Given our slow-to-start spring, there's lots of confusion about when seeds and plants should go into the ground, especially since the long-term forecast calls for a cooler than usual summer.
For years, Minnesotans have considered Memorial Day the "all clear" sign for planting, but being "safe" is not good enough for some vegetables.
Here's a guide to what you might wait to plant, what you can plant now and what would be best planted later in summer.
Popular heat-lovers such as tomatoes, peppers, eggplant and melons perform best when the air and the soil are warm. That means you may want to wait a week or so to put them in the ground. And because we're getting off to a slow start, choose early or mid-season tomatoes rather than late-maturing varieties.
Some vegetables that thrive in lower temperatures may still be seeded directly into the garden, including leaf lettuce, green onions and radishes. If the weather suddenly heats up and stays that way, the lettuce and radishes will probably turn bitter, bolt and go to seed. But given the cost of a packet of seed, it's a chance worth taking.
Spinach, another cool-season plant, does better planted in late summer, when it will be less troubled by spinach leaf miners. Broccoli, cabbage and cauliflower might grow well now if temperatures remain on the low side. But if you wait until July to start them, they'll mature in autumn, when cooler weather will improve their flavor.
Most any other vegetable can be direct-seeded into the garden now.
It's not too late to plant seeds for zinnias, cosmos, bachelor's buttons, California poppies and larkspur (annual delphiniums). And there's still a wide selection of geraniums, impatiens, marigolds, petunias and other favorite annuals available at garden centers, farmers' markets and building supply stores that are ready to be planted in the ground or in containers.
Since meteorologists are predicting a coolish summer, you should still be able to plant pansies or violas and expect them to look good for many more weeks. (In a typical year, the end of May would be late to plant these cool-season annuals.)
Other bedding plants that thrive in lower temperatures: lobelia (upright or trailing); cupflower (Nirembergia); nemesia, and three South African beauties that are usually potted and sold individually, gerbera daisy, osteospermum and diascia.
It's not too late to add perennials to the landscape, especially flowering perennials that will bloom later in the season. In addition to flowers, you can add perennial vegetables, such as rhubarb or asparagus crowns, or small-fruit bearing plants, such as strawberries, raspberries and blueberries.
Trees and shrubs
Although we're too far into spring to save money by using bare-root woody plants, you can still plant containerized or balled and burlapped trees and shrubs. By now, it's easier to shop for them because their leaves and flowers should be developed enough so you can see what you're getting. And by planting now, they should get off to a decent start before hotter summer weather sets in -- if it does.
If you have thin or bare areas in the lawn, loosen the soil and rake in some good-quality grass seed. The sooner, the better.
After you seed, be sure to keep the area relatively moist, particularly in windy or warm weather. And if your results are less than stellar, don't worry. You'll get another good chance to reseed in late August or early September.
Deb Brown is a garden writer and former extension horticulturist with the University of Minnesota. To ask her a gardening question, call 612-673-7793 and leave a message. She will answer questions in this column only.