When should I plant Rhubarb in Zone 3b?

Start Rhubarb seeds indoors around Mar 6. Transplant outdoors after Apr 17. Expect first harvest around Apr 17.

What is the last frost date for Zone 3b?

The average last spring frost date for Zone 3b is May 15. The first fall frost averages Sep 22, giving a 130-day growing season.

Can I grow Rhubarb in Zone 3b?

Yes. Rhubarb needs 90 days to harvest. Zone 3b has a 130-day growing season, which is sufficient.

Growing Rhubarb in Zone 3b

Zone 3b has harsh winters and a short growing season. Start Rhubarb early indoors to maximize your harvest window. Last frost: May 15. First frost: Sep 22.

Planting Calendar

Indoor

Outdoor

Harvest

Mar 6Sep 22

Season: May 15 – Sep 22 (130 days)

Zone3b

Last FrostMay 15

First FrostSep 22

Season Length130 days

Days to Harvest90

SunFull Sun

Frost ToleranceHeavy

Spacing1/sqft (12" apart)

When to Plant Rhubarb in Zone 3b

Start Seeds Indoors: Mar 6

Start Rhubarb seeds indoors around Mar 6 (10 weeks before last frost). Optimal germination temperature: 65°F. Germinates in 7–21 days.

Transplant Outdoors: Apr 17

Transplant Rhubarb seedlings outdoors after Apr 17. 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 17

First harvest approximately Apr 17 (~365 days from transplant). Continue harvesting until first frost (Sep 22). Rhubarb can overwinter in mild climates for continued harvest.

Rhubarb in Other Zones

1a 1b 2a 2b 3a 3b 4a 4b 5a 5b 6a 6b 7a 7b 8a 8b 9a 9b 10a 10b 11a 11b 12a 12b 13a 13b

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