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Koochiching County, MN — Planting Guide

Koochiching County is in USDA Zone 3a. The average last spring frost is May 22 and the first fall frost is September 18, giving you a growing season of approximately 119 days.

At an elevation of 508 ft, Koochiching County receives approximately 41.4 in of rainfall annually. Summer highs average 79°F with winter lows around -8°F. The predominant soil type is Silt Loam.

Based on 31 years of NOAA climate station data, the last frost date here varies by 37 days year to year — ranging from May 9 in warm years to June 15 in cold years. The growing season is trending longer by about 4.02 days per decade. Koochiching County scores 61/100 (Good) on the Microclimate Index.

🌡️ Zone

3a (-40°F to -35°F min)

❄️ Last Frost

May 22

🍂 First Frost

September 18

📅 Growing Season

119 days

⛰️ Elevation

508 ft

🌧️ Annual Rainfall

41.4 in

Koochiching County, MN Short season
119 days
Last Spring Frost May 22
119 growing days
First Fall Frost September 18

Monthly Watering Calendar

When you'll need to water your garden — based on average monthly rainfall vs. the ~1 inch/week most gardens need.

1"/wk 0" 1.3" 2.5" 3.8" 5" Jan 1.5" Feb 2" Mar 3" Apr 4" May 5" Jun 5" Jul 5" +0.5" Aug 3.8" +0.6" Sep 3.7" Oct 2.8" Nov 3.2" Dec 2.4"
Rainfall sufficient Supplemental water needed Heavy watering required - - - 1"/week garden need
View detailed monthly data
MonthAvg RainfallRainy DaysExtra Water NeededWatering Effort
Jan 1.5 in 8 days None
Feb 2 in 5 days None
Mar 3 in 7 days None
Apr 4 in 10 days None
May 5 in 9 days Low
Jun 5 in 9 days Low
Jul 5 in 8 days Low
Aug 3.8 in 10 days 0.5 in Low
Sep 3.7 in 8 days 0.6 in Moderate
Oct 2.8 in 8 days None
Nov 3.2 in 7 days None
Dec 2.4 in 7 days None

Annual total: 41.4 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.

Koochiching County Soil Profile

Soil Type

Silt Loam

Soil pH

5.8-7.2

Drainage

Well Drained

Frost Risk Probability

Based on 31 years of NOAA weather station data from 3 stations

Too early frost risk Safe to Plant May 22 → Sep 18 119 frost-free days Protect crops frost returns May Jun Jul Aug Sep Oct Nov Safe: Jun 15 Protect by: Oct 3

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 15 Oct 3 110 days
Cautious May 31 Sep 25 117 days
Average year May 22 Sep 18 119 days
Optimistic May 16 Sep 12 119 days
Aggressive (risky) May 9 Sep 3 117 days
📊
How predictable are frost dates here?

Not very — frost dates can vary by ±37 days year-to-year. Use the "Conservative" row in the table below, and keep row covers handy for surprise late frosts.

🌱
Is the growing season changing?

Yes — growing seasons are getting longer here (about 4 days per decade). Spring is arriving earlier than it used to. Good news for gardeners.

Gardening Difficulty Score

61 Good
Frost Timing Risk
10.0/10
Drought Risk
3.5/10
Soil Difficulty
0.0/10
Altitude Challenge
0.0/10
Climate Shift
10.0/10
Rainfall Challenge
0.0/10

Koochiching County offers good growing conditions. A little planning around frost dates goes a long way.

Zone 3a Frost Countdown
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Last Frost: May 22 First Frost: Sep 18

Local Gardening Help in Koochiching 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 Koochiching County's climate and soil.

County Extension Office

Koochiching 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.

Find Master Gardeners in MN →

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.

Request a Soil Test →

Services Available in Koochiching County

Soil testing Cold-climate gardening Pest diagnostics
Finding local nurseries & garden centers in Koochiching County

Why Buy Local

Local nurseries carry plants that are proven to grow in your area. Staff can give you advice specific to Koochiching 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 Koochiching County MN" or "garden center Koochiching 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 Koochiching County MN" or check your extension office and local parks department. Facebook groups like "Koochiching 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.

Sunlight & Day Length

Monthly daylight hours and peak sun — critical for onion varieties, photoperiod-sensitive plants, and solar garden planning.

