Onions are easy to grow from sets. Plant 1” deep and 1–3” apart. Harvest young plants for use as scallions, thinning to 3–4” spacing. Onions should be mulched and supplied with ample phosphorus while growing. Mulch deeply (up to 8”) in cold winter areas but only lightly in milder climates. Mulching will suppress weeds, maintain soil moisture and protect bulbs from “heaving” (working their way out of the soil) during extreme temperature cycles. Weed suppression is critical for onions ― you can grow weeds or onions, but not both. Our onion sets come in yellow, white or red and all are long-day onions.