How far apart should I plant Collard greens?

About 45 cm (18 in) apart, centre to centre. A mature plant spreads 50–80 cm (20–31 in).

Does Collard greens need full sun?

Full sun: at least 6 hours of direct sun a day.

How much water does Collard greens need?

Moderate water. Drought tolerance is low and waterlogging tolerance low.

How cold-hardy is Collard greens?

It tolerates about -12 °C (10 °F) once established, roughly USDA zone 8. As a biennial it is usually planted out after the last frost and flowers in its second year.

When does Collard greens flower?

About 54–67 weeks after planting, for 4–6 weeks.

Is Collard greens poisonous to cats and dogs?

For cats it is not known to be toxic; for dogs not known to be toxic; for people not known to be toxic. Not toxic; large amounts of brassica leaves can cause gas or stomach upset in pets.

What grows well with Collard greens?

Traditional lore says rhubarb planted near brassicas helps against clubroot and pests; the evidence is weak and not confirmed by trials. Nasturtiums act as a trap crop for cabbage white butterflies and blackfly, drawing some pressure away from brassicas.

Collard greens Brassica oleracea var. viridis

Collard greens (Brassica oleracea var. viridis) is a biennial vegetable in the Brassicaceae family, native to Cultivar group of wild cabbage (Mediterranean and Atlantic Europe). It grows 60 cm–1 m (24 in–3.3 ft) tall and 50–80 cm (20–31 in) wide, wants full sun and moderate water, and is hardy to about -12 °C (10 °F). Space plants about 45 cm (18 in) apart.

Plan Collard greens in your garden →
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Collard greens at a glance

Type	Biennial vegetable
Family	Brassicaceae
Mature height	60 cm–1 m (24 in–3.3 ft)
Mature spread	50–80 cm (20–31 in)
Spacing	45 cm (18 in) centre to centre
Sun	Full sun, at least 6 h of direct sun a day
Water	Moderate; drought tolerance low, waterlogging tolerance low
Soil pH	6–7.5
Cold hardiness	About -12 °C (10 °F) once established (roughly USDA zone 8)
Heat stress	Likely above about 30 °C (86 °F)
Flowering	about 54–67 weeks after planting, for 4–6 weeks
Days to maturity	About 75 days from planting
Wind tolerance	Low
Pollinator value	Low
Edible	Yes: leaves
Native to	Cultivar group of wild cabbage (Mediterranean and Atlantic Europe)
Common in gardens of	🇺🇸 United States, 🇧🇷 Brazil, 🇿🇦 South Africa, 🇰🇪 Kenya

Is Collard greens toxic?

People: not known to be toxic
Cats: not known to be toxic
Dogs: not known to be toxic

Not toxic; large amounts of brassica leaves can cause gas or stomach upset in pets.

If a child or pet may have eaten part of a plant, call a poison centre or vet straight away.

Companion planting: what to grow with Collard greens

Good neighbours

good With Rhubarb: Traditional lore says rhubarb planted near brassicas helps against clubroot and pests; the evidence is weak and not confirmed by trials. Evidence D
good With Nasturtium: Nasturtiums act as a trap crop for cabbage white butterflies and blackfly, drawing some pressure away from brassicas. Evidence C

Shared pests and diseases

Clubroot: Clubroot spores persist in soil up to 20 years; keep brassicas in a rotation. Evidence B

Questions about Collard greens

How far apart should I plant Collard greens?: About 45 cm (18 in) apart, centre to centre. A mature plant spreads 50–80 cm (20–31 in).
Does Collard greens need full sun?: Full sun: at least 6 hours of direct sun a day.
How much water does Collard greens need?: Moderate water. Drought tolerance is low and waterlogging tolerance low.
How cold-hardy is Collard greens?: It tolerates about -12 °C (10 °F) once established, roughly USDA zone 8. As a biennial it is usually planted out after the last frost and flowers in its second year.
When does Collard greens flower?: About 54–67 weeks after planting, for 4–6 weeks.
Is Collard greens poisonous to cats and dogs?: For cats it is not known to be toxic; for dogs not known to be toxic; for people not known to be toxic. Not toxic; large amounts of brassica leaves can cause gas or stomach upset in pets.
What grows well with Collard greens?: Traditional lore says rhubarb planted near brassicas helps against clubroot and pests; the evidence is weak and not confirmed by trials. Nasturtiums act as a trap crop for cabbage white butterflies and blackfly, drawing some pressure away from brassicas.

Sources and evidence

Evidence grade C (C: plausible, mixed evidence).

University extension gardening guides (general), Various land-grant university extensions
RHS Plant Finder, Royal Horticultural Society
EcoCrop crop environmental requirements, FAO

Notes and assumptions

Leaves are picked from the bottom up over months; plants usually overwinter in zone 7 and warmer.

Reference values for planning, not horticultural, veterinary or medical advice. Varieties, soils and local climates differ: check with a local nursery or extension service.

Related plants

Broccoli Brassica oleracea var. italica
Cauliflower Brassica oleracea var. botrytis
Cabbage Brassica oleracea var. capitata
Kale Brassica oleracea var. sabellica
Radish Raphanus sativus
Bok choy Brassica rapa subsp. chinensis
Brussels sprout Brassica oleracea var. gemmifera
Kohlrabi Brassica oleracea var. gongylodes