One of the first steps you take when you are determining your gardening schedule is find your USDA Zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

The USDA zone info for Bellevue can be reffered to in order to estimate when it's the best time to plant delphinium.

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 means that you can start planting them slightly earlier than plants that are more sensitive to the cold.

The earliest that you can plant delphinium in Bellevue 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 really do well. 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

The average date of last frost is April 15 in Bellevue. You can expect an average low temperature of -15°F in the coldest months of winter.

Since the USDA zone info for Bellevue is just an average the actual date of last frost changes from year to year. Half of the time in Bellevue you get a frost after April 15 so just be sure to be ready to protect your delphinium if you have a surprise late frost.

USDA Zone Info for Bellevue

Here is the info for USDA Zone 5b.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-15°F
Highest Expected Low	-10°F

This means that on a really cold year, the coldest it will get is -15°F. On most years you should be prepared to experience lows near -10°F.

Plants to Grow in Bellevue

You may be interested in your other planting guides for Bellevue.