Rhubarb illustration

Growing Rhubarb in Zone 10a

Zone 10a has a year-round growing season. Rhubarb can be planted almost any time with proper planning. Last frost: Feb 20. First frost: Dec 1.

Planting Calendar

Indoor
Outdoor
Harvest
Dec 12Dec 1

Season: Feb 20 – Dec 1 (284 days)

Zone10a
Last FrostFeb 20
First FrostDec 1
Season Length284 days
Days to Harvest90
SunFull Sun
Frost ToleranceHeavy
Spacing1/sqft (12" apart)

When to Plant Rhubarb in Zone 10a

Start Seeds Indoors: Dec 12

Start Rhubarb seeds indoors around Dec 12 (10 weeks before last frost). Optimal germination temperature: 65°F. Germinates in 7–21 days.

Transplant Outdoors: Jan 23

Transplant Rhubarb seedlings outdoors after Jan 23. Wait until soil temperature reaches 40°F. Space plants at 1/sqft (12" apart). Harden off plants for a week before moving outside.

Harvest: Jan 23

First harvest approximately Jan 23 (~365 days from transplant). Continue harvesting until first frost (Dec 1). Rhubarb can overwinter in mild climates for continued harvest.

Frequently Asked Questions

When should I plant Rhubarb in Zone 10a?

Start Rhubarb seeds indoors around Dec 12. Transplant outdoors after Jan 23. Expect first harvest around Jan 23.

What is the last frost date for Zone 10a?

The average last spring frost date for Zone 10a is Feb 20. The first fall frost averages Dec 1, giving a 284-day growing season.

Can I grow Rhubarb in Zone 10a?

Yes. Rhubarb needs 90 days to harvest. Zone 10a has a 284-day growing season, which is sufficient.

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

The best time to start Rhubarb in Zone 10a is Dec. Begin seeds indoors around Dec 12, then transplant outdoors after the last frost date of Feb 20.

How long does Rhubarb take to harvest?

Rhubarb takes approximately 90 days from planting to harvest. In Zone 10a, expect your first harvest around Jan 23.

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