Carter County, MT — Planting Guide
Carter County is in USDA Zone 4a. The average last spring frost is May 15 and the first fall frost is September 22, giving you a growing season of approximately 130 days.
At an elevation of 7,923 ft, Carter County receives approximately 19.8 in of rainfall annually. Summer highs average 81°F with winter lows around 6°F. The predominant soil type is Loam.
Based on 31 years of NOAA climate station data, the last frost date here varies by 29 days year to year — ranging from May 4 in warm years to June 2 in cold years. The growing season is trending longer by about 2.68 days per decade. Carter County scores 29/100 (Challenging) on the Microclimate Index.
🌡️ Zone
4a (-30°F to -25°F min)
❄️ Last Frost
May 15
🍂 First Frost
September 22
📅 Growing Season
130 days
⛰️ Elevation
7,923 ft
🌧️ Annual Rainfall
19.8 in
Monthly Watering Calendar
When you'll need to water your garden — based on average monthly rainfall vs. the ~1 inch/week most gardens need.
View detailed monthly data
| Month | Avg Rainfall | Rainy Days | Extra Water Needed | Watering Effort |
|---|---|---|---|---|
| Jan | 1.4 in | 7 days | — | None |
| Feb | 1.2 in | 6 days | — | None |
| Mar | 2 in | 7 days | — | None |
| Apr | 2.2 in | 6 days | 2.1 in | High |
| May | 2.4 in | 7 days | 1.9 in | High |
| Jun | 1.4 in | 4 days | 2.9 in | High |
| Jul | 1.6 in | 5 days | 2.7 in | High |
| Aug | 1.9 in | 6 days | 2.4 in | High |
| Sep | 1.4 in | 5 days | 2.9 in | High |
| Oct | 1.7 in | 5 days | 2.6 in | High |
| Nov | 1.3 in | 6 days | — | None |
| Dec | 1.3 in | 6 days | — | None |
Annual total: 19.8 in. Water needs vary by crop — tomatoes need ~1.2"/week while herbs like rosemary need only 0.3"/week. Check individual plant pages for crop-specific water budgets that factor in your county's rainfall and soil drainage.
Carter County Soil Profile
Soil Type
Loam
Soil pH
6.4-8.2
Drainage
Well Drained
Frost Risk Probability
Based on 31 years of NOAA weather station data from 3 stations
Beginners: Plant frost-sensitive crops (tomatoes, peppers, squash) after the "Safe" date on the left. Harvest or cover them before the "Protect by" date on the right. Hardy crops (lettuce, peas, kale) can go in the yellow transition zones.
How to read this table: "Conservative" means you're safe from frost 9 out of 10 years — best for beginners and frost-sensitive crops. "Average year" is the typical date. "Aggressive" means only 1 in 10 years is that warm — experienced gardeners with frost protection can try these dates.
| Planting Strategy | Last Spring Frost | First Fall Frost | Frost-Free Days |
|---|---|---|---|
| Conservative (safest) | Jun 2 | Oct 7 | 127 days |
| Cautious | May 21 | Oct 3 | 135 days |
| Average year | May 15 | Sep 22 | 130 days |
| Optimistic | May 11 | Sep 19 | 131 days |
| Aggressive (risky) | May 4 | Sep 11 | 130 days |
Not very — frost dates can vary by ±29 days year-to-year. Use the "Conservative" row in the table below, and keep row covers handy for surprise late frosts.
Yes — growing seasons are getting longer here (about 2.7 days per decade). Spring is arriving earlier than it used to. Good news for gardeners.
Gardening Difficulty Score
Carter County has challenging growing conditions. Season extension and careful variety selection are essential.
Local Gardening Help in Carter County
Free expert help is closer than you think. Your county's cooperative extension office connects you with trained gardeners, soil testing labs, and local programs — all specific to Carter County's climate and soil.
County Extension Office
Carter County Montana State University Extension Extension Office
Phone: 406-994-3402
Visit Extension Office Website →
Extension offices are run by land-grant universities and funded by the USDA. Their advice is free, research-based, and tailored to your county's specific conditions.
