Big Horn County, MT — Planting Guide
Big Horn County, Montana gardeners: here's your May plan
A quick May briefing for Big Horn County, Montana gardeners — what's urgent, what's next, and what can wait.
-
Time to transplant basil, cucumber, and kale
Frost risk is low now in Big Horn County, Montana. If you've been covering beds overnight, you can stop.
-
Seed basil, cucumber, and green beans outdoors
These tolerate cool soil, so you're not gambling by sowing now.
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Harvest radish, cress, and microgreens as they ripen
Taste as you pick. The first ripe produce is the best feedback loop you'll get all season.
Before June arrives, get these ready
- Transplants going out: alpine strawberries, aronia, and blackberries
- Starting indoors: cucumber, kale, and lettuce
- First harvests: lettuce, radish, and arugula
Big Horn County is in USDA Zone 5a. The average last spring frost is May 13 and the first fall frost is September 30, giving you a growing season of approximately 140 days.
At an elevation of 5,955 ft, Big Horn County receives approximately 22.5 in of rainfall annually. Summer highs average 83°F with winter lows around 2°F. The predominant soil type is Loam.
Based on 31 years of NOAA climate station data, the last frost date here varies by 33 days year to year — ranging from April 28 in warm years to May 31 in cold years. Big Horn County scores 50/100 (Moderate) on the Microclimate Index.
🌡️ Zone
5a (°F to °F min)
❄️ Last Frost
May 13
🍂 First Frost
September 30
📅 Growing Season
140 days
⛰️ Elevation
5,955 ft
🌧️ Annual Rainfall
22.5 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 | 5 days | — | None |
| Feb | 1.5 in | 6 days | — | None |
| Mar | 1.8 in | 7 days | — | None |
| Apr | 2.4 in | 6 days | 1.9 in | High |
| May | 2.9 in | 8 days | 1.4 in | Moderate |
| Jun | 1.7 in | 4 days | 2.6 in | High |
| Jul | 2.2 in | 5 days | 2.1 in | High |
| Aug | 2 in | 6 days | 2.3 in | High |
| Sep | 1.8 in | 5 days | 2.5 in | High |
| Oct | 2.1 in | 5 days | 2.2 in | High |
| Nov | 1.5 in | 5 days | — | None |
| Dec | 1.3 in | 6 days | — | None |
Annual total: 22.6 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.
Big Horn County Soil Profile
Soil Type
Loam
Soil pH
6.2-7.6
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) | May 31 | Oct 15 | 137 days |
| Cautious | May 22 | Oct 5 | 136 days |
| Average year | May 13 | Sep 30 | 140 days |
| Optimistic | May 8 | Sep 20 | 135 days |
| Aggressive (risky) | Apr 28 | Sep 8 | 133 days |
Not very — frost dates can vary by ±33 days year-to-year. Use the "Conservative" row in the table below, and keep row covers handy for surprise late frosts.
Gardening Difficulty Score
Big Horn County presents some gardening challenges. Choose adapted varieties and plan around frost dates.
Local Gardening Help in Big Horn 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 Big Horn County's climate and soil.
County Extension Office
Big Horn 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 Big Horn County
Finding local nurseries & garden centers in Big Horn County
Why Buy Local
Local nurseries carry plants that are proven to grow in your area. Staff can give you advice specific to Big Horn 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 Big Horn County MT" or "garden center Big Horn 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 Big Horn County MT" or check your extension office and local parks department. Facebook groups like "Big Horn 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
10.8 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 | 4.7 hr | Short day |
| February | 10.2 hr | 5.6 hr | Short day |
| March | 11.6 hr | 7.3 hr | Short day |
| April | 13.3 hr | 7.7 hr | Neutral |
| May | 14.7 hr | 8.9 hr | Long day |
| June | 15.5 hr | 10.8 hr | Long day |
| July | 15.1 hr | 10.7 hr | Long day |
| August | 13.9 hr | 9 hr | Neutral |
| September | 12.3 hr | 9 hr | Neutral |
| October | 10.7 hr | 7 hr | Short day |
| November | 9.3 hr | 5.6 hr | Short day |
| December | 8.5 hr | 4.5 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
Jul
Microbial activity peaks when soil is warm.
