Mahnomen County, MN — Planting Guide
Mahnomen County is in USDA Zone 3b. The average last spring frost is May 13 and the first fall frost is September 27, giving you a growing season of approximately 137 days.
At an elevation of 1,223 ft, Mahnomen County receives approximately 33.1 in of rainfall annually. Summer highs average 80°F with winter lows around -4°F. The predominant soil type is Silt Loam.
Based on 31 years of NOAA climate station data, the last frost date here varies by 30 days year to year — ranging from April 23 in warm years to May 23 in cold years. Mahnomen County scores 75/100 (Good) on the Microclimate Index.
🌡️ Zone
3b (-35°F to -30°F min)
❄️ Last Frost
May 13
🍂 First Frost
September 27
📅 Growing Season
137 days
⛰️ Elevation
1,223 ft
🌧️ Annual Rainfall
33.1 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 | 1.3 in | 7 days | — | None |
| Feb | 1.5 in | 6 days | — | None |
| Mar | 2.2 in | 9 days | — | None |
| Apr | 2.9 in | 10 days | — | None |
| May | 4.3 in | 11 days | — | Low |
| Jun | 3.8 in | 10 days | 0.5 in | Low |
| Jul | 3.7 in | 8 days | 0.6 in | Moderate |
| Aug | 3.6 in | 8 days | 0.7 in | Moderate |
| Sep | 3.1 in | 8 days | 1.2 in | Moderate |
| Oct | 2.4 in | 7 days | — | None |
| Nov | 2.4 in | 7 days | — | None |
| Dec | 2 in | 7 days | — | None |
Annual total: 33.2 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.
Mahnomen County Soil Profile
Soil Type
Silt Loam
Soil pH
5.9-7
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 23 | Oct 14 | 144 days |
| Cautious | May 16 | Oct 4 | 141 days |
| Average year | May 13 | Sep 27 | 137 days |
| Optimistic | May 7 | Sep 21 | 137 days |
| Aggressive (risky) | Apr 23 | Sep 12 | 142 days |
Not very — frost dates can vary by ±30 days year-to-year. Use the "Conservative" row in the table below, and keep row covers handy for surprise late frosts.
Gardening Difficulty Score
Mahnomen County offers good growing conditions. A little planning around frost dates goes a long way.
Local Gardening Help in Mahnomen 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 Mahnomen County's climate and soil.
County Extension Office
Mahnomen County University of Minnesota Extension Extension Office
Phone: 612-625-8173
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 Mahnomen County
Finding local nurseries & garden centers in Mahnomen County
Why Buy Local
Local nurseries carry plants that are proven to grow in your area. Staff can give you advice specific to Mahnomen 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 Mahnomen County MN" or "garden center Mahnomen 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 Mahnomen County MN" or check your extension office and local parks department. Facebook groups like "Mahnomen County Gardeners" or "Minnesota 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
15.7 hours
Summer solstice daylight
Shortest Day
8.3 hours
Winter solstice daylight
Peak Sun Hours
9.9 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 | 8.7 hr | 3.4 hr | Short day |
| February | 10 hr | 4.4 hr | Short day |
| March | 11.6 hr | 5.6 hr | Short day |
| April | 13.4 hr | 6.7 hr | Neutral |
| May | 14.9 hr | 8.5 hr | Long day |
| June | 15.7 hr | 9.9 hr | Long day |
| July | 15.4 hr | 9.7 hr | Long day |
| August | 14.1 hr | 8.9 hr | Long day |
| September | 12.3 hr | 7.4 hr | Neutral |
| October | 10.6 hr | 5.6 hr | Short day |
| November | 9.1 hr | 3.5 hr | Short day |
| December | 8.3 hr | 3.2 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 warm enough from Jul through Sep.
Best Month to Compost
Jul
Microbial activity peaks when soil is warm.
Active Composting
5 months
Solid season. Piles go dormant in winter.
