When to Plant Eggplant in Grant County, WA
This month in Grant County, Washington
Your garden in Grant County, Washington is working on a schedule, even when you're not. Here's where you should be this May.
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Plant out eggplant
Bring a watering can to the bed. Each transplant gets a drink the moment it's in the ground, not ten minutes later.
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Seed eggplant outdoors
Mark the row. Birds and stray feet both have opinions about unmarked beds.
Eggplant is a heat-loving solanaceous crop that produces glossy fruits in purple, white, or striped varieties. It requires long, warm growing seasons for best production.
Grant County, Washington is in USDA Zone 7a. The average last spring frost is April 29 and the first fall frost is October 10, giving you a growing season of approximately 164 days.
At an elevation of 3,122 feet, Grant County receives approximately 17.6 inches of rainfall annually with predominantly silt loam soil. Summer highs average 91°F, providing good warmth for Eggplant during the growing season. With low rainfall, drip irrigation is essential for growing Eggplant successfully. Mulch heavily to conserve soil moisture.
Grant County Soil Profile
Soil Type
Silt Loam
Soil pH
5.6-6.8
Drainage
Well Drained
Plant 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 Grant County
How your county's soil matches Eggplant's growing requirements.
Soil pH
Your soil pH (5.6–6.8) is within Eggplant's preferred range (5.5–7.0).
Soil Texture
The silt loam soil in Grant County is excellent for Eggplant — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is excellent (5.7%) — Eggplant will thrive.
How to Plant Eggplant
Succession Planting Eggplant
Sow every 7.4 weeks. Last sowing by Jul 17 to harvest before frost.
Plant Water Budget
Monthly Watering Guide for Eggplant
Eggplant needs approximately 1.1 inches of water per week (4.8" per month). Here's how your county's rainfall compares month by month.
| Month | Eggplant Needs | Rainfall | You Supplement | Action |
|---|---|---|---|---|
| Jan | — | 2.7" | 0" | ❄️ Dormant |
| Feb | — | 1.8" | 0" | ❄️ Dormant |
| Mar | — | 2" | 0" | ❄️ Dormant |
| Apr | 4.8" | 1.5" | 3.3" | 🚿 Regular watering |
| May | 4.8" | 1.1" | 3.7" | 🚿 Regular watering |
| Jun | 4.8" | 0.7" | 4.1" | 🚿 Regular watering |
| Jul | 4.8" | 0.2" | 4.6" | 🚿 Regular watering |
| Aug | 4.8" | 0.4" | 4.4" | 🚿 Regular watering |
| Sep | 4.8" | 0.6" | 4.2" | 🚿 Regular watering |
| Oct | 4.8" | 1.7" | 3.1" | 🚿 Regular watering |
| Nov | — | 2.5" | 0" | ❄️ Dormant |
| Dec | — | 2.5" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Apr–Oct in Grant County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.
Eggplant 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.
Eggplant Planting Timeline — Grant County, WA
Eggplant Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | February 25 | Feb 25 – Mar 11 |
| Transplant Outdoors | May 13 | May 13 – May 27 |
| Direct Sow | May 6 | May 6 – May 27 |
| Harvest | July 22 | Jul 22 – Sep 23 |
Plant 1" deep · 30" apart · Rows 42" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | Start Indoors |
| March | Start Indoors |
| April | — |
| May | Transplant Outdoors Direct Sow |
| June | — |
| July | Harvest |
| August | Harvest |
| September | Harvest |
| October | — |
| November | — |
| December | — |
Growing Conditions
☀️ Sun
Full Sun (6-8+ hours)
💧 Water
1.1"/week · 1-2 times/week
📅 Days to Maturity
65–85 days
🧪 Soil pH
Needs 5.5–7 · Your soil: ideal
🗺️ USDA Zone
Zone 7a
📆 Growing Season
164 days in Grant County
Growing Tips for Eggplant in Grant County
Direct sow Eggplant outdoors after April 29 in Grant County when soil has warmed and frost danger has passed.
Common pests for Eggplant in this region include tomato hornworm and aphids. Use row covers early in the season and inspect plants weekly.
Grant County receives only 18" of rain annually. Eggplant needs consistent moisture — install drip irrigation or water deeply 2-3 times per week.
General growing tips
Start seeds indoors 8-10 weeks before last frost. Transplant only after nighttime temperatures stay above 55F. Mulch to retain moisture and warmth around roots.
Companion Planting
Good Companions
Avoid Planting Near
Check more plant combinations with our Companion Planting Checker →
Eggplant in Other Locations
Frequently Asked Questions
When should I plant Eggplant in Grant County, WA?
Grant County is in Zone 7a with an average last frost of April 29. Plan your Eggplant planting based on this frost date — see the calendar above for exact timing.
What planting zone is Grant County, WA?
Grant County, Washington is in USDA Hardiness Zone 7a. The average last spring frost is April 29 and first fall frost is October 10.
Your Grant County Garden Planner — Free
A 24-page printable planner built for Grant 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.