Active Composting
2 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 | -5°F | 5°F | ❄️ Dormant | ~36 weeks |
| Feb | 1°F | 5°F | ❄️ Dormant | ~36 weeks |
| Mar | 7°F | 10°F | ❄️ Dormant | ~36 weeks |
| Apr | 24°F | 21°F | ❄️ Dormant | ~36 weeks |
| May | 39°F | 33°F | ❄️ Dormant | ~36 weeks |
| Jun | 49°F | 41°F | 🐢 Slow | ~24 weeks |
| Jul | 57°F | 49°F | ♻️ Active | ~14 weeks |
| Aug | 55°F | 50°F | ♻️ Active | ~14 weeks |
| Sep | 48°F | 46°F | 🐢 Slow | ~24 weeks |
| Oct | 36°F | 37°F | ❄️ Dormant | ~36 weeks |
| Nov | 19°F | 25°F | ❄️ Dormant | ~36 weeks |
| Dec | 5°F | 14°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 Big Horn 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 | Low | 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 Big Horn 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 18 | Aug 5 | — | Rapid growth, attracts pollinators, suppresses weeds |
| White clover | Apr 16 | Jul 29 | ✓ 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 9 | Sep 16 | — | 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 2 | Apr 29 | — | Deep taproot breaks compaction, excellent for clay soils |
| Hairy vetch | Jul 7 | Apr 29 | ✓ Yes | Excellent nitrogen fixer, good for depleted soils |
| Oats | Aug 23 | Apr 29 | — | Quick biomass, winterkills in cold zones — no spring tillage needed |
| Winter rye | Jun 21 | Apr 29 | — | Suppresses weeds, prevents erosion, breaks up compacted soil |
| Winter wheat | Jul 6 | Apr 29 | — | 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: 14 mph Summer: 10 mph
Fall: 13 mph Winter: 15 mph
Prevailing wind: W. Windy area — plant a windbreak hedge on the W side of your garden.
Windbreak Benefit
6.7/10
Moderately beneficial — a simple fence or trellis can protect delicate crops from wind stress.
Frost Pocket Risk
High
Hilly terrain with 1,175 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
11,263 gal
Per 1,000 sq ft of roof area (at 80% collection efficiency)
Recommended Setup
7 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
Apr, May, Jul, Oct
Highest rainfall months — your barrels will fill up quickly during these months.
Months to Draw From Storage
Jan, 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 22.6 inches of rain per year
- A 1,000 sq ft roof can collect roughly 11,263 gallons annually
- Rainwater harvesting is fully legal in your state
- Stock up on stored water before your dry season (Jan, Nov, Dec)
- Use a first-flush diverter to keep roof debris out of your collection
Soil & Growing Conditions in Big Horn County
Soil Type
Loam
Soil pH 6.2–7.6 · Well Drained drainage
Native soil is well-suited to most vegetables and herbs with regular compost additions.
Watering Needs
Drought stress: 5.5/10
Moderate drought pressure. Drip irrigation and mulching are highly recommended to maintain soil moisture through summer.
Season Tips
140-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.
Your Free Printable Garden Planner
Plan every bed, every planting, every harvest — in one place. This 24-page printable includes your zone's planting calendar, a month-by-month task list, a seed inventory tracker, a harvest log, and succession-planting charts. Built to print, write in, and actually use all season.
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 Big Horn County
106 vegetables that grow well in Zone 5a with planting dates for Big Horn County.
