When to Plant Geraniums in Clark County, SD
June to-do list for Clark County, South Dakota
Your Clark County, South Dakota garden is entering a new phase. Here's what's on the schedule for June and why each task matters now.
July will be here before you know it — start on
- Starting indoors: geraniums
- First harvests: geraniums
Geraniums (Pelargonium × hortorum) are tender perennials grown as warm-season annuals throughout North America. Prized for their bold flower clusters, long bloom period, and tolerance of summer heat when planted in well-drained soil, they anchor window boxes, containers, and bed borders from late spring until hard frost. Zones 9b–11b can overwinter plants in the ground.
Clark County, South Dakota is in USDA Zone 4b. The average last spring frost is May 3 and the first fall frost is October 5, giving you a growing season of approximately 155 days.
At an elevation of 799 feet, Clark County receives approximately 28.2 inches of rainfall annually with predominantly loam soil. Summer highs average 81°F, so choose short-season varieties of Geraniums to ensure they mature before fall.
Clark County Soil Profile
Soil Type
Loam
Soil pH
6.3-7.3
Drainage
Well Drained
Geraniums 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 Geraniums's growing requirements.
Soil pH
Your soil pH (6.3–7.3) overlaps with Geraniums's range (6.0–7.0), though not a perfect match.
Soil Texture
The loam soil in Clark County is excellent for Geraniums — good drainage, moisture retention, and nutrient holding capacity.
Drainage
Drainage is adequate for Geraniums.
Organic Matter
Organic matter is moderate (4.0%). Annual compost additions will help Geraniums.
How to Plant Geraniums
Succession Planting Geraniums
Sow every 8 weeks. Last sowing by Jun 27 to harvest before frost.
Geraniums Water Budget
Monthly Watering Guide for Geraniums
Geraniums needs approximately 1 inches of water per week (4.3" per month). Here's how your county's rainfall compares month by month.
| Month | Geraniums Needs | Rainfall | You Supplement | Action |
|---|---|---|---|---|
| Jan | — | 0.6" | 0" | ❄️ Dormant |
| Feb | — | 0.9" | 0" | ❄️ Dormant |
| Mar | — | 1.9" | 0" | ❄️ Dormant |
| Apr | — | 2.6" | 0" | ❄️ Dormant |
| May | 4.3" | 4" | 0.3" | 💧 Light watering |
| Jun | 4.3" | 4.5" | 0" | ✅ Rainfall sufficient |
| Jul | 4.3" | 3.9" | 0.4" | 💧 Light watering |
| Aug | 4.3" | 3.6" | 0.7" | 💧 Light watering |
| Sep | 4.3" | 2.9" | 1.4" | 💧 Light watering |
| Oct | 4.3" | 1.7" | 2.6" | 🚿 Regular watering |
| Nov | — | 0.9" | 0" | ❄️ Dormant |
| Dec | — | 0.7" | 0" | ❄️ Dormant |
Water needs are for active growing months only (May–Oct in Clark County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.
Geraniums 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.
Geraniums Planting Timeline — Clark County, SD
Geraniums Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | February 15 | Feb 15 – Mar 1 |
| Transplant Outdoors | May 10 | May 10 – May 24 |
| Bloom | July 19 | Jul 19 – Sep 27 |
Plant 0.1" deep · 12" apart · Rows 14" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | Start Indoors |
| March | Start Indoors |
| April | — |
| May | Transplant Outdoors |
| June | — |
| July | Bloom |
| August | Bloom |
| September | Bloom |
| October | — |
| November | — |
| December | — |
Growing Conditions
☀️ Sun
Full Sun (6-8+ hours)
💧 Water
1"/week · 1-2 times/week
📅 Days to Maturity
70–100 days
🧪 Soil pH
Needs 6–7 · Your soil: acceptable
🗺️ USDA Zone
Zone 4b
📆 Growing Season
155 days in Clark County
Growing Tips for Geraniums in Clark County
Direct sow Geraniums outdoors after May 03 in Clark County when soil has warmed and frost danger has passed.
General growing tips
Start seeds indoors 10–12 weeks before last frost — germination is slow and erratic without bottom heat (70–75°F). Transplant after frost danger passes. Geraniums rarely direct-sown; cuttings or transplants are the standard. Deadhead spent umbels weekly to maintain continuous bloom. Let soil dry slightly between waterings to prevent root rot. In zones 10–11 plants may be left in ground year-round or overwintered as houseplants.
Companion Planting
Good Companions
Check more plant combinations with our Companion Planting Checker →
Geraniums in Other Locations
Frequently Asked Questions
When should I plant Geraniums in Clark County, SD?
Clark County is in Zone 4b with an average last frost of May 3. Plan your Geraniums planting based on this frost date — see the calendar above for exact timing.
What planting zone is Clark County, SD?
Clark County, South Dakota is in USDA Hardiness Zone 4b. The average last spring frost is May 3 and first fall frost is October 5.
Your Clark County Garden Planner — Free
A 22-page printable planner built for Clark 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.