What to plant in April in Idaho
In Idaho (ID), April sits about 4 weeks before 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).
64 crops have a sowing or planting window this month, including mache (corn salad), pea, spinach, green onion / scallion, arugula, beet - and 16 of those windows close during April.
Dates here come from Idaho frost dates (last frost May 10, first frost Sep 25). For one crop in detail, see when to plant pea, spinach or arugula 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 April
Broccoli (start seeds indoors, by Apr 5) · Brussels Sprouts (start seeds indoors, by Apr 5) · Cabbage (start seeds indoors, by Apr 5) · Cauliflower (start seeds indoors, by Apr 5) · Kale (start seeds indoors, by Apr 5) · Basil (start seeds indoors, by Apr 12) · Collard Greens (start seeds indoors, by Apr 12) · Endive & Escarole (start seeds indoors, by Apr 12) · Kohlrabi (start seeds indoors, by Apr 12) · Malabar Spinach (start seeds indoors, by Apr 12) · Okra (start seeds indoors, by Apr 12) · Radicchio (start seeds indoors, by Apr 12) · Summer Savory (start seeds indoors, by Apr 12) · Mache (Corn Salad) (direct sow (spring), by Apr 19) · Pea (direct sow (spring), by Apr 19) · Spinach (direct sow (spring), by Apr 19)
Sow or plant outdoors in April (65)
Direct sowing and transplanting windows that fall in April, most urgent first. Windows are one-to-two-week bands around the ideal date.
| Crop | What to do | Window | This month |
|---|---|---|---|
| Mache (Corn Salad) | Direct sow (spring) | Mar 31 – Apr 19 | Last chance - ends Apr 19 |
| Pea | Direct sow (spring) | Mar 31 – Apr 19 | Last chance - ends Apr 19 |
| Spinach | Direct sow (spring) | Mar 31 – Apr 19 | Last chance - ends Apr 19 |
| Green Onion / Scallion | Transplant outdoors | Apr 5 – Apr 22 | Apr 5 – Apr 22 |
| Arugula | Direct sow (spring) | Apr 7 – Apr 26 | Apr 7 – Apr 26 |
| Beet | Direct sow (spring) | Apr 7 – Apr 26 | Apr 7 – Apr 26 |
| Fava Bean (Broad Bean) | Direct sow (spring) | Apr 7 – Apr 26 | Apr 7 – Apr 26 |
| Green Onion / Scallion | Direct sow (spring) | Apr 7 – Apr 26 | Apr 7 – Apr 26 |
| Mizuna | Direct sow (spring) | Apr 7 – Apr 26 | Apr 7 – Apr 26 |
| Onion | Direct sow (spring) | Apr 7 – Apr 26 | Apr 7 – Apr 26 |
| Radish | Direct sow (spring) | Apr 7 – Apr 26 | Apr 7 – Apr 26 |
| Shallot | Direct sow (spring) | Apr 7 – Apr 26 | Apr 7 – Apr 26 |
| Tatsoi | Direct sow (spring) | Apr 7 – Apr 26 | Apr 7 – Apr 26 |
| Cabbage | Transplant outdoors | Apr 12 – Apr 29 | Apr 12 – Apr 29 |
| Collard Greens | Transplant outdoors | Apr 12 – Apr 29 | Apr 12 – Apr 29 |
| Horseradish | Plant crowns / divisions | Apr 12 – Apr 29 | Apr 12 – Apr 29 |
| Kale | Transplant outdoors | Apr 12 – Apr 29 | Apr 12 – Apr 29 |
| Kohlrabi | Transplant outdoors | Apr 12 – Apr 29 | Apr 12 – Apr 29 |
| Onion | Transplant outdoors | Apr 12 – Apr 29 | Apr 12 – Apr 29 |
| Rhubarb | Plant crowns / divisions | Apr 12 – Apr 29 | Apr 12 – Apr 29 |
| Shallot | Transplant outdoors | Apr 12 – Apr 29 | Apr 12 – Apr 29 |
| Carrot | Direct sow (spring) | Apr 14 – May 3 | Opens Apr 14 |
| Chervil | Direct sow (spring) | Apr 14 – May 3 | Opens Apr 14 |
| Endive & Escarole | Direct sow (spring) | Apr 14 – May 3 | Opens Apr 14 |
| Kohlrabi | Direct sow (spring) | Apr 14 – May 3 | Opens Apr 14 |
| Lettuce | Direct sow (spring) | Apr 14 – May 3 | Opens Apr 14 |
| Mustard Greens | Direct sow (spring) | Apr 14 – May 3 | Opens Apr 14 |
| Rapini (Broccoli Raab) | Direct sow (spring) | Apr 14 – May 3 | Opens Apr 14 |
| Turnip | Direct sow (spring) | Apr 14 – May 3 | Opens Apr 14 |
| Watercress | Direct sow (spring) | Apr 14 – May 3 | Opens Apr 14 |
| Asparagus | Plant crowns / divisions | Apr 19 – May 6 | Opens Apr 19 |
