GreenlyWhat to plant in January in the Mountain West
Worked out for 15 cities from their own weather and frost dates, by zone.
What to sow and plant in January in the Mountain West, by zone: frost possible, highs of 50–61 °F (St. George): broad bean, peas, onion, spinach, lettuce and 14 more; frost possible, highs below 50 °F (Denver, Salt Lake City and 12 more): broad bean, spinach, cabbage, broccoli, parsley and 2 more.
In the Mountain West, January is winter.
Frost possible, highs of 50–61 °F: St. George
In January, on average, St. George has highs of 51 °F and lows of 32 °F, 1.2 in of rain on 5 days; the day lasts 9 h 53 min (on the 15th).
January falls in the frost season: frost-tender crops wait.
| How | What | Where |
|---|---|---|
| sow direct | Broad bean, peas, spinach, lettuce, radish, cabbage, Swiss chard, arugula, chamomile, daikon, kale, parsnip, turnip | St. George |
| plant sets | Onion, shallot | St. George |
| start indoors, plant out in February | Cauliflower, beet, kohlrabi | St. George |
| start indoors, plant out in March | Parsley | St. George |
Compared with December: no longer sown — garlic and Brussels sprouts.
Not starting in January: tomato (no month outdoors by these rules), bell pepper (no month outdoors by these rules), zucchini (March, started indoors) and green beans (April, sown direct) — dates for St. George.
Ready to harvest in January in St. George, if sown in the right month: broad bean (October), peas (November), spinach (November), lettuce (November), radish (December), carrot (November), Swiss chard (November) and beet (November).
Frost possible, highs below 50 °F: Denver, Salt Lake City, Colorado Springs, Reno and 10 more
In January, on average, these cities have highs of 31 to 46 °F and lows of 15 to 29 °F, 0.6 to 3.9 in of rain on 4 to 11 days; the day lasts 8 h 56 min to 9 h 47 min (on the 15th).
January falls in the frost season: frost-tender crops wait.
| How | What | Where |
|---|---|---|
| start indoors, plant out in February | Broad bean, spinach | Denver, Salt Lake City, Colorado Springs and 5 more |
| start indoors, plant out in February | Lettuce | Grand Junction and Pueblo |
| start indoors, plant out in March | Cabbage | all |
| start indoors, plant out in March | Broccoli | Denver, Salt Lake City, Colorado Springs and 9 more |
| start indoors, plant out in February | Cauliflower, Swiss chard, beet, arugula, chamomile, kale | Pueblo |
| start indoors, plant out in March | Parsley, Brussels sprouts | Denver, Salt Lake City, Colorado Springs and 4 more |
| start indoors, plant out in February | Kohlrabi | Denver, Salt Lake City, Colorado Springs and 4 more |
Compared with December: new — lettuce, cauliflower, Swiss chard, beet, arugula, chamomile and kale; no longer sown — garlic, crocus, daffodil, hyacinth and tulip.
Not starting in January: tomato (no month outdoors by these rules), bell pepper (no month outdoors by these rules), zucchini (April, started indoors), green beans (May, sown direct) and peas (March, sown direct) — dates for Grand Junction.
Ready to harvest in January in Grand Junction, if sown in the right month: broad bean (October), peas (November), spinach (November), broccoli (October) and turnip (November).
- Frost dates in Denver
- Frost dates in Salt Lake City
- Frost dates in Colorado Springs
- Frost dates in Reno
- Frost dates in Billings
- Frost dates in Cheyenne
- Frost dates in Helena
- Frost dates in Carson City
- Frost dates in Fort Collins
- Frost dates in Grand Junction
- Frost dates in Pueblo
- Frost dates in Missoula
- Frost dates in Elko
- Frost dates in Provo
How we work it out
For each city we use its average weather in January and the months after (highs, lows and rain for 2016–2025, ERA5 reanalysis via Open-Meteo) and its average frost dates. A crop starts in January if the month's mean temperature reaches the minimum soil temperature for germination on its card (we use the mean air temperature as a stand-in for the soil's) and if, over its first months (up to three), the average highs stay within its group's range, with no frost for crops that cannot take it. Crops started indoors count from the month they are planted out.
Temperature groups from Colorado State University Extension: cool-season crops prefer 60–80 °F and lose quality in heat; hardy ones grow in days as cool as 40 °F, semi-hardy ones from 40–50 °F (we use 50 °F); warm-season crops need days above 55 °F, and the most tender (tomato, pepper, eggplant, melon, watermelon, squash) above 60 °F, up to 95 °F. Crops the guide does not name go into the stricter group by their frost hardiness. Fava (broad) beans, which the guide does not name, count as hardy: hardy varieties are sown in fall and overwinter (RHS). Garlic and bulbs: a month before the first frost, and later only while the ground is not frozen (as on each city's page).
This is a general rule from averages: your garden can be a week or two earlier or later, and a greenhouse or a cold frame brings the season forward. Greenly works out the dates for your location.
- Moon planting calendar for January 2027
- What to plant in January: all climates
- Gardening in the United States: guide by region