View detailed monthly data
| Month | Soil 4" Deep | Soil 8" Deep | Compost Activity | Time to Finish |
|---|---|---|---|---|
| Jan | 6°F | 16°F | ❄️ Dormant | ~36 weeks |
| Feb | 8°F | 14°F | ❄️ Dormant | ~36 weeks |
| Mar | 18°F | 22°F | ❄️ Dormant | ~36 weeks |
| Apr | 34°F | 33°F | ❄️ Dormant | ~36 weeks |
| May | 51°F | 46°F | ♻️ Active | ~14 weeks |
| Jun | 60°F | 55°F | ♻️ Active | ~14 weeks |
| Jul | 68°F | 60°F | 🔥 Peak | ~8 weeks |
| Aug | 69°F | 62°F | 🔥 Peak | ~8 weeks |
| Sep | 61°F | 60°F | ♻️ Active | ~14 weeks |
| Oct | 45°F | 48°F | 🐢 Slow | ~24 weeks |
| Nov | 31°F | 37°F | ❄️ Dormant | ~36 weeks |
| Dec | 17°F | 24°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 Mahnomen 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 3 common pests in your area
| Pest | Risk Level | Peak Months |
|---|---|---|
| Aphids | Low | Jun, Jul, Aug |
| Cabbage worms | Low | Jun, Jul, Aug |
| Slugs | Moderate | May, Jun, Jul, Aug |
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 Mahnomen 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 19 | Aug 2 | — | Rapid growth, attracts pollinators, suppresses weeds |
| White clover | Apr 17 | Jul 19 | ✓ 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 | May 30 | Aug 30 | — | Deep roots break compaction, attract pollinators and beneficial insects |
Fall Cover Crops (3 options) — Plant after harvest to protect soil over winter
| Crop | Plant By | Terminate | N-Fixing | Soil Benefit |
|---|---|---|---|---|
| Oats | Aug 26 | Apr 29 | — | Quick biomass, winterkills in cold zones — no spring tillage needed |
| Winter rye | Jun 27 | Apr 22 | — | Suppresses weeds, prevents erosion, breaks up compacted soil |
| Winter wheat | Jun 27 | 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: 11 mph Summer: 9 mph
Fall: 10 mph Winter: 11 mph
Prevailing wind: SW. Moderate wind — consider a temporary windbreak for young seedlings.
Windbreak Benefit
4.8/10
Moderately beneficial — a simple fence or trellis can protect delicate crops from wind stress.
Frost Pocket Risk
Low
Relatively flat terrain (230 ft range). Frost pocket risk is minimal — garden placement is flexible.
Rainwater Harvesting Potential
How much water you can collect, when to collect it, and what size system you need for your garden.
Annual Collection
16,546 gal
Per 1,000 sq ft of roof area (at 80% collection efficiency)
Recommended Setup
6 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
May, Jun, Jul, Aug
Highest rainfall months — your barrels will fill up quickly during these months.
Months to Draw From Storage
Jan, Feb, 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 33.2 inches of rain per year
- A 1,000 sq ft roof can collect roughly 16,546 gallons annually
- Rainwater harvesting is fully legal in your state
- Stock up on stored water before your dry season (Jan, Feb, Dec)
- Use a first-flush diverter to keep roof debris out of your collection
Soil & Growing Conditions in Mahnomen County
Soil Type
Silt Loam
Soil pH 5.9–7 · Excessively Drained drainage
Native soil is well-suited to most vegetables and herbs with regular compost additions.
Watering Needs
Drought stress: 3.5/10
Low-to-moderate drought stress. Plan to water 1–2 times per week during peak summer. (33.1 in. annual rainfall)
Season Tips
137-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 Mahnomen County
