When to Plant Turnip in Custer County, MT
May in the garden — Custer County, Montana
Your garden in Custer County, Montana is working on a schedule, even when you're not. Here's where you should be this May.
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Outdoor sowing time: turnip
Rake a smooth bed, make a shallow furrow, drop seeds at the spacing on the packet, water gently, walk away.
A few tasks this May that'll pay off in June
- First harvests: turnip
Turnips are a fast-growing cool-season root vegetable with edible roots and greens. Baby turnips are sweet and tender while mature ones are more pungent.
Custer County, Montana is in USDA Zone 4b. The average last spring frost is May 14 and the first fall frost is September 27, giving you a growing season of approximately 136 days.
At an elevation of 5,983 feet, Custer County receives approximately 24 inches of rainfall annually with predominantly loam soil. Summer highs average 80°F, so choose short-season varieties of Turnip to ensure they mature before fall.
Custer County Soil Profile
Soil Type
Loam
Soil pH
6.5-8.1
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 Custer County
How your county's soil matches Turnip's growing requirements.
Soil pH
Your soil pH (6.5–8.1) is more alkaline than Turnip prefers (6.0–7.0). Add sulfur or peat moss to lower pH.
Soil Texture
The loam soil in Custer County is excellent for Turnip — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is moderate (2.7%). Annual compost additions will help Turnip.
How to Plant Turnip
Fall planting: Sow 12 weeks before your first frost date for a fall harvest.
Succession Planting Turnip
Sow every 4.6 weeks. Last sowing by Jul 29 to harvest before frost.
For a dedicated fall crop, sow by Jul 05.
Plant Water Budget
Water stress score is 8/10 — consider drought-tolerant varieties and mulching
Monthly Watering Guide for Turnip
Turnip needs approximately 1 inches of water per week (4.3" per month). Here's how your county's rainfall compares month by month.
| Month | Turnip Needs | Rainfall | You Supplement | Action |
|---|---|---|---|---|
| Jan | — | 1.7" | 0" | ❄️ Dormant |
| Feb | — | 1.6" | 0" | ❄️ Dormant |
| Mar | — | 2.3" | 0" | ❄️ Dormant |
| Apr | — | 2.6" | 0" | ❄️ Dormant |
| May | 4.3" | 2.6" | 1.7" | 💧 Light watering |
| Jun | 4.3" | 1.4" | 2.9" | 🚿 Regular watering |
| Jul | 4.3" | 2.2" | 2.1" | 💧 Light watering |
| Aug | 4.3" | 2.3" | 2" | 💧 Light watering |
| Sep | 4.3" | 2.1" | 2.2" | 🚿 Regular watering |
| Oct | — | 1.9" | 0" | ❄️ Dormant |
| Nov | — | 1.9" | 0" | ❄️ Dormant |
| Dec | — | 1.4" | 0" | ❄️ Dormant |
Water needs are for active growing months only (May–Sep in Custer County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.
Turnip 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.
Turnip Planting Timeline — Custer County, MT
Turnip Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Direct Sow | May 7 | May 7 – May 28 |
| Harvest | June 18 | Jun 18 – Jul 23 |
| Fall Sowing | July 5 | Jul 5 – Jul 19 |
Plant 0.5" deep · 4" apart · Rows 12" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | — |
| April | — |
| May | Direct Sow |
| June | Harvest |
| July | Fall Sowing Harvest |
| August | — |
| September | — |
| October | — |
| November | — |
| December | — |
Growing Conditions
☀️ Sun
Full Sun (6-8+ hours)
💧 Water
1"/week · 1-2 times/week
📅 Days to Maturity
40–60 days
🧪 Soil pH
Needs 6–7 · Your soil: too_alkaline
🗺️ USDA Zone
Zone 4b
📆 Growing Season
136 days in Custer County
Growing Tips for Turnip in Custer County
Direct sow Turnip outdoors after May 14 in Custer County when soil has warmed and frost danger has passed.
Common pests for Turnip in this region include cabbage worm and flea beetles. Use row covers early in the season and inspect plants weekly.
Custer County receives only 24" of rain annually. Turnip needs consistent moisture — install drip irrigation or water deeply 2-3 times per week.
General growing tips
Direct sow in early spring or late summer. Harvest when roots are 2-3 inches in diameter for best flavor. Both the roots and the greens are nutritious and edible.
Companion Planting
Good Companions
Avoid Planting Near
Check more plant combinations with our Companion Planting Checker →
Turnip in Other Locations
Frequently Asked Questions
When should I plant Turnip in Custer County, MT?
Custer County is in Zone 4b with an average last frost of May 14. Plan your Turnip planting based on this frost date — see the calendar above for exact timing.
What planting zone is Custer County, MT?
Custer County, Montana is in USDA Hardiness Zone 4b. The average last spring frost is May 14 and first fall frost is September 27.
Your Custer County Garden Planner — Free
A 24-page printable planner built for Custer County (Zone 4b). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.