| Bok Choy / Pak Choi | Transplant outdoors | Apr 19 – May 6 | Opens Apr 19 |
| Broccoli | Transplant outdoors | Apr 19 – May 6 | Opens Apr 19 |
| Brussels Sprouts | Transplant outdoors | Apr 19 – May 6 | Opens Apr 19 |
| Cauliflower | Transplant outdoors | Apr 19 – May 6 | Opens Apr 19 |
| Chives | Plant crowns / divisions | Apr 19 – May 6 | Opens Apr 19 |
| Endive & Escarole | Transplant outdoors | Apr 19 – May 6 | Opens Apr 19 |
| Leek | Transplant outdoors | Apr 19 – May 6 | Opens Apr 19 |
| Lettuce | Transplant outdoors | Apr 19 – May 6 | Opens Apr 19 |
| Napa Cabbage | Transplant outdoors | Apr 19 – May 6 | Opens Apr 19 |
| Parsley | Transplant outdoors | Apr 19 – May 6 | Opens Apr 19 |
| Radicchio | Transplant outdoors | Apr 19 – May 6 | Opens Apr 19 |
| Sorrel | Plant crowns / divisions | Apr 19 – May 6 | Opens Apr 19 |
| Swiss Chard | Transplant outdoors | Apr 19 – May 6 | Opens Apr 19 |
| Watercress | Transplant outdoors | Apr 19 – May 6 | Opens Apr 19 |
| Bok Choy / Pak Choi | Direct sow (spring) | Apr 21 – May 10 | Opens Apr 21 |
| Borage | Direct sow (spring) | Apr 21 – May 10 | Opens Apr 21 |
| Cilantro / Coriander | Direct sow (spring) | Apr 21 – May 10 | Opens Apr 21 |
| Collard Greens | Direct sow (spring) | Apr 21 – May 10 | Opens Apr 21 |
| Kale | Direct sow (spring) | Apr 21 – May 10 | Opens Apr 21 |
| Leek | Direct sow (spring) | Apr 21 – May 10 | Opens Apr 21 |
| Napa Cabbage | Direct sow (spring) | Apr 21 – May 10 | Opens Apr 21 |
| Parsley | Direct sow (spring) | Apr 21 – May 10 | Opens Apr 21 |
| Potato | Direct sow (spring) | Apr 21 – May 10 | Opens Apr 21 |
| Radicchio | Direct sow (spring) | Apr 21 – May 10 | Opens Apr 21 |
| Salsify | Direct sow (spring) | Apr 21 – May 10 | Opens Apr 21 |
| Fennel (Bulb) | Transplant outdoors | Apr 26 – May 13 | Opens Apr 26 |
| Globe Artichoke | Plant crowns / divisions | Apr 26 – May 13 | Opens Apr 26 |
| Lemon Balm | Transplant outdoors | Apr 26 – May 13 | Opens Apr 26 |
| Mint | Transplant outdoors | Apr 26 – May 13 | Opens Apr 26 |
| Tarragon | Transplant outdoors | Apr 26 – May 13 | Opens Apr 26 |
| Fennel (Bulb) | Direct sow (spring) | Apr 28 – May 17 | Opens Apr 28 |
| Lemon Balm | Direct sow (spring) | Apr 28 – May 17 | Opens Apr 28 |
| Parsnip | Direct sow (spring) | Apr 28 – May 17 | Opens Apr 28 |
| Swiss Chard | Direct sow (spring) | Apr 28 – May 17 | Opens Apr 28 |
Start seeds indoors in April (31)
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 |
|---|---|---|---|
| Broccoli | Start seeds indoors | Mar 22 – Apr 5 | Last chance - ends Apr 5 |
| Brussels Sprouts | Start seeds indoors | Mar 22 – Apr 5 | Last chance - ends Apr 5 |
| Cabbage | Start seeds indoors | Mar 22 – Apr 5 | Last chance - ends Apr 5 |
| Cauliflower | Start seeds indoors | Mar 22 – Apr 5 | Last chance - ends Apr 5 |
| Kale | Start seeds indoors | Mar 22 – Apr 5 | Last chance - ends Apr 5 |
| Basil | Start seeds indoors | Mar 29 – Apr 12 | Last chance - ends Apr 12 |
| Collard Greens | Start seeds indoors | Mar 29 – Apr 12 | Last chance - ends Apr 12 |
| Endive & Escarole | Start seeds indoors | Mar 29 – Apr 12 | Last chance - ends Apr 12 |
| Kohlrabi | Start seeds indoors | Mar 29 – Apr 12 | Last chance - ends Apr 12 |
| Malabar Spinach | Start seeds indoors | Mar 29 – Apr 12 | Last chance - ends Apr 12 |
| Okra | Start seeds indoors | Mar 29 – Apr 12 | Last chance - ends Apr 12 |
| Radicchio | Start seeds indoors | Mar 29 – Apr 12 | Last chance - ends Apr 12 |
| Summer Savory | Start seeds indoors | Mar 29 – Apr 12 | Last chance - ends Apr 12 |
| Bitter Melon | Start seeds indoors | Apr 5 – Apr 19 | Apr 5 – Apr 19 |
| Bok Choy / Pak Choi | Start seeds indoors | Apr 5 – Apr 19 | Apr 5 – Apr 19 |
