When to Plant Yam in Duval County, FL
This month in Duval County, Florida
We've pulled the most time-sensitive tasks for Duval County, Florida this May and put them front and centre. Tackle them in order.
True yams are tropical tubers distinct from sweet potatoes, producing large starchy roots that can weigh several pounds. They are a staple food in tropical regions worldwide.
Duval County, Florida is in USDA Zone 9b. The average last spring frost is February 24 and the first fall frost is November 29, giving you a growing season of approximately 278 days.
At an elevation of 337 feet, Duval County receives approximately 56.9 inches of rainfall annually with predominantly sand soil. Summer highs average 102°F, so Yam may need afternoon shade and extra watering during peak heat. Sandy soil warms quickly in spring — great for early planting — but Yam will need more frequent watering and organic matter to retain nutrients. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Yam root diseases.
Duval County Soil Profile
Soil Type
Sand
Soil pH
5-5.8
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 Duval County
How your county's soil matches Yam's growing requirements.
Soil pH
Your soil pH (5.0–5.8) is more acidic than Yam prefers (5.5–6.5). Add garden lime to raise pH.
Soil Texture
Sandy soil in Duval County warms quickly in spring but drains fast. Yam will need more frequent watering and regular compost additions to retain nutrients.
Organic Matter
Organic matter is low (1.4%). Add 2-3 inches of compost before planting Yam.
How to Plant Yam
Plant Water Budget
Monthly Watering Guide for Yam
Yam needs approximately 1 inches of water per week (4.3" per month). Here's how your county's rainfall compares month by month.
| Month | Yam Needs | Rainfall | You Supplement | Action |
|---|---|---|---|---|
| Jan | — | 2.6" | 0" | ❄️ Dormant |
| Feb | 4.3" | 2.8" | 1.5" | 💧 Light watering |
| Mar | 4.3" | 3.6" | 0.7" | 💧 Light watering |
| Apr | 4.3" | 3" | 1.3" | 💧 Light watering |
| May | 4.3" | 3.5" | 0.8" | 💧 Light watering |
| Jun | 4.3" | 8.7" | 0" | ✅ Rainfall sufficient |
| Jul | 4.3" | 7.8" | 0" | ✅ Rainfall sufficient |
| Aug | 4.3" | 8.9" | 0" | ✅ Rainfall sufficient |
| Sep | 4.3" | 6.3" | 0" | ✅ Rainfall sufficient |
| Oct | 4.3" | 4.7" | 0" | ✅ Rainfall sufficient |
| Nov | 4.3" | 2.6" | 1.7" | 💧 Light watering |
| Dec | — | 2.4" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Feb–Nov in Duval County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.
Yam 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.
Yam Planting Timeline — Duval County, FL
Yam Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | January 13 | Jan 13 – Jan 27 |
| Transplant Outdoors | March 3 | Mar 3 – Mar 17 |
| Direct Sow | February 24 | Feb 24 – Mar 17 |
| Harvest | September 1 | Sep 1 – Dec 29 |
Plant 0.5" deep · 6" apart · Rows 12" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | Start Indoors |
| February | Direct Sow |
| March | Transplant Outdoors Direct Sow |
| April | — |
| May | — |
| June | — |
| July | — |
| August | — |
| September | Harvest |
| October | Harvest |
| November | Harvest |
| December | Harvest |
Growing Conditions
☀️ Sun
Full Sun (6-8+ hours)
💧 Water
1"/week · Only during dry spells
📅 Days to Maturity
180–330 days
🧪 Soil pH
Needs 5.5–6.5 · Your soil: too_acidic
🗺️ USDA Zone
Zone 9b
📆 Growing Season
278 days in Duval County
Growing Tips for Yam in Duval County
Direct sow Yam outdoors after February 24 in Duval County when soil has warmed and frost danger has passed.
Sandy soil in Duval County dries quickly — mulch Yam with 2-3 inches of straw and water deeply 2-3 times per week rather than lightly every day.
With summer highs reaching 102°F in Duval County, provide afternoon shade for Yam and water deeply in the morning.
Your 279.0-day growing season in Duval County is tight for Yam (180.0-330.0 days to maturity). Start indoors and choose early-maturing varieties.
General growing tips
Plant tuber pieces in mounds of loose, rich soil. Provide sturdy trellising for climbing vines. Yams require a long, warm growing season of 8-11 months. Harvest when vines die back.
Companion Planting
Good Companions
Check more plant combinations with our Companion Planting Checker →
Yam in Other Locations
Frequently Asked Questions
When should I plant Yam in Duval County, FL?
Duval County is in Zone 9b with an average last frost of February 24. Plan your Yam planting based on this frost date — see the calendar above for exact timing.
What planting zone is Duval County, FL?
Duval County, Florida is in USDA Hardiness Zone 9b. The average last spring frost is February 24 and first fall frost is November 29.
Your Duval County Garden Planner — Free
A 24-page printable planner built for Duval County (Zone 9b). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.