Master Gardener Program
Free gardening help from trained volunteers
Master Gardeners are community volunteers who complete 40–60 hours of university horticultural training. They answer gardening questions, diagnose plant problems, and offer workshops — all free.
Many extension offices run a Master Gardener hotline where you can call or email with photos of plant problems for free diagnosis.
Soil Testing
Available through your extension office
Before amending your soil, get it tested. Your extension office offers soil testing (typically $10–$25) that tells you exact pH, nutrient levels, and amendment recommendations specific to what you want to grow.
Services Available in Carter County
Finding local nurseries & garden centers in Carter County
Why Buy Local
Local nurseries carry plants that are proven to grow in your area. Staff can give you advice specific to Carter County's soil and climate that big-box stores can't. Plants from local growers are typically hardier because they're already acclimated to your zone.
How to Find Them
Search for "nurseries near Carter County MT" or "garden center Carter County" on Google Maps. Also check with your extension office — they often maintain lists of reputable local nurseries and plant sales.
Community gardens & gardening groups
Community gardens are a great way to learn from experienced gardeners in your area, especially if you're limited on space. Search "community garden Carter County MT" or check your extension office and local parks department. Facebook groups like "Carter County Gardeners" or "Montana Gardening" are also excellent for local advice and plant swaps.
What to Plant After Your Harvest
After your first crops finish, use the remaining frost-free days to grow a second round.
Show 6 more succession options
Sunlight & Day Length
Monthly daylight hours and peak sun — critical for onion varieties, photoperiod-sensitive plants, and solar garden planning.
Longest Day
15.5 hours
Summer solstice daylight
Shortest Day
8.5 hours
Winter solstice daylight
Peak Sun Hours
11 hr/day peak (summer)
Peak sun hours (green dashed line below) account for cloud cover — this is the usable direct sunlight your garden actually receives. Most vegetables need 6+ peak sun hours.
Onion tip: Your long summer days (14+ hours) support long-day onion varieties like Walla Walla, Sweet Spanish, and Ailsa Craig.
View detailed monthly data
| Month | Daylight Hours | Peak Sun Hours | Day Length |
|---|---|---|---|
| January | 8.9 hr | 4.8 hr | Short day |
| February | 10.1 hr | 6 hr | Short day |
| March | 11.6 hr | 6.9 hr | Short day |
| April | 13.3 hr | 7.9 hr | Neutral |
| May | 14.7 hr | 9.5 hr | Long day |
| June | 15.5 hr | 11 hr | Long day |
| July | 15.2 hr | 10.7 hr | Long day |
| August | 13.9 hr | 9 hr | Neutral |
| September | 12.3 hr | 8.6 hr | Neutral |
| October | 10.7 hr | 6.8 hr | Short day |
| November | 9.2 hr | 5.2 hr | Short day |
| December | 8.5 hr | 4.6 hr | Short day |
Peak sun hours factor in typical cloud cover — use these for solar panel and shade-planning calculations.
Soil Temperature & Composting Calendar
Monthly soil temps tell you when to plant warm-season crops, and when your compost pile is actively working.
Plant Warm Crops When
Soil reaches 60°F+
Soil rarely reaches 60°F — use black plastic mulch to warm soil.
Best Month to Compost
Apr
Microbial activity peaks when soil is warm.
Active Composting
0 months
Short season — insulate pile or use indoor vermicomposting.
View detailed monthly data
| Month | Soil 4" Deep | Soil 8" Deep | Compost Activity | Time to Finish |
|---|---|---|---|---|
| Jan | -10°F | -0°F | ❄️ Dormant | ~36 weeks |
| Feb | -8°F | -1°F | ❄️ Dormant | ~36 weeks |
| Mar | 3°F | 4°F | ❄️ Dormant | ~36 weeks |
| Apr | 17°F | 14°F | ❄️ Dormant | ~36 weeks |
| May | 30°F | 25°F | ❄️ Dormant | ~36 weeks |
| Jun | 40°F | 34°F | ❄️ Dormant | ~36 weeks |
| Jul | 47°F | 41°F | 🐢 Slow | ~24 weeks |
| Aug | 47°F | 44°F | 🐢 Slow | ~24 weeks |
| Sep | 39°F | 39°F | ❄️ Dormant | ~36 weeks |
| Oct | 28°F | 31°F | ❄️ Dormant | ~36 weeks |
| Nov | 11°F | 19°F | ❄️ Dormant | ~36 weeks |
| Dec | -1°F | 7°F | ❄️ Dormant | ~36 weeks |
Highlighted rows = soil 60°F+ (safe for warm-season transplants). Compost finishes fastest during peak activity months.