87 vegetables that grow well in Zone 3b with planting dates for Mahnomen County.
Show all 87 vegetables with planting dates
| Plant | Start Indoors | Direct Sow | Transplant | Harvest | Days to Maturity |
|---|---|---|---|---|---|
| Acorn Squash | Apr 1 | May 27 | Jun 3 | Aug 26 – Sep 30 | 80–100 |
| Amaranth | Mar 11 | May 27 | Jun 3 | Sep 2 – Oct 7 | 90–120 |
| Arugula | Apr 1 | May 6 | May 13 | Jun 17 – Aug 19 | 30–50 |
| Asparagus | — | — | May 27 | — | 730–1095 |
| Beets | — | May 6 | — | Jul 1 – Jul 29 | 50–70 |
| Belgian Endive | Apr 1 | May 6 | May 13 | Sep 2 – Sep 16 | 110–150 |
| Black Beans | — | May 27 | — | Aug 26 – Sep 30 | 90–120 |
| Bok Choy | Apr 1 | May 6 | May 13 | Jun 24 – Jul 29 | 40–60 |
| Broccoli | Apr 1 | May 6 | May 13 | Jul 15 – Aug 26 | 60–90 |
| Broccoli Rabe | Apr 1 | May 6 | May 13 | Jun 24 – Jul 29 | 40–60 |
| Brussels Sprouts | Apr 1 | May 6 | May 13 | Aug 12 – Sep 16 | 90–130 |
| Butternut Squash | Apr 1 | May 27 | Jun 3 | Sep 2 – Oct 7 | 85–110 |
| Cabbage | Apr 1 | May 6 | May 13 | Jul 15 – Sep 9 | 60–100 |
| Carrots | — | May 6 | — | Jul 8 – Aug 12 | 60–80 |
| Cauliflower | Apr 1 | May 6 | May 13 | Jul 8 – Sep 9 | 55–100 |
| Celeriac | Apr 1 | May 6 | May 13 | Aug 26 – Sep 16 | 100–120 |
| Celery | Apr 1 | May 6 | May 13 | Aug 5 – Sep 16 | 80–120 |
| Celtuce | Apr 1 | May 6 | May 13 | Jul 15 – Aug 26 | 60–90 |
| Chard | Apr 1 | May 6 | May 13 | Jul 8 – Aug 26 | 50–60 |
| Chickpeas | Apr 1 | May 6 | May 13 | Aug 5 – Sep 16 | 80–110 |
| Chicory | Apr 1 | May 6 | May 13 | Jul 15 – Aug 26 | 60–85 |
| Chinese Cabbage | Apr 1 | May 6 | May 13 | Jul 8 – Aug 5 | 50–70 |
| Collard Greens | Apr 1 | May 6 | May 13 | Jul 8 – Sep 9 | 55–75 |
| Corn | — | May 27 | — | Jul 29 – Sep 23 | 60–100 |
| Cress | Apr 1 | May 6 | May 13 | May 27 – Jun 17 | 14–21 |
| Crookneck Squash | Apr 1 | May 27 | Jun 3 | Jul 22 – Aug 19 | 45–60 |
| Cucumber | Apr 1 | May 27 | Jun 3 | Jul 29 – Sep 23 | 50–70 |
| Daikon | — | May 6 | — | Jul 1 – Jul 29 | 50–70 |
| Delicata Squash | Apr 1 | May 27 | Jun 3 | Aug 26 – Sep 30 | 80–100 |
| Edamame | — | May 27 | — | Aug 12 – Sep 23 | 75–100 |
| Endive | Apr 1 | May 6 | May 13 | Jul 1 – Aug 5 | 45–65 |
| Escarole | Apr 1 | May 6 | May 13 | Jul 8 – Aug 5 | 50–70 |
| Fava Beans | Apr 1 | May 6 | May 13 | Jul 29 – Sep 9 | 75–100 |
| Garlic | — | — | — | — | 90–240 |
| Green Beans | — | May 27 | — | Jul 22 – Sep 16 | 50–65 |
| Horseradish | — | — | May 27 | Sep 30 | 120–180 |
| Hubbard Squash | Apr 1 | May 27 | Jun 3 | Sep 16 – Oct 7 | 100–120 |
| Kabocha | Apr 1 | May 27 | Jun 3 | Sep 2 – Sep 30 | 85–100 |
| Kai Lan | Apr 1 | May 6 | May 13 | Jul 1 – Jul 29 | 45–60 |
| Kale | Apr 1 | May 6 | May 13 | Jul 8 – Sep 2 | 50–70 |
| Kidney Beans | — | May 27 | — | Aug 26 – Sep 30 | 85–110 |
| Kohlrabi | Apr 1 | May 6 | May 13 | Jul 1 – Aug 5 | 45–65 |
| Komatsuna | Apr 1 | May 6 | May 13 | Jun 17 – Jul 22 | 35–50 |
| Leeks | Apr 1 | May 6 | May 13 | Aug 12 – Sep 16 | 90–150 |
| Lentils | Apr 1 | May 6 | May 13 | Aug 5 – Sep 16 | 80–110 |
| Lettuce | Apr 1 | May 6 | May 13 | Jun 17 – Aug 26 | 30–60 |
| Lima Beans | — | May 27 | — | Jul 29 – Sep 9 | 60–90 |
| Mache | Apr 1 | May 6 | May 13 | Jun 24 – Jul 29 | 40–60 |
| Microgreens | Apr 1 | May 6 | May 13 | May 20 – Jun 17 | 7–21 |
| Mizuna | Apr 1 | May 6 | May 13 | Jun 17 – Jul 15 | 30–45 |
| Mustard Greens | Apr 1 | May 6 | May 13 | Jun 17 – Aug 19 | 30–50 |