Show all 106 vegetables with planting dates
| Plant | Start Indoors | Direct Sow | Transplant | Harvest | Days to Maturity |
|---|---|---|---|---|---|
| Acorn Squash | Apr 8 | May 20 | May 27 | Aug 19 – Sep 23 | 80–100 |
| Amaranth | Mar 18 | May 20 | May 27 | Aug 26 – Oct 14 | 90–120 |
| Arugula | Apr 8 | Apr 29 | May 13 | Jun 17 – Aug 19 | 30–50 |
| Asparagus | — | — | May 27 | — | 730–1095 |
| Beets | — | Apr 29 | — | Jun 24 – Jul 22 | 50–70 |
| Belgian Endive | Apr 8 | Apr 29 | May 13 | Sep 2 – Oct 28 | 110–150 |
| Bitter Melon | Mar 18 | May 20 | May 27 | Jul 29 – Sep 9 | 60–90 |
| Black Beans | — | May 20 | — | Aug 19 – Oct 7 | 90–120 |
| Bok Choy | Apr 8 | Apr 29 | May 13 | Jun 24 – Jul 29 | 40–60 |
| Broccoli | Apr 8 | Apr 29 | May 13 | Jul 15 – Aug 26 | 60–90 |
| Broccoli Rabe | Apr 8 | Apr 29 | May 13 | Jun 24 – Jul 29 | 40–60 |
| Brussels Sprouts | Apr 8 | Apr 29 | May 13 | Aug 12 – Oct 7 | 90–130 |
| Butternut Squash | Apr 8 | May 20 | May 27 | Aug 26 – Sep 30 | 85–110 |
| Cabbage | Apr 8 | Apr 29 | May 13 | Jul 15 – Sep 9 | 60–100 |
| Calabash | Mar 18 | May 20 | May 27 | Aug 19 – Oct 14 | 80–120 |
| Carrots | — | Apr 29 | — | Jul 1 – Aug 5 | 60–80 |
| Cauliflower | Apr 8 | Apr 29 | May 13 | Jul 8 – Sep 9 | 55–100 |
| Celeriac | Apr 8 | Apr 29 | May 13 | Aug 26 – Sep 30 | 100–120 |
| Celery | Apr 8 | Apr 29 | May 13 | Aug 5 – Sep 30 | 80–120 |
| Celtuce | Apr 8 | Apr 29 | May 13 | Jul 15 – Aug 26 | 60–90 |
| Chard | Apr 8 | Apr 29 | May 13 | Jul 8 – Aug 26 | 50–60 |
| Chickpeas | Apr 8 | Apr 29 | May 13 | Aug 5 – Sep 16 | 80–110 |
| Chicory | Apr 8 | Apr 29 | May 13 | Jul 15 – Aug 26 | 60–85 |
| Chinese Cabbage | Apr 8 | Apr 29 | May 13 | Jul 8 – Aug 5 | 50–70 |
| Christmas Lima Beans | Mar 18 | May 20 | May 27 | Aug 19 – Sep 23 | 80–100 |
| Collard Greens | Apr 8 | Apr 29 | May 13 | Jul 8 – Sep 9 | 55–75 |
| Corn | — | May 20 | — | Jul 22 – Sep 16 | 60–100 |
| Cowpeas | — | May 20 | — | Jul 22 – Sep 2 | 60–90 |
| Cress | Apr 8 | Apr 29 | May 13 | May 27 – Jun 17 | 14–21 |
| Crookneck Squash | Apr 8 | May 20 | May 27 | Jul 15 – Aug 12 | 45–60 |
| Crosne | — | Apr 29 | — | Sep 30 – Oct 14 | 150–200 |
| Cucumber | Apr 8 | May 20 | May 27 | Jul 22 – Sep 16 | 50–70 |
| Daikon | — | Apr 29 | — | Jun 24 – Jul 22 | 50–70 |
| Delicata Squash | Apr 8 | May 20 | May 27 | Aug 19 – Sep 23 | 80–100 |
