May in the upper Midwest is when the real work of planting begins. Throughout the region, the last frost day falls in this month, and it’s time to put seeds and transplants in the ground. This regional planting guide will help you understand what to plant when in May in Minnesota, Wisconsin, Michigan, and Iowa.
Upper Midwest Planting Guide
May is a transitional period in the garden. There is a lot to do, and much of that involves planting. This is when you’ll get most of your plants or seeds in beds for the coming growing season.
Now is the time to sow seeds for summer vegetables, to plant summer bulbs, to put in annuals and any new perennials, to start certain seeds indoors, and to get transplants outdoors from seeds you began inside in early spring.
What to Plant in May in the Upper Midwest States
This is a rough set of guidelines for the upper Midwest. If you are more to the north in this region, shift a little later, and in the south, shift earlier.
- Throughout May you can do staggered plantings of your cool weather vegetables, like radishes. This will give you a steadier supply during the growing season.
- In early to mid-May you can sow seeds outside for late cabbage varieties, carrots, chard, beets, kohlrabi, leaf lettuce, mustard and collard greens, turnips, spinach, peas, and potatoes.
- In mid-May move transplants outdoors for seeds you started inside. These may include broccoli, cauliflower, early cabbage varieties, head lettuce, onions, and Brussels sprouts.
- By the end of the month you can direct sow seeds outside for beans, pumpkin, sweet corn, watermelon, tomatoes, winter squashes, peppers, eggplant, and okra.
- Once the danger of frost has passed, you can plant annual flowers outside.
- The last week of the month is also a good time in most parts of this region to begin putting in summer bulbs.
- If you have any new perennials to plant, you can do it starting in late May but also continue throughout the summer.
- Any houseplants that enjoy the outdoors in summer can safely be moved out toward the end of the month.