One of the hardest parts of gardening in Missoula is knowing when to do what. Our short season leaves little room for error, and seed packets written for the whole country rarely account for how late our spring arrives. A month-by-month schedule built around our actual frost dates takes the guesswork out of it. Here is roughly how the seed-starting year looks for a Missoula garden.
Everything here is anchored to our average last spring frost around May 19 and our first fall frost around September 22. Watch the weather each year and adjust, but this gives you a dependable framework.
February and March: Start the Slow Crops Indoors
The seed-starting year really begins indoors in late winter. Peppers are first, since they are slow to germinate and grow, so start them indoors in mid to late March, about eight to ten weeks before they go out. Onions and leeks from seed also like an early start around this time.
Late March into early April is when tomatoes go in. Tomatoes need about six to eight weeks indoors before transplanting, so starting them in late March to mid-April lines them up to go out after the last frost. Resist the urge to start tomatoes in February. Started too early, they outgrow their pots and turn leggy long before it is safe to plant them out.
April: Cool-Season Crops Go Outside
April is when the outdoor garden wakes up, even though the last frost is still weeks away. Cool-season crops tolerate cold soil and light frost, so you can direct sow them well before May 19. As soon as the soil can be worked, sow peas, spinach, radishes, lettuce, and other hardy greens directly in the ground. Carrots and beets can go in during April too.
This is also the time to start hardy transplants like broccoli, cabbage, and kale, either started indoors a few weeks earlier or bought as starts, and set them out in mid to late April. These plants handle the cool weather and get a jump on the season. Keep a row cover handy to throw over tender young plants if a hard freeze threatens.
May: The Big Transition
May is the busiest month and the one that requires the most patience. Early in the month you can keep direct sowing cool-season crops and succession planting more lettuce and greens. But the warm-season crops still have to wait.
Around and after our last frost on May 19, once the soil has warmed, it is finally time for the warm-season crops. Direct sow beans, squash, cucumbers, and corn into warm soil, and transplant out your tomatoes and peppers after hardening them off. Many gardeners wait until the very end of May or the first days of June for peppers and the most cold-sensitive crops, since cold soil sets them back. There is no prize for planting these early.
June Through August: Plant for Fall
Once everything is in by mid-June, the focus shifts to maintenance and, importantly, planning for fall. The fall garden is the most overlooked opportunity in our climate. From late June through August, keep succession sowing quick crops like lettuce, radishes, and bush beans every couple of weeks so you always have something coming.
In mid to late summer, usually late July into August, start a fresh round of cool-season crops for fall harvest. Sow more spinach, lettuce, kale, and other hardy greens, along with quick root crops. They mature in the cooling weather of September and often taste better than spring plantings. With a row cover or cold frame, many of these keep producing well past the first fall frost.
September and Beyond
As fall arrives, the season winds down but is not over. Harvest warm-season crops ahead of the first frost around September 22, and keep picking cold-hardy crops, which often improve after a light frost. Garlic gets planted in fall, usually in September or October, to overwinter for next year’s harvest. And as beds empty, a layer of compost and mulch sets the soil up for spring.
Kept on a schedule like this, a Missoula garden produces from the first spring greens through the last fall harvest. If you want a planting calendar built specifically for your garden and your goals, that is exactly what I do. Take a look at the vegetable garden consulting page and reach out.