Longest Day

15.8 hours

Summer solstice daylight

Shortest Day

8.2 hours

Winter solstice daylight

Peak Sun Hours

10.1 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.

14hr 12hr 2h 6h 10h 13h 17h Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Daylight hours (sunrise to sunset) Peak sun hours (direct sunlight after cloud cover) ▪ Gold zone = long day (14+ hr) ▪ Blue zone = short day (<12 hr)

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
MonthDaylight HoursPeak Sun HoursDay Length
January 8.6 hr 3.3 hr Short day
February 10 hr 4.5 hr Short day
March 11.6 hr 5.7 hr Short day
April 13.4 hr 6.6 hr Neutral
May 15 hr 8.9 hr Long day
June 15.8 hr 9.4 hr Long day
July 15.5 hr 10.1 hr Long day
August 14.1 hr 9 hr Long day
September 12.3 hr 7.2 hr Neutral
October 10.5 hr 5.3 hr Short day
November 9 hr 3.6 hr Short day
December 8.2 hr 3.1 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 Jun 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.

60°F 70°F 20° 40° 60° 80° Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
4" depth 8" depth - - - 60°F (corn, beans) - - - 70°F (tomatoes, peppers)
View detailed monthly data
MonthSoil 4" DeepSoil 8" DeepCompost ActivityTime to Finish
Jan 6°F 18°F ❄️ Dormant ~36 weeks
Feb 9°F 14°F ❄️ Dormant ~36 weeks
Mar 20°F 21°F ❄️ Dormant ~36 weeks
Apr 36°F 34°F ❄️ Dormant ~36 weeks
May 51°F 45°F ♻️ Active ~14 weeks
Jun 61°F 55°F ♻️ Active ~14 weeks
Jul 70°F 61°F 🔥 Peak ~8 weeks
Aug 68°F 65°F 🔥 Peak ~8 weeks
Sep 61°F 60°F ♻️ Active ~14 weeks
Oct 45°F 50°F 🐢 Slow ~24 weeks
Nov 33°F 37°F ❄️ Dormant ~36 weeks
Dec 17°F 25°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 Koochiching County

Computed from local climate patterns — warmer, humid conditions increase pest generations and fungal disease risk.

Insect Pest Pressure

4.1 / 10

Moderate — common pests appear but manageable with monitoring.

Disease Risk

5.8 / 10

Moderate — watch for mildew and blight during wet periods.

Seasonal Risk

Spring Low
Summer Moderate
Fall Low
Winter Low
View 4 common pests in your area
PestRisk LevelPeak Months
Aphids Moderate Jun, Jul, Aug
Cabbage worms Low Jun, Jul, Aug
Flea beetles Low May, Jun, Jul
Slugs Low May, Jun, Jul, Aug
Organic pest management tips
  • Use row covers on susceptible crops during peak pest months
  • Apply neem oil preventatively every 7-14 days during active pest season
  • Interplant with strong-scented herbs (basil, marigold) to confuse pests
  • Hand-pick larger pests (beetles, caterpillars) in early morning when they're sluggish
  • Practice crop rotation — never plant the same family in the same spot within 3 years

Cover Crops for Koochiching 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 29 Jul 24 Rapid growth, attracts pollinators, suppresses weeds
White clover Apr 23 Jul 10 ✓ 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 10 Sep 4 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 16 May 1 Quick biomass, winterkills in cold zones — no spring tillage needed
Winter rye Jun 17 May 8 Suppresses weeds, prevents erosion, breaks up compacted soil
Winter wheat Jun 23 May 8 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: 10 mph

Fall: 11 mph   Winter: 11 mph

Prevailing wind: SW. Moderate wind — consider a temporary windbreak for young seedlings.

Windbreak Benefit

5.3/10

Moderately beneficial — a simple fence or trellis can protect delicate crops from wind stress.

Frost Pocket Risk

Low

Relatively flat terrain (98 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

20,633 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 1,500 gal tank.

Legal Status

Unrestricted

Rainwater harvesting is fully legal in your state with no restrictions.

Best Collection Months

Apr, May, Jun, Jul

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 41.4 inches of rain per year
  • A 1,000 sq ft roof can collect roughly 20,633 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 Koochiching County

Soil Type

Silt Loam

Soil pH 5.8–7.2 · Well 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. (41.4 in. annual rainfall)

Season Tips

119-day frost-free season

A short season means indoor starts are critical for warm-season crops. Prioritise cold-hardy, fast-maturing varieties and use row covers to extend autumn harvests.