Pest & Disease Pressure in Carter County
Computed from local climate patterns — warmer, humid conditions increase pest generations and fungal disease risk.
Insect Pest Pressure
Moderate — common pests appear but manageable with monitoring.
Disease Risk
Low disease risk — dry conditions reduce fungal problems.
Seasonal Risk
View 5 common pests in your area
| Pest | Risk Level | Peak Months |
|---|---|---|
| Aphids | Moderate | May, Jun, Jul, Aug |
| Cabbage worms | Moderate | Jun, Jul, Aug |
| Colorado potato beetle | Moderate | Jun, Jul |
| Flea beetles | Low | May, Jun, Jul |
| Slugs | Moderate | May, Jun, Jul, Aug, Sep |
Organic pest management tips
- Maintain healthy soil with regular compost additions to build natural pest resistance
- Practice crop rotation annually to break pest cycles
- Encourage beneficial insects with flowering herbs like dill, fennel, and yarrow
Cover Crops for Carter County
Cover crops protect bare soil, fix nitrogen, suppress weeds, and improve soil structure — with county-specific planting dates.
Spring Cover Crops (2 options) — Build soil before the main growing season
| Crop | Plant By | Terminate | N-Fixing | Soil Benefit |
|---|---|---|---|---|
| Buckwheat | May 17 | Jul 28 | — | Rapid growth, attracts pollinators, suppresses weeds |
| White clover | Apr 15 | Jul 28 | ✓ Yes | Living mulch, fixes nitrogen, permanent ground cover |
Summer Cover Crops (1 options) — Fill gaps and suppress weeds between plantings
| Crop | Plant By | Terminate | N-Fixing | Soil Benefit |
|---|---|---|---|---|
| Sunflowers | Jun 6 | Sep 8 | — | Deep roots break compaction, attract pollinators and beneficial insects |
Fall Cover Crops (5 options) — Plant after harvest to protect soil over winter
| Crop | Plant By | Terminate | N-Fixing | Soil Benefit |
|---|---|---|---|---|
| Daikon radish | Aug 4 | Apr 24 | — | Deep taproot breaks compaction, excellent for clay soils |
| Hairy vetch | Jul 12 | Apr 24 | ✓ Yes | Excellent nitrogen fixer, good for depleted soils |
| Oats | Aug 19 | May 1 | — | Quick biomass, winterkills in cold zones — no spring tillage needed |
| Winter rye | Jun 16 | Apr 24 | — | Suppresses weeds, prevents erosion, breaks up compacted soil |
| Winter wheat | Jun 22 | May 1 | — | Erosion control, weed suppression, good biomass |
Wind & Microclimate
Wind dries soil, stresses plants, and affects frost patterns. Understanding your exposure helps with garden placement.
Seasonal Wind Speed
Spring: 15 mph Summer: 12 mph
Fall: 12 mph Winter: 16 mph
Prevailing wind: W. Windy area — plant a windbreak hedge on the W side of your garden.
Windbreak Benefit
7.4/10
Strongly recommended — a windbreak (fence, hedge, or row of tall crops like corn or sunflowers) will significantly improve garden yields.
Frost Pocket Risk
High
Hilly terrain with 1,492 ft of elevation range — cold air pools in low spots. Avoid planting frost-sensitive crops in valleys.
Rainwater Harvesting Potential
How much water you can collect, when to collect it, and what size system you need for your garden.
