When to Plant Zinnia in Jackson County, OR
Zinnia (Zinnia elegans) is a fast-growing, heat-loving annual that produces bold, dahlia-like blooms from early summer until hard frost. One of the easiest flowers to grow from direct-sown seed, zinnias thrive in hot, dry conditions and are magnets for butterflies and beneficial insects. They make excellent companion plants alongside marigolds in the vegetable garden.
Jackson County, Oregon is in USDA Zone 8a. The average last spring frost is May 7 and the first fall frost is October 10, giving you a growing season of approximately 156 days.
At an elevation of 422 feet, Jackson County receives approximately 46 inches of rainfall annually with predominantly silt loam soil. Summer highs average 88°F, providing good warmth for Zinnia during the growing season.
Jackson County Soil Profile
Soil Type
Silt Loam
Soil pH
5.3-6.4
Drainage
Well Drained
Monthly Watering Guide for Zinnia
Zinnia needs approximately 1 inches of water per week (4.3" per month). Here's how your county's rainfall compares month by month.
| Month | Zinnia Needs | Rainfall | You Supplement | Action |
|---|---|---|---|---|
| Jan | — | 6.1" | 0" | ❄️ Dormant |
| Feb | — | 5.8" | 0" | ❄️ Dormant |
| Mar | — | 5.1" | 0" | ❄️ Dormant |
| Apr | — | 3" | 0" | ❄️ Dormant |
| May | 4.3" | 2.8" | 1.5" | 💧 Light watering |
| Jun | 4.3" | 1.7" | 2.6" | 🚿 Regular watering |
| Jul | 4.3" | 0.7" | 3.6" | 🚿 Regular watering |
| Aug | 4.3" | 1" | 3.3" | 🚿 Regular watering |
| Sep | 4.3" | 1.8" | 2.5" | 🚿 Regular watering |
| Oct | 4.3" | 3.5" | 0.8" | 💧 Light watering |
| Nov | — | 6.4" | 0" | ❄️ Dormant |
| Dec | — | 8.2" | 0" | ❄️ Dormant |
Water needs are for active growing months only (May–Oct in Jackson County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.
Zinnia Planting Timeline — Jackson County, OR
Zinnia Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | April 9 | Apr 9 – Apr 23 |
| Transplant Outdoors | April 30 | Apr 30 – May 14 |
| Direct Sow | April 30 | Apr 30 – May 21 |
| Bloom | July 9 | Jul 9 – Nov 26 |
Plant 0.3" deep · 12" apart · Rows 18" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | — |
| April | Start Indoors Transplant Outdoors Direct Sow |
| May | Transplant Outdoors Direct Sow |
| June | — |
| July | Bloom |
| August | Bloom |
| September | Bloom |
| October | Bloom |
| November | Bloom |
| December | — |
Growing Conditions
☀️ Sun
Full Sun (6-8+ hours)
💧 Water
Low — drought tolerant
📅 Days to Maturity
60–70 days
🧪 Soil pH
Needs 5.5–7.5 · Your soil: N/A
🗺️ USDA Zone
Zone 8a
📆 Growing Season
156 days in Jackson County
Growing Tips for Jackson County
Direct-sow after last frost when soil reaches 60°F; seeds germinate in 5-7 days. In zones 3-5 a brief indoor start (4 weeks) is worthwhile but transplant carefully — zinnias dislike root disturbance. Deadhead frequently to extend bloom. Excellent cut flower; harvesting regularly encourages branching. Avoid overhead watering to reduce powdery mildew.
Companion Planting
Good Companions
Avoid Planting Near
Check more plant combinations with our Companion Planting Checker →
Zinnia in Other Locations
Frequently Asked Questions
When should I plant Zinnia in Jackson County, OR?
Jackson County is in Zone 8a with an average last frost of May 7. Plan your Zinnia planting based on this frost date — see the calendar above for exact timing.
What planting zone is Jackson County, OR?
Jackson County, Oregon is in USDA Hardiness Zone 8a. The average last spring frost is May 7 and first fall frost is October 10.
Your Jackson County Garden Planner — Free
A 22-page printable planner built for Jackson County (Zone 8a). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.