INFORMATION ON AVERAGE LAST SPRING FREEZE DATES IN UTAH
Answer by: Loralie Cox, Utah State University Extension Cache County Horticulture Agent
With spring approaching, it is time once again to think about planting and gardening. Knowing the average last frost date gives gardeners the opportunity to make specific plans for planting both hardy and tender plants in the garden.
Cold hardy vegetables can be planted four to six weeks before the last frost date. Some of these include broccoli, cabbage, lettuce, onions, peas and spinach. These crops thrive in cool weather and should not be planted late in the spring. Pea seeds, for example, can germinate when soil temperatures are about 40 F while tomato seeds germinate best when soil temperatures are above 65 F. Beets, carrots, chard, onion sets and radishes are hardy plants that can be planted two to four weeks before the last frost date.
Plants that are not cold hardy should be planted around the frost free date. These include beans, squash, corn and tomatoes. Peppers, eggplant, cucumbers and melons require hot weather to grow well and should be planted about a week after the last expected frost. These plants may be injured if planted too early and consequently may not grow or flower well throughout the rest of the season. To get a jump on the season, several of these warm season vegetables may be started by seed inside, then planted outside when temperatures warm.
If planted indoors, tomato and pepper seeds should be planted six to eight weeks before the last frost. The seedlings should have a bright light source such as a south window or a fluorescent light structure placed several inches above. Squash, cucumbers and melons should be seeded about two to three weeks before transplanting to the garden.