When to Plant Comfrey in St. Johns County, FL
Comfrey is a vigorous perennial herb valued as a dynamic accumulator of nutrients. Its leaves make excellent mulch, compost activator, and liquid fertilizer.
St. Johns County, Florida is in USDA Zone 9a. The average last spring frost is February 9 and the first fall frost is December 2, giving you a growing season of approximately 296 days.
At an elevation of 57 feet, St. Johns County receives approximately 51.1 inches of rainfall annually with predominantly sand soil. Summer highs average 99°F, so Comfrey may need afternoon shade and extra watering during peak heat. Sandy soil warms quickly in spring — great for early planting — but Comfrey will need more frequent watering and organic matter to retain nutrients. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Comfrey root diseases.
St. Johns County Soil Profile
Soil Type
Sand
Soil pH
4.9-6.1
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 St. Johns County
How your county's soil matches Comfrey's growing requirements.
Soil pH
Your soil pH (4.9–6.1) is more acidic than Comfrey prefers (6.0–7.0). Add garden lime to raise pH.
Soil Texture
Sandy soil in St. Johns County warms quickly in spring but drains fast. Comfrey will need more frequent watering and regular compost additions to retain nutrients.
Organic Matter
Organic matter is low (1.5%). Add 2-3 inches of compost before planting Comfrey.
How to Plant Comfrey
Succession Planting Comfrey
Sow every 6.9 weeks. Last sowing by Sep 03 to harvest before frost.
Plant Water Budget
Water stress score is 6/10 — consider drought-tolerant varieties and mulching
Monthly Watering Guide for Comfrey
Comfrey needs approximately 1 inches of water per week (4.3" per month). Here's how your county's rainfall compares month by month.
| Month | Comfrey Needs | Rainfall | You Supplement | Action |
|---|---|---|---|---|
| Jan | — | 2.4" | 0" | ❄️ Dormant |
| Feb | 4.3" | 2.4" | 1.9" | 💧 Light watering |
| Mar | 4.3" | 2.8" | 1.5" | 💧 Light watering |
| Apr | 4.3" | 2.8" | 1.5" | 💧 Light watering |
| May | 4.3" | 3.5" | 0.8" | 💧 Light watering |
| Jun | 4.3" | 7" | 0" | ✅ Rainfall sufficient |
| Jul | 4.3" | 7.1" | 0" | ✅ Rainfall sufficient |
| Aug | 4.3" | 7.6" | 0" | ✅ Rainfall sufficient |
| Sep | 4.3" | 6.9" | 0" | ✅ Rainfall sufficient |
| Oct | 4.3" | 4.3" | 0" | ✅ Rainfall sufficient |
| Nov | 4.3" | 2.1" | 2.2" | 🚿 Regular watering |
| Dec | 4.3" | 2.3" | 2" | 💧 Light watering |
Water needs are for active growing months only (Feb–Dec in St. Johns County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.
Comfrey 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.
Comfrey Planting Timeline — St. Johns County, FL
Comfrey Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Transplant Outdoors | February 16 | Feb 16 – Mar 2 |
| Harvest | April 20 | Apr 20 – Jun 29 |
Plant 0.5" deep · 8" apart · Rows 12" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | Transplant Outdoors |
| March | Transplant Outdoors |
| April | Harvest |
| May | Harvest |
| June | Harvest |
| July | — |
| August | — |
| September | — |
| October | — |
| November | — |
| December | — |
Growing Conditions
☀️ Sun
Partial Shade (3-6 hours)
💧 Water
1"/week · 1-2 times/week
📅 Days to Maturity
60–90 days
🧪 Soil pH
Needs 6–7 · Your soil: too_acidic
🗺️ USDA Zone
Zone 9a
📆 Growing Season
296 days in St. Johns County
Growing Tips for Comfrey in St. Johns County
Direct sow Comfrey outdoors after February 09 in St. Johns County when soil has warmed and frost danger has passed.
Sandy soil in St. Johns County dries quickly — mulch Comfrey with 2-3 inches of straw and water deeply 2-3 times per week rather than lightly every day.
With summer highs reaching 99°F in St. Johns County, provide afternoon shade for Comfrey and water deeply in the morning.
General growing tips
Plant root cuttings 2 inches deep. Choose Bocking 14 variety to prevent self-seeding. Cut leaves 3-4 times per season for mulch or compost. Avoid planting near pathways as it spreads.
Companion Planting
Good Companions
Check more plant combinations with our Companion Planting Checker →
Comfrey in Other Locations
Frequently Asked Questions
When should I plant Comfrey in St. Johns County, FL?
St. Johns County is in Zone 9a with an average last frost of February 9. Plan your Comfrey planting based on this frost date — see the calendar above for exact timing.
What planting zone is St. Johns County, FL?
St. Johns County, Florida is in USDA Hardiness Zone 9a. The average last spring frost is February 9 and first fall frost is December 2.
Plan Your Garden with Confidence
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