| Napa Cabbage | Apr 1 | May 6 | May 13 | Jul 8 – Aug 12 | 55–75 |
| Onion | Apr 1 | May 6 | May 13 | Aug 12 – Sep 16 | 90–120 |
| Pac Choi | Apr 1 | May 6 | May 13 | Jun 24 – Jul 22 | 40–55 |
| Parsnip | — | May 6 | — | Aug 19 – Sep 9 | 100–130 |
| Patty Pan Squash | Apr 1 | May 27 | Jun 3 | Jul 22 – Aug 19 | 45–60 |
| Peas | Apr 1 | May 6 | May 13 | Jul 8 – Sep 2 | 55–70 |
| Peppers | Feb 25 | May 27 | Jun 3 | Aug 5 – Oct 7 | 60–90 |
| Pole Beans | Mar 11 | May 27 | Jun 3 | Jul 29 – Sep 23 | 55–70 |
| Potatoes | Mar 11 | May 27 | Jun 3 | Aug 12 – Oct 7 | 70–120 |
| Pumpkin | Apr 1 | May 27 | Jun 3 | Sep 2 – Oct 7 | 85–120 |
| Purslane | Apr 1 | May 6 | May 13 | Jun 24 – Jul 29 | 40–60 |
| Radish | — | May 6 | — | Jun 3 – Jun 24 | 22–35 |
| Rhubarb | — | — | Jun 10 | — | 365–730 |
| Romanesco | Apr 1 | May 6 | May 13 | Jul 29 – Sep 9 | 75–100 |
| Rutabaga | — | May 6 | — | Jul 29 – Sep 2 | 80–100 |
| Salsify | — | May 6 | — | Aug 19 – Sep 9 | 100–130 |
| Savoy Cabbage | Apr 1 | May 6 | May 13 | Jul 22 – Sep 16 | 70–110 |
| Scallions | Apr 1 | May 6 | May 13 | Jul 8 – Aug 5 | 50–70 |
| Scarlet Runner Beans | Mar 11 | May 27 | Jun 3 | Aug 5 – Sep 9 | 60–80 |
| Shiso | Mar 18 | May 20 | Jun 3 | Jul 29 – Sep 23 | 50–70 |
| Snap Peas | Mar 11 | May 27 | Jun 3 | Jul 29 – Sep 23 | 55–70 |
| Snow Peas | Apr 1 | May 6 | May 13 | Jul 8 – Sep 2 | 50–65 |
| Soybeans | — | May 27 | — | Aug 19 – Sep 30 | 80–120 |
| Spaghetti Squash | Apr 1 | May 27 | Jun 3 | Sep 2 – Sep 30 | 85–100 |
| Spinach | Apr 1 | May 6 | May 13 | Jun 17 – Aug 19 | 35–50 |
| Squash (Summer) | Apr 1 | May 27 | Jun 3 | Jul 22 – Sep 23 | 45–65 |
| Squash (Winter) | Apr 1 | May 27 | Jun 3 | Aug 26 – Oct 7 | 80–120 |
| Sunchoke | — | — | May 27 | Sep 16 – Sep 30 | 110–150 |
| Sunflower | Mar 11 | May 27 | Jun 3 | Aug 12 – Sep 30 | 70–100 |
| Sweet Corn | — | May 27 | — | Jul 29 – Sep 9 | 60–90 |
| Tatsoi | Apr 1 | May 6 | May 13 | Jun 17 – Jul 22 | 35–50 |
| Tomatoes | Mar 11 | May 27 | Jun 3 | Aug 5 – Oct 7 | 60–85 |
| Turnip | — | May 6 | — | Jun 17 – Jul 22 | 40–60 |
| Watercress | Apr 1 | May 6 | May 13 | Jun 24 – Jul 29 | 40–60 |
| Wax Beans | — | May 27 | — | Jul 22 – Sep 16 | 50–65 |
| Zucchini | Apr 1 | May 27 | Jun 3 | Jul 22 – Sep 16 | 45–60 |
🍓 Fruits to Grow in Mahnomen County
15 fruits that grow well in Zone 3b with planting dates for Mahnomen County.
Show all 15 fruits with planting dates
| Plant | Start Indoors | Direct Sow | Transplant | Harvest | Days to Maturity |
|---|---|---|---|---|---|
| Alpine Strawberries | — | — | Jun 10 | Sep 9 – Oct 14 | 90–180 |
| Aronia | — | — | Jun 10 | — | 730–1095 |
| Blueberries | — | — | Jun 10 | — | 730–1095 |
| Cranberries | — | — | Jun 10 | — | 730–1095 |
| Currants | — | — | Jun 10 | — | 730–1095 |
| Elderberries | — | — | Jun 10 | — | 730–1095 |
| Goji Berries | — | — | Jun 10 | — | 730–1095 |
| Gooseberries | — | — | Jun 10 | — | 730–1095 |
| Hardy Kiwi | — | — | Jun 10 | — | 1095–1825 |
| Haskaps | — | — | Jun 10 | — | 730–1095 |
| Jostaberry | — | — | Jun 10 | — | 730–1095 |
| Lingonberries | — | — | Jun 10 | — | 730–1095 |
| Raspberries | — | — | Jun 10 | — | 365–730 |
| Serviceberries | — | — | Jun 10 | — | 730–1095 |
| Strawberries | — | — | Jun 10 | Sep 9 – Oct 14 | 90–365 |
🌿 Herbs to Grow in Mahnomen County
22 herbs that grow well in Zone 3b with planting dates for Mahnomen County.