| Edamame | — | May 20 | — | Aug 5 – Sep 16 | 75–100 |
| Eggplant | Mar 4 | May 20 | May 27 | Aug 5 – Oct 7 | 65–85 |
| Endive | Apr 8 | Apr 29 | May 13 | Jul 1 – Aug 5 | 45–65 |
| Escarole | Apr 8 | Apr 29 | May 13 | Jul 8 – Aug 5 | 50–70 |
| Fava Beans | Apr 8 | Apr 29 | May 13 | Jul 29 – Sep 9 | 75–100 |
| Fennel | Mar 18 | May 20 | May 27 | Jul 29 – Sep 9 | 60–90 |
| Garlic | — | — | — | — | 90–240 |
| Green Beans | — | May 20 | — | Jul 15 – Sep 9 | 50–65 |
| Horseradish | — | — | May 27 | Sep 30 – Nov 11 | 120–180 |
| Hot Peppers | Mar 4 | May 20 | May 27 | Aug 5 – Nov 11 | 70–120 |
| Hubbard Squash | Apr 8 | May 20 | May 27 | Sep 9 – Oct 14 | 100–120 |
| Kabocha | Apr 8 | May 20 | May 27 | Aug 26 – Sep 23 | 85–100 |
| Kai Lan | Apr 8 | Apr 29 | May 13 | Jul 1 – Jul 29 | 45–60 |
| Kale | Apr 8 | Apr 29 | May 13 | Jul 8 – Sep 2 | 50–70 |
| Kidney Beans | — | May 20 | — | Aug 19 – Sep 23 | 85–110 |
| Kohlrabi | Apr 8 | Apr 29 | May 13 | Jul 1 – Aug 5 | 45–65 |
| Komatsuna | Apr 8 | Apr 29 | May 13 | Jun 17 – Jul 22 | 35–50 |
| Leeks | Apr 8 | Apr 29 | May 13 | Aug 12 – Oct 28 | 90–150 |
| Lentils | Apr 8 | Apr 29 | May 13 | Aug 5 – Sep 16 | 80–110 |
| Lettuce | Apr 8 | Apr 29 | May 13 | Jun 17 – Aug 26 | 30–60 |
| Lima Beans | — | May 20 | — | Jul 22 – Sep 2 | 60–90 |
| Mache | Apr 8 | Apr 29 | May 13 | Jun 24 – Jul 29 | 40–60 |
| Melon | Apr 8 | May 20 | May 27 | Aug 5 – Sep 23 | 70–100 |
| Microgreens | Apr 8 | Apr 29 | May 13 | May 20 – Jun 17 | 7–21 |
| Mitsuba | Apr 8 | Apr 29 | May 6 | Jul 1 – Aug 26 | 50–70 |
| Mizuna | Apr 8 | Apr 29 | May 13 | Jun 17 – Jul 15 | 30–45 |
| Mustard Greens | Apr 8 | Apr 29 | May 13 | Jun 17 – Aug 19 | 30–50 |
| Napa Cabbage | Apr 8 | Apr 29 | May 13 | Jul 8 – Aug 12 | 55–75 |
| New Zealand Spinach | Mar 18 | May 20 | May 27 | Jul 22 – Aug 19 | 55–70 |
| Okra | Mar 18 | May 20 | May 27 | Jul 22 – Sep 16 | 50–65 |
| Onion | Apr 8 | Apr 29 | May 13 | Aug 12 – Sep 30 | 90–120 |
| Pac Choi | Apr 8 | Apr 29 | May 13 | Jun 24 – Jul 22 | 40–55 |
| Parsnip | — | Apr 29 | — | Aug 12 – Sep 23 | 100–130 |
| Patty Pan Squash | Apr 8 | May 20 | May 27 | Jul 15 – Aug 12 | 45–60 |
| Peas | Apr 8 | Apr 29 | May 13 | Jul 8 – Sep 2 | 55–70 |
| Peppers | Mar 4 | May 20 | May 27 | Jul 29 – Oct 7 | 60–90 |
| Pole Beans | Mar 18 | May 20 | May 27 | Jul 22 – Sep 16 | 55–70 |
