When to Plant Larkspur in Asotin County, WA
Your July planting checklist for Asotin County, Washington
Your Asotin County, Washington garden is entering a new phase. Here's what's on the schedule for July and why each task matters now.
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Collect larkspur at their peak
This is the payoff month. Bring a basket, bring a friend, and get into the beds.
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Plant your fall garden: larkspur
Mid-season soil is hot. Sow a bit deeper than the packet suggests to find cooler, damper ground.
Get ahead of August
- First harvests: larkspur
Larkspur (Consolida ajacis) is a cool-season annual that produces tall, delicate spires of blue, purple, pink, and white flowers reminiscent of its perennial cousin, delphinium. Direct-sown into cold soil or fall-sown in mild-winter climates, it blooms in spring before going to seed as summer heat arrives. An excellent cut flower and cottage-garden staple.
Asotin County, Washington is in USDA Zone 7a. The average last spring frost is May 9 and the first fall frost is September 30, giving you a growing season of approximately 144 days.
At an elevation of 2,029 feet, Asotin County receives approximately 14 inches of rainfall annually with predominantly silt loam soil. Summer highs average 85°F, providing good warmth for Larkspur during the growing season. With low rainfall, drip irrigation is essential for growing Larkspur successfully. Mulch heavily to conserve soil moisture.
Asotin County Soil Profile
Soil Type
Silt Loam
Soil pH
5.5-6.5
Drainage
Well Drained
Larkspur 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 Asotin County
How your county's soil matches Larkspur's growing requirements.
Soil pH
Your soil pH (5.5–6.5) overlaps with Larkspur's range (6.0–7.0), though not a perfect match.
Soil Texture
The silt loam soil in Asotin County is excellent for Larkspur — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is excellent (4.7%) — Larkspur will thrive.
How to Plant Larkspur
Fall planting: Sow 10 weeks before your first frost date for a fall harvest.
Succession Planting Larkspur
Sow every 6.9 weeks. Last sowing by Jul 02 to harvest before frost.
For a dedicated fall crop, sow by Jul 22.
Larkspur Water Budget
Monthly Watering Guide for Larkspur
Larkspur needs approximately 0.5 inches of water per week (2.2" per month). Here's how your county's rainfall compares month by month.
| Month | Larkspur Needs | Rainfall | You Supplement | Action |
|---|---|---|---|---|
| Jan | — | 2" | 0" | ❄️ Dormant |
| Feb | — | 1.7" | 0" | ❄️ Dormant |
| Mar | — | 1.5" | 0" | ❄️ Dormant |
| Apr | — | 0.9" | 0" | ❄️ Dormant |
| May | 2.2" | 0.8" | 1.4" | 🚿 Regular watering |
| Jun | 2.2" | 0.6" | 1.6" | 🚿 Regular watering |
| Jul | 2.2" | 0.2" | 2" | 🚿 Regular watering |
| Aug | 2.2" | 0.3" | 1.9" | 🚿 Regular watering |
| Sep | 2.2" | 0.5" | 1.7" | 🚿 Regular watering |
| Oct | — | 1.2" | 0" | ❄️ Dormant |
| Nov | — | 2.4" | 0" | ❄️ Dormant |
| Dec | — | 1.9" | 0" | ❄️ Dormant |
Water needs are for active growing months only (May–Sep in Asotin County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.
Larkspur 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.
Larkspur Planting Timeline — Asotin County, WA
Larkspur Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Direct Sow | April 11 | Apr 11 – May 2 |
| Bloom | June 20 | Jun 20 – Aug 29 |
| Fall Sowing | July 22 | Jul 22 – Aug 5 |
Plant 0.1" deep · 8" apart · Rows 12" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | — |
| April | Direct Sow |
| May | Direct Sow |
| June | Bloom |
| July | Fall Sowing Bloom |
| August | Fall Sowing Bloom |
| September | — |
| October | — |
| November | — |
| December | — |
Growing Conditions
☀️ Sun
Full Sun (6-8+ hours)
💧 Water
0.5"/week · Only during dry spells
📅 Days to Maturity
60–90 days
🧪 Soil pH
Needs 6–7 · Your soil: acceptable
🗺️ USDA Zone
Zone 7a
📆 Growing Season
144 days in Asotin County
Growing Tips for Larkspur in Asotin County
Direct sow Larkspur outdoors after May 09 in Asotin County when soil has warmed and frost danger has passed.
Asotin County receives only 14" of rain annually. Larkspur needs consistent moisture — install drip irrigation or water deeply 2-3 times per week.
General growing tips
Larkspur does not transplant well — direct-sow only. In cold climates (zones 2–6), sow directly in early spring as soon as soil can be worked, 4–6 weeks before last frost; cold soil improves germination. In zones 7–10, fall-sow 8–10 weeks before first frost for spring bloom. Press seeds lightly into soil; they need darkness to germinate — cover with 1/8–1/4 inch of soil. Thin to 6–12 inches to prevent powdery mildew. Allow seed pods to mature and self-sow for naturalized colonies. All parts are toxic if ingested.
Companion Planting
Good Companions
Check more plant combinations with our Companion Planting Checker →
Larkspur in Other Locations
Frequently Asked Questions
When should I plant Larkspur in Asotin County, WA?
Asotin County is in Zone 7a with an average last frost of May 9. Plan your Larkspur planting based on this frost date — see the calendar above for exact timing.
What planting zone is Asotin County, WA?
Asotin County, Washington is in USDA Hardiness Zone 7a. The average last spring frost is May 9 and first fall frost is September 30.
Your Asotin County Garden Planner — Free
A 22-page printable planner built for Asotin 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.