What to plant in May in Montana
In Montana (MT), the average last frost (May 15) falls in May itself. The state averages 123 frost-free days a year (last frost May 15, first frost September 15; USDA zones 3a, 3b, 4a, 4b, 5a, 5b, 6a).
91 crops have a sowing or planting window this month, including arugula, beet, fava bean (broad bean), green onion / scallion, mizuna, onion - and 59 of those windows close during May.
Dates here come from Montana frost dates (last frost May 15, first frost Sep 15). For one crop in detail, see when to plant arugula, beet or onion in Montana.
Montana covers a very wide range of climates, so dates near you can be two weeks or more either side of these. Enter your ZIP code in the planting calendar for dates tuned to your town.
Montana: planting activity through the year
Last chance in May
Cantaloupe / Muskmelon (start seeds indoors, by May 1) · Cucumber (start seeds indoors, by May 1) · Pumpkin (start seeds indoors, by May 1) · Sunflower (start seeds indoors, by May 1) · Watermelon (start seeds indoors, by May 1) · Winter Squash (start seeds indoors, by May 1) · Zucchini / Summer Squash (start seeds indoors, by May 1) · Arugula (direct sow (spring), by May 1) · Beet (direct sow (spring), by May 1) · Fava Bean (Broad Bean) (direct sow (spring), by May 1) · Green Onion / Scallion (direct sow (spring), by May 1) · Mizuna (direct sow (spring), by May 1) · Onion (direct sow (spring), by May 1) · Radish (direct sow (spring), by May 1) · Shallot (direct sow (spring), by May 1) · Tatsoi (direct sow (spring), by May 1) · Cabbage (transplant outdoors, by May 4) · Collard Greens (transplant outdoors, by May 4) · Horseradish (plant crowns / divisions, by May 4) · Kale (transplant outdoors, by May 4) · Kohlrabi (transplant outdoors, by May 4) · Onion (transplant outdoors, by May 4) · Rhubarb (plant crowns / divisions, by May 4) · Shallot (transplant outdoors, by May 4) · Carrot (direct sow (spring), by May 8) · Chervil (direct sow (spring), by May 8) · Endive & Escarole (direct sow (spring), by May 8) · Kohlrabi (direct sow (spring), by May 8) · Lettuce (direct sow (spring), by May 8) · Mustard Greens (direct sow (spring), by May 8) · Rapini (Broccoli Raab) (direct sow (spring), by May 8) · Turnip (direct sow (spring), by May 8) · Watercress (direct sow (spring), by May 8) · Asparagus (plant crowns / divisions, by May 11) · Bok Choy / Pak Choi (transplant outdoors, by May 11) · Broccoli (transplant outdoors, by May 11) · Brussels Sprouts (transplant outdoors, by May 11) · Cauliflower (transplant outdoors, by May 11) · Chives (plant crowns / divisions, by May 11) · Endive & Escarole (transplant outdoors, by May 11) · Leek (transplant outdoors, by May 11) · Lettuce (transplant outdoors, by May 11) · Napa Cabbage (transplant outdoors, by May 11) · Parsley (transplant outdoors, by May 11) · Radicchio (transplant outdoors, by May 11) · Sorrel (plant crowns / divisions, by May 11) · Swiss Chard (transplant outdoors, by May 11) · Watercress (transplant outdoors, by May 11) · Bok Choy / Pak Choi (direct sow (spring), by May 15) · Borage (direct sow (spring), by May 15) · Cilantro / Coriander (direct sow (spring), by May 15) · Collard Greens (direct sow (spring), by May 15) · Kale (direct sow (spring), by May 15) · Leek (direct sow (spring), by May 15) · Napa Cabbage (direct sow (spring), by May 15) · Parsley (direct sow (spring), by May 15) · Potato (direct sow (spring), by May 15) · Radicchio (direct sow (spring), by May 15) · Salsify (direct sow (spring), by May 15)
Sow or plant outdoors in May (121)
Direct sowing and transplanting windows that fall in May, most urgent first. Windows are one-to-two-week bands around the ideal date.
