What to plant in May in Idaho
In Idaho (ID), May comes about 1 week after the average last frost (May 10). The state averages 138 frost-free days a year (last frost May 10, first frost September 25; USDA zones 3b, 4b, 5b, 6a, 6b, 7a).
84 crops have a sowing or planting window this month, including carrot, chervil, endive & escarole, kohlrabi, lettuce, mustard greens - and 44 of those windows close during May.
Dates here come from Idaho frost dates (last frost May 10, first frost Sep 25). For one crop in detail, see when to plant carrot, lettuce or broccoli in Idaho.
Idaho 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.
Idaho: planting activity through the year
Last chance in May
Carrot (direct sow (spring), by May 3) · Chervil (direct sow (spring), by May 3) · Endive & Escarole (direct sow (spring), by May 3) · Kohlrabi (direct sow (spring), by May 3) · Lettuce (direct sow (spring), by May 3) · Mustard Greens (direct sow (spring), by May 3) · Rapini (Broccoli Raab) (direct sow (spring), by May 3) · Turnip (direct sow (spring), by May 3) · Watercress (direct sow (spring), by May 3) · Asparagus (plant crowns / divisions, by May 6) · Bok Choy / Pak Choi (transplant outdoors, by May 6) · Broccoli (transplant outdoors, by May 6) · Brussels Sprouts (transplant outdoors, by May 6) · Cauliflower (transplant outdoors, by May 6) · Chives (plant crowns / divisions, by May 6) · Endive & Escarole (transplant outdoors, by May 6) · Leek (transplant outdoors, by May 6) · Lettuce (transplant outdoors, by May 6) · Napa Cabbage (transplant outdoors, by May 6) · Parsley (transplant outdoors, by May 6) · Radicchio (transplant outdoors, by May 6) · Sorrel (plant crowns / divisions, by May 6) · Swiss Chard (transplant outdoors, by May 6) · Watercress (transplant outdoors, by May 6) · Bok Choy / Pak Choi (direct sow (spring), by May 10) · Borage (direct sow (spring), by May 10) · Cilantro / Coriander (direct sow (spring), by May 10) · Collard Greens (direct sow (spring), by May 10) · Kale (direct sow (spring), by May 10) · Leek (direct sow (spring), by May 10) · Napa Cabbage (direct sow (spring), by May 10) · Parsley (direct sow (spring), by May 10) · Potato (direct sow (spring), by May 10) · Radicchio (direct sow (spring), by May 10) · Salsify (direct sow (spring), by May 10) · Fennel (Bulb) (transplant outdoors, by May 13) · Globe Artichoke (plant crowns / divisions, by May 13) · Lemon Balm (transplant outdoors, by May 13) · Mint (transplant outdoors, by May 13) · Tarragon (transplant outdoors, by May 13) · Fennel (Bulb) (direct sow (spring), by May 17) · Lemon Balm (direct sow (spring), by May 17) · Parsnip (direct sow (spring), by May 17) · Swiss Chard (direct sow (spring), by May 17)
Sow or plant outdoors in May (104)
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 |
|---|---|---|---|
| Carrot | Direct sow (spring) | Apr 14 – May 3 | Last chance - ends May 3 |
| Chervil | Direct sow (spring) | Apr 14 – May 3 | Last chance - ends May 3 |
| Endive & Escarole | Direct sow (spring) | Apr 14 – May 3 | Last chance - ends May 3 |
| Kohlrabi | Direct sow (spring) | Apr 14 – May 3 | Last chance - ends May 3 |
| Lettuce | Direct sow (spring) | Apr 14 – May 3 | Last chance - ends May 3 |