Annual Collection
9,868 gal
Per 1,000 sq ft of roof area (at 80% collection efficiency)
Recommended Setup
8 rain barrels (55 gal each)
For a typical 500 sq ft garden. Serious collectors: consider a 1,750 gal tank.
Legal Status
Unrestricted
Rainwater harvesting is fully legal in your state with no restrictions.
Best Collection Months
Mar, Apr, May, Aug
Highest rainfall months — your barrels will fill up quickly during these months.
Months to Draw From Storage
Feb, Nov, Dec
Dry months when you'll rely on stored water — size your storage for this gap.
Rainwater collection tips for your area
- Your county receives approximately 19.8 inches of rain per year
- A 1,000 sq ft roof can collect roughly 9,868 gallons annually
- Rainwater harvesting is fully legal in your state
- In your dry climate, every drop counts — consider a larger cistern system
- Position collection tanks in shade to reduce evaporation and algae growth
Soil & Growing Conditions in Carter County
Soil Type
Loam
Soil pH 6.4–8.2 · Well Drained drainage
Good candidate for raised beds to maximise drainage and extend the season.
Watering Needs
Drought stress: 7.5/10
High drought stress. Consistent irrigation is essential — consider drip systems, heavy mulch, and drought-tolerant varieties.
Season Tips
130-day frost-free season
Start warm-season crops indoors and focus on short-season varieties. Cold frames extend your season by 3–4 weeks in fall.
Free Garden Planner
Plan your entire garden season — organize planting dates, track what you're growing, and know exactly when to start seeds, transplant, and harvest.
Recommended for Your Garden
Test your soil pH, nitrogen, phosphorus, and potassium levels before planting.
Get instant, accurate soil pH readings to fine-tune your amendments.
Boost soil fertility and structure with rich, well-aged organic compost.
🥬 Vegetables to Grow in Carter County
96 vegetables that grow well in Zone 4a with planting dates for Carter County.
Show all 96 vegetables with planting dates
| Plant | Start Indoors | Direct Sow | Transplant | Harvest | Days to Maturity |
|---|---|---|---|---|---|
| Acorn Squash | Apr 3 | May 29 | Jun 5 | Aug 28 – Oct 2 | 80–100 |
| Amaranth | Mar 13 | May 29 | Jun 5 | Sep 4 – Oct 23 | 90–120 |
| Arugula | Apr 3 | May 8 | May 15 | Jun 19 – Aug 21 | 30–50 |
| Asparagus | — | — | May 29 | — | 730–1095 |
| Beets | — | May 8 | — | Jul 3 – Jul 31 | 50–70 |
| Belgian Endive | Apr 3 | May 8 | May 15 | Sep 4 – Oct 9 | 110–150 |
| Black Beans | — | May 29 | — | Aug 28 – Oct 16 | 90–120 |
| Bok Choy | Apr 3 | May 8 | May 15 | Jun 26 – Jul 31 | 40–60 |
| Broccoli | Apr 3 | May 8 | May 15 | Jul 17 – Aug 28 | 60–90 |
| Broccoli Rabe | Apr 3 | May 8 | May 15 | Jun 26 – Jul 31 | 40–60 |