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.

Get My Free Planner →

Recommended for Your Garden

🧪
Soil Test Kit $12-25

Test your soil pH, nitrogen, phosphorus, and potassium levels before planting.

📏
Digital pH Meter $10-20

Get instant, accurate soil pH readings to fine-tune your amendments.

🍂
Organic Compost $8-30

Boost soil fertility and structure with rich, well-aged organic compost.

🥬 Vegetables to Grow in Koochiching County

87 vegetables that grow well in Zone 3a with planting dates for Koochiching County.

Show all 87 vegetables with planting dates
Plant Start Indoors Direct Sow Transplant Harvest Days to Maturity
Acorn Squash Apr 10 Jun 5 Jun 12 Sep 4 – Oct 9 80–100
Amaranth Mar 20 Jun 5 Jun 12 Sep 11 – Oct 16 90–120
Arugula Apr 10 May 15 May 22 Jun 26 – Aug 28 30–50
Asparagus Jun 5 730–1095
Beets May 15 Jul 10 – Aug 7 50–70
Belgian Endive Apr 10 May 15 May 22 Sep 11 – Sep 25 110–150
Black Beans Jun 5 Sep 4 – Oct 9 90–120
Bok Choy Apr 10 May 15 May 22 Jul 3 – Aug 7 40–60
Broccoli Apr 10 May 15 May 22 Jul 24 – Sep 4 60–90
Broccoli Rabe Apr 10 May 15 May 22 Jul 3 – Aug 7 40–60
Brussels Sprouts Apr 10 May 15 May 22 Aug 21 – Sep 25 90–130
Butternut Squash Apr 10 Jun 5 Jun 12 Sep 11 – Oct 16 85–110
Cabbage Apr 10 May 15 May 22 Jul 24 – Sep 18 60–100
Carrots May 15 Jul 17 – Aug 21 60–80
Cauliflower Apr 10 May 15 May 22 Jul 17 – Sep 18 55–100
Celeriac Apr 10 May 15 May 22 Sep 4 – Sep 25 100–120
Celery Apr 10 May 15 May 22 Aug 14 – Sep 25 80–120
Celtuce Apr 10 May 15 May 22 Jul 24 – Sep 4 60–90
Chard Apr 10 May 15 May 22 Jul 17 – Sep 4 50–60
Chickpeas Apr 10 May 15 May 22 Aug 14 – Sep 25 80–110
Chicory Apr 10 May 15 May 22 Jul 24 – Sep 4 60–85
Chinese Cabbage Apr 10 May 15 May 22 Jul 17 – Aug 14 50–70
Collard Greens Apr 10 May 15 May 22 Jul 17 – Sep 18 55–75
Corn Jun 5 Aug 7 – Oct 2 60–100
Cress Apr 10 May 15 May 22 Jun 5 – Jun 26 14–21
Crookneck Squash Apr 10 Jun 5 Jun 12 Jul 31 – Aug 28 45–60
Cucumber Apr 10 Jun 5 Jun 12 Aug 7 – Oct 2 50–70
Daikon May 15 Jul 10 – Aug 7 50–70
Delicata Squash Apr 10 Jun 5 Jun 12 Sep 4 – Oct 9 80–100
Edamame Jun 5 Aug 21 – Oct 2 75–100
Endive Apr 10 May 15 May 22 Jul 10 – Aug 14 45–65
Escarole Apr 10 May 15 May 22 Jul 17 – Aug 14 50–70
Fava Beans Apr 10 May 15 May 22 Aug 7 – Sep 18 75–100
Garlic 90–240
Green Beans Jun 5 Jul 31 – Sep 25 50–65
Horseradish Jun 5 Oct 9 120–180
Hubbard Squash Apr 10 Jun 5 Jun 12 Sep 25 – Oct 16 100–120
Kabocha Apr 10 Jun 5 Jun 12 Sep 11 – Oct 9 85–100