| Cucamelon | Start seeds indoors | Apr 5 – Apr 19 | Apr 5 – Apr 19 |
| Fennel (Bulb) | Start seeds indoors | Apr 5 – Apr 19 | Apr 5 – Apr 19 |
| Lettuce | Start seeds indoors | Apr 5 – Apr 19 | Apr 5 – Apr 19 |
| Luffa (Loofah Gourd) | Start seeds indoors | Apr 5 – Apr 19 | Apr 5 – Apr 19 |
| Napa Cabbage | Start seeds indoors | Apr 5 – Apr 19 | Apr 5 – Apr 19 |
| New Zealand Spinach | Start seeds indoors | Apr 5 – Apr 19 | Apr 5 – Apr 19 |
| Peanut | Start seeds indoors | Apr 5 – Apr 19 | Apr 5 – Apr 19 |
| Swiss Chard | Start seeds indoors | Apr 5 – Apr 19 | Apr 5 – Apr 19 |
| Watercress | Start seeds indoors | Apr 5 – Apr 19 | Apr 5 – Apr 19 |
| Cantaloupe / Muskmelon | Start seeds indoors | Apr 12 – Apr 26 | Apr 12 – Apr 26 |
| Cucumber | Start seeds indoors | Apr 12 – Apr 26 | Apr 12 – Apr 26 |
| Pumpkin | Start seeds indoors | Apr 12 – Apr 26 | Apr 12 – Apr 26 |
| Sunflower | Start seeds indoors | Apr 12 – Apr 26 | Apr 12 – Apr 26 |
| Watermelon | Start seeds indoors | Apr 12 – Apr 26 | Apr 12 – Apr 26 |
| Winter Squash | Start seeds indoors | Apr 12 – Apr 26 | Apr 12 – Apr 26 |
| Zucchini / Summer Squash | Start seeds indoors | Apr 12 – Apr 26 | Apr 12 – Apr 26 |
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.
Last-frost month: April garden jobs in Idaho
- The average last frost is May 10. Hardy crops can go out now - mache (corn salad), pea, spinach, green onion / scallion - but hold tender ones like tomatoes, peppers and squash until after that date.
- Start hardening off indoor seedlings 7-10 days before they go out: a few hours of outdoor shade first, building up to full sun and nights outside.
- Keep row cover or old sheets handy and watch the 10-day forecast - a clear, still night after a warm spell is the classic late-frost setup.
- Soil temperature matters as much as the calendar: most warm-season seed rots below about 60°F. Check the frost dates guide for how the Idaho average is worked out.
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 April?
64 crops have a window in April: mache (corn salad), pea, spinach, green onion / scallion, arugula, beet, fava bean (broad bean), mizuna, onion, radish and more. The tables above give the exact dates for each.
Is it too late to plant tomatoes in Idaho in April?
Not too late - it's actually a little early. In Idaho the next tomato window opens around May 10: transplant outdoors.
Is it too late to plant lettuce in Idaho in April?
No - start seeds indoors runs Apr 5 – Apr 19 in Idaho, so do it before April 19.
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 should I start indoors in April in Idaho?
Broccoli (Mar 22 – Apr 5), Brussels Sprouts (Mar 22 – Apr 5), Cabbage (Mar 22 – Apr 5), Cauliflower (Mar 22 – Apr 5), Kale (Mar 22 – Apr 5), Basil (Mar 29 – Apr 12), Collard Greens (Mar 29 – Apr 12), Endive & Escarole (Mar 29 – Apr 12), Kohlrabi (Mar 29 – Apr 12), Malabar Spinach (Mar 29 – Apr 12), Okra (Mar 29 – Apr 12), Radicchio (Mar 29 – Apr 12), Summer Savory (Mar 29 – Apr 12), Bitter Melon (Apr 5 – Apr 19), Bok Choy / Pak Choi (Apr 5 – Apr 19), Cucamelon (Apr 5 – Apr 19), Fennel (Bulb) (Apr 5 – Apr 19), Lettuce (Apr 5 – Apr 19), Luffa (Loofah Gourd) (Apr 5 – Apr 19), Napa Cabbage (Apr 5 – Apr 19), New Zealand Spinach (Apr 5 – Apr 19), Peanut (Apr 5 – Apr 19), Swiss Chard (Apr 5 – Apr 19), Watercress (Apr 5 – Apr 19), Cantaloupe / Muskmelon (Apr 12 – Apr 26), Cucumber (Apr 12 – Apr 26), Pumpkin (Apr 12 – Apr 26), Sunflower (Apr 12 – Apr 26), Watermelon (Apr 12 – Apr 26), Winter Squash (Apr 12 – Apr 26), Zucchini / Summer Squash (Apr 12 – Apr 26).
What to plant in April 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.