| Brussels Sprouts | Apr 3 | May 8 | May 15 | Aug 14 – Oct 9 | 90–130 |
| Butternut Squash | Apr 3 | May 29 | Jun 5 | Sep 4 – Oct 9 | 85–110 |
| Cabbage | Apr 3 | May 8 | May 15 | Jul 17 – Sep 11 | 60–100 |
| Carrots | — | May 8 | — | Jul 10 – Aug 14 | 60–80 |
| Cauliflower | Apr 3 | May 8 | May 15 | Jul 10 – Sep 11 | 55–100 |
| Celeriac | Apr 3 | May 8 | May 15 | Aug 28 – Oct 2 | 100–120 |
| Celery | Apr 3 | May 8 | May 15 | Aug 7 – Oct 2 | 80–120 |
| Celtuce | Apr 3 | May 8 | May 15 | Jul 17 – Aug 28 | 60–90 |
| Chard | Apr 3 | May 8 | May 15 | Jul 10 – Aug 28 | 50–60 |
| Chickpeas | Apr 3 | May 8 | May 15 | Aug 7 – Sep 18 | 80–110 |
| Chicory | Apr 3 | May 8 | May 15 | Jul 17 – Aug 28 | 60–85 |
| Chinese Cabbage | Apr 3 | May 8 | May 15 | Jul 10 – Aug 7 | 50–70 |
| Christmas Lima Beans | Mar 13 | May 29 | Jun 5 | Aug 28 – Oct 2 | 80–100 |
| Collard Greens | Apr 3 | May 8 | May 15 | Jul 10 – Sep 11 | 55–75 |
| Corn | — | May 29 | — | Jul 31 – Sep 25 | 60–100 |
| Cress | Apr 3 | May 8 | May 15 | May 29 – Jun 19 | 14–21 |
| Crookneck Squash | Apr 3 | May 29 | Jun 5 | Jul 24 – Aug 21 | 45–60 |
| Crosne | — | May 8 | — | Oct 9 – Oct 2 | 150–200 |
| Cucumber | Apr 3 | May 29 | Jun 5 | Jul 31 – Sep 25 | 50–70 |
| Daikon | — | May 8 | — | Jul 3 – Jul 31 | 50–70 |
| Delicata Squash | Apr 3 | May 29 | Jun 5 | Aug 28 – Oct 2 | 80–100 |
| Edamame | — | May 29 | — | Aug 14 – Sep 25 | 75–100 |
| Endive | Apr 3 | May 8 | May 15 | Jul 3 – Aug 7 | 45–65 |
| Escarole | Apr 3 | May 8 | May 15 | Jul 10 – Aug 7 | 50–70 |
| Fava Beans | Apr 3 | May 8 | May 15 | Jul 31 – Sep 11 | 75–100 |
| Fennel | Mar 13 | May 29 | Jun 5 | Aug 7 – Sep 18 | 60–90 |
| Garlic | — | — | — | — | 90–240 |
| Green Beans | — | May 29 | — | Jul 24 – Sep 18 | 50–65 |
| Horseradish | — | — | May 29 | Oct 2 – Oct 23 | 120–180 |
| Hubbard Squash | Apr 3 | May 29 | Jun 5 | Sep 18 – Oct 23 | 100–120 |
| Kabocha | Apr 3 | May 29 | Jun 5 | Sep 4 – Oct 2 | 85–100 |
| Kai Lan | Apr 3 | May 8 | May 15 | Jul 3 – Jul 31 | 45–60 |
| Kale | Apr 3 | May 8 | May 15 | Jul 10 – Sep 4 | 50–70 |
| Kidney Beans | — | May 29 | — | Aug 28 – Oct 2 | 85–110 |
| Kohlrabi | Apr 3 | May 8 | May 15 | Jul 3 – Aug 7 | 45–65 |
| Komatsuna | Apr 3 | May 8 | May 15 | Jun 19 – Jul 24 | 35–50 |
| Leeks | Apr 3 | May 8 | May 15 | Aug 14 – Oct 9 | 90–150 |
| Lentils | Apr 3 | May 8 | May 15 | Aug 7 – Sep 18 | 80–110 |
| Lettuce | Apr 3 | May 8 | May 15 | Jun 19 – Aug 28 | 30–60 |
| Lima Beans | — | May 29 | — | Jul 31 – Sep 11 | 60–90 |
| Mache | Apr 3 | May 8 | May 15 | Jun 26 – Jul 31 | 40–60 |
| Melon | Apr 3 | May 29 | Jun 5 | Aug 14 – Oct 2 | 70–100 |
| Microgreens | Apr 3 | May 8 | May 15 | May 22 – Jun 19 | 7–21 |
| Mitsuba | Apr 3 | May 8 | May 8 | Jul 3 – Aug 28 | 50–70 |