Show all 22 herbs with planting dates
| Plant | Start Indoors | Direct Sow | Transplant | Harvest | Days to Maturity |
|---|---|---|---|---|---|
| Angelica | Apr 1 | May 6 | May 6 | — | 365–730 |
| Bee Balm | — | — | May 20 | Aug 19 – Sep 23 | 90–120 |
| Borage | Apr 1 | May 6 | May 6 | Jul 1 – Aug 19 | 50–60 |
| Caraway | Apr 1 | May 6 | May 6 | — | 365–450 |
| Catnip | — | — | May 20 | Jul 22 – Sep 23 | 60–80 |
| Chamomile | Apr 1 | May 6 | May 6 | Jul 8 – Sep 9 | 60–90 |
| Chervil | Apr 1 | May 6 | May 6 | Jun 17 – Aug 19 | 40–60 |
| Chives | — | — | May 20 | Jul 22 – Sep 23 | 60–90 |
| Cilantro | Apr 1 | May 6 | May 6 | Jun 17 – Aug 19 | 40–60 |
| Comfrey | — | — | May 20 | Jul 22 – Sep 23 | 60–90 |
| Dill | Apr 1 | May 6 | May 6 | Jun 17 – Aug 19 | 40–60 |
| Echinacea | — | — | May 20 | Sep 23 | 120–180 |
| Garlic Chives | — | — | May 20 | Jul 22 – Sep 23 | 60–90 |
| Horehound | — | — | May 20 | Aug 5 – Sep 23 | 75–90 |
| Hyssop | — | — | May 20 | Jul 29 – Sep 23 | 70–90 |
| Lemon Balm | — | — | May 20 | Jul 22 – Sep 9 | 60–70 |
| Lovage | — | — | May 20 | Jul 29 – Sep 23 | 70–90 |
| Mint | — | — | May 20 | Jul 22 – Sep 23 | 60–90 |
| Parsley | Apr 1 | May 6 | May 6 | Jul 8 – Sep 9 | 60–80 |
| Sorrel | Apr 1 | May 6 | May 6 | Jun 17 – Aug 19 | 40–60 |
| Valerian | — | — | May 20 | Sep 23 | 120–180 |
| Yarrow | — | — | May 20 | Aug 19 – Sep 23 | 90–120 |
Monthly Planting Guide for Mahnomen County
Gardening Guides & Resources
Helpful guides from The Ultimate Homestead to improve your garden in Mahnomen County.
Frequently Asked Questions
What planting zone is Mahnomen County, MN?
Mahnomen County is in USDA Hardiness Zone 3b. 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 Mahnomen County, MN?
Based on 31 years of NOAA weather station data, the median last spring frost in Mahnomen County falls around May 13. In 8 out of 10 years, last frost lands between April 23 and May 23 — a 30-day window of variability. Use May 23 as your conservative safe-to-plant date for frost-sensitive crops.
When is the first fall frost in Mahnomen County, MN?
The median first fall frost in Mahnomen County arrives around September 27. In cold years it can arrive as early as September 12; in mild years as late as October 14. Harvest or protect frost-sensitive crops — tomatoes, peppers, basil, squash — before this date.
How long is the growing season in Mahnomen County?
Mahnomen County has a frost-free growing season of approximately 137 days. Focus on short-season varieties and start warm-season crops indoors 6–8 weeks before last frost.
What is the soil like in Mahnomen County for gardening?
Mahnomen County has predominantly Silt Loam soil with a pH range of 5.9–7 and Excessively Drained drainage. Most vegetables and herbs grow well with standard composting and seasonal soil amendment.
What is grown commercially in Mahnomen County?
Mahnomen County has commercial agriculture that includes Soybeans, Corn, Hay, Dairy, Sweet Corn. These crops reflect the local climate and soil conditions — what succeeds commercially often translates well to home gardens in the same area.
Is Mahnomen County a good location for home gardening?
Mahnomen County scores 75/100 (Good) on our Microclimate Index, which combines frost reliability, drought pressure, soil challenge, elevation risk, and long-term climate trend. This is an above-average location for home gardening with relatively predictable growing conditions.
Plan Your Garden with Confidence
Get our free Garden Planner — designed to help Mahnomen County gardeners in Zone 3b 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.