| Crop | What to do | Window | This month |
|---|---|---|---|
| Arugula | Direct sow (spring) | Apr 12 – May 1 | Last chance - ends May 1 |
| Beet | Direct sow (spring) | Apr 12 – May 1 | Last chance - ends May 1 |
| Fava Bean (Broad Bean) | Direct sow (spring) | Apr 12 – May 1 | Last chance - ends May 1 |
| Green Onion / Scallion | Direct sow (spring) | Apr 12 – May 1 | Last chance - ends May 1 |
| Mizuna | Direct sow (spring) | Apr 12 – May 1 | Last chance - ends May 1 |
| Onion | Direct sow (spring) | Apr 12 – May 1 | Last chance - ends May 1 |
| Radish | Direct sow (spring) | Apr 12 – May 1 | Last chance - ends May 1 |
| Shallot | Direct sow (spring) | Apr 12 – May 1 | Last chance - ends May 1 |
| Tatsoi | Direct sow (spring) | Apr 12 – May 1 | Last chance - ends May 1 |
| Cabbage | Transplant outdoors | Apr 17 – May 4 | Last chance - ends May 4 |
| Collard Greens | Transplant outdoors | Apr 17 – May 4 | Last chance - ends May 4 |
| Horseradish | Plant crowns / divisions | Apr 17 – May 4 | Last chance - ends May 4 |
| Kale | Transplant outdoors | Apr 17 – May 4 | Last chance - ends May 4 |
| Kohlrabi | Transplant outdoors | Apr 17 – May 4 | Last chance - ends May 4 |
| Onion | Transplant outdoors | Apr 17 – May 4 | Last chance - ends May 4 |
| Rhubarb | Plant crowns / divisions | Apr 17 – May 4 | Last chance - ends May 4 |
| Shallot | Transplant outdoors | Apr 17 – May 4 | Last chance - ends May 4 |
| Carrot | Direct sow (spring) | Apr 19 – May 8 | Last chance - ends May 8 |
| Chervil | Direct sow (spring) | Apr 19 – May 8 | Last chance - ends May 8 |
| Endive & Escarole | Direct sow (spring) | Apr 19 – May 8 | Last chance - ends May 8 |
| Kohlrabi | Direct sow (spring) | Apr 19 – May 8 | Last chance - ends May 8 |
| Lettuce | Direct sow (spring) | Apr 19 – May 8 | Last chance - ends May 8 |
| Mustard Greens | Direct sow (spring) | Apr 19 – May 8 | Last chance - ends May 8 |
| Rapini (Broccoli Raab) | Direct sow (spring) | Apr 19 – May 8 | Last chance - ends May 8 |
| Turnip | Direct sow (spring) | Apr 19 – May 8 | Last chance - ends May 8 |
| Watercress | Direct sow (spring) | Apr 19 – May 8 | Last chance - ends May 8 |
| Asparagus | Plant crowns / divisions | Apr 24 – May 11 | Last chance - ends May 11 |
| Bok Choy / Pak Choi | Transplant outdoors | Apr 24 – May 11 | Last chance - ends May 11 |
| Broccoli | Transplant outdoors | Apr 24 – May 11 | Last chance - ends May 11 |
| Brussels Sprouts | Transplant outdoors | Apr 24 – May 11 | Last chance - ends May 11 |
| Cauliflower | Transplant outdoors | Apr 24 – May 11 | Last chance - ends May 11 |
| Chives | Plant crowns / divisions | Apr 24 – May 11 | Last chance - ends May 11 |
| Endive & Escarole | Transplant outdoors | Apr 24 – May 11 | Last chance - ends May 11 |
| Leek | Transplant outdoors | Apr 24 – May 11 | Last chance - ends May 11 |
| Lettuce | Transplant outdoors | Apr 24 – May 11 | Last chance - ends May 11 |
| Napa Cabbage | Transplant outdoors | Apr 24 – May 11 | Last chance - ends May 11 |
| Parsley | Transplant outdoors | Apr 24 – May 11 | Last chance - ends May 11 |
| Radicchio | Transplant outdoors | Apr 24 – May 11 | Last chance - ends May 11 |