| Mustard Greens | Direct sow (spring) | Apr 14 – May 3 | Last chance - ends May 3 |
| Rapini (Broccoli Raab) | Direct sow (spring) | Apr 14 – May 3 | Last chance - ends May 3 |
| Turnip | Direct sow (spring) | Apr 14 – May 3 | Last chance - ends May 3 |
| Watercress | Direct sow (spring) | Apr 14 – May 3 | Last chance - ends May 3 |
| Asparagus | Plant crowns / divisions | Apr 19 – May 6 | Last chance - ends May 6 |
| Bok Choy / Pak Choi | Transplant outdoors | Apr 19 – May 6 | Last chance - ends May 6 |
| Broccoli | Transplant outdoors | Apr 19 – May 6 | Last chance - ends May 6 |
| Brussels Sprouts | Transplant outdoors | Apr 19 – May 6 | Last chance - ends May 6 |
| Cauliflower | Transplant outdoors | Apr 19 – May 6 | Last chance - ends May 6 |
| Chives | Plant crowns / divisions | Apr 19 – May 6 | Last chance - ends May 6 |
| Endive & Escarole | Transplant outdoors | Apr 19 – May 6 | Last chance - ends May 6 |
| Leek | Transplant outdoors | Apr 19 – May 6 | Last chance - ends May 6 |
| Lettuce | Transplant outdoors | Apr 19 – May 6 | Last chance - ends May 6 |
| Napa Cabbage | Transplant outdoors | Apr 19 – May 6 | Last chance - ends May 6 |
| Parsley | Transplant outdoors | Apr 19 – May 6 | Last chance - ends May 6 |
| Radicchio | Transplant outdoors | Apr 19 – May 6 | Last chance - ends May 6 |
| Sorrel | Plant crowns / divisions | Apr 19 – May 6 | Last chance - ends May 6 |
| Swiss Chard | Transplant outdoors | Apr 19 – May 6 | Last chance - ends May 6 |
| Watercress | Transplant outdoors | Apr 19 – May 6 | Last chance - ends May 6 |
| Bok Choy / Pak Choi | Direct sow (spring) | Apr 21 – May 10 | Last chance - ends May 10 |
| Borage | Direct sow (spring) | Apr 21 – May 10 | Last chance - ends May 10 |
| Cilantro / Coriander | Direct sow (spring) | Apr 21 – May 10 | Last chance - ends May 10 |
| Collard Greens | Direct sow (spring) | Apr 21 – May 10 | Last chance - ends May 10 |
| Kale | Direct sow (spring) | Apr 21 – May 10 | Last chance - ends May 10 |
| Leek | Direct sow (spring) | Apr 21 – May 10 | Last chance - ends May 10 |
| Napa Cabbage | Direct sow (spring) | Apr 21 – May 10 | Last chance - ends May 10 |
| Parsley | Direct sow (spring) | Apr 21 – May 10 | Last chance - ends May 10 |
| Potato | Direct sow (spring) | Apr 21 – May 10 | Last chance - ends May 10 |
| Radicchio | Direct sow (spring) | Apr 21 – May 10 | Last chance - ends May 10 |
| Salsify | Direct sow (spring) | Apr 21 – May 10 | Last chance - ends May 10 |
| Fennel (Bulb) | Transplant outdoors | Apr 26 – May 13 | Last chance - ends May 13 |
| Globe Artichoke | Plant crowns / divisions | Apr 26 – May 13 | Last chance - ends May 13 |
| Lemon Balm | Transplant outdoors | Apr 26 – May 13 | Last chance - ends May 13 |
| Mint | Transplant outdoors | Apr 26 – May 13 | Last chance - ends May 13 |
| Tarragon | Transplant outdoors | Apr 26 – May 13 | Last chance - ends May 13 |
| Fennel (Bulb) | Direct sow (spring) | Apr 28 – May 17 | Last chance - ends May 17 |
| Lemon Balm | Direct sow (spring) | Apr 28 – May 17 | Last chance - ends May 17 |
| Parsnip | Direct sow (spring) | Apr 28 – May 17 | Last chance - ends May 17 |
| Swiss Chard | Direct sow (spring) | Apr 28 – May 17 | Last chance - ends May 17 |
| Celeriac | Transplant outdoors | May 3 – May 20 | May 3 – May 20 |
