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Roseau County, MN — Planting Guide

Roseau County is in USDA Zone 3b. The average last spring frost is May 21 and the first fall frost is September 22, giving you a growing season of approximately 124 days.

At an elevation of 655 ft, Roseau County receives approximately 32 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 36 days year to year — ranging from April 28 in warm years to June 4 in cold years. The growing season is trending shorter by about 1.91 days per decade. Roseau County scores 61/100 (Good) on the Microclimate Index.

🌡️ Zone

3b (-35°F to -30°F min)

❄️ Last Frost

May 21

🍂 First Frost

September 22

📅 Growing Season

124 days

⛰️ Elevation

655 ft

🌧️ Annual Rainfall

32 in

Roseau County, MN Short season
124 days
Last Spring Frost May 21
124 growing days
First Fall Frost September 22

Monthly Watering Calendar for Roseau County

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

Why this matters: Watering by the calendar wastes water. Watering by the soil moisture (or by a free rain gauge) cuts your water use 30%+ and produces healthier roots. Roseau County's 32" annual baseline is the starting point.

1"/wk 0" 1.3" 2.5" 3.8" 5" Jan 1.2" Feb 1.6" Mar 1.8" Apr 2.9" +0.4" May 3.9" Jun 4.3" +0.5" Jul 3.8" +0.6" Aug 3.7" +1.9" Sep 2.4" Oct 2.7" Nov 1.9" Dec 1.7"
Rainfall sufficient Supplemental water needed Heavy watering required - - - 1"/week garden need
View detailed monthly data
MonthAvg RainfallRainy DaysExtra Water NeededWatering Effort
Jan 1.2 in 8 days None
Feb 1.6 in 7 days None
Mar 1.8 in 7 days None
Apr 2.9 in 10 days None
May 3.9 in 11 days 0.4 in Low
Jun 4.3 in 10 days Low
Jul 3.8 in 8 days 0.5 in Low
Aug 3.7 in 9 days 0.6 in Moderate
Sep 2.4 in 8 days 1.9 in High
Oct 2.7 in 7 days None
Nov 1.9 in 7 days None
Dec 1.7 in 7 days None

Annual total: 31.9 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.

Roseau County Soil Profile

Soil Type

Silt Loam

Soil pH

5.9-7.2

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 21 → Sep 22 124 frost-free days Protect crops frost returns Apr May Jun Jul Aug Sep Oct Nov Safe: Jun 4 Protect by: Oct 8

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 4 Oct 8 126 days
Cautious May 28 Sep 28 123 days
Average year May 21 Sep 22 124 days
Optimistic May 11 Sep 14 126 days
Aggressive (risky) Apr 28 Sep 7 132 days
📊
How predictable are frost dates here?

Not very — frost dates can vary by ±36 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 shorter here (about 1.9 days per decade). Use the "Conservative" dates and choose fast-maturing varieties.

Gardening Difficulty Score

61 Good
Frost Timing Risk
10.0/10
Drought Risk
5.5/10
Soil Difficulty
0.0/10
Altitude Challenge
0.0/10
Climate Shift
7.6/10
Rainfall Challenge
0.0/10

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

Zone 3b Frost Countdown
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Last Frost: May 21 First Frost: Sep 22

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

County Extension Office

Roseau 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 Roseau County

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

Why Buy Local

Local nurseries carry plants that are proven to grow in your area. Staff can give you advice specific to Roseau 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 Roseau County MN" or "garden center Roseau 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 Roseau County MN" or check your extension office and local parks department. Facebook groups like "Roseau 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 1 more succession options
After Napa Cabbage (harvest ends Aug 20) 33 days until frost

Sunlight & Day Length in Roseau County

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

Why this matters: Day length is the trigger that tells lettuce, spinach, and cilantro to bolt. In Roseau County, knowing when that day-length threshold arrives helps you plant a final round in time to harvest before it bolts.

Longest Day

15.9 hours

Summer solstice daylight

Shortest Day

8.1 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 8.5 hr 3.3 hr Short day
February 9.9 hr 4.5 hr Short day
March 11.6 hr 5.8 hr Short day
April 13.5 hr 7.3 hr Neutral
May 15 hr 8.3 hr Long day
June 15.9 hr 9.4 hr Long day
July 15.6 hr 10.1 hr Long day
August 14.2 hr 9 hr Long day
September 12.3 hr 7.4 hr Neutral
October 10.5 hr 5.5 hr Short day
November 8.9 hr 3.7 hr Short day
December 8.1 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 in Roseau County

Monthly soil temps tell you when to plant warm-season crops, and when your compost pile is actively working.

