When to Plant Cress in Island County, WA
Your May game plan for Island County, Washington
May is a pivotal month for Island County, Washington gardens. Focus on these tasks first and you'll set up the rest of the season for success.
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Sow cress in trays indoors
Bottom-water once the first true leaves appear — it keeps stems dry and knocks back damping-off.
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Collect cress at their peak
This is the payoff month. Bring a basket, bring a friend, and get into the beds.
Garden cress is one of the fastest-growing edibles, producing peppery sprouts in as little as two weeks. It is excellent for microgreens and garnishes.
Island County, Washington is in USDA Zone 8b. The average last spring frost is March 30 and the first fall frost is November 3, giving you a growing season of approximately 218 days.
At an elevation of 9 feet, Island County receives approximately 45.5 inches of rainfall annually with predominantly silt loam soil. Summer highs average 85°F, providing good warmth for Cress during the growing season.
Island County Soil Profile
Soil Type
Silt Loam
Soil pH
5.6-6.7
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 Island County
How your county's soil matches Cress's growing requirements.
Soil pH
Your soil pH (5.6–6.7) overlaps with Cress's range (6.0–7.0), though not a perfect match.
Soil Texture
The silt loam soil in Island County is excellent for Cress — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is excellent (5.3%) — Cress will thrive.
How to Plant Cress
Fall planting: Sow 10 weeks before your first frost date for a fall harvest.
Succession Planting Cress
Sow every 1.6 weeks. Last sowing by Oct 13 to harvest before frost.
For a dedicated fall crop, sow by Aug 25.
Plant Water Budget
Monthly Watering Guide for Cress
Cress needs approximately 1 inches of water per week (4.3" per month). Here's how your county's rainfall compares month by month.
| Month | Cress Needs | Rainfall | You Supplement | Action |
|---|---|---|---|---|
| Jan | — | 6.8" | 0" | ❄️ Dormant |
| Feb | — | 4.7" | 0" | ❄️ Dormant |
| Mar | 4.3" | 4.5" | 0" | ✅ Rainfall sufficient |
| Apr | 4.3" | 3.7" | 0.6" | 💧 Light watering |
| May | 4.3" | 2.3" | 2" | 💧 Light watering |
| Jun | 4.3" | 1.6" | 2.7" | 🚿 Regular watering |
| Jul | 4.3" | 0.7" | 3.6" | 🚿 Regular watering |
| Aug | 4.3" | 0.8" | 3.5" | 🚿 Regular watering |
| Sep | 4.3" | 1.6" | 2.7" | 🚿 Regular watering |
| Oct | 4.3" | 4.2" | 0.1" | 💧 Light watering |
| Nov | 4.3" | 7" | 0" | ✅ Rainfall sufficient |
| Dec | — | 7.8" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Mar–Nov in Island County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.
Cress 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.
Cress Planting Timeline — Island County, WA
Cress Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | February 23 | Feb 23 – Mar 9 |
| Transplant Outdoors | March 30 | Mar 30 – Apr 13 |
| Direct Sow | March 16 | Mar 16 – Apr 6 |
| Harvest | April 13 | Apr 13 – May 4 |
| Fall Sowing | August 25 | Aug 25 – Sep 8 |
Plant 0.5" deep · 2" apart · Rows 6" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | Start Indoors |
| March | Start Indoors Transplant Outdoors Direct Sow |
| April | Transplant Outdoors Direct Sow Harvest |
| May | Harvest |
| June | — |
| July | — |
| August | Fall Sowing |
| September | Fall Sowing |
| October | — |
| November | — |
| December | — |
Growing Conditions
☀️ Sun
Partial Shade (3-6 hours)
💧 Water
1"/week · Only during dry spells
📅 Days to Maturity
14–21 days
🧪 Soil pH
Needs 6–7 · Your soil: acceptable
🗺️ USDA Zone
Zone 8b
📆 Growing Season
218 days in Island County
Growing Tips for Cress in Island County
Direct sow Cress outdoors after March 30 in Island County when soil has warmed and frost danger has passed.
Your generous 218.0-day season in Island County allows multiple plantings of Cress. Sow every 7.0 days for continuous harvest.
Common pests for Cress in this region include cabbage worm and flea beetles. Use row covers early in the season and inspect plants weekly.
General growing tips
Sow seeds thickly on moist soil or paper towels. Keep moist and harvest when 2-3 inches tall. Succession sow every few days for continuous supply. Grows well indoors year-round.
Companion Planting
Good Companions
Check more plant combinations with our Companion Planting Checker →
Cress in Other Locations
Frequently Asked Questions
When should I plant Cress in Island County, WA?
Island County is in Zone 8b with an average last frost of March 30. Plan your Cress planting based on this frost date — see the calendar above for exact timing.
What planting zone is Island County, WA?
Island County, Washington is in USDA Hardiness Zone 8b. The average last spring frost is March 30 and first fall frost is November 3.
Your Island County Garden Planner — Free
A 24-page printable planner built for Island 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.