Before planting it is a good idea to find your USDA Zone info to estimate your garden schedule. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

A way of determining when it's a good idea to plant delphinium is to use the USDA zone info for Steamboat Springs.

Planting Calendar for Delphinium

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

Delphinium are one of those plants that can tolerate a tiny bit of cold weather which tells us that you can get them planted just a bit earlier than other frost tender plants.

The earliest that you can plant delphinium 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 delphinium and expect a good harvest is probably August. If you wait any later than that and your delphinium may not have a chance to really do well. Starting your delphinium indoors is a great way to get them started a little bit earlier.

Last Frost Date

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

It's important to remember that USDA zone info for Steamboat Springs may not be accurate from year to year and the actual date of last frost changes from year to year. Since half of the time in Steamboat Springs you get a frost after May 15 be ready to cover your delphinium if you have a surprise late frost.

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.