The practical takeaway: Soil heats slower than air in spring and cools slower in fall. That's why "warm" April air doesn't mean "plant tomatoes" — soil still trails by weeks. Roseau County's monthly soil curve makes the lag visible.

Plant Warm Crops When

Soil reaches 60°F+

Soil warm enough from Jun through Aug.

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 23° 45° 68° 90° 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 10°F 17°F ❄️ Dormant ~36 weeks
Mar 17°F 21°F ❄️ Dormant ~36 weeks
Apr 35°F 34°F ❄️ Dormant ~36 weeks
May 51°F 46°F ♻️ Active ~14 weeks
Jun 63°F 56°F ♻️ Active ~14 weeks
Jul 70°F 62°F 🔥 Peak ~8 weeks
Aug 71°F 64°F 🔥 Peak ~8 weeks
Sep 59°F 60°F ♻️ Active ~14 weeks
Oct 48°F 48°F 🐢 Slow ~24 weeks
Nov 30°F 36°F ❄️ Dormant ~36 weeks
Dec 16°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 Roseau County

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

For new gardeners: The most successful gardeners in high-pressure regions don't spray more — they design around the problem. Crop rotation, companion planting, and resistant varieties beat reactive spraying.

Insect Pest Pressure

4.3 / 10

Moderate — common pests appear but manageable with monitoring.

Disease Risk

2.3 / 10

Low disease risk — dry conditions reduce fungal problems.

Seasonal Risk

Spring Low
Summer Moderate
Fall Low
Winter Low
View 3 common pests in your area
PestRisk LevelPeak Months
Aphids Moderate Jun, Jul, Aug
Cabbage worms Moderate Jun, Jul, Aug
Slugs Low 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 Roseau County

Cover crops protect bare soil, fix nitrogen, suppress weeds, and improve soil structure — with planting dates calibrated for your area.

Quick context: Bare soil is wasted soil — it loses nutrients to rain, dries out, compacts, and gets taken over by weeds. Cover crops (clovers, ryegrass, vetch, peas) are the "between seasons" trick that makes soil better every year. In Roseau County, you can fit a cover crop into the gaps.

Spring Cover Crops (2 options) — Build soil before the main growing season
Crop Plant By Terminate N-Fixing Soil Benefit
Buckwheat May 29 Jul 14 Rapid growth, attracts pollinators, suppresses weeds
White clover Apr 23 Jul 14 ✓ 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 18 Sep 1 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 18 May 7 Quick biomass, winterkills in cold zones — no spring tillage needed
Winter rye Jun 22 Apr 30 Suppresses weeds, prevents erosion, breaks up compacted soil
Winter wheat Jun 27 May 7 Erosion control, weed suppression, good biomass

Wind & Microclimate in Roseau County

What this means for you: Pollinators avoid windy days. Roseau County's 9.7 mph average wind isn't enough to stop bees and butterflies — but plant fruiting crops (tomatoes, peppers, squash) in protected microclimates and you'll see noticeably better fruit set.

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: 12 mph   Winter: 13 mph

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

Windbreak Benefit

6.5/10

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

Frost Pocket Risk

Low

Relatively flat terrain (93 ft range). Frost pocket risk is minimal — garden placement is flexible.

Rainwater Harvesting in Roseau County

How much water you can collect, when to collect it, and what size system you need for your garden.

For new gardeners: The first inch of rain washes the roof clean — a first-flush diverter sends it to waste before the barrel fills. Worth the extra $20 for cleaner garden water. Roseau County gets 32" annually, so you'll fill and flush many times per year.

Annual Collection

15,898 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 31.9 inches of rain per year
  • A 1,000 sq ft roof can collect roughly 15,898 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 Roseau County

Soil Type

Silt Loam

Soil pH 5.9–7.2 · 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

124-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.

Your Free Printable Garden Planner

Plan every bed, every planting, every harvest — in one place. This 22-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.

Instant PDF download. No spam, unsubscribe any time.

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 Roseau County

86 vegetables that grow well in Zone 3b with planting dates for Roseau County.

