When can I plant Delphinium in Zone 10b

One of the best tools that we have as gardeners to help us figure out our 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 our area.

A common way of determining when it's a good idea to plant delphinium is to look at the USDA zone info for Zone 10b.


Planting Calendar for Delphinium

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

Delphinium do ok in moderate cold which tells us that you can plant them slightly earlier than other frost tender plants.

JanFebMarAprMayJunJulAugSepOctNovDec
Legend 
A good time to plant delphinium
Possibly ok, but a risky time to plant delphinium
Probably not a good time to plant delphinium

The earliest that you can plant delphinium in Zone 10b is February. However, you really should wait until March if you don't want to take any chances.

The last month that you can plant delphinium and expect a good harvest is probably September. 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 couple of weeks earlier.

Last Frost Date

On average the last frost is on January 31 in Zone 10b. In the coldest months of winter we can expect an average low temperature of 35°F.

Keep in mind that USDA zone info for Zone 10b may not be accurate from year to year and our actual date of last frost changes from year to year. Half of the time in Zone 10b we get a frost after January 31 so always be ready to cover your delphinium in the event of one of those late frosts.

USDA Zone Info for Zone 10b

Here is the info for USDA Zone 10b.

Average Date of Last Frost (spring)January 31
Average Date of First Frost (fall)December 15
Lowest Expected Low35°F
Highest Expected Low40°F

This means that on a really cold year, the coldest it will get is 35°F. On most years you should be prepared to experience lows near 40°F.

Plants to Grow in Zone 10b

You may be interested in our other planting guides for Zone 10b.