| Celery | Transplant outdoors | May 3 – May 20 | May 3 – May 20 |
| Oregano | Transplant outdoors | May 3 – May 20 | May 3 – May 20 |
| Sage | Transplant outdoors | May 3 – May 20 | May 3 – May 20 |
| Thyme | Transplant outdoors | May 3 – May 20 | May 3 – May 20 |
| Dill | Direct sow (spring) | May 5 – May 24 | May 5 – May 24 |
| Sunflower | Direct sow (spring) | May 5 – May 24 | May 5 – May 24 |
| Ground Cherry | Transplant outdoors | May 10 – May 27 | May 10 – May 27 |
| New Zealand Spinach | Transplant outdoors | May 10 – May 27 | May 10 – May 27 |
| Peanut | Transplant outdoors | May 10 – May 27 | May 10 – May 27 |
| Pumpkin | Transplant outdoors | May 10 – May 27 | May 10 – May 27 |
| Rosemary | Transplant outdoors | May 10 – May 27 | May 10 – May 27 |
| Shiso (Perilla) | Transplant outdoors | May 10 – May 27 | May 10 – May 27 |
| Summer Savory | Transplant outdoors | May 10 – May 27 | May 10 – May 27 |
| Sunflower | Transplant outdoors | May 10 – May 27 | May 10 – May 27 |
| Sweet Marjoram | Transplant outdoors | May 10 – May 27 | May 10 – May 27 |
| Tomatillo | Transplant outdoors | May 10 – May 27 | May 10 – May 27 |
| Tomato | Transplant outdoors | May 10 – May 27 | May 10 – May 27 |
| Winter Squash | Transplant outdoors | May 10 – May 27 | May 10 – May 27 |
| Zucchini / Summer Squash | Transplant outdoors | May 10 – May 27 | May 10 – May 27 |
| Amaranth (Leaf) | Direct sow (spring) | May 12 – May 31 | May 12 – May 31 |
| Bush Bean | Direct sow (spring) | May 12 – May 31 | May 12 – May 31 |
| Edamame (Soybean) | Direct sow (spring) | May 12 – May 31 | May 12 – May 31 |
| New Zealand Spinach | Direct sow (spring) | May 12 – May 31 | May 12 – May 31 |
| Pole Bean | Direct sow (spring) | May 12 – May 31 | May 12 – May 31 |
| Pumpkin | Direct sow (spring) | May 12 – May 31 | May 12 – May 31 |
| Shiso (Perilla) | Direct sow (spring) | May 12 – May 31 | May 12 – May 31 |
| Summer Savory | Direct sow (spring) | May 12 – May 31 | May 12 – May 31 |
| Sweet Corn | Direct sow (spring) | May 12 – May 31 | May 12 – May 31 |
| Sweet Marjoram | Direct sow (spring) | May 12 – May 31 | May 12 – May 31 |
| Winter Squash | Direct sow (spring) | May 12 – May 31 | May 12 – May 31 |
| Zucchini / Summer Squash | Direct sow (spring) | May 12 – May 31 | May 12 – May 31 |
| Basil | Transplant outdoors | May 17 – Jun 3 | Opens May 17 |
| Bell Pepper | Transplant outdoors | May 17 – Jun 3 | Opens May 17 |
| Bitter Melon | Transplant outdoors | May 17 – Jun 3 | Opens May 17 |
| Cantaloupe / Muskmelon | Transplant outdoors | May 17 – Jun 3 | Opens May 17 |
| Chili Pepper | Transplant outdoors | May 17 – Jun 3 | Opens May 17 |
| Cucamelon | Transplant outdoors | May 17 – Jun 3 | Opens May 17 |
| Cucumber | Transplant outdoors | May 17 – Jun 3 | Opens May 17 |
| Luffa (Loofah Gourd) | Transplant outdoors | May 17 – Jun 3 | Opens May 17 |
| Malabar Spinach | Transplant outdoors | May 17 – Jun 3 | Opens May 17 |
| Okra | Transplant outdoors | May 17 – Jun 3 | Opens May 17 |
| Watermelon | Transplant outdoors | May 17 – Jun 3 | Opens May 17 |
| Basil | Direct sow (spring) | May 19 – Jun 7 | Opens May 19 |
| Bitter Melon | Direct sow (spring) | May 19 – Jun 7 | Opens May 19 |
