When to Plant Sunflower in Clark County, NV
What to do in June
Your garden in Clark County, Nevada is working on a schedule, even when you're not. Here's where you should be this June.
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Collect sunflower at their peak
Morning harvests are best — cooler temperatures mean crisper produce and longer fridge life.
July prep starts now
- First harvests: sunflower
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.
Clark County, Nevada is in USDA Zone 9b. The average last spring frost is February 28 and the first fall frost is November 23, giving you a growing season of approximately 268 days.
At an elevation of 2,811 feet, Clark County receives approximately 9.3 inches of rainfall annually with predominantly sandy loam soil. Summer highs average 111°F, so Sunflower may need afternoon shade and extra watering during peak heat. Sandy soil warms quickly in spring — great for early planting — but Sunflower will need more frequent watering and organic matter to retain nutrients. With low rainfall, drip irrigation is essential for growing Sunflower successfully. Mulch heavily to conserve soil moisture.
Clark County Soil Profile
Soil Type
Sandy Loam
Soil pH
7.3-8.4
Drainage
Well Drained
Sunflower 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 Clark County
How your county's soil matches Sunflower's growing requirements.
Soil pH
Your soil pH (7.3–8.4) is more alkaline than Sunflower prefers (6.0–7.5). Add sulfur or peat moss to lower pH.
Soil Texture
Sandy soil in Clark County warms quickly in spring but drains fast. Sunflower will need more frequent watering and regular compost additions to retain nutrients.
Drainage
Drainage is adequate for Sunflower.
Organic Matter
Organic matter is low (0.8%). Add 2-3 inches of compost before planting Sunflower.
How to Plant Sunflower
Succession Planting Sunflower
Sow every 8 weeks. Last sowing by Aug 15 to harvest before frost.
Sunflower Water Budget
Water stress score is 10/10 — consider drought-tolerant varieties and mulching
Monthly Watering Guide for Sunflower
Sunflower needs approximately 0.5 inches of water per week (2.2" per month). Here's how your county's rainfall compares month by month.
| Month | Sunflower Needs | Rainfall | You Supplement | Action |
|---|---|---|---|---|
| Jan | — | 0.7" | 0" | ❄️ Dormant |
| Feb | 2.2" | 0.6" | 1.6" | 🚿 Regular watering |
| Mar | 2.2" | 0.6" | 1.6" | 🚿 Regular watering |
| Apr | 2.2" | 0.3" | 1.9" | 🚿 Regular watering |
| May | 2.2" | 0.2" | 2" | 🚿 Regular watering |
| Jun | 2.2" | 0.3" | 1.9" | 🚿 Regular watering |
| Jul | 2.2" | 1.5" | 0.7" | 💧 Light watering |
| Aug | 2.2" | 1.9" | 0.3" | 💧 Light watering |
| Sep | 2.2" | 1.2" | 1" | 💧 Light watering |
| Oct | 2.2" | 0.9" | 1.3" | 🚿 Regular watering |
| Nov | 2.2" | 0.5" | 1.7" | 🚿 Regular watering |
| Dec | — | 0.7" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Feb–Nov in Clark County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.
Sunflower 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.
Sunflower Planting Timeline — Clark County, NV
Sunflower Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | February 7 | Feb 7 – Feb 21 |
| Transplant Outdoors | January 31 | Jan 31 – Feb 14 |
| Direct Sow | January 31 | Jan 31 – Feb 21 |
| Bloom | April 25 | Apr 25 – Oct 10 |
Plant 1" deep · 18" apart · Rows 24" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | Transplant Outdoors Direct Sow |
| February | Start Indoors Transplant Outdoors Direct Sow |
| March | — |
| April | Bloom |
| May | Bloom |
| June | Bloom |
| July | Bloom |
| August | Bloom |
| September | Bloom |
| October | Bloom |
| November | — |
| December | — |
Growing Conditions
☀️ Sun
Full Sun (6-8+ hours)
💧 Water
0.5"/week · 1-2 times/week
📅 Days to Maturity
70–100 days
🧪 Soil pH
Needs 6–7.5 · Your soil: too_alkaline
🗺️ USDA Zone
Zone 9b
📆 Growing Season
268 days in Clark County
Growing Tips for Sunflower in Clark County
Direct sow Sunflower outdoors after February 28 in Clark County when soil has warmed and frost danger has passed.
Sandy soil in Clark County dries quickly — mulch Sunflower with 2-3 inches of straw and water deeply 2-3 times per week rather than lightly every day.
With summer highs reaching 111°F in Clark County, provide afternoon shade for Sunflower and water deeply in the morning.
Common pests for Sunflower in this region include aphids and slugs. Use row covers early in the season and inspect plants weekly.
Clark County receives only 9" of rain annually. Sunflower needs consistent moisture — install drip irrigation or water deeply 2-3 times per week.
General growing tips
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 Clark County, NV?
Clark County is in Zone 9b with an average last frost of February 28. Plan your Sunflower planting based on this frost date — see the calendar above for exact timing.
What planting zone is Clark County, NV?
Clark County, Nevada is in USDA Hardiness Zone 9b. The average last spring frost is February 28 and first fall frost is November 23.
Your Clark County Garden Planner — Free
A 22-page printable planner built for Clark 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.