When to Plant Sunflower in Middlesex County, NJ
Sunflower (Helianthus annuus) is a fast-growing North American native annual famous for its towering stems and brilliant yellow heads. It thrives in full sun and heat, producing large, pollen-rich blooms that attract bees, butterflies, and seed-eating birds. Varieties range from 18-inch dwarfs to 12-foot giants and nearly every color except blue.
Middlesex County, New Jersey is in USDA Zone 7a. The average last spring frost is March 29 and the first fall frost is November 12, giving you a growing season of approximately 228 days.
At an elevation of 947 feet, Middlesex County receives approximately 45.5 inches of rainfall annually with predominantly silt loam soil. Summer highs average 94°F, providing good warmth for Sunflower during the growing season.
Middlesex County Soil Profile
Soil Type
Silt Loam
Soil pH
5-6.6
Drainage
Well Drained
Monthly Watering Guide for Sunflower
Sunflower needs approximately 1 inches of water per week (4.3" per month). Here's how your county's rainfall compares month by month.
| Month | Sunflower Needs | Rainfall | You Supplement | Action |
|---|---|---|---|---|
| Jan | — | 3.3" | 0" | ❄️ Dormant |
| Feb | — | 3.1" | 0" | ❄️ Dormant |
| Mar | 4.3" | 3.6" | 0.7" | 💧 Light watering |
| Apr | 4.3" | 4.2" | 0.1" | 💧 Light watering |
| May | 4.3" | 4.8" | 0" | ✅ Rainfall sufficient |
| Jun | 4.3" | 4.9" | 0" | ✅ Rainfall sufficient |
| Jul | 4.3" | 4" | 0.3" | 💧 Light watering |
| Aug | 4.3" | 4.3" | 0" | ✅ Rainfall sufficient |
| Sep | 4.3" | 3.4" | 0.9" | 💧 Light watering |
| Oct | 4.3" | 3.7" | 0.6" | 💧 Light watering |
| Nov | 4.3" | 3.2" | 1.1" | 💧 Light watering |
| Dec | — | 3" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Mar–Nov in Middlesex County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.
Sunflower Planting Timeline — Middlesex County, NJ
Sunflower Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | March 8 | Mar 8 – Mar 22 |
| Transplant Outdoors | March 29 | Mar 29 – Apr 12 |
| Direct Sow | March 29 | Mar 29 – Apr 19 |
| Bloom | June 21 | Jun 21 – Sep 27 |
Plant 1" deep · 18" apart · Rows 24" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | Start Indoors Transplant Outdoors Direct Sow |
| April | Transplant Outdoors Direct Sow |
| May | — |
| June | Bloom |
| July | Bloom |
| August | Bloom |
| September | Bloom |
| October | — |
| November | — |
| December | — |
Growing Conditions
☀️ Sun
Full Sun (6-8+ hours)
💧 Water
Low — drought tolerant
📅 Days to Maturity
70–100 days
🧪 Soil pH
Needs 6–7.5 · Your soil: N/A
🗺️ USDA Zone
Zone 7a
📆 Growing Season
228 days in Middlesex County
Growing Tips for Middlesex County
Direct-sow 1 inch deep after last frost; germination takes 7-14 days at 65-75°F soil. Sunflowers dislike root disturbance so direct sowing is strongly preferred over transplanting. Plant in succession every 2 weeks for extended bloom. Stake tall varieties. Avoid overwatering — they tolerate drought once established. Birds will self-deadhead seed heads; leave them up through fall for wildlife.
Companion Planting
Good Companions
Avoid Planting Near
Check more plant combinations with our Companion Planting Checker →
Sunflower in Other Locations
Frequently Asked Questions
When should I plant Sunflower in Middlesex County, NJ?
Middlesex County is in Zone 7a with an average last frost of March 29. Plan your Sunflower planting based on this frost date — see the calendar above for exact timing.
What planting zone is Middlesex County, NJ?
Middlesex County, New Jersey is in USDA Hardiness Zone 7a. The average last spring frost is March 29 and first fall frost is November 12.
Your Middlesex County Garden Planner — Free
A 22-page printable planner built for Middlesex 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.