How to grow Cucumber

Cucumis sativus · cukes

Fast-growing warm-season vine that produces hydrating fruits. Requires high humidity and consistent moisture to prevent bitter fruit.

Cucumber — Photo: Stephen Ausmus, USDA ARS, Public domain, Wikimedia Commons

Quick facts

Type	Vegetable
Family	Cucurbitaceae
Light	Full sun
Soil pH	6–7
Frost	does not tolerate frost
Soil for sowing	from 18 °C
Germination	7 days
Seedlings ready	35 days
Sowing to harvest	65 days
Where it grows	Greenhouse, Open ground, At home

When to plant

Sow for seedlings about 6 weeks before planting out.

Plant out in open ground about a week after your last spring frost, once the soil is warm.

In an unheated greenhouse everything moves about three weeks earlier.

The first harvest comes about 65 days after the shoots appear.

Care

Greenhouse

Stage	Watering	Temperature	Feeding
Seedlings	every 2 days	20…25 °C	—
Growth	every 3 days	18…28 °C	nitrogen, 14 days into the stage
Flowering	every 2 days	18…30 °C	balanced (NPK), at the start of the stage
Fruiting	every 1 days	18…30 °C	potassium, at the start of the stage; potassium, 14 days into the stage

Open ground

Stage	Watering	Temperature	Feeding
Seedlings	every 2 days	18…25 °C	—
Growth	every 4 days	15…28 °C	nitrogen, 14 days into the stage
Flowering	every 3 days	15…30 °C	balanced (NPK), at the start of the stage
Fruiting	every 2 days	15…30 °C	potassium, at the start of the stage; potassium, 14 days into the stage

At home

Stage	Watering	Temperature	Feeding
Seedlings	every 2 days	20…24 °C	—
Growth	every 3 days	18…24 °C	balanced (NPK), 14 days into the stage
Flowering	every 2 days	18…25 °C	phosphorus and potassium, at the start of the stage
Fruiting	every 1 days	18…25 °C	potassium, at the start of the stage

Growing notes

Light

Full sun is ideal, though some partial shade can prevent leaf scorch in extreme heat.

Soil

Rich, sandy loam with plenty of organic matter; must be well-draining.

Care

Provide a trellis or fence for climbing varieties to improve air circulation. Water consistently at the base of the plant to avoid wetting leaves, which prevents powdery mildew. Harvest frequently to encourage the plant to produce more fruit.

How to tell it is ripe

Fruit is evenly green, firm and crisp-looking: this is the best eating stage.
Size fits the type: about 5 cm for small pickles, 10–15 cm for dills and 15–20 cm for slicing cucumbers.
Over-mature fruit starts to turn yellow and has hard seeds and a bitter taste.
A cucumber at its best feels firm and crisp all over when held.
Cut with a sharp knife or pruners in the early morning every other day, and never leave yellow fruit on the vine because it stops the plant cropping.

Pests and diseases of Cucumber

Anthracnose
Bacterial wilt
Broad mite
Chafer grubs
Cucumber beetles
Downy Mildew
Fusarium Wilt
Grey Mold
Leaf Curl Virus
Leaf Miner
Two-spotted spider mite
Verticillium Wilt
White mould (Sclerotinia)
Whitefly

Sources

Figures cited from these sources.