When to plant Dahlias in Coconino County County,
Plant Dahlias in Coconino County County, between June 4 and June 25 — the only viable window. Zone 7a's short season (122 frost-free days) rules out a fall crop.
When to Plant Dahlias in Coconino County, AZ
Your June gardening checklist
If you only do a handful of things in the garden this June, make it these. They're sequenced around your zone's frost timing.
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Move dahlias from tray to bed
Water the tray well an hour before you transplant. Roots slide out cleanly and settle in faster.
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Plant dahlias from seed, right in the garden
Mark the row. Birds and stray feet both have opinions about unmarked beds.
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Fire up the seed-starting tray: dahlias
Bottom-water once the first true leaves appear — it keeps stems dry and knocks back damping-off.
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.
Coconino County, Arizona is in USDA Zone 7a. The average last spring frost is May 28 and the first fall frost is September 27, giving you a growing season of approximately 122 days.
At an elevation of 7,869 feet, Coconino County receives approximately 13.9 inches of rainfall annually with predominantly sandy loam soil. Summer highs average 96°F, so Dahlias may need afternoon shade and extra watering during peak heat. Sandy soil warms quickly in spring — great for early planting — but Dahlias will need more frequent watering and organic matter to retain nutrients. With low rainfall, drip irrigation is essential for growing Dahlias successfully. Mulch heavily to conserve soil moisture.
Coconino County Soil Profile
Soil Type
Sandy Loam
Soil pH
7.2-8.6
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 Coconino County
How your county's soil matches Dahlias's growing requirements.
Soil pH
Your soil pH (7.2–8.6) is more alkaline than Dahlias prefers (6.0–7.5). Add sulfur or peat moss to lower pH.
Soil Texture
Sandy soil in Coconino County warms quickly in spring but drains fast. Dahlias will need more frequent watering and regular compost additions to retain nutrients.
Drainage
Drainage is adequate for Dahlias.
Organic Matter
Organic matter is low (0.8%). Add 2-3 inches of compost before planting Dahlias.
How to Plant Dahlias
Dahlias Water Budget
Water stress score is 10/10 — 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 | — | 1" | 0" | ❄️ Dormant |
| Feb | — | 0.7" | 0" | ❄️ Dormant |
| Mar | — | 0.8" | 0" | ❄️ Dormant |
| Apr | — | 0.4" | 0" | ❄️ Dormant |
| May | 4.3" | 0.3" | 4" | 🚿 Regular watering |
| Jun | 4.3" | 0.4" | 3.9" | 🚿 Regular watering |
| Jul | 4.3" | 2.6" | 1.7" | 💧 Light watering |
| Aug | 4.3" | 3" | 1.3" | 💧 Light watering |
| Sep | 4.3" | 1.7" | 2.6" | 🚿 Regular watering |
| Oct | — | 1.3" | 0" | ❄️ Dormant |
| Nov | — | 0.8" | 0" | ❄️ Dormant |
| Dec | — | 0.9" | 0" | ❄️ Dormant |
Water needs are for active growing months only (May–Sep in Coconino 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 — Coconino County, AZ
Dahlias Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | April 30 | Apr 30 – May 14 |
| Transplant Outdoors | June 4 | Jun 4 – Jun 18 |
| Direct Sow | June 4 | Jun 4 – Jun 25 |
| Bloom | August 13 | Aug 13 – Dec 17 |
Plant 5" deep · 18" apart · Rows 24" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | — |
| April | Start Indoors |
| May | Start Indoors |
| June | Transplant Outdoors Direct Sow |
| July | — |
| August | Bloom |
| September | Bloom |
| October | Bloom |
| November | Bloom |
| December | Bloom |
Growing Conditions
☀️ Sun
Full Sun (6-8+ hours)
💧 Water
1"/week · 2-3 times/week
📅 Days to Maturity
70–120 days
🧪 Soil pH
Needs 6–7.5 · Your soil: too_alkaline
🗺️ USDA Zone
Zone 7a
📆 Growing Season
122 days in Coconino County
Growing Tips for Dahlias in Coconino County
Direct sow Dahlias outdoors after May 28 in Coconino County when soil has warmed and frost danger has passed.
Sandy soil in Coconino County dries quickly — mulch Dahlias with 2-3 inches of straw and water deeply 2-3 times per week rather than lightly every day.
With summer highs reaching 96°F in Coconino County, provide afternoon shade for Dahlias and water deeply in the morning.
Your 122.0-day growing season in Coconino County is tight for Dahlias (70.0-120.0 days to maturity). Start indoors and choose early-maturing varieties.
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 Coconino County, AZ?
Coconino County is in Zone 7a with an average last frost of May 28. Plan your Dahlias planting based on this frost date — see the calendar above for exact timing.
What planting zone is Coconino County, AZ?
Coconino County, Arizona is in USDA Hardiness Zone 7a. The average last spring frost is May 28 and first fall frost is September 27.
When should I plant Dahlias in Coconino County County, ?
In Coconino County County, , plant Dahlias after the last frost (around May 28) and before the first frost (around September 27). Best results when soil holds above 50°F.
What growing zone is Coconino County County, for Dahlias?
Coconino County County sits in USDA Zone 7a. Dahlias grows reliably in zones 3a through 10b, so it's a good fit here.
Can Dahlias grow in Coconino County County's climate?
Yes — Dahlias grows well in Coconino County County's temperate climate. Coconino County County averages a 122-day frost-free season, with last frost around May 28 and first frost around September 27.
Your Coconino County Garden Planner — Free
A 22-page printable planner built for Coconino County (Zone 7a). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.