Show all 86 vegetables with planting dates
Plant Start Indoors Direct Sow Transplant Fall Plant Harvest Days to Maturity
Acorn Squash Apr 9 Jun 4 Jun 11 Sep 3 – Oct 8 80–100
Amaranth Mar 19 Jun 4 Jun 11 Sep 10 – Oct 15 90–120
Arugula Apr 9 May 14 May 21 Jun 30 Jun 25 – Aug 27 30–50
Asparagus Jun 4 730–1095
Beets May 14 Jun 30 Jul 9 – Aug 6 50–70
Belgian Endive Apr 9 May 14 May 21 Jun 30 Sep 10 – Sep 24 110–150
Black Beans Jun 4 Sep 3 – Oct 8 90–120
Bok Choy Apr 9 May 14 May 21 Jun 30 Jul 2 – Aug 6 40–60
Broccoli Apr 9 May 14 May 21 Jun 30 Jul 23 – Sep 3 60–90
Broccoli Rabe Apr 9 May 14 May 21 Jun 30 Jul 2 – Aug 6 40–60
Brussels Sprouts Apr 9 May 14 May 21 Jun 30 Aug 20 – Sep 24 90–130
Butternut Squash Apr 9 Jun 4 Jun 11 Sep 10 – Oct 15 85–110
Cabbage Apr 9 May 14 May 21 Jun 30 Jul 23 – Sep 17 60–100
Carrots May 14 Jun 30 Jul 16 – Aug 20 60–80
Cauliflower Apr 9 May 14 May 21 Jun 30 Jul 16 – Sep 17 55–100
Celeriac Apr 9 May 14 May 21 Jun 30 Sep 3 – Sep 24 100–120
Celery Apr 9 May 14 May 21 Jun 30 Aug 13 – Sep 24 80–120
Celtuce Apr 9 May 14 May 21 Jun 30 Jul 23 – Sep 3 60–90
Chard Apr 9 May 14 May 21 Jun 30 Jul 16 – Sep 3 50–60
Chickpeas Apr 9 May 14 May 21 Jun 30 Aug 13 – Sep 24 80–110
Chicory Apr 9 May 14 May 21 Jun 30 Jul 23 – Sep 3 60–85
Chinese Cabbage Apr 9 May 14 May 21 Jun 30 Jul 16 – Aug 13 50–70
Collard Greens Apr 9 May 14 May 21 Jun 30 Jul 16 – Sep 17 55–75
Corn Jun 4 Aug 6 – Oct 1 60–100
Cress Apr 9 May 14 May 21 Jun 30 Jun 4 – Jun 25 14–21
Crookneck Squash Apr 9 Jun 4 Jun 11 Jul 30 – Aug 27 45–60
Cucumber Apr 9 Jun 4 Jun 11 Aug 6 – Oct 1 50–70
Daikon May 14 Jun 30 Jul 9 – Aug 6 50–70
Delicata Squash Apr 9 Jun 4 Jun 11 Sep 3 – Oct 8 80–100
Edamame Jun 4 Aug 20 – Oct 1 75–100
Endive Apr 9 May 14 May 21 Jun 30 Jul 9 – Aug 13 45–65
Escarole Apr 9 May 14 May 21 Jun 30 Jul 16 – Aug 13 50–70
Fava Beans Apr 9 May 14 May 21 Jun 30 Aug 6 – Sep 17 75–100
Garlic Aug 11 Nov 10 – Dec 15 90–240
Green Beans Jun 4 Jul 30 – Sep 24 50–65
Horseradish Jun 4 Oct 8 120–180
Hubbard Squash Apr 9 Jun 4 Jun 11 Sep 24 – Oct 15 100–120
Kabocha Apr 9 Jun 4 Jun 11 Sep 10 – Oct 8 85–100
Kai Lan Apr 9 May 14 May 21 Jun 30 Jul 9 – Aug 6 45–60
Kale Apr 9 May 14 May 21 Jun 30 Jul 16 – Sep 10 50–70
Kidney Beans Jun 4 Sep 3 – Oct 8 85–110
Kohlrabi Apr 9 May 14 May 21 Jun 30 Jul 9 – Aug 13 45–65
