One of the best tools that you have as gardeners to help us figure out your gardening schedule is the USDA zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

The best time to plant tree onions in Steamboat Springs should be estimated by referring to the USDA zone info.

Planting Calendar for Tree onions

Frost tolerance for tree onions:	Tolerant of a very small amount of frost.
When to plant:	Up to 3 weeks before last frost.

You can plant tree onions a bit earlier in the year because they do ok in moderate cold.

The earliest that you can plant tree onions in Steamboat Springs is April. However, you really should wait until May if you don't want to take any chances.

The last month that you can plant tree onions and expect a good harvest is probably August. Any later than that and your tree onions may not have a chance to grow to maturity. You can get started a little bit earlier by starting your tree onions indoors.

Last Frost Date

On average the last frost is on May 15 in Steamboat Springs. In the coldest months of winter you can expect an average low temperature of -25°F.

Just be sure to remember that the actual date of last frost is an average because it is based on the USDA zone info for Steamboat Springs and it will vary from year to year. Since half of the time in Steamboat Springs it frosts late in the year after May 15 be ready to protect your tree onions in the event of one of those late frosts.

USDA Zone Info for Steamboat Springs

Here is the info for USDA Zone 4b.

Average Date of Last Frost (spring)	May 15
Average Date of First Frost (fall)	September 15
Lowest Expected Low	-25°F
Highest Expected Low	-20°F

This means that on a really cold year, the coldest it will get is -25°F. On most years you should be prepared to experience lows near -20°F.

Plants to Grow in Steamboat Springs

You may be interested in your other planting guides for Steamboat Springs.