One of the best tools that you have as gardeners to help us figure out your gardening schedule is the USDA zone info. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

The first chance to plant delphinium in Mount Rainier should be determined by looking at the USDA zone info.

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 tend to make it in mild cold which tells us that you can plant them a bit earlier in the year than other frost tender plants.

The earliest that you can plant delphinium in Mount Rainier is March. However, you really should wait until April 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. Any later than that and your delphinium may not have a chance to fully mature. If you are starting your delphinium indoors then you might be able to get away with starting them a few weeks earlier.

Last Frost Date

In Mount Rainier the average date of last frost happens on April 15. In the coldest months of winter you can expect an average low temperature of 0°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 Mount Rainier and it changes from year to year. Half of the time in Mount Rainier it frosts late in the year after April 15 so be sure to be ready to protect your delphinium in the event of a surprise late frost.

USDA Zone Info for Mount Rainier

Here is the info for USDA Zone 7a.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	0°F
Highest Expected Low	5°F

This means that on a really cold year, the coldest it will get is 0°F. On most years you should be prepared to experience lows near 5°F.

Plants to Grow in Mount Rainier

You may be interested in your other planting guides for Mount Rainier.