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When to Plant Rhubarb in Clay County, TN

Clay County, Tennessee Zone 7a May

May in Clay County, Tennessee — your action list

May is a pivotal month for Clay County, Tennessee gardens. Focus on these tasks first and you'll set up the rest of the season for success.

Avg. last frost April 12
Avg. first frost October 27
Soil temp (4") 60°F
Watering Moderate
Pest pressure Low
Daylight 13.9 hrs
  1. Set out rhubarb seedlings

    Your last frost (April 12) has passed. These warm-season crops can handle outdoor soil now.

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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.

Clay County, Tennessee is in USDA Zone 7a. The average last spring frost is April 12 and the first fall frost is October 27, giving you a growing season of approximately 198 days.

At an elevation of 1,418 feet, Clay County receives approximately 42.5 inches of rainfall annually with predominantly silt loam soil. Summer highs average 86°F, providing good warmth for Rhubarb during the growing season.

Clay County, TN (Zone 7a) Moderate season
198 days
Last Spring Frost April 12
198 growing days
First Fall Frost October 27
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Clay County Soil Profile

Soil Type

Silt Loam

Soil pH

5.7-7.1

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season
Transplant: Apr 28
Recommended (50%) ✓ Fits season
Transplant: May 3
Safe Start (90%) ✓ Fits season
Transplant: May 16

Percentages indicate frost risk at transplant. The 70% safe window means there is a 30% chance of frost after transplant — suitable for cold-hardy crops or gardeners with frost protection. The 90% safe window is best for tender plants.

Soil Compatibility in Clay County

How your county's soil matches Rhubarb's growing requirements.

Soil pH

Your soil pH (5.7–7.1) overlaps with Rhubarb's range (6.0–7.0), though not a perfect match.

Soil Texture

The silt loam soil in Clay County is excellent for Rhubarb — good drainage, moisture retention, and nutrient holding capacity.

Drainage

Drainage is adequate for Rhubarb.

Organic Matter

Organic matter is moderate (2.6%). Annual compost additions will help Rhubarb.

How to Plant Rhubarb

1"
Planting Depth
30"
Between Plants
42"
Between Rows

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
0.9″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft
Drought risk

Water stress score is 6/10 — consider drought-tolerant varieties and mulching

Monthly Watering Guide for Rhubarb

Rhubarb needs approximately 1 inches of water per week (4.3" per month). Here's how your county's rainfall compares month by month.

Month Rhubarb Needs Rainfall You Supplement Action
Jan 3.9" 0" ❄️ Dormant
Feb 3.5" 0" ❄️ Dormant
Mar 4" 0" ❄️ Dormant
Apr 4.3" 3.6" 0.7" 💧 Light watering
May 4.3" 3" 1.3" 💧 Light watering
Jun 4.3" 3.6" 0.7" 💧 Light watering
Jul 4.3" 4.4" 0" ✅ Rainfall sufficient
Aug 4.3" 4.3" 0" ✅ Rainfall sufficient
Sep 4.3" 3" 1.3" 💧 Light watering
Oct 4.3" 2.4" 1.9" 💧 Light watering
Nov 3.3" 0" ❄️ Dormant
Dec 3.5" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Clay County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.

Rhubarb Heat Requirements (GDD)

What are Growing Degree Days (GDD)?

Growing Degree Days measure the total warmth your plants receive during the growing season. Think of it as a "heat bank" — every day above 50°F deposits warmth that helps your plants grow.

Each plant needs a certain amount of accumulated heat to mature. If your county provides more GDD than the plant needs, it's a great fit. If it's close, you may want to choose faster-maturing varieties or start seeds indoors to get a head start.

Rhubarb needs ~7,939 GDD — county provides 2,871 GDD May not mature

Rhubarb Planting Timeline — Clay County, TN

Rhubarb Planting Calendar

Activity When Date Range
Transplant Outdoors May 3 May 3 – May 17

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
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Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1"/week · Natural rainfall sufficient

📅 Days to Maturity

365–730 days

🧪 Soil pH

Needs 6–7 · Your soil: acceptable

🗺️ USDA Zone

Zone 7a

📆 Growing Season

198 days in Clay County

Growing Tips for Rhubarb in Clay County

Direct sow Rhubarb outdoors after April 12 in Clay County when soil has warmed and frost danger has passed.

Your 198.0-day growing season in Clay County is tight for Rhubarb (365.0-730.0 days to maturity). Start indoors and choose early-maturing varieties.

General growing tips

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

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Rhubarb in Clay County, TN?

Clay County is in Zone 7a with an average last frost of April 12. Plan your Rhubarb planting based on this frost date — see the calendar above for exact timing.

What planting zone is Clay County, TN?

Clay County, Tennessee is in USDA Hardiness Zone 7a. The average last spring frost is April 12 and first fall frost is October 27.

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Your Clay County Garden Planner — Free

A 24-page printable planner built for Clay County (Zone 7a). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.

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Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Clay County, TN. Local conditions may vary. Last updated: May 2026.

Sources & credits

Every number on this page traces back to a primary horticulture or government data source. Click through to verify.