Kai Lan Apr 10 May 15 May 22 Jul 10 – Aug 7 45–60
Kale Apr 10 May 15 May 22 Jul 17 – Sep 11 50–70
Kidney Beans Jun 5 Sep 4 – Oct 9 85–110
Kohlrabi Apr 10 May 15 May 22 Jul 10 – Aug 14 45–65
Komatsuna Apr 10 May 15 May 22 Jun 26 – Jul 31 35–50
Leeks Apr 10 May 15 May 22 Aug 21 – Sep 25 90–150
Lentils Apr 10 May 15 May 22 Aug 14 – Sep 25 80–110
Lettuce Apr 10 May 15 May 22 Jun 26 – Sep 4 30–60
Lima Beans Jun 5 Aug 7 – Sep 18 60–90
Mache Apr 10 May 15 May 22 Jul 3 – Aug 7 40–60
Microgreens Apr 10 May 15 May 22 May 29 – Jun 26 7–21
Mizuna Apr 10 May 15 May 22 Jun 26 – Jul 24 30–45
Mustard Greens Apr 10 May 15 May 22 Jun 26 – Aug 28 30–50
Napa Cabbage Apr 10 May 15 May 22 Jul 17 – Aug 21 55–75
Onion Apr 10 May 15 May 22 Aug 21 – Sep 25 90–120
Pac Choi Apr 10 May 15 May 22 Jul 3 – Jul 31 40–55
Parsnip May 15 Aug 28 – Sep 18 100–130
Patty Pan Squash Apr 10 Jun 5 Jun 12 Jul 31 – Aug 28 45–60
Peas Apr 10 May 15 May 22 Jul 17 – Sep 11 55–70
Peppers Mar 6 Jun 5 Jun 12 Aug 14 – Oct 16 60–90
Pole Beans Mar 20 Jun 5 Jun 12 Aug 7 – Oct 2 55–70
Potatoes Mar 20 Jun 5 Jun 12 Aug 21 – Oct 16 70–120
Pumpkin Apr 10 Jun 5 Jun 12 Sep 11 – Oct 16 85–120
Purslane Apr 10 May 15 May 22 Jul 3 – Aug 7 40–60
Radish May 15 Jun 12 – Jul 3 22–35
Rhubarb Jun 19 365–730
Romanesco Apr 10 May 15 May 22 Aug 7 – Sep 18 75–100
Rutabaga May 15 Aug 7 – Sep 11 80–100
Salsify May 15 Aug 28 – Sep 18 100–130
Savoy Cabbage Apr 10 May 15 May 22 Jul 31 – Sep 25 70–110
Scallions Apr 10 May 15 May 22 Jul 17 – Aug 14 50–70
Scarlet Runner Beans Mar 20 Jun 5 Jun 12 Aug 14 – Sep 18 60–80
Shiso Mar 27 May 29 Jun 12 Aug 7 – Oct 2 50–70
Snap Peas Mar 20 Jun 5 Jun 12 Aug 7 – Oct 2 55–70
Snow Peas Apr 10 May 15 May 22 Jul 17 – Sep 11 50–65
Soybeans Jun 5 Aug 28 – Oct 9 80–120
Spaghetti Squash Apr 10 Jun 5 Jun 12 Sep 11 – Oct 9 85–100
Spinach Apr 10 May 15 May 22 Jun 26 – Aug 28 35–50
Squash (Summer) Apr 10 Jun 5 Jun 12 Jul 31 – Oct 2 45–65
Squash (Winter) Apr 10 Jun 5 Jun 12 Sep 4 – Oct 16 80–120
Sunchoke Jun 5 Sep 25 – Oct 9 110–150
Sunflower Mar 20 Jun 5 Jun 12 Aug 21 – Oct 9 70–100
Sweet Corn Jun 5 Aug 7 – Sep 18 60–90
Tatsoi Apr 10 May 15 May 22 Jun 26 – Jul 31 35–50
Tomatoes Mar 20 Jun 5 Jun 12 Aug 14 – Oct 16 60–85
Turnip May 15 Jun 26 – Jul 31 40–60
Watercress Apr 10 May 15 May 22 Jul 3 – Aug 7 40–60
Wax Beans Jun 5 Jul 31 – Sep 25 50–65
Zucchini Apr 10 Jun 5 Jun 12 Jul 31 – Sep 25 45–60

🍓 Fruits to Grow in Koochiching County

15 fruits that grow well in Zone 3a with planting dates for Koochiching County.