| Mizuna | Apr 3 | May 8 | May 15 | Jun 19 – Jul 17 | 30–45 |
| Mustard Greens | Apr 3 | May 8 | May 15 | Jun 19 – Aug 21 | 30–50 |
| Napa Cabbage | Apr 3 | May 8 | May 15 | Jul 10 – Aug 14 | 55–75 |
| Onion | Apr 3 | May 8 | May 15 | Aug 14 – Oct 2 | 90–120 |
| Pac Choi | Apr 3 | May 8 | May 15 | Jun 26 – Jul 24 | 40–55 |
| Parsnip | — | May 8 | — | Aug 21 – Oct 2 | 100–130 |
| Patty Pan Squash | Apr 3 | May 29 | Jun 5 | Jul 24 – Aug 21 | 45–60 |
| Peas | Apr 3 | May 8 | May 15 | Jul 10 – Sep 4 | 55–70 |
| Peppers | Feb 27 | May 29 | Jun 5 | Aug 7 – Oct 16 | 60–90 |
| Pole Beans | Mar 13 | May 29 | Jun 5 | Jul 31 – Sep 25 | 55–70 |
| Potatoes | Mar 13 | May 29 | Jun 5 | Aug 14 – Oct 23 | 70–120 |
| Pumpkin | Apr 3 | May 29 | Jun 5 | Sep 4 – Oct 23 | 85–120 |
| Purslane | Apr 3 | May 8 | May 15 | Jun 26 – Jul 31 | 40–60 |
| Radicchio | Apr 3 | May 8 | May 15 | Jul 17 – Aug 21 | 60–80 |
| Radish | — | May 8 | — | Jun 5 – Jun 26 | 22–35 |
| Rhubarb | — | — | Jun 12 | — | 365–730 |
| Romanesco | Apr 3 | May 8 | May 15 | Jul 31 – Sep 11 | 75–100 |
| Rutabaga | — | May 8 | — | Jul 31 – Sep 4 | 80–100 |
| Salsify | — | May 8 | — | Aug 21 – Oct 2 | 100–130 |
| Savoy Cabbage | Apr 3 | May 8 | May 15 | Jul 24 – Sep 18 | 70–110 |
| Scallions | Apr 3 | May 8 | May 15 | Jul 10 – Aug 7 | 50–70 |
| Scarlet Runner Beans | Mar 13 | May 29 | Jun 5 | Aug 7 – Sep 11 | 60–80 |
| Shallot | Apr 3 | May 8 | May 15 | Aug 14 – Oct 2 | 90–120 |
| Shiso | Mar 20 | May 22 | Jun 5 | Jul 31 – Sep 25 | 50–70 |
| Snap Peas | Mar 13 | May 29 | Jun 5 | Jul 31 – Sep 25 | 55–70 |
| Snow Peas | Apr 3 | May 8 | May 15 | Jul 10 – Sep 4 | 50–65 |
| Soybeans | — | May 29 | — | Aug 21 – Oct 16 | 80–120 |
| Spaghetti Squash | Apr 3 | May 29 | Jun 5 | Sep 4 – Oct 2 | 85–100 |
| Spinach | Apr 3 | May 8 | May 15 | Jun 19 – Aug 21 | 35–50 |
| Squash (Summer) | Apr 3 | May 29 | Jun 5 | Jul 24 – Sep 25 | 45–65 |
| Squash (Winter) | Apr 3 | May 29 | Jun 5 | Aug 28 – Oct 23 | 80–120 |
| Sunchoke | — | — | May 29 | Sep 18 – Oct 23 | 110–150 |
| Sunflower | Mar 13 | May 29 | Jun 5 | Aug 14 – Oct 2 | 70–100 |
| Sweet Corn | — | May 29 | — | Jul 31 – Sep 11 | 60–90 |
| Tatsoi | Apr 3 | May 8 | May 15 | Jun 19 – Jul 24 | 35–50 |
| Tomatillo | Mar 13 | May 29 | Jun 5 | Aug 7 – Oct 16 | 60–85 |
| Tomatoes | Mar 13 | May 29 | Jun 5 | Aug 7 – Oct 16 | 60–85 |
| Turnip | — | May 8 | — | Jun 19 – Jul 24 | 40–60 |
| Watercress | Apr 3 | May 8 | May 15 | Jun 26 – Jul 31 | 40–60 |
| Watermelon | Apr 3 | May 29 | Jun 5 | Aug 14 – Oct 2 | 70–100 |
| Wax Beans | — | May 29 | — | Jul 24 – Sep 18 | 50–65 |
| Zucchini | Apr 3 | May 29 | Jun 5 | Jul 24 – Sep 18 | 45–60 |
🍓 Fruits to Grow in Carter County
22 fruits that grow well in Zone 4a with planting dates for Carter County.
