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When to Plant Rhubarb in USDA Zone 5b

Rhubarb is a long-lived perennial vegetable grown for its tart, colorful stalks. Only the stalks are edible as the leaves contain toxic oxalic acid.

In Zone 5b, the average last spring frost is around April 18 and the first fall frost is around October 13, giving you a growing season of approximately 178 days.

Zone 5b Moderate season
178 days
Last Spring Frost April 18
178 growing days
First Fall Frost October 13

Rhubarb Planting Timeline — Zone 5b

Where Is USDA Zone 5b?

The map below highlights the states that contain Zone 5b. Click any state to see the Rhubarb planting schedule for that location.

Prints a clean, ink-friendly version without maps or navigation.

Rhubarb Planting Calendar — Zone 5b

Activity When Date Range
Transplant Outdoors May 9 May 9 – May 23

Plant 1" deep · 30" apart · Rows 42" apart

Month-by-Month Timeline

MonthActivities
January
February
March
April
May Transplant Outdoors
June
July
August
September
October
November
December

Free Zone 5b Planting Calendar PDF

Know exactly when to plant every crop in your zone. Get a printable month-by-month calendar customized for Zone 5b with start dates, transplant windows, and harvest times.

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Growing Conditions

Sun

Full Sun (6-8+ hours)

💧 Water

Moderate — regular watering

Days to Maturity

365–730 days

Soil pH

6 – 7

Zone Temperature Range

-15°F to -10°F average annual minimum

Growing Season

178 days (Zone 5b average)

Planting Specifications

Planting Depth1 inches
Plant Spacing30 inches apart
Row Spacing42 inches between rows

Growing Tips for Rhubarb in Zone 5b

Plant crowns in early spring in rich, well-drained soil. Do not harvest stalks the first year. Pull (do not cut) stalks at harvest to avoid introducing rot.

Companion Planting

Good Companions

Level Up Your Garden

Saving Rhubarb Seeds

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Seed Starting Trays $8-20

Start seeds indoors with reusable cell trays and humidity domes.

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Soil Test Kit $12-25

Test your soil pH, nitrogen, phosphorus, and potassium levels before planting.

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Garden Plant Markers $6-12

Keep your garden organized with durable, weather-resistant plant labels.

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Frequently Asked Questions

When should I plant Rhubarb in Zone 5b?

In Zone 5b, plan your Rhubarb planting around the average last frost date of April 18. Transplant seedlings around May 9.

Can Rhubarb grow in Zone 5b?

Yes, Rhubarb can grow well in Zone 5b, hardy in USDA zones 3a through 8b. Zone 5b has a growing season of approximately 178 days, which is sufficient for Rhubarb (365-730 days to maturity).

What is the last frost date for Zone 5b?

The average last spring frost in Zone 5b is around April 18, and the first fall frost is around October 13. This gives a growing season of approximately 178 days. These are 50% probability dates — actual frost dates vary year to year.

What should I plant next to Rhubarb?

Good companion plants for Rhubarb include Garlic, Onion, Cabbage. These companions can help with pest control, pollination, and nutrient sharing.

🌱

Plan Your Garden with Confidence

Get our free Garden Planner — organize your planting dates for Zone 5b, track your crops, and plan your garden season from seed to harvest.

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Free download. Plan your entire garden season in minutes.

Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals, University Cooperative Extension planting guides. Planting dates are estimates based on average frost dates — local conditions may vary. Last updated: April 2026.