When to Plant Lettuce in Morrow County, OR
Lettuce is a fast-growing cool-season green available in leaf, romaine, butterhead, and crisphead types. It is the foundation of salads and one of the easiest crops to grow.
Morrow County, Oregon is in USDA Zone 6a. The average last spring frost is April 25 and the first fall frost is October 15, giving you a growing season of approximately 173 days.
At an elevation of 2,335 feet, Morrow County receives approximately 20.9 inches of rainfall annually with predominantly silt loam soil. Summer highs average 88°F, providing good warmth for Lettuce during the growing season.
Morrow County Soil Profile
Soil Type
Silt Loam
Soil pH
5.4-6.8
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 Morrow County
How your county's soil matches Lettuce's growing requirements.
Soil pH
Your soil pH (5.4–6.8) overlaps with Lettuce's range (6.0–7.0), though not a perfect match.
Soil Texture
The silt loam soil in Morrow County is excellent for Lettuce — good drainage, moisture retention, and nutrient holding capacity.
Drainage
Drainage is adequate for Lettuce.
Organic Matter
Organic matter is excellent (4.6%) — Lettuce will thrive.
How to Plant Lettuce
Fall planting: Sow 10 weeks before your first frost date for a fall harvest.
Succession Planting Lettuce
Sow every 3.4 weeks. Last sowing by Aug 16 to harvest before frost.
For a dedicated fall crop, sow by Aug 06.
Plant Water Budget
Water stress score is 6/10 — consider drought-tolerant varieties and mulching
Monthly Watering Guide for Lettuce
Lettuce needs approximately 0.7 inches of water per week (3" per month). Here's how your county's rainfall compares month by month.
| Month | Lettuce Needs | Rainfall | You Supplement | Action |
|---|---|---|---|---|
| Jan | — | 3" | 0" | ❄️ Dormant |
| Feb | — | 2.8" | 0" | ❄️ Dormant |
| Mar | — | 2.1" | 0" | ❄️ Dormant |
| Apr | 3" | 1.4" | 1.6" | 🚿 Regular watering |
| May | 3" | 1.2" | 1.8" | 🚿 Regular watering |
| Jun | 3" | 0.7" | 2.3" | 🚿 Regular watering |
| Jul | 3" | 0.4" | 2.6" | 🚿 Regular watering |
| Aug | 3" | 0.4" | 2.6" | 🚿 Regular watering |
| Sep | 3" | 0.8" | 2.2" | 🚿 Regular watering |
| Oct | 3" | 1.7" | 1.3" | 💧 Light watering |
| Nov | — | 3.2" | 0" | ❄️ Dormant |
| Dec | — | 3.2" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Apr–Oct in Morrow County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.
Lettuce 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.
Lettuce Planting Timeline — Morrow County, OR
Lettuce Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | March 21 | Mar 21 – Apr 4 |
| Transplant Outdoors | April 25 | Apr 25 – May 9 |
| Direct Sow | April 11 | Apr 11 – May 2 |
| Harvest | May 30 | May 30 – Aug 8 |
| Fall Sowing | August 6 | Aug 6 – Aug 20 |
Plant 0.5" deep · 6" apart · Rows 12" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | Start Indoors |
| April | Start Indoors Transplant Outdoors Direct Sow |
| May | Transplant Outdoors Direct Sow Harvest |
| June | Harvest |
| July | Harvest |
| August | Fall Sowing Harvest |
| September | — |
| October | — |
| November | — |
| December | — |
Growing Conditions
☀️ Sun
Partial Shade (3-6 hours)
💧 Water
0.7"/week · 1-2 times/week
📅 Days to Maturity
30–60 days
🧪 Soil pH
Needs 6–7 · Your soil: acceptable
🗺️ USDA Zone
Zone 6a
📆 Growing Season
173 days in Morrow County
Growing Tips for Lettuce in Morrow County
Direct sow Lettuce outdoors after April 25 in Morrow County when soil has warmed and frost danger has passed.
Your generous 173.0-day season in Morrow County allows multiple plantings of Lettuce. Sow every 15.0 days for continuous harvest.
Common pests for Lettuce in this region include aphids and slugs. Use row covers early in the season and inspect plants weekly.
General growing tips
Sow seeds directly every 2 weeks for continuous harvest. Provide afternoon shade in warm weather to delay bolting. Harvest in the morning for crispest leaves.
Recommended Lettuce Varieties for Morrow County
Bolt-resistant varieties for warm summers — grow as spring/fall crop
Companion Planting
Good Companions
Avoid Planting Near
Check more plant combinations with our Companion Planting Checker →
Very easy to save. Let a few plants bolt each season.
Lettuce in Other Locations
Frequently Asked Questions
When should I plant Lettuce in Morrow County, OR?
Morrow County is in Zone 6a with an average last frost of April 25. Plan your Lettuce planting based on this frost date — see the calendar above for exact timing.
What planting zone is Morrow County, OR?
Morrow County, Oregon is in USDA Hardiness Zone 6a. The average last spring frost is April 25 and first fall frost is October 15.
Plan Your Garden with Confidence
Get our free Garden Planner — designed to help Morrow County gardeners in Zone 6a organize planting dates, track what's growing, and never miss a planting window.
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