When to Plant Sweet Potatoes in Salem County, NJ
Your May game plan for Salem County, New Jersey
Here's what deserves your attention in Salem County, New Jersey this month. Everything below is tailored to Zone 7b and timed around your local frost dates.
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Fire up the seed-starting tray: sweet potatoes
A seed-starting mix and a sunny window (or a grow light) are all you need. Keep soil warm — around 70°F — for fast germination.
Sweet potatoes are a warm-season root crop that produces nutritious, sweet tubers in orange, white, and purple varieties. They need a long, hot growing season.
Salem County, New Jersey is in USDA Zone 7b. The average last spring frost is April 6 and the first fall frost is November 1, giving you a growing season of approximately 209 days.
At an elevation of 1,061 feet, Salem County receives approximately 38.9 inches of rainfall annually with predominantly silt loam soil. Summer highs average 88°F, providing good warmth for Sweet Potatoes during the growing season.
Salem County Soil Profile
Soil Type
Silt Loam
Soil pH
4.9-6.4
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 Salem County
How your county's soil matches Sweet Potatoes's growing requirements.
Soil pH
Your soil pH (4.9–6.4) overlaps with Sweet Potatoes's range (5.5–6.5), though not a perfect match.
Soil Texture
The silt loam soil in Salem County is excellent for Sweet Potatoes — good drainage, moisture retention, and nutrient holding capacity.
Drainage
Drainage is adequate for Sweet Potatoes.
Organic Matter
Organic matter is moderate (3.4%). Annual compost additions will help Sweet Potatoes.
How to Plant Sweet Potatoes
Plant Water Budget
Monthly Watering Guide for Sweet Potatoes
Sweet Potatoes needs approximately 1 inches of water per week (4.3" per month). Here's how your county's rainfall compares month by month.
| Month | Sweet Potatoes Needs | Rainfall | You Supplement | Action |
|---|---|---|---|---|
| Jan | — | 2.7" | 0" | ❄️ Dormant |
| Feb | — | 2.8" | 0" | ❄️ Dormant |
| Mar | — | 3.1" | 0" | ❄️ Dormant |
| Apr | 4.3" | 3.8" | 0.5" | 💧 Light watering |
| May | 4.3" | 3.3" | 1" | 💧 Light watering |
| Jun | 4.3" | 3.8" | 0.5" | 💧 Light watering |
| Jul | 4.3" | 3.8" | 0.5" | 💧 Light watering |
| Aug | 4.3" | 3.6" | 0.7" | 💧 Light watering |
| Sep | 4.3" | 3.6" | 0.7" | 💧 Light watering |
| Oct | 4.3" | 2.9" | 1.4" | 💧 Light watering |
| Nov | 4.3" | 2.5" | 1.8" | 💧 Light watering |
| Dec | — | 3" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Apr–Nov in Salem County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.
Sweet Potatoes 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.
Sweet Potatoes Planting Timeline — Salem County, NJ
Sweet Potatoes Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | February 16 | Feb 16 – Mar 2 |
| Transplant Outdoors | April 20 | Apr 20 – May 4 |
| Direct Sow | April 13 | Apr 13 – May 4 |
| Harvest | July 20 | Jul 20 – Sep 7 |
Plant 1" deep · 15" apart · Rows 24" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | Start Indoors |
| March | Start Indoors |
| April | Transplant Outdoors Direct Sow |
| May | Transplant Outdoors Direct Sow |
| June | — |
| July | Harvest |
| August | Harvest |
| September | Harvest |
| October | — |
| November | — |
| December | — |
Growing Conditions
☀️ Sun
Full Sun (6-8+ hours)
💧 Water
1"/week · Natural rainfall sufficient
📅 Days to Maturity
90–120 days
🧪 Soil pH
Needs 5.5–6.5 · Your soil: acceptable
🗺️ USDA Zone
Zone 7b
📆 Growing Season
209 days in Salem County
Growing Tips for Sweet Potatoes in Salem County
Direct sow Sweet Potatoes outdoors after April 06 in Salem County when soil has warmed and frost danger has passed.
General growing tips
Plant slips (rooted sprouts) after soil is thoroughly warm. Build raised mounds for better root development. Cure harvested roots at 80-85F for 10 days to develop sweetness.
Companion Planting
Good Companions
Avoid Planting Near
Check more plant combinations with our Companion Planting Checker →
Sweet Potatoes in Other Locations
Frequently Asked Questions
When should I plant Sweet Potatoes in Salem County, NJ?
Salem County is in Zone 7b with an average last frost of April 6. Plan your Sweet Potatoes planting based on this frost date — see the calendar above for exact timing.
What planting zone is Salem County, NJ?
Salem County, New Jersey is in USDA Hardiness Zone 7b. The average last spring frost is April 6 and first fall frost is November 1.
Your Salem County Garden Planner — Free
A 24-page printable planner built for Salem County (Zone 7b). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.