| Potatoes | Mar 18 | May 20 | May 27 | Aug 5 – Oct 14 | 70–120 |
| Pumpkin | Apr 8 | May 20 | May 27 | Aug 26 – Oct 14 | 85–120 |
| Purslane | Apr 8 | Apr 29 | May 13 | Jun 24 – Jul 29 | 40–60 |
| Radicchio | Apr 8 | Apr 29 | May 13 | Jul 15 – Aug 19 | 60–80 |
| Radish | — | Apr 29 | — | May 27 – Jun 17 | 22–35 |
| Rhubarb | — | — | Jun 3 | — | 365–730 |
| Romanesco | Apr 8 | Apr 29 | May 13 | Jul 29 – Sep 9 | 75–100 |
| Rutabaga | — | Apr 29 | — | Jul 22 – Aug 26 | 80–100 |
| Salsify | — | Apr 29 | — | Aug 12 – Sep 23 | 100–130 |
| Savoy Cabbage | Apr 8 | Apr 29 | May 13 | Jul 22 – Sep 16 | 70–110 |
| Scallions | Apr 8 | Apr 29 | May 13 | Jul 8 – Aug 5 | 50–70 |
| Scarlet Runner Beans | Mar 18 | May 20 | May 27 | Jul 29 – Sep 2 | 60–80 |
| Shallot | Apr 8 | Apr 29 | May 13 | Aug 12 – Sep 30 | 90–120 |
| Shiso | Mar 25 | May 20 | May 27 | Jul 22 – Sep 16 | 50–70 |
| Snap Peas | Mar 18 | May 20 | May 27 | Jul 22 – Sep 16 | 55–70 |
| Snow Peas | Apr 8 | Apr 29 | May 13 | Jul 8 – Sep 2 | 50–65 |
| Soybeans | — | May 20 | — | Aug 12 – Oct 7 | 80–120 |
| Spaghetti Squash | Apr 8 | May 20 | May 27 | Aug 26 – Sep 23 | 85–100 |
| Spinach | Apr 8 | Apr 29 | May 13 | Jun 17 – Aug 19 | 35–50 |
| Squash (Summer) | Apr 8 | May 20 | May 27 | Jul 15 – Sep 16 | 45–65 |
| Squash (Winter) | Apr 8 | May 20 | May 27 | Aug 19 – Oct 14 | 80–120 |
| Sunchoke | — | — | May 27 | Sep 16 – Nov 11 | 110–150 |
| Sunflower | Mar 18 | May 20 | May 27 | Aug 5 – Sep 23 | 70–100 |
| Sweet Corn | — | May 20 | — | Jul 22 – Sep 2 | 60–90 |
| Sweet Potatoes | Mar 18 | May 20 | May 27 | Aug 26 – Oct 14 | 90–120 |
| Tatsoi | Apr 8 | Apr 29 | May 13 | Jun 17 – Jul 22 | 35–50 |
| Tomatillo | Mar 18 | May 20 | May 27 | Jul 29 – Oct 7 | 60–85 |
| Tomatoes | Mar 18 | May 20 | May 27 | Jul 29 – Oct 7 | 60–85 |
| Turnip | — | Apr 29 | — | Jun 10 – Jul 15 | 40–60 |
| Watercress | Apr 8 | Apr 29 | May 13 | Jun 24 – Jul 29 | 40–60 |
| Watermelon | Apr 8 | May 20 | May 27 | Aug 5 – Sep 23 | 70–100 |
| Wax Beans | — | May 20 | — | Jul 15 – Sep 9 | 50–65 |
| Winter Melon | Mar 18 | May 20 | May 27 | Aug 26 – Oct 14 | 90–120 |
| Yard Long Beans | Mar 18 | May 20 | May 27 | Jul 22 – Sep 2 | 55–80 |
| Zucchini | Apr 8 | May 20 | May 27 | Jul 15 – Sep 9 | 45–60 |
🍓 Fruits to Grow in Big Horn County
27 fruits that grow well in Zone 5a with planting dates for Big Horn County.
