When to Plant Zinnia in Codington County, SD
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.
Codington County, South Dakota is in USDA Zone 4b. The average last spring frost is May 3 and the first fall frost is October 6, giving you a growing season of approximately 156 days.
At an elevation of 679 feet, Codington County receives approximately 20.6 inches of rainfall annually with predominantly loam soil. Summer highs average 81°F, so choose short-season varieties of Zinnia to ensure they mature before fall.
Codington County Soil Profile
Soil Type
Loam
Soil pH
6.0-7.0
Drainage
Well Drained
Zinnia Planting Timeline — Codington County, SD
Zinnia Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | April 5 | Apr 5 – Apr 19 |
| Transplant Outdoors | May 10 | May 10 – May 24 |
| Direct Sow | May 10 | May 10 – May 31 |
| Bloom | July 19 | Jul 19 – Oct 4 |
Plant 0.3" deep · 12" apart · Rows 18" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | — |
| April | Start Indoors |
| May | Transplant Outdoors Direct Sow |
| June | — |
| July | Bloom |
| August | Bloom |
| September | Bloom |
| October | Bloom |
| November | — |
| 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 4b
📆 Growing Season
156 days in Codington County
Growing Tips for Codington 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 Codington County, SD?
Codington County is in Zone 4b with an average last frost of May 3. Plan your Zinnia planting based on this frost date — see the calendar above for exact timing.
What planting zone is Codington County, SD?
Codington County, South Dakota is in USDA Hardiness Zone 4b. The average last spring frost is May 3 and first fall frost is October 6.
Your Codington County Garden Planner — Free
A 22-page printable planner built for Codington County (Zone 4b). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.