leafy green
EdibleCollard Greens
Brassica oleracea (Acephala Group)
Considered non-toxic to cats and dogs (source: ASPCA (not listed; brassica)).
A sunny south-facing window with 6+ hours, or a grow light.
Keep evenly moist — water when the top inch of soil is dry.
Forgiving and beginner-friendly.
Collards are a tough, heat- and cold-tolerant leafy green from the same species as kale and cabbage. They keep producing large leaves over a long season when picked from the bottom.
About Collard Greens
Collard greens (Brassica oleracea, Acephala Group) are a sturdy leafy green from the same species as kale and cabbage, with broad, smooth leaves. The group has Mediterranean and European origins, and collards became a cornerstone of Southern American cooking. For a renter their strength is endurance: they tolerate both heat and cold and keep producing large leaves over a long season when you pick from the bottom up. Give one or two plants a roomy, deeper 8-litre pot.
They want bright light and even water, and they grow to about 0.3 to 0.5 m. Harvest the oldest outer leaves first and leave the crown to keep pushing new growth, so a couple of plants can supply you for months. The flavor mellows and sweetens after a spell of cooler temperatures. A first harvest usually comes around 55 to 75 days from sowing, after which the plant keeps giving.
What it’s like to grow
Collards are tough and productive, and they read trouble plainly. Pale, floppy leaves mean the light is too weak, since this one really does want a bright spot. Aphids and cabbage worms gather on the leaf undersides, so check there if growth looks chewed. They take medium water, and picking the outer leaves first keeps them productive. They're non-toxic to cats and dogs. A good fit for a grower who wants a long-lasting, heat- and cold-tolerant green and has a bright window or a strong grow light to keep it sturdy.
What to expect
First harvest in about 55–75 days. It’s forgiving, so it’s a good one to learn on. No sunny window? It also does fine under a clip-on grow light.
See what you’ll need to get started ↓Companions
Tips
- Harvest the oldest outer leaves first and leave the crown to keep growing.
- Give a roomy, deeper pot and bright light for sturdy leaves.
- Flavor mellows and sweetens after cooler temperatures.
Common problems
- Aphids and cabbage worms on leaf undersides.
- Pale, floppy leaves in insufficient light.
Common questions
Is Collard Greens toxic to cats and dogs?
Collard Greens is non-toxic to cats and dogs, which makes it a safe pick if you have pets. Source: ASPCA (not listed; brassica).
How much light does Collard Greens need?
Collard Greens wants bright light — a south-facing window with six or more hours of sun, or a grow light to make up for it.
How often should I water Collard Greens?
Water Collard Greens when the top inch of soil feels dry, then let it drain. Aim for evenly moist, not soggy.
What temperature does Collard Greens need?
Collard Greens is happiest around 15–24 °C. It tolerates brief dips to about -7 °C, but cold drafts and sudden chills set it back.
How long does Collard Greens take to grow?
Expect a first harvest about 55–75 days from sowing under good conditions. A sturdy, long-lived plant you harvest leaf-by-leaf from the bottom up for months.
Can I grow Collard Greens without a sunny window?
Yes. Collard Greens does well under an affordable clip-on grow light, so a bright window isn't essential.
How big does Collard Greens get?
An upright leafy plant ~0.3–0.5 m tall; grow one or two and pick outer leaves.
How do I propagate Collard Greens?
Sow seed in a roomy deep pot and harvest the lower leaves as the plant grows.
What pests affect Collard Greens?
Watch for aphids, whitefly, cabbage loopers and flea beetles. Check new growth and the undersides of leaves often, and treat early with a rinse or insecticidal soap before they spread.
Is Collard Greens easy to grow?
Yes. Collard Greens is forgiving and one of the better plants to learn on.
Gear for Collard Greens
Gear suggestions to get you started — general picks, not paid placements.
Pet-toxicity from the ASPCA. Care details are general guidance, not professional or veterinary advice; only eat plants you can positively identify as the edible plant and part described. Photo: Eric Bronson, CC BY 2.0, via Wikimedia Commons (CC-BY). Care info last updated 2026-06-02.