Show all 27 fruits with planting dates
| Plant | Start Indoors | Direct Sow | Transplant | Harvest | Days to Maturity |
|---|---|---|---|---|---|
| Alpine Strawberries | — | — | Jun 3 | Sep 2 – Nov 18 | 90–180 |
| Aronia | — | — | Jun 3 | — | 730–1095 |
| Blackberries | — | — | Jun 3 | — | 365–730 |
| Blueberries | — | — | Jun 3 | — | 730–1095 |
| Boysenberries | — | — | Jun 3 | — | 365–730 |
| Cantaloupe | — | — | Jun 3 | Aug 12 – Sep 16 | 70–90 |
| Che Fruit | — | — | Jun 3 | — | 1095–1825 |
| Cranberries | — | — | Jun 3 | — | 730–1095 |
| Currants | — | — | Jun 3 | — | 730–1095 |
| Elderberries | — | — | Jun 3 | — | 730–1095 |
| Goji Berries | — | — | Jun 3 | — | 730–1095 |
| Gooseberries | — | — | Jun 3 | — | 730–1095 |
| Grapes | — | — | Jun 3 | — | 730–1095 |
| Ground Cherry | — | — | Jun 3 | Aug 12 – Oct 7 | 65–80 |
| Hardy Kiwi | — | — | Jun 3 | — | 1095–1825 |
| Haskaps | — | — | Jun 3 | — | 730–1095 |
| Honeydew | — | — | Jun 3 | Aug 26 – Oct 7 | 80–110 |
| Jostaberry | — | — | Jun 3 | — | 730–1095 |
| Lingonberries | — | — | Jun 3 | — | 730–1095 |
| Medlar | — | — | Jun 3 | — | 1095–1825 |
| Mulberries | — | — | Jun 3 | — | 730–1825 |
| Pawpaw | — | — | Jun 3 | — | 1095–2555 |
| Persimmon | — | — | Jun 3 | — | 1095–2555 |
| Quince | — | — | Jun 3 | — | 1095–1825 |
| Raspberries | — | — | Jun 3 | — | 365–730 |
| Serviceberries | — | — | Jun 3 | — | 730–1095 |
| Strawberries | — | — | Jun 3 | Sep 2 – Nov 18 | 90–365 |
🌿 Herbs to Grow in Big Horn County
37 herbs that grow well in Zone 5a with planting dates for Big Horn County.
Show all 37 herbs with planting dates
| Plant | Start Indoors | Direct Sow | Transplant | Harvest | Days to Maturity |
|---|---|---|---|---|---|
| Angelica | Apr 8 | Apr 29 | May 6 | — | 365–730 |
| Anise | Apr 8 | Apr 29 | May 6 | Aug 5 – Oct 21 | 90–120 |
| Basil | Mar 25 | May 20 | May 27 | Jul 22 – Sep 23 | 50–75 |
| Bee Balm | — | — | May 20 | Aug 19 – Nov 4 | 90–120 |
| Borage | Apr 8 | Apr 29 | May 6 | Jul 1 – Aug 19 | 50–60 |
| Caraway | Apr 8 | Apr 29 | May 6 | — | 365–450 |
| Catnip | — | — | May 20 | Jul 22 – Sep 23 | 60–80 |
| Chamomile | Apr 8 | Apr 29 | May 6 | Jul 8 – Sep 16 | 60–90 |
| Chervil | Apr 8 | Apr 29 | May 6 | Jun 17 – Aug 19 | 40–60 |
| Chives | — | — | May 20 | Jul 22 – Sep 30 | 60–90 |
| Cilantro | Apr 8 | Apr 29 | May 6 | Jun 17 – Aug 19 | 40–60 |
| Comfrey | — | — | May 20 | Jul 22 – Sep 30 | 60–90 |
| Cumin | Apr 8 | Apr 29 | May 6 | Aug 19 – Oct 21 | 100–120 |
| Dill | Apr 8 | Apr 29 | May 6 | Jun 17 – Aug 19 | 40–60 |
| Echinacea | — | — | May 20 | Sep 23 – Nov 4 | 120–180 |
| Epazote | Mar 25 | May 20 | May 27 | Jul 15 – Sep 9 | 45–60 |
| Fennel (herb) | Apr 8 | Apr 29 | May 6 | Jul 8 – Sep 16 | 60–90 |
| Feverfew | — | — | May 20 | Aug 19 – Nov 4 | 90–120 |
| Garlic Chives | — | — | May 20 | Jul 22 – Sep 30 | 60–90 |
| Horehound | — | — | May 20 | Aug 5 – Sep 30 | 75–90 |
| Hyssop | — | — | May 20 | Jul 29 – Sep 30 | 70–90 |
| Lavender | — | — | May 20 | Aug 19 – Nov 4 | 90–200 |
| Lemon Balm | — | — | May 20 | Jul 22 – Sep 9 | 60–70 |
| Lemon Thyme | — | — | May 20 | Jul 29 – Sep 30 | 70–90 |
| Lovage | — | — | May 20 | Jul 29 – Sep 30 | 70–90 |
| Mint | — | — | May 20 | Jul 22 – Sep 30 | 60–90 |
| Oregano | — | — | May 20 | Jul 22 – Sep 30 | 60–90 |
| Parsley | Apr 8 | Apr 29 | May 6 | Jul 8 – Sep 9 | 60–80 |
| Rue | — | — | May 20 | Jul 29 – Sep 30 | 70–90 |
| Sage | — | — | May 20 | Aug 5 – Sep 30 | 75–90 |
| Savory | — | — | May 20 | Jul 15 – Sep 9 | 50–70 |
| Sorrel | Apr 8 | Apr 29 | May 6 | Jun 17 – Aug 19 | 40–60 |
