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When to Plant Delphinium in Rancho Cucamonga, CA

The USDA Zone info is a great tool for gardeners to help us determine your gardening schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

By checking out the USDA zone info for Rancho Cucamonga you should be able to estimate 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.

Since delphinium are one of those plants that can tolerate a tiny bit of cold weather you can plant them a bit earlier in the year 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 Rancho Cucamonga 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. You probably don't want to wait any later than that or else your delphinium may not have a chance to really do well. Starting your delphinium indoors is a great way to get them started a few weeks earlier.

Last Frost Date

The average date of last frost is February 15 in Rancho Cucamonga. You should expect an average low temperature of 25°F in the coldest months of winter.

Since the USDA zone info for Rancho Cucamonga may not be accurate from year to year the actual date of last frost will vary from year to year. Half of the time in Rancho Cucamonga you get a frost after February 15 so make sure that you are ready to protect your delphinium if you have a late frost.

USDA Zone Info for Rancho Cucamonga

Here is the info for USDA Zone 9b.

Average Date of Last Frost (spring)February 15
Average Date of First Frost (fall)December 15
Lowest Expected Low25°F
Highest Expected Low30°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 30°F.

Plants to Grow in Rancho Cucamonga

You may be interested in your other planting guides for Rancho Cucamonga.