| Sorrel | Plant crowns / divisions | Apr 24 – May 11 | Last chance - ends May 11 |
| Swiss Chard | Transplant outdoors | Apr 24 – May 11 | Last chance - ends May 11 |
| Watercress | Transplant outdoors | Apr 24 – May 11 | Last chance - ends May 11 |
| Bok Choy / Pak Choi | Direct sow (spring) | Apr 26 – May 15 | Last chance - ends May 15 |
| Borage | Direct sow (spring) | Apr 26 – May 15 | Last chance - ends May 15 |
| Cilantro / Coriander | Direct sow (spring) | Apr 26 – May 15 | Last chance - ends May 15 |
| Collard Greens | Direct sow (spring) | Apr 26 – May 15 | Last chance - ends May 15 |
| Kale | Direct sow (spring) | Apr 26 – May 15 | Last chance - ends May 15 |
| Leek | Direct sow (spring) | Apr 26 – May 15 | Last chance - ends May 15 |
| Napa Cabbage | Direct sow (spring) | Apr 26 – May 15 | Last chance - ends May 15 |
| Parsley | Direct sow (spring) | Apr 26 – May 15 | Last chance - ends May 15 |
| Potato | Direct sow (spring) | Apr 26 – May 15 | Last chance - ends May 15 |
| Radicchio | Direct sow (spring) | Apr 26 – May 15 | Last chance - ends May 15 |
| Salsify | Direct sow (spring) | Apr 26 – May 15 | Last chance - ends May 15 |
| Fennel (Bulb) | Transplant outdoors | May 1 – May 18 | May 1 – May 18 |
| Globe Artichoke | Plant crowns / divisions | May 1 – May 18 | May 1 – May 18 |
| Lemon Balm | Transplant outdoors | May 1 – May 18 | May 1 – May 18 |
| Mint | Transplant outdoors | May 1 – May 18 | May 1 – May 18 |
| Tarragon | Transplant outdoors | May 1 – May 18 | May 1 – May 18 |
| Fennel (Bulb) | Direct sow (spring) | May 3 – May 22 | May 3 – May 22 |
| Lemon Balm | Direct sow (spring) | May 3 – May 22 | May 3 – May 22 |
| Parsnip | Direct sow (spring) | May 3 – May 22 | May 3 – May 22 |
| Swiss Chard | Direct sow (spring) | May 3 – May 22 | May 3 – May 22 |
| Celeriac | Transplant outdoors | May 8 – May 25 | May 8 – May 25 |
| Celery | Transplant outdoors | May 8 – May 25 | May 8 – May 25 |
| Oregano | Transplant outdoors | May 8 – May 25 | May 8 – May 25 |
| Sage | Transplant outdoors | May 8 – May 25 | May 8 – May 25 |
| Thyme | Transplant outdoors | May 8 – May 25 | May 8 – May 25 |
| Dill | Direct sow (spring) | May 10 – May 29 | May 10 – May 29 |
| Sunflower | Direct sow (spring) | May 10 – May 29 | May 10 – May 29 |
| Ground Cherry | Transplant outdoors | May 15 – Jun 1 | Opens May 15 |
| New Zealand Spinach | Transplant outdoors | May 15 – Jun 1 | Opens May 15 |
| Peanut | Transplant outdoors | May 15 – Jun 1 | Opens May 15 |
| Pumpkin | Transplant outdoors | May 15 – Jun 1 | Opens May 15 |
| Rosemary | Transplant outdoors | May 15 – Jun 1 | Opens May 15 |
| Shiso (Perilla) | Transplant outdoors | May 15 – Jun 1 | Opens May 15 |
| Summer Savory | Transplant outdoors | May 15 – Jun 1 | Opens May 15 |
| Sunflower | Transplant outdoors | May 15 – Jun 1 | Opens May 15 |
| Sweet Marjoram | Transplant outdoors | May 15 – Jun 1 | Opens May 15 |
| Tomatillo | Transplant outdoors | May 15 – Jun 1 | Opens May 15 |
| Tomato | Transplant outdoors | May 15 – Jun 1 | Opens May 15 |
| Winter Squash | Transplant outdoors | May 15 – Jun 1 | Opens May 15 |