| Tarragon | — | — | May 20 | Jul 22 – Sep 30 | 60–90 |
| Thai Basil | Mar 25 | May 20 | May 27 | Jul 22 – Sep 23 | 50–75 |
| Thyme | — | — | May 20 | Jul 29 – Sep 30 | 70–90 |
| Valerian | — | — | May 20 | Sep 23 – Nov 4 | 120–180 |
| Yarrow | — | — | May 20 | Aug 19 – Nov 4 | 90–120 |
Monthly Planting Guide for Big Horn County
Gardening Guides & Resources
Helpful guides from The Ultimate Homestead to improve your garden in Big Horn County.
Frequently Asked Questions
What planting zone is Big Horn County, MT?
Big Horn County is in USDA Hardiness Zone 5a. 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 Big Horn County, MT?
Based on 31 years of NOAA weather station data, the median last spring frost in Big Horn County falls around May 13. In 8 out of 10 years, last frost lands between April 28 and May 31 — a 33-day window of variability. Use May 31 as your conservative safe-to-plant date for frost-sensitive crops.
When is the first fall frost in Big Horn County, MT?
The median first fall frost in Big Horn County arrives around September 30. In cold years it can arrive as early as September 8; in mild years as late as October 15. Harvest or protect frost-sensitive crops — tomatoes, peppers, basil, squash — before this date.
How long is the growing season in Big Horn County?
Big Horn County has a frost-free growing season of approximately 140 days. Focus on short-season varieties and start warm-season crops indoors 6–8 weeks before last frost.
What is the soil like in Big Horn County for gardening?
Big Horn County has predominantly Loam soil with a pH range of 6.2–7.6 and Well Drained drainage. Most vegetables and herbs grow well with standard composting and seasonal soil amendment.
What is grown commercially in Big Horn County?
Big Horn County has commercial agriculture that includes Hay, Cattle, Wheat. These crops reflect the local climate and soil conditions — what succeeds commercially often translates well to home gardens in the same area.
Is Big Horn County a good location for home gardening?
Big Horn County scores 50/100 (Moderate) on our Microclimate Index, which combines frost reliability, drought pressure, soil challenge, elevation risk, and long-term climate trend. Conditions here are moderate — most common crops grow well with standard timing and care.
Your Big Horn County Garden Planner — Free
A 24-page printable planner built for Big Horn County (Zone 5a). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.
The Gardener's Encyclopedia to Companion Planting
The pairings that make vegetables, herbs, and flowers grow better — and the ones that quietly wreck a bed.
- Proven pairings for 200+ vegetables, herbs, flowers, and fruits
- Full seed-starting + planting schedule with timing and spacing
- Bonus: square-foot gardening guide + printable seasonal planners
Seed Saving & Storage Guide
Most saved seeds go bad before next season. This shows exactly when to pick, how to dry, and where to store seeds from 200 plants so yours don't.
- 200 plants, step-by-step: life cycle, pollination type, isolation
- Exact temperature + humidity ranges that keep seeds viable
- Bonus: searchable Google Sheets tracker + custom GPT assistant
Composting Guide for Homesteaders
Turn kitchen scraps and yard waste into compost that actually feeds the garden — instead of a pile that smells, attracts pests, and never breaks down.
- 14 sections on composting methods, soil science, and troubleshooting
- The 7-step hot-compost system from start to finish
- Bonus tools: troubleshooting chart, safety guide, monitoring log