what growing zone is boise idaho

What Growing Zone is Boise, Idaho In?

Boise, Idaho, primarily falls within the USDA plant hardiness zone 6b, with some areas extending into zone 7a. This means the average minimum winter temperature in Boise ranges from -5 to 5 degrees Fahrenheit. Understanding your growing zone is crucial for selecting plants that can survive the winter in your specific area.

Understanding USDA Plant Hardiness Zones

The USDA Plant Hardiness Zone Map divides North America into 13 zones based on average annual minimum winter temperatures. Each zone is further divided into “a” and “b” subzones, representing 5-degree Fahrenheit differences. This system helps gardeners and growers choose plants that are likely to thrive in their local climate.

Boise’s Specific Growing Zone

While much of Boise is in zone 6b (-5 to 0°F), higher elevations and microclimates within the city can experience colder temperatures, potentially aligning with zone 6a (-10 to -5°F). Conversely, sheltered urban areas and south-facing slopes may offer slightly warmer conditions, pushing them into zone 7a (0 to 5°F). It’s essential to consider your specific location and microclimate when choosing plants.

Factors Affecting Boise’s Growing Zone

Several factors influence the actual growing conditions in Boise, regardless of the official USDA zone. These include:

• Elevation: Higher elevations generally experience colder temperatures.
• Microclimates: Buildings, walls, and bodies of water can create warmer or colder pockets within a small area.
• Snow Cover: Snow can insulate the ground and protect plant roots from extreme cold.
• Soil Type: Well-draining soil can help prevent root rot during wet winters.

Choosing Plants for Boise

When selecting plants for your Boise garden, prioritize those rated for zone 6 or lower to ensure winter hardiness. Consider experimenting with plants rated for zone 7 in sheltered locations or with winter protection. Local nurseries are excellent resources for advice on plants that thrive in Boise’s specific conditions. You can learn more about the USDA plant hardiness zone on Wikipedia.

Frequently Asked Questions

What does it mean to be in growing zone 6b?

Growing zone 6b means the average minimum winter temperature in your area is between -5 and 0 degrees Fahrenheit. Plants rated for zone 6 or lower should generally survive the winter.

Can I grow plants from zone 7 in Boise?

Yes, you can try growing zone 7 plants in sheltered areas or with winter protection, such as mulch or row covers. However, success is not guaranteed.

Where can I find plants that are suitable for Boise’s growing zone?

Local nurseries and garden centers are the best places to find plants that are known to thrive in Boise. They can offer advice specific to your area.

How accurate are growing zones?

Growing zones are a helpful guideline, but they don’t account for all factors that affect plant hardiness, such as microclimates and soil conditions. Consider them as a starting point and observe how plants perform in your garden.

Does Boise’s growing zone affect when I should plant?

Yes, knowing your growing zone helps determine the appropriate planting times. For example, you may need to wait until after the last frost date to plant tender annuals.

Summary

Boise, Idaho is primarily in USDA plant hardiness zone 6b, meaning the average minimum winter temperature is -5 to 0°F. When selecting plants, choose those rated for zone 6 or lower for best results, and consider microclimates and local nursery advice for optimal success in your garden. Knowing the growing zone and the factors influencing it helps you select the right plants for success in your garden.