| Zucchini / Summer Squash | Transplant outdoors | May 15 – Jun 1 | Opens May 15 |
| Amaranth (Leaf) | Direct sow (spring) | May 17 – Jun 5 | Opens May 17 |
| Bush Bean | Direct sow (spring) | May 17 – Jun 5 | Opens May 17 |
| Edamame (Soybean) | Direct sow (spring) | May 17 – Jun 5 | Opens May 17 |
| New Zealand Spinach | Direct sow (spring) | May 17 – Jun 5 | Opens May 17 |
| Pole Bean | Direct sow (spring) | May 17 – Jun 5 | Opens May 17 |
| Pumpkin | Direct sow (spring) | May 17 – Jun 5 | Opens May 17 |
| Shiso (Perilla) | Direct sow (spring) | May 17 – Jun 5 | Opens May 17 |
| Summer Savory | Direct sow (spring) | May 17 – Jun 5 | Opens May 17 |
| Sweet Corn | Direct sow (spring) | May 17 – Jun 5 | Opens May 17 |
| Sweet Marjoram | Direct sow (spring) | May 17 – Jun 5 | Opens May 17 |
| Winter Squash | Direct sow (spring) | May 17 – Jun 5 | Opens May 17 |
| Zucchini / Summer Squash | Direct sow (spring) | May 17 – Jun 5 | Opens May 17 |
| Basil | Transplant outdoors | May 22 – Jun 8 | Opens May 22 |
| Bell Pepper | Transplant outdoors | May 22 – Jun 8 | Opens May 22 |
| Bitter Melon | Transplant outdoors | May 22 – Jun 8 | Opens May 22 |
| Cantaloupe / Muskmelon | Transplant outdoors | May 22 – Jun 8 | Opens May 22 |
| Chili Pepper | Transplant outdoors | May 22 – Jun 8 | Opens May 22 |
| Cucamelon | Transplant outdoors | May 22 – Jun 8 | Opens May 22 |
| Cucumber | Transplant outdoors | May 22 – Jun 8 | Opens May 22 |
| Luffa (Loofah Gourd) | Transplant outdoors | May 22 – Jun 8 | Opens May 22 |
| Malabar Spinach | Transplant outdoors | May 22 – Jun 8 | Opens May 22 |
| Okra | Transplant outdoors | May 22 – Jun 8 | Opens May 22 |
| Watermelon | Transplant outdoors | May 22 – Jun 8 | Opens May 22 |
| Basil | Direct sow (spring) | May 24 – Jun 12 | Opens May 24 |
| Bitter Melon | Direct sow (spring) | May 24 – Jun 12 | Opens May 24 |
| Cantaloupe / Muskmelon | Direct sow (spring) | May 24 – Jun 12 | Opens May 24 |
| Chayote | Direct sow (spring) | May 24 – Jun 12 | Opens May 24 |
| Cucamelon | Direct sow (spring) | May 24 – Jun 12 | Opens May 24 |
| Cucumber | Direct sow (spring) | May 24 – Jun 12 | Opens May 24 |
| Lima Bean | Direct sow (spring) | May 24 – Jun 12 | Opens May 24 |
| Luffa (Loofah Gourd) | Direct sow (spring) | May 24 – Jun 12 | Opens May 24 |
| Malabar Spinach | Direct sow (spring) | May 24 – Jun 12 | Opens May 24 |
| Okra | Direct sow (spring) | May 24 – Jun 12 | Opens May 24 |
| Peanut | Direct sow (spring) | May 24 – Jun 12 | Opens May 24 |
| Southern Pea (Cowpea) | Direct sow (spring) | May 24 – Jun 12 | Opens May 24 |
| Watermelon | Direct sow (spring) | May 24 – Jun 12 | Opens May 24 |
| Eggplant | Transplant outdoors | May 29 – Jun 15 | Opens May 29 |
| Ginger | Transplant outdoors | May 29 – Jun 15 | Opens May 29 |
| Sweet Potato | Transplant outdoors | May 29 – Jun 15 | Opens May 29 |
| Turmeric | Transplant outdoors | May 29 – Jun 15 | Opens May 29 |
For fall and winter harvests (2)
Sowings counted back from Montana's first fall frost, so the crop matures before the cold - or, for garlic and similar, planted after it.
