It can't wait. Cool season vegetables must go in the ground soon. Unless they are planted during cool weather, these plants won't develop properly and they will fail when it gets too hot. They can take temperatures a few degrees below freezing. If we experience a really hard cold snap, they can be protected with a frost cloth or sheets. I realize that conventional wisdom says not to plant until after Mother's Day. That's wrong. Maybe your granny says that. But I'm the former Director of Horticulture at Denver Botanic Gardens. Science and horticultural experience dictate when we plant, not some arbitrary date. Prepare the beds by turning over the soil. Work in some compost. Rake it smooth. As you plant, add a bit of vegetable fertilizer into the holes. Most leafy greens can be planted now. These include cabbage, lettuce, chard, arugula, spinach, parsley, cilantro, mustard, cauliflower and broccoli. Root crops can also be planted. Start with onion sets. Then plant seeds of radish, beets, carrots and turnips. Read more here: https://www.9news.com/article/life/home-garden/proctors-tips/plant-cool-season-crops-now/73-efc5ed84-1608-4df2-a098-7453d5bb7a4b