Show all 22 fruits with planting dates
| Plant | Start Indoors | Direct Sow | Transplant | Harvest | Days to Maturity |
|---|---|---|---|---|---|
| Alpine Strawberries | — | — | Jun 12 | Sep 11 – Nov 6 | 90–180 |
| Aronia | — | — | Jun 12 | — | 730–1095 |
| Blueberries | — | — | Jun 12 | — | 730–1095 |
| Cantaloupe | — | — | Jun 12 | Aug 21 – Sep 25 | 70–90 |
| Cranberries | — | — | Jun 12 | — | 730–1095 |
| Currants | — | — | Jun 12 | — | 730–1095 |
| Elderberries | — | — | Jun 12 | — | 730–1095 |
| Goji Berries | — | — | Jun 12 | — | 730–1095 |
| Gooseberries | — | — | Jun 12 | — | 730–1095 |
| Grapes | — | — | Jun 12 | — | 730–1095 |
| Ground Cherry | — | — | Jun 12 | Aug 21 – Oct 16 | 65–80 |
| Hardy Kiwi | — | — | Jun 12 | — | 1095–1825 |
| Haskaps | — | — | Jun 12 | — | 730–1095 |
| Honeydew | — | — | Jun 12 | Sep 4 – Oct 16 | 80–110 |
| Jostaberry | — | — | Jun 12 | — | 730–1095 |
| Lingonberries | — | — | Jun 12 | — | 730–1095 |
| Medlar | — | — | Jun 12 | — | 1095–1825 |
| Mulberries | — | — | Jun 12 | — | 730–1825 |
| Persimmon | — | — | Jun 12 | — | 1095–2555 |
| Raspberries | — | — | Jun 12 | — | 365–730 |
| Serviceberries | — | — | Jun 12 | — | 730–1095 |
| Strawberries | — | — | Jun 12 | Sep 11 – Nov 6 | 90–365 |
🌿 Herbs to Grow in Carter County
32 herbs that grow well in Zone 4a with planting dates for Carter County.
Show all 32 herbs with planting dates
| Plant | Start Indoors | Direct Sow | Transplant | Harvest | Days to Maturity |
|---|---|---|---|---|---|
| Angelica | Apr 3 | May 8 | May 8 | — | 365–730 |
| Anise | Apr 3 | May 8 | May 8 | Aug 7 – Oct 2 | 90–120 |
| Basil | Mar 20 | May 22 | Jun 5 | Jul 31 – Oct 2 | 50–75 |
| Bee Balm | — | — | May 22 | Aug 21 – Oct 16 | 90–120 |
| Borage | Apr 3 | May 8 | May 8 | Jul 3 – Aug 21 | 50–60 |
| Caraway | Apr 3 | May 8 | May 8 | — | 365–450 |
| Catnip | — | — | May 22 | Jul 24 – Sep 25 | 60–80 |
| Chamomile | Apr 3 | May 8 | May 8 | Jul 10 – Sep 18 | 60–90 |
| Chervil | Apr 3 | May 8 | May 8 | Jun 19 – Aug 21 | 40–60 |
| Chives | — | — | May 22 | Jul 24 – Oct 2 | 60–90 |
| Cilantro | Apr 3 | May 8 | May 8 | Jun 19 – Aug 21 | 40–60 |
| Comfrey | — | — | May 22 | Jul 24 – Oct 2 | 60–90 |
| Dill | Apr 3 | May 8 | May 8 | Jun 19 – Aug 21 | 40–60 |
| Echinacea | — | — | May 22 | Sep 25 – Oct 16 | 120–180 |
| Fennel (herb) | Apr 3 | May 8 | May 8 | Jul 10 – Sep 18 | 60–90 |
| Garlic Chives | — | — | May 22 | Jul 24 – Oct 2 | 60–90 |
| Horehound | — | — | May 22 | Aug 7 – Oct 2 | 75–90 |
| Hyssop | — | — | May 22 | Jul 31 – Oct 2 | 70–90 |
| Lemon Balm | — | — | May 22 | Jul 24 – Sep 11 | 60–70 |
| Lovage | — | — | May 22 | Jul 31 – Oct 2 | 70–90 |
| Mint | — | — | May 22 | Jul 24 – Oct 2 | 60–90 |
| Oregano | — | — | May 22 | Jul 24 – Oct 2 | 60–90 |
| Parsley | Apr 3 | May 8 | May 8 | Jul 10 – Sep 11 | 60–80 |
| Rue | — | — | May 22 | Jul 31 – Oct 2 | 70–90 |
| Sage | — | — | May 22 | Aug 7 – Oct 2 | 75–90 |