| Cantaloupe / Muskmelon | Direct sow (spring) | May 19 – Jun 7 | Opens May 19 |
| Chayote | Direct sow (spring) | May 19 – Jun 7 | Opens May 19 |
| Cucamelon | Direct sow (spring) | May 19 – Jun 7 | Opens May 19 |
| Cucumber | Direct sow (spring) | May 19 – Jun 7 | Opens May 19 |
| Lima Bean | Direct sow (spring) | May 19 – Jun 7 | Opens May 19 |
| Luffa (Loofah Gourd) | Direct sow (spring) | May 19 – Jun 7 | Opens May 19 |
| Malabar Spinach | Direct sow (spring) | May 19 – Jun 7 | Opens May 19 |
| Okra | Direct sow (spring) | May 19 – Jun 7 | Opens May 19 |
| Peanut | Direct sow (spring) | May 19 – Jun 7 | Opens May 19 |
| Southern Pea (Cowpea) | Direct sow (spring) | May 19 – Jun 7 | Opens May 19 |
| Watermelon | Direct sow (spring) | May 19 – Jun 7 | Opens May 19 |
| Eggplant | Transplant outdoors | May 24 – Jun 10 | Opens May 24 |
| Ginger | Transplant outdoors | May 24 – Jun 10 | Opens May 24 |
| Sweet Potato | Transplant outdoors | May 24 – Jun 10 | Opens May 24 |
| Turmeric | Transplant outdoors | May 24 – Jun 10 | Opens May 24 |
For fall and winter harvests (1)
Sowings counted back from Idaho'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 26 – Jun 12 | Opens May 26 |
Keep sowing (succession)
Repeat sowings of crops already in the ground, for a steady harvest instead of a glut.
- Pea: sow again on May 11 and May 23
- Spinach: sow again on May 11 and May 23
- Beet: sow again on May 18
- Radish: sow again on May 2 and May 12 and May 22
- Arugula: sow again on May 6 and May 18 and May 30
- Green Onion / Scallion: sow again on May 3 and May 24
- Mache (Corn Salad): sow again on May 3 and May 17 and May 31
- Tatsoi: sow again on May 6 and May 18 and May 30
- Mizuna: sow again on May 6 and May 18 and May 30
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 Idaho
Every crop has its own full-year dates for Idaho: indoor start, transplant or direct sowing, and harvest.
Main planting month: May garden jobs in Idaho
- With the average last frost on May 10, 75 crops can go in outdoors this month, including carrot, chervil, endive & escarole, kohlrabi.
- 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 Idaho
Idaho spans USDA zones 3b, 4b, 5b, 6a, 6b, 7a. 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 Idaho in May?
84 crops have a window in May: carrot, chervil, endive & escarole, kohlrabi, lettuce, mustard greens, rapini (broccoli raab), turnip, watercress, asparagus and more. The tables above give the exact dates for each.
Is it too late to plant tomatoes in Idaho in May?
No - transplant outdoors runs May 10 – May 27 in Idaho, so do it before May 27.
Is it too late to plant lettuce in Idaho in May?
No - direct sow (spring) runs Apr 14 – May 3 in Idaho, so do it before May 3.
When is the first frost in Idaho?
The statewide average first fall frost is around September 25 and the last spring frost around May 10. Idaho covers a wide range of climates, so local dates can differ by two weeks or more - look yours up by ZIP code.
What can I harvest in Idaho in May?
From plantings made on time: radish, spinach, arugula, tatsoi, mizuna, mustard greens, mache (corn salad), lettuce, turnip, rapini (broccoli raab).
What to plant in May in other states
Dates are computed from Idaho’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.