Show all 15 fruits with planting dates
Plant Start Indoors Direct Sow Transplant Harvest Days to Maturity
Alpine Strawberries Jun 19 Sep 18 – Oct 23 90–180
Aronia Jun 19 730–1095
Blueberries Jun 19 730–1095
Cranberries Jun 19 730–1095
Currants Jun 19 730–1095
Elderberries Jun 19 730–1095
Goji Berries Jun 19 730–1095
Gooseberries Jun 19 730–1095
Hardy Kiwi Jun 19 1095–1825
Haskaps Jun 19 730–1095
Jostaberry Jun 19 730–1095
Lingonberries Jun 19 730–1095
Raspberries Jun 19 365–730
Serviceberries Jun 19 730–1095
Strawberries Jun 19 Sep 18 – Oct 23 90–365

🌿 Herbs to Grow in Koochiching County

22 herbs that grow well in Zone 3a with planting dates for Koochiching County.

Show all 22 herbs with planting dates
Plant Start Indoors Direct Sow Transplant Harvest Days to Maturity
Angelica Apr 10 May 15 May 15 365–730
Bee Balm May 29 Aug 28 – Oct 2 90–120
Borage Apr 10 May 15 May 15 Jul 10 – Aug 28 50–60
Caraway Apr 10 May 15 May 15 365–450
Catnip May 29 Jul 31 – Oct 2 60–80
Chamomile Apr 10 May 15 May 15 Jul 17 – Sep 18 60–90
Chervil Apr 10 May 15 May 15 Jun 26 – Aug 28 40–60
Chives May 29 Jul 31 – Oct 2 60–90
Cilantro Apr 10 May 15 May 15 Jun 26 – Aug 28 40–60
Comfrey May 29 Jul 31 – Oct 2 60–90
Dill Apr 10 May 15 May 15 Jun 26 – Aug 28 40–60
Echinacea May 29 Oct 2 120–180
Garlic Chives May 29 Jul 31 – Oct 2 60–90
Horehound May 29 Aug 14 – Oct 2 75–90
Hyssop May 29 Aug 7 – Oct 2 70–90
Lemon Balm May 29 Jul 31 – Sep 18 60–70
Lovage May 29 Aug 7 – Oct 2 70–90
Mint May 29 Jul 31 – Oct 2 60–90
Parsley Apr 10 May 15 May 15 Jul 17 – Sep 18 60–80
Sorrel Apr 10 May 15 May 15 Jun 26 – Aug 28 40–60
Valerian May 29 Oct 2 120–180
Yarrow May 29 Aug 28 – Oct 2 90–120

Monthly Planting Guide for Koochiching County

Gardening Guides & Resources

Helpful guides from The Ultimate Homestead to improve your garden in Koochiching County.

Frequently Asked Questions

What planting zone is Koochiching County, MN?

Koochiching County is in USDA Hardiness Zone 3a. 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 Koochiching County, MN?

Based on 31 years of NOAA weather station data, the median last spring frost in Koochiching County falls around May 22. In 8 out of 10 years, last frost lands between May 9 and June 15 — a 37-day window of variability. Use June 15 as your conservative safe-to-plant date for frost-sensitive crops.

When is the first fall frost in Koochiching County, MN?

The median first fall frost in Koochiching County arrives around September 18. In cold years it can arrive as early as September 3; in mild years as late as October 3. Harvest or protect frost-sensitive crops — tomatoes, peppers, basil, squash — before this date.

How long is the growing season in Koochiching County?

Koochiching County has a frost-free growing season of approximately 119 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 4.02 days per decade.

What is the soil like in Koochiching County for gardening?

Koochiching County has predominantly Silt Loam soil with a pH range of 5.8–7.2 and Well Drained drainage. Most vegetables and herbs grow well with standard composting and seasonal soil amendment.

What is grown commercially in Koochiching County?

Koochiching County has commercial agriculture that includes Corn, Soybeans, Hay, 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 Koochiching County a good location for home gardening?

Koochiching County scores 61/100 (Good) 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.

🌱

Plan Your Garden with Confidence

Get our free Garden Planner — designed to help Koochiching County gardeners in Zone 3a 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.

Level Up Your Garden

Data sources: USDA Plant Hardiness Zone Map (2023), NOAA GHCN-D daily station data (1994–2024) from 3 weather stations in or near Koochiching County (31 years of records). Frost dates represent 50% probability averages; local conditions vary by elevation and microclimate. Last updated: April 2026.