Before planting it is a good idea to find your USDA Zone info to estimate your garden schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

By looking at the USDA zone info for Keller you will be able to determine when it's possible 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 plant them slightly earlier than other plants that might not handle the cold.

The earliest that you can plant delphinium in Keller 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

On average all chance of frost has passed is on March 15 in Keller. In the coldest months of winter you can expect an average low temperature of 10°F.

Since the USDA zone info for Keller is just an average the actual date of last frost can change quite a bit from year to year. Half of the time in Keller it frosts late in the year after March 15 so make sure that you are ready to protect your delphinium in the event of a late frost.

USDA Zone Info for Keller

Here is the info for USDA Zone 8a.

Average Date of Last Frost (spring)	March 15
Average Date of First Frost (fall)	November 15
Lowest Expected Low	10°F
Highest Expected Low	15°F

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

Plants to Grow in Keller

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