Komatsuna Apr 9 May 14 May 21 Jun 30 Jun 25 – Jul 30 35–50
Leeks Apr 9 May 14 May 21 Jun 30 Aug 20 – Sep 24 90–150
Lentils Apr 9 May 14 May 21 Jun 30 Aug 13 – Sep 24 80–110
Lettuce Apr 9 May 14 May 21 Jun 30 Jun 25 – Sep 3 30–60
Lima Beans Jun 4 Aug 6 – Sep 17 60–90
Mache Apr 9 May 14 May 21 Jun 30 Jul 2 – Aug 6 40–60
Microgreens Apr 9 May 14 May 21 Jun 30 May 28 – Jun 25 7–21
Mizuna Apr 9 May 14 May 21 Jun 30 Jun 25 – Jul 23 30–45
Mustard Greens Apr 9 May 14 May 21 Jun 30 Jun 25 – Aug 27 30–50
Napa Cabbage Apr 9 May 14 May 21 Jun 30 Jul 16 – Aug 20 55–75
Onion Apr 9 May 14 May 21 Jun 30 Aug 20 – Sep 24 90–120
Pac Choi Apr 9 May 14 May 21 Jun 30 Jul 2 – Jul 30 40–55
Parsnip May 14 Jun 30 Aug 27 – Sep 17 100–130
Patty Pan Squash Apr 9 Jun 4 Jun 11 Jul 30 – Aug 27 45–60
Peas Apr 9 May 14 May 21 Jun 30 Jul 16 – Sep 10 55–70
Peppers Mar 5 Jun 4 Jun 11 Aug 13 – Oct 15 60–90
Pole Beans Mar 19 Jun 4 Jun 11 Aug 6 – Oct 1 55–70
Potatoes Mar 19 Jun 4 Jun 11 Aug 20 – Oct 15 70–120
Pumpkin Apr 9 Jun 4 Jun 11 Sep 10 – Oct 15 85–120
Purslane Apr 9 May 14 May 21 Jun 30 Jul 2 – Aug 6 40–60
Radish May 14 Jun 30 Jun 11 – Jul 2 22–35
Rhubarb Jun 18 365–730
Romanesco Apr 9 May 14 May 21 Jun 30 Aug 6 – Sep 17 75–100
Rutabaga May 14 Jun 30 Aug 6 – Sep 10 80–100
Salsify May 14 Jun 30 Aug 27 – Sep 17 100–130
Savoy Cabbage Apr 9 May 14 May 21 Jun 30 Jul 30 – Sep 24 70–110
Scallions Apr 9 May 14 May 21 Jun 30 Jul 16 – Aug 13 50–70
Scarlet Runner Beans Mar 19 Jun 4 Jun 11 Aug 13 – Sep 17 60–80
Shiso Mar 26 May 28 Jun 11 Aug 6 – Oct 1 50–70
Snap Peas Mar 19 Jun 4 Jun 11 Aug 6 – Oct 1 55–70
Snow Peas Apr 9 May 14 May 21 Jun 30 Jul 16 – Sep 10 50–65
Soybeans Jun 4 Aug 27 – Oct 8 80–120
Spaghetti Squash Apr 9 Jun 4 Jun 11 Sep 10 – Oct 8 85–100
Spinach Apr 9 May 14 May 21 Jun 30 Jun 25 – Aug 27 35–50
Squash (Summer) Apr 9 Jun 4 Jun 11 Jul 30 – Oct 1 45–65
Squash (Winter) Apr 9 Jun 4 Jun 11 Sep 3 – Oct 15 80–120
Sunchoke Jun 4 Sep 24 – Oct 8 110–150
Sweet Corn Jun 4 Aug 6 – Sep 17 60–90
Tatsoi Apr 9 May 14 May 21 Jun 30 Jun 25 – Jul 30 35–50
Tomatoes Mar 19 Jun 4 Jun 11 Aug 13 – Oct 15 60–85
Turnip May 14 Jun 30 Jun 25 – Jul 30 40–60
Watercress Apr 9 May 14 May 21 Jun 30 Jul 2 – Aug 6 40–60
Wax Beans Jun 4 Jul 30 – Sep 24 50–65
Zucchini Apr 9 Jun 4 Jun 11 Jul 30 – Sep 24 45–60

