Vegetables: It should be safe around April 15 or so to plant seeds of certain cool season crops directly outside in your garden beds if the soil has been worked up and is ready for seeding. Crops like carrots, peas, radishes and beets should be direct-seeded outside instead of started indoors. If you plant too early, or in cold wet soil, seeds are likely to rot instead of germinating. The same goes for seed potatoes and even onion sets. That’s where an inexpensive soil thermometer that you can purchase at your local garden center can be really handy, because Mother Nature does not always respect calendar dates, and even though the date is right, the weather may not be. Seed potatoes need a minimum soil temperature of 40 degrees to sprout. Beets, carrots, radishes, lettuce and spinach all need a minimum soil temperature of 45 degrees to germinate. Snow peas and sugar snap peas need a minimum temperature of 50 degrees to germinate. You may also now plant out seedlings of spinach, chard, mustards, kale and lettuce that you started inside, but will need to cover them if frost is predicted.
Fruits: Remove straw mulch from strawberry beds if you haven’t already. Strawberries will need to covered with a blanket or floating row cover if frost is predicted, as the flowers are very susceptible to frost damage. It is best if you use hoops or stakes to keep the covering material from resting directly on the plants. New strawberries can be planted around the 15th of May if no frost is predicted. For more information on growing strawberries visit https://learningstore.uwex.edu/ and type A1597 into the search box to view the publication “Growing Strawberries in Wisconsin.”
— Lisa Johnson, Dane County UW-Extension horticulture educator