Planting Onion Seedlings By the Ides of May, we’ve planted the onion bed, carrots, summer squash, peas, and massive messes of greens. There’s much more still to plant as the season warms: Beets, pole beans, bush beans, flowers for cutting, and, of course, tomatoes. Placing straw over mounds of compost. Summer squash seeds are germinating in these mounds. The magnificent Melchi, our Chief Morale Officer, cuddles with gardeners planting the greens beds.