Cucumber / Cuke (Cucumis sativus) growing guide

Quick facts

Category: fruiting
Difficulty: intermediate
Days to harvest: 50 to 70 days
Harvest type: continuous production over weeks or months
Spacing: 50 cm between plants

Environment

Temperature: 18–28°C
pH: 5.5 to 6.5
EC (hydroponic): 1.8 to 2.8 mS/cm
Daily light: 22 to 30 mol/m²/day (strict, will fail outside this range)

Climate and zones

USDA zones: 10 to 13 (winter low around -1°C or warmer)
Frost tolerance: frost sensitive (dies at first frost)
Season: warm (summer crops, frost-sensitive)

Viable growing environments:

outdoor year-round (in zone)
outdoor in growing season (annual)
unheated greenhouse / hoop house
heated greenhouse
indoor (heated home)
indoor hydroponics under grow lights

USDA zone bounds reflect outdoor year-round survival. Anywhere outside the bounded zone range, this crop still grows as an annual in the warm months (outdoor_seasonal), under cover (greenhouse), or indoors under lights.

Growing systems

Cucumber works in:

drip / Dutch buckets
media bed (ebb and flow)
soil bed

Root mass is heavy - thin-channel systems (NFT, vertical towers) can't hold this crop mechanically, hence the system list above.

Growing media

The substrate the roots sit in. Choice depends on the system (clay pebbles don't fit NFT channels; rockwool isn't used in media beds) and the crop (cucumber works in the media listed below).

Medium	pH effect	Water retention	Bacterial surface
Expanded clay pebbles (LECA)	neutral / inert	low	high
Coco coir (Coconut coir)	slightly acidic	high	moderate
Perlite (Expanded volcanic glass)	neutral / inert	very low	low
Rockwool (Mineral wool)	alkaline until pre-soaked	very high	low
Soil-based mix (Potting soil)	varies by source	high	high

Bacterial surface area matters for aquaponics: clay pebbles, lava rock, and pumice double as biofilter substrate. Low-surface media (rockwool, perlite, pea gravel) work in hydroponics but need a separate biofilter in aquaponics.

Nutrient demand by stage

NPK ratios are relative weights at each growth stage; the nutrient mix calculator scales them to absolute grams or ml. EC targets shift through the plant's life: seedlings need a much lighter solution than fruiting adults.

Stage	N	P	K	EC target (mS/cm)
seedling	1	1	1	1
vegetative	3	1	2	2
flowering	2	2	3	2.3
fruiting	1	2	4	2.6

Companion-growing notes

Heavy uptake of potassium, nitrogen. Co-grown crops with the same demand will end up deficient even at "correct" EC. Plan around this in shared reservoirs.
Very high transpiration. Reservoir level drops fast once the plant is mature; expect daily top-ups and watch for EC creeping up as water evaporates faster than salts.

Aquaponics suitability

Compatible with typical aquaponics nutrient profiles. Fish waste provides enough nitrogen for healthy growth; supplemental potassium, calcium, and iron may still be needed depending on fish stocking density.

Care notes

One of the most productive hydroponic crops per square meter. Dutch bucket, rockwool slab, or perlite bag systems are standard for commercial production. EC 2.0-3.0 mS/cm. pH 5.5-6.5. Temperature: 22–28°C daytime, 18–20°C night (cucumbers are heat-loving; below 15°C growth stalls). Very high light (DLI 20-30 mol/m2/day). Use parthenocarpic (seedless) varieties for indoor growing: 'Tyria', 'Picowell', 'Katrina', 'Marketmore 76' (slicing). Train the vine vertically on string, removing all lateral shoots below the first meter of growth, then allowing laterals above that to produce 1-2 fruits each before pinching. A well-managed cucumber plant produces 20-40 fruits over a 3-4 month season. Harvest frequently (every 1-2 days) to keep the plant producing new fruit. Cucumber plants are heavy water consumers and sensitive to salt buildup; flush the root zone regularly. Powdery mildew is the most common disease; resistant varieties and good airflow are the primary defenses. Spider mites thrive in the warm, dry conditions cucumbers prefer; monitor undersides of leaves. For home hydroponic growers, one or two cucumber plants produce more than a household can eat.

Notable varieties

A starting shortlist of cultivars worth knowing about. Not exhaustive: the seed catalogs list hundreds of named varieties. These are the ones home growers commonly choose between.

Cultivar	Type	Breeder / origin	Days	Size	Notes
Marketmore 76	open-pollinated	Cornell	58	230 g	Cornell-bred slicing cucumber, 1976 release. Dark green 20cm fruit, disease-resistant package (CMV, DM, PM, S). The reliable US-market slicer in most climates. Open-pollinated, seed saves true.
Diva	hybrid		58	200 g	Parthenocarpic F1 (sets fruit without pollination) so suits greenhouses, hoop houses, and any season too cool for active bee activity. Smooth thin skin, no bitterness, eat unpeeled. All-female (gynoecious) flowering.
Suyo Long	heirloom		60	350 g	Chinese trellising heirloom producing 40-50cm ribbed fruit. Mild, no bitterness, thin skin. Must be trellised vertically or fruit curls and twists. Tolerates hot humid summers better than American slicing types.
Boston Pickling	heirloom		55	80 g	Pre-1880 pickling heirloom. 8-15cm bumpy fruit specifically for jar pickling at the smaller end of that range. Productive on standard bush habit; supports without trellising.
Lemon Cucumber	heirloom		70	100 g	Pre-1894 heirloom. Round pale-yellow fruit the size of a tennis ball. Mild flavor distinct from green cucumbers, never bitter. Sprawling vine habit, productive once it starts. Eat at golf-ball to baseball size.