🍓 Fruits to Grow in Roseau County

15 fruits that grow well in Zone 3b with planting dates for Roseau County.

Show all 15 fruits with planting dates
Plant Start Indoors Direct Sow Transplant Fall Plant Harvest Days to Maturity
Alpine Strawberries Jun 18 Sep 17 – Oct 22 90–180
Aronia Jun 18 730–1095
Blueberries Jun 18 730–1095
Cranberries Jun 18 730–1095
Currants Jun 18 730–1095
Elderberries Jun 18 730–1095
Goji Berries Jun 18 730–1095
Gooseberries Jun 18 730–1095
Hardy Kiwi Jun 18 1095–1825
Haskaps Jun 18 730–1095
Jostaberry Jun 18 730–1095
Lingonberries Jun 18 730–1095
Raspberries Jun 18 365–730
Serviceberries Jun 18 730–1095
Strawberries Jun 18 Sep 17 – Oct 22 90–365

🌿 Herbs to Grow in Roseau County

20 herbs that grow well in Zone 3b with planting dates for Roseau County.

Show all 20 herbs with planting dates
Plant Start Indoors Direct Sow Transplant Fall Plant Harvest Days to Maturity
Angelica Apr 9 May 14 May 14 Jun 30 365–730
Bee Balm May 28 Aug 27 – Oct 1 90–120
Borage Apr 9 May 14 May 14 Jun 30 Jul 9 – Aug 27 50–60
Caraway Apr 9 May 14 May 14 Jun 30 365–450
Catnip May 28 Jul 30 – Oct 1 60–80
Chamomile Apr 9 May 14 May 14 Jun 30 Jul 16 – Sep 17 60–90
Chervil Apr 9 May 14 May 14 Jun 30 Jun 25 – Aug 27 40–60
Chives May 28 Jul 30 – Oct 1 60–90
Cilantro Apr 9 May 14 May 14 Jun 30 Jun 25 – Aug 27 40–60
Comfrey May 28 Jul 30 – Oct 1 60–90
Dill Apr 9 May 14 May 14 Jun 30 Jun 25 – Aug 27 40–60
Garlic Chives May 28 Jul 30 – Oct 1 60–90
Horehound May 28 Aug 13 – Oct 1 75–90
Hyssop May 28 Aug 6 – Oct 1 70–90
Lemon Balm May 28 Jul 30 – Sep 17 60–70
Lovage May 28 Aug 6 – Oct 1 70–90
Mint May 28 Jul 30 – Oct 1 60–90
Parsley Apr 9 May 14 May 14 Jun 30 Jul 16 – Sep 17 60–80
Sorrel Apr 9 May 14 May 14 Jun 30 Jun 25 – Aug 27 40–60
Valerian May 28 Oct 1 120–180

🌸 Flowers to Grow in Roseau County

49 flowers that grow well in Zone 3b with planting dates for Roseau County.

