Before planting it is a good idea to find your USDA Zone info to determine your garden schedule. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

It's possible to estimate when it's a good idea to plant rhubarb by looking at the USDA zone info for California.

Planting Calendar for Rhubarb

Frost tolerance for rhubarb:	Tolerant of some frost.
When to plant:	Up to 5 weeks before last frost.

Rhubarb do ok in mild cold which tells us that you can plant them a little bit earlier in the year than more sensitive plants.

The earliest that you can plant rhubarb in California 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 rhubarb and expect a good harvest is probably September. If you wait any later than that and your rhubarb may not have a chance to grow to maturity. If you are starting your rhubarb indoors then you might be able to get away with starting them a few weeks earlier.

Last Frost Date

In California the average date of last frost happens on April 15. It might get as low as -5°F during the coldest months of winter.

Since the USDA zone info for California is just an average the actual date of last frost can change quite a bit from year to year. Half of the time in California last frost occurs after April 15 so just be sure to be ready to cover your rhubarb if you have one of those late frosts.

USDA Zone Info for California

Here is the info for USDA Zone 6b.

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

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

Plants to Grow in California

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