Rhubarb illustration

Growing Rhubarb in Zone 10b

Zone 10b has a year-round growing season. Rhubarb can be planted almost any time with proper planning. Last frost: Jan 28. First frost: Dec 22.

Planting Calendar

Indoor
Outdoor
Harvest
Nov 19Dec 22

Season: Jan 28 – Dec 22 (328 days)

Zone10b
Last FrostJan 28
First FrostDec 22
Season Length328 days
Days to Harvest90
SunFull Sun
Frost ToleranceHeavy
Spacing1/sqft (12" apart)

When to Plant Rhubarb in Zone 10b

Start Seeds Indoors: Nov 19

Start Rhubarb seeds indoors around Nov 19 (10 weeks before last frost). Optimal germination temperature: 65°F. Germinates in 7–21 days.

Transplant Outdoors: Dec 31

Transplant Rhubarb seedlings outdoors after Dec 31. Wait until soil temperature reaches 40°F. Space plants at 1/sqft (12" apart). Harden off plants for a week before moving outside.

Harvest: Dec 31

First harvest approximately Dec 31 (~365 days from transplant). Continue harvesting until first frost (Dec 22). Rhubarb can overwinter in mild climates for continued harvest.

Frequently Asked Questions

When should I plant Rhubarb in Zone 10b?

Start Rhubarb seeds indoors around Nov 19. Transplant outdoors after Dec 31. Expect first harvest around Dec 31.

What is the last frost date for Zone 10b?

The average last spring frost date for Zone 10b is Jan 28. The first fall frost averages Dec 22, giving a 328-day growing season.

Can I grow Rhubarb in Zone 10b?

Yes. Rhubarb needs 90 days to harvest. Zone 10b has a 328-day growing season, which is sufficient.

What is the best month to plant Rhubarb in Zone 10b?

The best time to start Rhubarb in Zone 10b is Nov. Begin seeds indoors around Nov 19, then transplant outdoors after the last frost date of Jan 28.

How long does Rhubarb take to harvest?

Rhubarb takes approximately 90 days from planting to harvest. In Zone 10b, expect your first harvest around Dec 31.

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