When to plant Dahlias in Washington County County,
In Zone 6a (Washington County County), direct-sow Dahlias between April 28 and May 19 for spring, after the April 21 last-frost mark.
When to Plant Dahlias in Washington County, KS
June in the garden — Washington County, Kansas
June is a pivotal month for Washington County, Kansas gardens. Focus on these tasks first and you'll set up the rest of the season for success.
Before July arrives, get these ready
- First harvests: dahlias
Dahlias (Dahlia spp.) are the undisputed stars of the late-summer and fall garden, producing an extraordinary range of flower forms — from compact pompons to dinner plate-sized blooms spanning 12 inches — in virtually every color except true blue. Blooming from midsummer until the first hard frost, a single tuber grows into a massive, flower-laden plant that can produce dozens of cut flowers per week. Modern breeding has expanded the palette and forms dramatically; the American Dahlia Society recognizes over 20 flower forms. Extremely rewarding for gardeners willing to invest in the planting, staking, and (in cold zones) annual lifting of tubers.
Washington County, Kansas is in USDA Zone 6a. The average last spring frost is April 21 and the first fall frost is October 14, giving you a growing season of approximately 176 days.
At an elevation of 562 feet, Washington County receives approximately 26.9 inches of rainfall annually with predominantly loam soil. Summer highs average 84°F, so choose short-season varieties of Dahlias to ensure they mature before fall.
Washington County Soil Profile
Soil Type
Loam
Soil pH
6.8-7.6
Drainage
Well Drained
Dahlias 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 Washington County
How your county's soil matches Dahlias's growing requirements.
Soil pH
Your soil pH (6.8–7.6) overlaps with Dahlias's range (6.0–7.5), though not a perfect match.
Soil Texture
The loam soil in Washington County is excellent for Dahlias — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is moderate (3.4%). Annual compost additions will help Dahlias.
How to Plant Dahlias
Succession Planting Dahlias
Sow every 8 weeks. Last sowing by Jun 16 to harvest before frost.
Dahlias Water Budget
Water stress score is 6/10 — consider drought-tolerant varieties and mulching
Monthly Watering Guide for Dahlias
Dahlias needs approximately 1 inches of water per week (4.3" per month). Here's how your county's rainfall compares month by month.
| Month | Dahlias Needs | Rainfall | You Supplement | Action |
|---|---|---|---|---|
| Jan | — | 0.8" | 0" | ❄️ Dormant |
| Feb | — | 0.9" | 0" | ❄️ Dormant |
| Mar | — | 1.6" | 0" | ❄️ Dormant |
| Apr | 4.3" | 3.2" | 1.1" | 💧 Light watering |
| May | 4.3" | 4" | 0.3" | 💧 Light watering |
| Jun | 4.3" | 4" | 0.3" | 💧 Light watering |
| Jul | 4.3" | 3.1" | 1.2" | 💧 Light watering |
| Aug | 4.3" | 3.5" | 0.8" | 💧 Light watering |
| Sep | 4.3" | 2.4" | 1.9" | 💧 Light watering |
| Oct | 4.3" | 1.7" | 2.6" | 🚿 Regular watering |
| Nov | — | 1" | 0" | ❄️ Dormant |
| Dec | — | 0.8" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Apr–Oct in Washington County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.
Dahlias 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.
Dahlias Planting Timeline — Washington County, KS
Dahlias Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | March 24 | Mar 24 – Apr 7 |
| Transplant Outdoors | April 28 | Apr 28 – May 12 |
| Direct Sow | April 28 | Apr 28 – May 19 |
| Bloom | July 14 | Jul 14 – Oct 27 |
Plant 5" deep · 18" apart · Rows 24" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | Start Indoors |
| April | Start Indoors Transplant Outdoors Direct Sow |
| 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
1"/week · 1-2 times/week
📅 Days to Maturity
70–120 days
🧪 Soil pH
Needs 6–7.5 · Your soil: acceptable
🗺️ USDA Zone
Zone 6a
📆 Growing Season
176 days in Washington County
Growing Tips for Dahlias in Washington County
Direct sow Dahlias outdoors after April 21 in Washington County when soil has warmed and frost danger has passed.
Common pests for Dahlias in this region include aphids and slugs. Use row covers early in the season and inspect plants weekly.
General growing tips
Plant tubers after all danger of frost has passed and soil temperature reaches 60°F — typically 1–2 weeks after last frost in most zones. Lay tubers horizontally 4–6 inches deep with the eye (growth point) facing up. Do not water until sprouts emerge; wet soil rots dormant tubers. Stake tall varieties (over 3 feet) at planting time to avoid root disturbance later. Pinch growing tips at 12–16 inches to encourage branching and more blooms. Deadhead regularly to extend the blooming season. In zones 8b and warmer, tubers can overwinter in the ground with a layer of mulch. In zones 3–8a, lift tubers after the first killing frost, cure for a week, and store in slightly damp vermiculite or peat at 40–50°F until spring. Divide tubers every year or two; each division must have an eye (bud) to grow.
Companion Planting
Good Companions
Check more plant combinations with our Companion Planting Checker →
Dahlias in Other Locations
Frequently Asked Questions
When should I plant Dahlias in Washington County, KS?
Washington County is in Zone 6a with an average last frost of April 21. Plan your Dahlias planting based on this frost date — see the calendar above for exact timing.
What planting zone is Washington County, KS?
Washington County, Kansas is in USDA Hardiness Zone 6a. The average last spring frost is April 21 and first fall frost is October 14.
When should I plant Dahlias in Washington County County, ?
In Washington County County, , plant Dahlias after the last frost (around April 21) and before the first frost (around October 14). Best results when soil holds above 50°F.
What growing zone is Washington County County, for Dahlias?
Washington County County sits in USDA Zone 6a. Dahlias grows reliably in zones 3a through 10b, so it's a good fit here.
Can Dahlias grow in Washington County County's climate?
Yes — Dahlias grows well in Washington County County's temperate climate. Washington County County averages a 176-day frost-free season, with last frost around April 21 and first frost around October 14.
Your Washington County Garden Planner — Free
A 22-page printable planner built for Washington County (Zone 6a). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.