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Collard Greens in the US

You can sow collard greens straight into the soil or get them started indoors, depending on your zone and when your last frost is. For most folks, this means sowing from early spring right through to late summer or early fall, ensuring they grow during the cool season. Just pop the seeds about half an inch (1 cm) deep, spaced a few inches apart. If you're sowing directly, thin them out later. Check your USDA zone; the GrowMore CookMore app has all the specific timings for you, making sure you get them in at the right cool part of the season.

If you've started your collard greens indoors, get them pricked out into individual pots once they've got a couple of true leaves. Give them a good few weeks to harden off outside before planting them out properly after your last frost. Aim for a foot (30 cm) or so between plants in rows about 18 inches (45 cm) apart. They're big plants, you see, and they like their space. You can even grow a couple in a big container, mind, if your backyard is on the smaller side.