When to Plant Valerian in Bristol County, RI
May in Bristol County, Rhode Island — your action list
A quick May briefing for Bristol County, Rhode Island gardeners — what's urgent, what's next, and what can wait.
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Time to transplant valerian
Your last frost (April 26) has passed. These warm-season crops can handle outdoor soil now.
Valerian is a tall perennial herb with fragrant white or pink flower clusters, valued for its root which is used as a natural sleep aid. It attracts pollinators and earthworms.
Bristol County, Rhode Island is in USDA Zone 7a. The average last spring frost is April 26 and the first fall frost is October 17, giving you a growing season of approximately 174 days.
At an elevation of 335 feet, Bristol County receives approximately 41.9 inches of rainfall annually with predominantly silt loam soil. Summer highs average 87°F, providing good warmth for Valerian during the growing season.
Bristol County Soil Profile
Soil Type
Silt Loam
Soil pH
4.8-6.2
Drainage
Well Drained
Plant Planting Risk Windows
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 Bristol County
How your county's soil matches Valerian's growing requirements.
Soil pH
Your soil pH (4.8–6.2) overlaps with Valerian's range (5.5–7.0), though not a perfect match.
Soil Texture
The silt loam soil in Bristol County is excellent for Valerian — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is moderate (4.0%). Annual compost additions will help Valerian.
How to Plant Valerian
Plant Water Budget
Monthly Watering Guide for Valerian
Valerian needs approximately 1 inches of water per week (4.3" per month). Here's how your county's rainfall compares month by month.
| Month | Valerian Needs | Rainfall | You Supplement | Action |
|---|---|---|---|---|
| Jan | — | 2.8" | 0" | ❄️ Dormant |
| Feb | — | 3.1" | 0" | ❄️ Dormant |
| Mar | — | 3.6" | 0" | ❄️ Dormant |
| Apr | 4.3" | 3.6" | 0.7" | 💧 Light watering |
| May | 4.3" | 3.7" | 0.6" | 💧 Light watering |
| Jun | 4.3" | 4.2" | 0.1" | 💧 Light watering |
| Jul | 4.3" | 4.5" | 0" | ✅ Rainfall sufficient |
| Aug | 4.3" | 3.8" | 0.5" | 💧 Light watering |
| Sep | 4.3" | 3.2" | 1.1" | 💧 Light watering |
| Oct | 4.3" | 3.1" | 1.2" | 💧 Light watering |
| Nov | — | 3.5" | 0" | ❄️ Dormant |
| Dec | — | 3" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Apr–Oct in Bristol County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.
Valerian 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.
Valerian Planting Timeline — Bristol County, RI
Valerian Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Transplant Outdoors | May 3 | May 3 – May 17 |
| Harvest | September 6 | Sep 6 – Dec 13 |
Plant 0.5" deep · 8" apart · Rows 12" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | — |
| April | — |
| May | Transplant Outdoors |
| June | — |
| July | — |
| August | — |
| September | Harvest |
| October | Harvest |
| November | Harvest |
| December | Harvest |
Growing Conditions
☀️ Sun
Partial Shade (3-6 hours)
💧 Water
1"/week · Natural rainfall sufficient
📅 Days to Maturity
120–180 days
🧪 Soil pH
Needs 5.5–7 · Your soil: acceptable
🗺️ USDA Zone
Zone 7a
📆 Growing Season
174 days in Bristol County
Growing Tips for Valerian in Bristol County
Direct sow Valerian outdoors after April 26 in Bristol County when soil has warmed and frost danger has passed.
Your 174.0-day growing season in Bristol County is tight for Valerian (120.0-180.0 days to maturity). Start indoors and choose early-maturing varieties.
General growing tips
Start seeds indoors and transplant after last frost. Harvest roots in fall of the second year. Deadhead flowers unless you want self-seeding. Cats are attracted to valerian root.
Companion Planting
Good Companions
Check more plant combinations with our Companion Planting Checker →
Valerian in Other Locations
Frequently Asked Questions
When should I plant Valerian in Bristol County, RI?
Bristol County is in Zone 7a with an average last frost of April 26. Plan your Valerian planting based on this frost date — see the calendar above for exact timing.
What planting zone is Bristol County, RI?
Bristol County, Rhode Island is in USDA Hardiness Zone 7a. The average last spring frost is April 26 and first fall frost is October 17.
Your Bristol County Garden Planner — Free
A 24-page printable planner built for Bristol 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.