Some crops are less risky to plant early, and there are some tricks and tools that can help you protect your plants on those often cold spring nights.
Early greens and peas
With proper cover, such as floating row covers, also called remay cloth, you can get a head start on seeding some crops like peas, lettuce, spinach, the mustard family, and arugula. We like to use metal hoops over top of the rows, spaced about 6 feet apart. The floating row cover sits on top of the hoops and gets buried by soil on either side, and at both ends, to seal it.
Onions and potatoes
Root, tubers, and bulbs like onions, scallions, garlic, leeks, potatoes, will also be okay in normal cool May temperatures because they are insulated by the ground. Do keep them covered with row covers as their tender greens above the ground are susceptible below 32 degrees.
You can transplant members of the brassica family (broccoli, cabbage, collard greens, brussels sprouts, kohlrabi, cauliflower, and kale) outside now as long as they have been hardened off.
Make sure to harden off your plants. Any plants you buy from inside of a greenhouse have not been hardened off. Those that are sold from outside have likely been conditioned to the cold weather and are ready to be planted outside.
And don’t forget: young plants need food! Learn more about fertilizing young plants here.
Interested in learning more? The Grower’s Library at Johnny’s Selected Seeds may have the information you’re looking for.