Show all 49 flowers with planting dates
Plant Start Indoors Direct Sow Transplant Fall Plant Bloom Days to Maturity
Ageratum Mar 26 Jun 4 Jun 4 Jul 30 – Oct 1 60–75
Alliums Aug 11 Sep 22 – Oct 20 28–42
Astilbe Mar 12 Jun 4 Aug 27 – Oct 15 70–100
Bachelor's Button Mar 26 May 14 May 21 Jul 23 – Sep 17 60–90
Begonias Mar 5 Jun 4 Aug 13 – Oct 8 70–90
Black-eyed Susan Mar 12 May 21 Jun 4 Aug 27 – Oct 29 60–80
Bleeding Hearts Mar 12 Jun 4 Jul 30 – Sep 10 60–90
Calendula Apr 2 May 14 May 21 Jul 9 – Sep 17 50–70
Celosia Apr 9 Jun 11 Jun 11 Aug 13 – Oct 22 60–90
Columbine Mar 12 Jun 4 Jun 4 Jul 30 – Sep 10 70–100
Coreopsis Mar 12 May 28 Jun 4 Aug 27 – Oct 29 60–80
Cosmos Apr 23 May 28 May 28 Aug 6 – Oct 15 60–90
Crocus Aug 11 Jun 9 – Jul 7 10–20
Daffodils Aug 11 Jun 16 – Jul 14 20–40
Dahlias Apr 23 Jun 4 Jun 4 Sep 10 – Oct 29 70–120
Daylily Mar 12 Jun 4 Sep 10 – Oct 29 60–90
Dianthus Mar 12 May 7 May 21 Jul 9 – Sep 3 60–80
Echinacea (Purple Coneflower) Mar 12 Jun 4 Jun 4 Sep 3 – Oct 29 70–90
Foxglove Mar 12 Jun 4 Jun 4 Jul 30 – Sep 10 80–120
Gaillardia (Blanket Flower) Mar 26 Jun 4 Jun 4 Aug 13 – Nov 5 70–100
Geraniums Mar 5 Jun 4 Aug 13 – Oct 8 70–100
Gladiolus Jun 4 Jun 4 Sep 10 – Oct 29 70–100
Hostas Feb 26 Jun 4 Sep 10 – Oct 29 60–90
Hyacinths Aug 11 Jul 7 – Jul 28 14–28
Hydrangeas Feb 26 Jun 4 Aug 27 – Oct 15 90–150
Impatiens Mar 19 Jun 4 Aug 20 – Oct 8 60–75
Irises Division Jun 4 Jul 30 – Aug 27 60–100
Larkspur Apr 16 Jun 25 – Aug 6 60–90
Lilies Division Jun 4 Aug 27 – Oct 22 70–120
Lobelia Mar 12 May 28 Jul 23 – Sep 10 70–80
Lupine Mar 12 Jun 4 Jun 4 Jul 30 – Sep 10 75–100
Marigolds Apr 9 Jun 4 Jun 4 Jul 30 – Oct 8 50–70
Nasturtium Apr 23 Jun 4 Jun 4 Jul 30 – Oct 8 55–65
Pansy Feb 26 May 21 Jul 16 – Aug 27 70–90
Peonies Division Jun 4 Aug 13 – Sep 10 90–120
Petunia Mar 19 Jun 4 Aug 20 – Oct 15 70–90
Phlox Mar 12 Jun 4 Jun 4 Aug 27 – Oct 22 80–110
Portulaca Apr 9 Jun 11 Jun 11 Jul 30 – Oct 1 50–70
Roses Feb 26 Jun 4 Aug 27 – Oct 29 90–180
Salvia Mar 12 Jun 4 Aug 13 – Oct 8 70–90
Sedum (Stonecrop) Mar 12 Jun 4 Oct 8 – Nov 19 60–90
Snapdragon Mar 5 May 21 Jul 30 – Sep 17 70–100
Sunflower Apr 30 Jun 4 Jun 4 Aug 27 – Oct 22 70–100
Sweet Alyssum Mar 26 May 21 May 21 Jul 2 – Aug 27 45–60
Sweet Pea Apr 2 Apr 23 May 21 Aug 13 – Sep 24 65–85
Tulips Aug 11 Jun 30 – Jul 21 15–30
Vinca (Annual) Mar 5 Jun 4 Aug 13 – Oct 8 70–90
Yarrow Mar 12 May 21 Jun 4 Aug 27 – Oct 29 60–90
Zinnia Apr 23 Jun 4 Jun 4 Aug 13 – Oct 15 60–70

Monthly Planting Guide for Roseau County

Gardening Guides & Resources

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

Frequently Asked Questions

What planting zone is Roseau County, MN?

Roseau 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 Roseau County, MN?

Based on 31 years of NOAA weather station data, the median last spring frost in Roseau County falls around May 21. In 8 out of 10 years, last frost lands between April 28 and June 4 — a 36-day window of variability. Use June 4 as your conservative safe-to-plant date for frost-sensitive crops.

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

The median first fall frost in Roseau County arrives around September 22. In cold years it can arrive as early as September 7; in mild years as late as October 8. Harvest or protect frost-sensitive crops — tomatoes, peppers, basil, squash — before this date.

How long is the growing season in Roseau County?

Roseau County has a frost-free growing season of approximately 124 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 shorter by about 1.91 days per decade.

What is the soil like in Roseau County for gardening?

Roseau County has predominantly Silt Loam soil with a pH range of 5.9–7.2 and Well Drained drainage. Most vegetables and herbs grow well with standard composting and seasonal soil amendment.

What is grown commercially in Roseau County?

Roseau 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 Roseau County a good location for home gardening?

Roseau 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.

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Your Roseau County Garden Planner — Free

A 22-page printable planner built for Roseau County (Zone 3b). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.

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The Gardener's Encyclopedia to Companion Planting

The Gardener's Encyclopedia to Companion Planting

$27 $293 value

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
See what's inside →
Reader favourite
Seed Saving & Storage Guide

Seed Saving & Storage Guide

$27 $157 value

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
Save a lifetime of seed money →
Composting Guide for Homesteaders

Composting Guide for Homesteaders

$27 $210 value

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
Start composting today →

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

Sources & credits

Every number on this page traces back to a primary horticulture or government data source. Click through to verify.