| Savory | — | — | May 22 | Jul 17 – Sep 11 | 50–70 |
| Sorrel | Apr 3 | May 8 | May 8 | Jun 19 – Aug 21 | 40–60 |
| Tarragon | — | — | May 22 | Jul 24 – Oct 2 | 60–90 |
| Thai Basil | Mar 20 | May 22 | Jun 5 | Jul 31 – Oct 2 | 50–75 |
| Thyme | — | — | May 22 | Jul 31 – Oct 2 | 70–90 |
| Valerian | — | — | May 22 | Sep 25 – Oct 16 | 120–180 |
| Yarrow | — | — | May 22 | Aug 21 – Oct 16 | 90–120 |
Monthly Planting Guide for Carter County
Gardening Guides & Resources
Helpful guides from The Ultimate Homestead to improve your garden in Carter County.
Frequently Asked Questions
What planting zone is Carter County, MT?
Carter County is in USDA Hardiness Zone 4a. This zone classification determines which perennial plants survive winter and sets the baseline for frost timing across the county.
When is the last frost in Carter County, MT?
Based on 31 years of NOAA weather station data, the median last spring frost in Carter County falls around May 15. In 8 out of 10 years, last frost lands between May 4 and June 2 — a 29-day window of variability. Use June 2 as your conservative safe-to-plant date for frost-sensitive crops.
When is the first fall frost in Carter County, MT?
The median first fall frost in Carter County arrives around September 22. In cold years it can arrive as early as September 11; in mild years as late as October 7. Harvest or protect frost-sensitive crops — tomatoes, peppers, basil, squash — before this date.
How long is the growing season in Carter County?
Carter County has a frost-free growing season of approximately 130 days. Focus on short-season varieties and start warm-season crops indoors 6–8 weeks before last frost. Climate records show the growing season is trending longer by about 2.68 days per decade.
What is the soil like in Carter County for gardening?
Carter County has predominantly Loam soil with a pH range of 6.4–8.2 and Well Drained drainage. Most vegetables and herbs grow well with standard composting and seasonal soil amendment.
What is grown commercially in Carter County?
Carter County has commercial agriculture that includes Cattle, Wheat, Hay, Sugar Beets. These crops reflect the local climate and soil conditions — what succeeds commercially often translates well to home gardens in the same area.
Is Carter County a good location for home gardening?
Carter County scores 29/100 (Challenging) on our Microclimate Index, which combines frost reliability, drought pressure, soil challenge, elevation risk, and long-term climate trend. Gardening here benefits from close attention to frost timing and season extension due to the challenging microclimate factors.
Plan Your Garden with Confidence
Get our free Garden Planner — designed to help Carter County gardeners in Zone 4a organize planting dates, track what's growing, and never miss a planting window.
Get Your Free Garden Planner →Free download. Plan your entire garden season in minutes.
