When to plant Basil in Jefferson County County,
Jefferson County County's spring Basil window runs April 28 through May 19. time plantings around the expected last-frost window for best survival.
When to Plant Basil in Jefferson County, IA
June to-do list for Jefferson County, Iowa
If you only do a handful of things in the garden this June, make it these. They're sequenced around your zone's frost timing.
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Time to start basil inside
Starting these indoors now means sturdy transplants ready the moment your soil warms up.
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Basket week: basil
Taste as you pick. The first ripe produce is the best feedback loop you'll get all season.
Get ahead of July
- First harvests: basil
Basil is a fragrant warm-season herb essential to Italian and Thai cuisines. It comes in many varieties including sweet, Thai, purple, and lemon types.
Jefferson County, Iowa is in USDA Zone 5b. The average last spring frost is April 21 and the first fall frost is October 14, giving you a growing season of approximately 176 days.
At an elevation of 1,279 feet, Jefferson County receives approximately 37.9 inches of rainfall annually with predominantly silt loam soil. Summer highs average 83°F, so choose short-season varieties of Basil to ensure they mature before fall.
Jefferson County Soil Profile
Soil Type
Silt Loam
Soil pH
6-7.2
Drainage
Well Drained
Basil 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 Jefferson County
How your county's soil matches Basil's growing requirements.
Soil pH
Your soil pH (6.0–7.2) overlaps with Basil's range (6.0–7.0), though not a perfect match.
Soil Texture
The silt loam soil in Jefferson County is excellent for Basil — good drainage, moisture retention, and nutrient holding capacity.
Drainage
Drainage is adequate for Basil.
Organic Matter
Organic matter is excellent (4.5%) — Basil will thrive.
How to Plant Basil
Succession Planting Basil
Sow every 5.7 weeks. Last sowing by Jul 31 to harvest before frost.
Basil Water Budget
Water stress score is 6/10 — consider drought-tolerant varieties and mulching
Monthly Watering Guide for Basil
Basil needs approximately 0.6 inches of water per week (2.6" per month). Here's how your county's rainfall compares month by month.
| Month | Basil Needs | Rainfall | You Supplement | Action |
|---|---|---|---|---|
| Jan | — | 1.5" | 0" | ❄️ Dormant |
| Feb | — | 1.7" | 0" | ❄️ Dormant |
| Mar | — | 2.9" | 0" | ❄️ Dormant |
| Apr | 2.6" | 3.3" | 0" | ✅ Rainfall sufficient |
| May | 2.6" | 4.1" | 0" | ✅ Rainfall sufficient |
| Jun | 2.6" | 4.6" | 0" | ✅ Rainfall sufficient |
| Jul | 2.6" | 4.1" | 0" | ✅ Rainfall sufficient |
| Aug | 2.6" | 4.5" | 0" | ✅ Rainfall sufficient |
| Sep | 2.6" | 3.4" | 0" | ✅ Rainfall sufficient |
| Oct | 2.6" | 2.9" | 0" | ✅ Rainfall sufficient |
| Nov | — | 2.9" | 0" | ❄️ Dormant |
| Dec | — | 1.8" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Apr–Oct in Jefferson County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.
Basil 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.
Basil Planting Timeline — Jefferson County, IA
Basil Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | March 3 | Mar 3 – Mar 17 |
| Transplant Outdoors | May 5 | May 5 – May 19 |
| Direct Sow | April 28 | Apr 28 – May 19 |
| Harvest | June 30 | Jun 30 – Sep 1 |
Plant 0.5" deep · 8" apart · Rows 12" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | Start Indoors |
| April | Direct Sow |
| May | Transplant Outdoors Direct Sow |
| June | Harvest |
| July | Harvest |
| August | Harvest |
| September | Harvest |
| October | — |
| November | — |
| December | — |
Growing Conditions
☀️ Sun
Full Sun (6-8+ hours)
💧 Water
0.6"/week · Natural rainfall sufficient
📅 Days to Maturity
50–75 days
🧪 Soil pH
Needs 6–7 · Your soil: acceptable
🗺️ USDA Zone
Zone 5b
📆 Growing Season
176 days in Jefferson County
Growing Tips for Basil in Jefferson County
Direct sow Basil outdoors after April 21 in Jefferson County when soil has warmed and frost danger has passed.
General growing tips
Start seeds indoors or direct sow after last frost. Pinch flower buds to extend leaf production. Harvest leaves from the top down, cutting just above a leaf pair.
Companion Planting
Good Companions
Avoid Planting Near
Check more plant combinations with our Companion Planting Checker →
Isolate 150 ft between varieties. Different basil species can cross.
Basil in Other Locations
Frequently Asked Questions
When should I plant Basil in Jefferson County, IA?
Jefferson County is in Zone 5b with an average last frost of April 21. Plan your Basil planting based on this frost date — see the calendar above for exact timing.
What planting zone is Jefferson County, IA?
Jefferson County, Iowa is in USDA Hardiness Zone 5b. The average last spring frost is April 21 and first fall frost is October 14.
When should I plant Basil in Jefferson County County, ?
In Jefferson County County, , plant Basil after the last frost (around April 21) and before the first frost (around October 14). Best results when soil holds above 50°F.
What growing zone is Jefferson County County, for Basil?
Jefferson County County sits in USDA Zone 5b. Basil grows reliably in zones 4a through 11b, so it's a good fit here.
Can Basil grow in Jefferson County County's climate?
Yes — Basil grows well in Jefferson County County's temperate climate. Jefferson County County averages a 176-day frost-free season, with last frost around April 21 and first frost around October 14.
Your Jefferson County Garden Planner — Free
A 22-page printable planner built for Jefferson 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.