Maine's frost dates guide the timing of various gardening tasks. For example, onions and leeks should be started indoors around March 3, about 10 weeks before the last frost. Peppers and tomatoes can be started indoors by March 17, roughly 8 weeks before the last frost. Direct-sowing of hardy crops like peas and spinach is ideal around April 7, 5 weeks before the last frost. Tender plants like tomatoes and peppers should only be transplanted outdoors after June 6, about a week after the late frost date. These guidelines help ensure plants thrive without being damaged by unexpected cold.