USDA Idaho Hardiness Zones: 3b, 4a, 4b, 5a, 5b, 6a, 6b, 7a, 7b
Idaho has a rich and varied climate due to its mountainous terrain and desert areas. The higher the elevation, the cooler the average temperatures, and the more rainfall the state receives. On the other hand, the eastern and western mountain regions keep other areas of the state from receiving as much rainfall.
Although much of Idaho experiences all four seasons, the state’s southwestern portion is a high desert. It receives very little rainfall, and temperatures are cooler due to the increase in elevation. It is also very windy in this area.
Although growing in Idaho can be challenging due to the short growing seasons, there are plenty of plants that you can grow in your gardens as long as you know your specific planting zones.
Idaho Planting Zone – A Quick Overview:
- If you live in the Boise area or the southwestern part of the state, you’ll probably find that you are in growing zones 6a, 6b or 7a.
- As you move through the high desert to the west near Nampa, you may find yourself in Idaho Gardening zone 7a.
- The most northern tip of Idaho sits in the growing zones of 5a, 5b and 6a.
- A little bit south, in the area of Coeur D’Alene, you’ll probably see milder zones 6b and 7a.
- The higher elevations towards the east are mostly 4b, 5a, and 5b zones, but you’ll also see small sections of 4a and 3b growing zones, especially in Fremont and Clark Counties.
Using the Idaho Growing Zones Map
The hardiness map for Idaho is taken from the 2012 USDA map data. This map was created by the USDA to help farmers and gardeners plan their gardens. By knowing your USDA Idaho growing zone, you can calculate your first and last frost dates and know when to plant and what plants will grow in your area.
You can find your own zone by typing your zip code into the search bar or by locating your area on the map. The place you live will have a color corresponding to the map legend. This color shows you your Idaho climate zone.
Idaho is a highly varied climate, and these zones are just a rough estimate of the one you live in. But your specific zone may vary a little bit, depending on your elevation and terrain. You may want to ask local farmers and gardeners for advice on what zone you actually live in.
You can mitigate your growing zone a bit by using the principle of micro-climates. You can adjust your climate a bit by using buildings or hedges to shield your garden from high winds. You can also use boulders or hedgerows around your garden to reflect light and warmth back to your plants.
Finally, you can use swales to direct water towards your garden for irrigation if you need to.
Idaho: A Varied Climate for Planting
Idaho’s short growing season means you’ll either need to start seeds indoors or choose varieties with shorter growing seasons. Adams Gardens says that you can plant cool-weather crops outdoors as early as March, such as beets, broccoli, cauliflower, peas, spinach, and cabbage. However, beans and cucumbers should wait until the middle of May.
Fruit trees can be tricky to grow in the harsh climate, but you might consider hardy varieties of apples, pears, plums, and pie cherries. Hydrangeas, lilacs, and azaleas will also grow well in the harsher Idaho climate, but you may need to offer them some wind protection.
Regardless of what you want to plant, look for short-season varieties as well as plants that are native to Idaho, such as sagebrush. There are many options for native landscaping plants as well as flowers, fruit trees, and vegetables.