When to Plant Lettuce in Jasper County, IA
Your May gardening checklist
May is a pivotal month for Jasper County, Iowa gardens. Focus on these tasks first and you'll set up the rest of the season for success.
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Move lettuce from tray to bed
Plant tomatoes deep — bury the stem up to the first true leaves to grow extra roots. Everything else goes in at the same depth it grew in the tray.
Get ahead of June
- Starting indoors: lettuce
- First harvests: lettuce
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.
Jasper County, Iowa is in USDA Zone 5b. The average last spring frost is May 2 and the first fall frost is October 7, giving you a growing season of approximately 158 days.
At an elevation of 1,048 feet, Jasper County receives approximately 38 inches of rainfall annually with predominantly silt loam soil. Summer highs average 85°F, providing good warmth for Lettuce during the growing season.
Jasper County Soil Profile
Soil Type
Silt Loam
Soil pH
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 Jasper County
How your county's soil matches Lettuce's growing requirements.
Soil pH
Your soil pH (6.0–6.7) is within Lettuce's preferred range (6.0–7.0).
Soil Texture
The silt loam soil in Jasper County is excellent for Lettuce — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is excellent (4.2%) — 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 08 to harvest before frost.
For a dedicated fall crop, sow by Jul 29.
Plant Water Budget
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 | — | 1.5" | 0" | ❄️ Dormant |
| Feb | — | 1.8" | 0" | ❄️ Dormant |
| Mar | — | 2.3" | 0" | ❄️ Dormant |
| Apr | — | 4" | 0" | ❄️ Dormant |
| May | 3" | 4.7" | 0" | ✅ Rainfall sufficient |
| Jun | 3" | 5.3" | 0" | ✅ Rainfall sufficient |
| Jul | 3" | 4" | 0" | ✅ Rainfall sufficient |
| Aug | 3" | 3.9" | 0" | ✅ Rainfall sufficient |
| Sep | 3" | 2.9" | 0.1" | 💧 Light watering |
| Oct | 3" | 2.8" | 0.2" | 💧 Light watering |
| Nov | — | 2.5" | 0" | ❄️ Dormant |
| Dec | — | 2.3" | 0" | ❄️ Dormant |
Water needs are for active growing months only (May–Oct in Jasper 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 — Jasper County, IA
Lettuce Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | March 28 | Mar 28 – Apr 11 |
| Transplant Outdoors | May 2 | May 2 – May 16 |
| Direct Sow | April 18 | Apr 18 – May 9 |
| Harvest | June 6 | Jun 6 – Aug 15 |
| Fall Sowing | July 29 | Jul 29 – Aug 12 |
Plant 0.5" deep · 6" apart · Rows 12" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | Start Indoors |
| April | Start Indoors Direct Sow |
| May | Transplant Outdoors Direct Sow |
| June | Harvest |
| July | Fall Sowing Harvest |
| August | Fall Sowing Harvest |
| September | — |
| October | — |
| November | — |
| December | — |
Growing Conditions
☀️ Sun
Partial Shade (3-6 hours)
💧 Water
0.7"/week · Natural rainfall sufficient
📅 Days to Maturity
30–60 days
🧪 Soil pH
Needs 6–7 · Your soil: ideal
🗺️ USDA Zone
Zone 5b
📆 Growing Season
158 days in Jasper County
Growing Tips for Lettuce in Jasper County
Direct sow Lettuce outdoors after May 02 in Jasper County when soil has warmed and frost danger has passed.
Your generous 158.0-day season in Jasper 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 Jasper 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 Jasper County, IA?
Jasper County is in Zone 5b with an average last frost of May 2. Plan your Lettuce planting based on this frost date — see the calendar above for exact timing.
What planting zone is Jasper County, IA?
Jasper County, Iowa is in USDA Hardiness Zone 5b. The average last spring frost is May 2 and first fall frost is October 7.
Your Jasper County Garden Planner — Free
A 24-page printable planner built for Jasper County (Zone 5b). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.