When to Plant Gladiolus in Thurston County, WA
Your June planting checklist for Thurston County, Washington
We've pulled the most time-sensitive tasks for Thurston County, Washington this June and put them front and centre. Tackle them in order.
-
Start harvesting gladiolus
If you can't use it all right away, check the food-preservation section of your planner.
Looking ahead to July
- First harvests: gladiolus
Gladiolus (Gladiolus spp.) produce tall, stately spikes of trumpet-shaped blooms in a rich array of colors, making them one of the most popular cut flowers in the world. Each spike carries 12–20 florets that open in succession from bottom to top over 7–10 days. By planting corms every two weeks from last frost through early summer, gardeners create a continuous succession of fresh blooms from midsummer through fall. Corms multiply each season — a single planting becomes a growing collection over the years. Ideal for back-of- border planting, cutting gardens, and mixed summer containers.
Thurston County, Washington is in USDA Zone 8b. The average last spring frost is April 15 and the first fall frost is October 29, giving you a growing season of approximately 197 days.
At an elevation of 213 feet, Thurston County receives approximately 37.3 inches of rainfall annually with predominantly silt loam soil. Summer highs average 89°F, providing good warmth for Gladiolus during the growing season.
Thurston County Soil Profile
Soil Type
Silt Loam
Soil pH
5.3-6.6
Drainage
Well Drained
Gladiolus 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 Thurston County
How your county's soil matches Gladiolus's growing requirements.
Soil pH
Your soil pH (5.3–6.6) is more acidic than Gladiolus prefers (6.0–6.5). Add garden lime to raise pH.
Soil Texture
The silt loam soil in Thurston County is excellent for Gladiolus — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is excellent (4.6%) — Gladiolus will thrive.
How to Plant Gladiolus
Succession Planting Gladiolus
Sow every 8 weeks. Last sowing by Jul 21 to harvest before frost.
Gladiolus Water Budget
Monthly Watering Guide for Gladiolus
Gladiolus needs approximately 1 inches of water per week (4.3" per month). Here's how your county's rainfall compares month by month.
| Month | Gladiolus Needs | Rainfall | You Supplement | Action |
|---|---|---|---|---|
| Jan | — | 4.9" | 0" | ❄️ Dormant |
| Feb | — | 4.6" | 0" | ❄️ Dormant |
| Mar | — | 4.2" | 0" | ❄️ Dormant |
| Apr | 4.3" | 2.7" | 1.6" | 💧 Light watering |
| May | 4.3" | 2.2" | 2.1" | 💧 Light watering |
| Jun | 4.3" | 1.4" | 2.9" | 🚿 Regular watering |
| Jul | 4.3" | 0.7" | 3.6" | 🚿 Regular watering |
| Aug | 4.3" | 0.7" | 3.6" | 🚿 Regular watering |
| Sep | 4.3" | 1.7" | 2.6" | 🚿 Regular watering |
| Oct | 4.3" | 3" | 1.3" | 💧 Light watering |
| Nov | — | 5.3" | 0" | ❄️ Dormant |
| Dec | — | 6" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Apr–Oct in Thurston County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.
Gladiolus 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.
Gladiolus Planting Timeline — Thurston County, WA
Gladiolus Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Transplant Outdoors | April 15 | Apr 15 – Apr 29 |
| Direct Sow | April 15 | Apr 15 – May 6 |
| Bloom | June 24 | Jun 24 – Dec 9 |
Plant 5" deep · 5" apart · Rows 12" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | — |
| April | Transplant Outdoors Direct Sow |
| May | Direct Sow |
| June | Bloom |
| July | Bloom |
| August | Bloom |
| September | Bloom |
| October | Bloom |
| November | Bloom |
| December | Bloom |
Growing Conditions
☀️ Sun
Full Sun (6-8+ hours)
💧 Water
1"/week · Only during dry spells
📅 Days to Maturity
70–100 days
🧪 Soil pH
Needs 6–6.5 · Your soil: too_acidic
🗺️ USDA Zone
Zone 8b
📆 Growing Season
197 days in Thurston County
Growing Tips for Gladiolus in Thurston County
Direct sow Gladiolus outdoors after April 15 in Thurston County when soil has warmed and frost danger has passed.
General growing tips
Plant corms 4–6 inches deep, pointed end up, as soon as soil reaches 60°F after last frost. Space 4–6 inches apart; rows 12 inches apart. Stake or grow through a support grid — tall varieties reach 4–5 feet and tip in wind. Begin succession plantings every 2 weeks through early July for continuous bloom. Water deeply once a week; mulch to conserve moisture and suppress weeds. Cut spikes for vases when the lowest floret just begins to open. After first killing frost (in cold zones), dig corms, let dry for 3–4 weeks in a ventilated spot, remove cormels, and store in mesh bags at 35–50°F. In zones 7b–8a, corms sometimes survive mild winters in ground with heavy mulch; in zones 8b+, in-ground overwintering is reliable.
Companion Planting
Good Companions
Check more plant combinations with our Companion Planting Checker →
Gladiolus in Other Locations
Frequently Asked Questions
When should I plant Gladiolus in Thurston County, WA?
Thurston County is in Zone 8b with an average last frost of April 15. Plan your Gladiolus planting based on this frost date — see the calendar above for exact timing.
What planting zone is Thurston County, WA?
Thurston County, Washington is in USDA Hardiness Zone 8b. The average last spring frost is April 15 and first fall frost is October 29.
Your Thurston County Garden Planner — Free
A 22-page printable planner built for Thurston County (Zone 8b). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.