbance
- Plant: After all danger of frost when soil has warmed to at least 16-21°C (60-70°F), typically mid to late May; seeds will not germinate in soil below 10°C (50°F)
- Harvest: Flowers in early-to-mid summer; harvest fruit from midsummer until first frost, picking every 1-2 days to keep vines productive
Hardiness
USDA hardiness zones: 2–11
Temperature: down to -46°C
Troubleshooting
Almost every cucumber worry shows up on the leaves or the fruit, and the cause is usually heat, water, or a pest you can catch early. Take heart: find what matches below and step in before a small thing has a chance to travel down the vine.
Daytime wilting that never bounces back, then flopping stems
If your vines flag in the daytime and never bounce back, the usual culprit is bacterial wilt, carried in by cucumber beetles that feed on the leaves. You can check by cutting a wilted stem, pressing the cut ends together, and drawing them apart slowly to look for sticky, stringy ooze. Sadly there is no cure, so pull and destroy any plant that has it, and peek at the stem bases for the frass and entry holes that would instead point to a squash vine borer.
Fix:
- Remove and destroy infected plants; bacterial wilt cannot be cured
- Control cucumber beetles early in the season
- Use floating row covers on young plants, removing them at flowering for pollination
A pale powdery film on leaves going yellow and dry
That dusty white film is powdery mildew, a fungus that moves in once you get warm days, cool nights, and vines packed close together. It tends to start on the older, shaded leaves and will smudge a little under your finger. Snip out the worst leaves, open things up with wider spacing or a trellis, and keep your cucumbers in full sun, where the fungus has a much harder time.
Fix:
- Remove heavily infected leaves
- Improve air circulation by spacing or trellising
- Apply a labeled fungicide at first sign if pressure is high
A bitter taste settling into the skin and stem end
Bitterness comes from cucurbitacins, which the plant produces when heat or drought leaves it stressed. The taste gathers in the skin and the stem end, so peeling the fruit and trimming that end takes most of it away. To head it off, water steadily through hot weather, mulch to even out the soil, and pick a burpless or bitter-free variety.
Fix:
- Peel fruit and trim the stem end before eating
- Water consistently and mulch to even out soil moisture
Lopsided cucumbers with a pinched, curling end
Crooked, pinched cucumbers usually mean poor pollination, often after cool, rainy days have kept the bees indoors. Each fruit needs plenty of bee visits to fill out evenly, and a flower that gets too few will set a lopsided one. Remove the misshapen fruit so the vine can spend its energy elsewhere, hold off on insecticides while the plants are flowering, and tuck a few flowers nearby to invite pollinators in.
Fix:
- Remove misshapen fruit so the vine redirects energy
- Avoid spraying insecticides while plants are flowering
- Maintain even watering
Toxicity
You can relax completely here. The fruit is harmless to people, pets, livestock, and birds, so a slice that drops in the garden is nothing to fret over. The one small thing to keep in mind is that the stems and leaves wear fine prickly hairs that may scratch sensitive skin while you harvest.
Safe for
People · Cats · Dogs · Horses · Rabbits · Livestock · Birds
Cats None
Cucumber is safe for cats, and many will happily nibble a slice with no trouble at all. The flesh is mostly water, so offer it in small pieces as a light treat.
Dogs None
Dogs can enjoy cucumber with no risk, and the crunchy, low-calorie slices make a fine snack. Cut it into bite-sized pieces so an eager eater does not gulp a whole chunk.
Horses Safe
Horses take to cucumber well, and a few sliced pieces make a refreshing summer treat. Keep it to small amounts alongside their usual forage.
Rabbits Safe
Rabbits can have cucumber in moderation, though it brings little fiber and lots of water. A thin slice or two now and then is plenty beside their hay.
Livestock Safe
Cattle, goats, and sheep can all eat cucumbers and the trimmed vines safely. Just introduce extra fruit a little at a time so a sudden pile does not upset their digestion.
Birds Safe
Both pet birds and backyard hens peck away cheerfully at cucumber, flesh and seeds alike. It is a hydrating snack to share, with no part of the plant off limits.
People Safe
Cucumber is a kitchen staple you can eat raw, pickled, or sliced into salads, and every part of the fruit is safe. The skin and stem end of a stressed fruit may taste bitter, but that is just flavor, not danger.
Stems and leaves bear slightly prickly hairs that can irritate sensitive skin; gloves are optional when harvesting spiny-fruited varieties.
Varieties
Cucumbers fall mostly into slicers and picklers, with a few tidy and seedless types that are lovely to know about. These are the friendly names you are most likely to meet.
Marketmore 76
A dependable classic slicer that keeps on giving, with strong resistance to scab and cucumber mosaic virus.
Straight Eight
A treasured heirloom slicer that gives you straight, dark green fruit around 8 inches long.
Boston Pickling
A generous heirloom pickler whose short, blocky fruit wears that telltale bumpy skin.
Spacemaster
A neat little bush type that settles happily into small gardens and containers.
Diva
A parthenocarpic, seedless pick that sets fruit without any pollination and offers thin, non-bitter skin.
Companions
Cucumbers do well beside beans, corn, and quick radishes, and poorly next to potatoes or strongly aromatic sage that extension guides flag as bad neighbors.
Plant near
beans: Extension companion-planting guides list beans as a traditional cucumber companion; legumes fix nitrogen that benefits neighboring crops.
corn: Listed as a compatible companion in extension guides; tall corn can also serve as a windbreak and partial support.
radish: Traditional extension-listed companion; quick-maturing radishes use space efficiently between young cucumber plants.
How to propagate
Good news for a first try: cucumbers come up easily from seed, and that is nearly the only way anyone starts them. All they really ask of you is warm soil and the gentlest possible handling of their roots.
SeedEasy
Direct sow after the last frost once soil reaches at least 16°C (60°F), or start indoors 2-4 weeks before transplanting · Seeds germinate in 3-10 days in warm soil; transplants establish within 1-2 weeks
Most gardeners simply grow cucumbers straight from seed, and it really is the easy, reliable path, so trust it. Once the last frost has passed and the soil has warmed to at least 60°F (16°C), sow the seed 0.5 to 1 inch (1.5 to 2.5 cm) deep in hills or rows, and you will see them break ground in 3 to 10 days. If you would like a head start, sow indoors 2 to 4 weeks before transplanting, but use peat or paper pots, since the roots dislike being disturbed and the transplants need a week or two to settle in.
Myths
Growing cucumbers close to melons or squash makes them cross and taste off.
You can plant them side by side without worry, since cucumbers cannot cross with melons or squash at all; they are separate species, so a neighbor has no say in how your cucumbers taste. Any off-flavor traces back to cucurbitacins the plant makes under heat and drought stress. And even when cucumber varieties do cross with one another, it only changes the seeds, never this season's fruit.
A cucumber that tastes bitter has gone bad and is unsafe to eat.
There is no need to toss it out. The bitterness is simply cucurbitacins that have built up in the skin and stem end of a stressed fruit, not any sign of spoilage. Peel the cucumber, trim that stem end, and most of the bitter taste leaves right along with it.