| Crop | What to do | Window | This month |
|---|---|---|---|
| Brussels Sprouts | Start transplants for fall | May 16 – Jun 2 | Opens May 16 |
| Rutabaga | Sow for a fall crop | May 30 – Jun 16 | Opens May 30 |
Start seeds indoors in May (7)
Indoor sowings for transplants later. Six to eight weeks under lights is typical for tomatoes and peppers; onions and leeks need longer.
| Crop | What to do | Window | This month |
|---|---|---|---|
| Cantaloupe / Muskmelon | Start seeds indoors | Apr 17 – May 1 | Last chance - ends May 1 |
| Cucumber | Start seeds indoors | Apr 17 – May 1 | Last chance - ends May 1 |
| Pumpkin | Start seeds indoors | Apr 17 – May 1 | Last chance - ends May 1 |
| Sunflower | Start seeds indoors | Apr 17 – May 1 | Last chance - ends May 1 |
| Watermelon | Start seeds indoors | Apr 17 – May 1 | Last chance - ends May 1 |
| Winter Squash | Start seeds indoors | Apr 17 – May 1 | Last chance - ends May 1 |
| Zucchini / Summer Squash | Start seeds indoors | Apr 17 – May 1 | Last chance - ends May 1 |
Keep sowing (succession)
Repeat sowings of crops already in the ground, for a steady harvest instead of a glut.
- Pea: sow again on May 4 and May 16 and May 28
- Spinach: sow again on May 4 and May 16 and May 28
- Mache (Corn Salad): sow again on May 8 and May 22
Harvesting in May
First harvests expected this month from crops sown or planted on time earlier in the season.
Planting dates for popular crops in Montana
Every crop has its own full-year dates for Montana: indoor start, transplant or direct sowing, and harvest.
Main planting month: May garden jobs in Montana
- With the average last frost on May 15, 87 crops can go in outdoors this month, including arugula, beet, fava bean (broad bean), green onion / scallion.
- Transplant on a cloudy afternoon and water in well - see transplanting seedlings without shock.
- Once the soil has warmed, lay mulch around established plants to hold moisture and smother weeds.
- Sow quick crops little and often - lettuce, radish and beans every two to three weeks give a steady harvest instead of a glut (succession planting).
USDA zone chart for Montana
Montana spans USDA zones 3a, 3b, 4a, 4b, 5a, 5b, 6a. Colder zones, usually higher or further inland, have a later last spring frost and an earlier first fall frost than the state average.
Questions gardeners ask
What vegetables can I plant in Montana in May?
91 crops have a window in May: arugula, beet, fava bean (broad bean), green onion / scallion, mizuna, onion, radish, shallot, tatsoi, cabbage and more. The tables above give the exact dates for each.
Is it too late to plant tomatoes in Montana in May?
No - transplant outdoors runs May 15 – Jun 1 in Montana.
Is it too late to plant lettuce in Montana in May?
No - direct sow (spring) runs Apr 19 – May 8 in Montana, so do it before May 8.
When is the first frost in Montana?
The statewide average first fall frost is around September 15 and the last spring frost around May 15. Montana covers a wide range of climates, so local dates can differ by two weeks or more - look yours up by ZIP code.
What should I start indoors in May in Montana?
Cantaloupe / Muskmelon (Apr 17 – May 1), Cucumber (Apr 17 – May 1), Pumpkin (Apr 17 – May 1), Sunflower (Apr 17 – May 1), Watermelon (Apr 17 – May 1), Winter Squash (Apr 17 – May 1), Zucchini / Summer Squash (Apr 17 – May 1).
What to plant in May in other states
Dates are computed from Montana’s statewide average frost dates (from NOAA/NCEI climate normals) and each crop’s timing in our crop database. Your garden may be a week or two either side - for dates tuned to your ZIP code, use the planting calendar.