Rhubarb illustration

Growing Rhubarb in Zone 3a

Zone 3a has harsh winters and a short growing season. Start Rhubarb early indoors to maximize your harvest window. Last frost: May 22. First frost: Sep 12.

Planting Calendar

Indoor
Outdoor
Harvest
Mar 13Sep 12

Season: May 22 – Sep 12 (113 days)

Zone3a
Last FrostMay 22
First FrostSep 12
Season Length113 days
Days to Harvest90
SunFull Sun
Frost ToleranceHeavy
Spacing1/sqft (12" apart)

When to Plant Rhubarb in Zone 3a

Start Seeds Indoors: Mar 13

Start Rhubarb seeds indoors around Mar 13 (10 weeks before last frost). Optimal germination temperature: 65°F. Germinates in 7–21 days.

Transplant Outdoors: Apr 24

Transplant Rhubarb seedlings outdoors after Apr 24. Wait until soil temperature reaches 40°F. Space plants at 1/sqft (12" apart). Harden off plants for a week before moving outside.

Harvest: Apr 24

First harvest approximately Apr 24 (~365 days from transplant). Continue harvesting until first frost (Sep 12). Rhubarb can overwinter in mild climates for continued harvest.

Frequently Asked Questions

When should I plant Rhubarb in Zone 3a?

Start Rhubarb seeds indoors around Mar 13. Transplant outdoors after Apr 24. Expect first harvest around Apr 24.

What is the last frost date for Zone 3a?

The average last spring frost date for Zone 3a is May 22. The first fall frost averages Sep 12, giving a 113-day growing season.

Can I grow Rhubarb in Zone 3a?

Yes. Rhubarb needs 90 days to harvest. Zone 3a has a 113-day growing season, which is sufficient.

What is the best month to plant Rhubarb in Zone 3a?

The best time to start Rhubarb in Zone 3a is Mar. Begin seeds indoors around Mar 13, then transplant outdoors after the last frost date of May 22.

How long does Rhubarb take to harvest?

Rhubarb takes approximately 90 days from planting to harvest. In Zone 3a, expect your first harvest around Apr 24.

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