Missouri’s significant north-to-south climate variation presents a distinct challenge for vegetable gardeners. The growing season can be weeks longer in the southern Bootheel region compared to the northern border. This geographical reality makes a single, statewide planting schedule unreliable for timing crops. This guide provides regional context and specific planting windows, allowing gardeners to tailor schedules to their specific Missouri location.
Understanding Missouri’s Planting Zones and Average Frost Dates
For perennial plants, Missouri falls within USDA Hardiness Zones 5b through 7a, which dictate a plant’s ability to survive winter temperatures. For annual vegetable gardening, the average last spring and first fall frost dates are more important. These dates define the frost-free window when tender crops can thrive outdoors.
The average date of the last spring frost varies significantly, generally falling between late March and early May. Northern and central regions typically see their last frost around the third week of April. Warmer southeastern lowlands, such as the Bootheel, often have their last frost by the end of March or the first week of April. The growing season typically extends for approximately 170 days.
The average first fall frost occurs earliest in the north and latest in the south. Northern and central Missouri anticipate the first frost in the second or third week of October. This date extends to late October or early November in the far southern regions. These dates are based on a 50% probability of a 32°F temperature occurring, so local weather monitoring remains important.
Spring Planting Schedules: Cool-Season and Warm-Season Crops
Spring planting is divided into two phases based on the plant’s tolerance for cold temperatures and light frost. Cool-season crops are hardy and can be planted four to six weeks before the area’s average last spring frost date. These vegetables thrive in milder early spring temperatures and tolerate light freezes, down to about 27°F to 29°F.
Direct-sowing of crops like peas, spinach, radishes, and leaf lettuce can begin as early as the end of March in the northern half of the state. Transplants for cole crops, including broccoli, cabbage, and cauliflower, should be set out around late March or early April. Planting these crops too late risks them bolting when the summer heat arrives in May.
Warm-season crops, including tomatoes, peppers, corn, squash, and beans, are sensitive to frost. They must only be planted after the danger of freezing temperatures has fully passed. The soil temperature is also a factor, as many warm-season vegetables require soil warmth above 60°F for optimal root growth and development. This typically means waiting until late April or May to set out transplants.
Transplants for long-season crops like tomatoes and peppers are usually started indoors six to eight weeks before the planned outdoor planting date. Direct-sowing of seeds for warm-season vegetables, such as sweet corn, bush beans, and cucumbers, occurs once the soil is reliably warm in May. Planting these heat-loving crops too early can result in stunted growth and poor yields.
Planning for Fall and Succession Planting
A second growing season, or fall garden, allows for harvesting cool-season crops well into the autumn. Planning this second harvest requires calculating backward from the average first fall frost date, using the crop’s “days to maturity.” This ensures the plant has enough time to mature before the season-ending hard freeze.
Fall transplants of broccoli, Brussels sprouts, and cabbage should be set out during August. Direct seeding of fall favorites like carrots, beets, spinach, and leaf lettuce generally takes place from late July through August. Planting during the heat of August can be tricky, so pre-moistening the soil with cool water can aid in seed germination.
Succession planting maximizes yield from a small space by having multiple, staggered harvests. This involves replanting short-cycle crops every few weeks after the initial planting. Loose-leaf lettuce is an excellent candidate for this method, with new seeds sown every two to three weeks for a continuous supply.
This strategy can also involve planting both early- and late-maturing varieties of the same vegetable simultaneously to extend the harvest window. Fast-growing warm-season crops like bush beans and summer squash can be succession planted in late July or early August to produce a late-season crop.