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Thompson, MB — Planting Guide

Thompson is in USDA Zone 3b. The average last spring frost is May 25 and the first fall frost is September 29, giving you a growing season of approximately 127 days.

At an elevation of 728 ft, Thompson receives approximately 11.2 in of rainfall annually. The predominant soil type is Black Chernozem.

🌡️ Zone

3b (-35°F to -30°F min)

❄️ Last Frost

May 25

🍂 First Frost

September 29

📅 Growing Season

127 days

⛰️ Elevation

728 ft

🌧️ Annual Rainfall

11.2 in

Thompson, MB Short season
127 days
Last Spring Frost May 25
127 growing days
First Fall Frost September 29

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 0.5" Feb 0.6" Mar 0.9" Apr 1.1" +3.2" May 1.1" +2.9" Jun 1.4" +3" Jul 1.3" +3.2" Aug 1.1" +3.2" Sep 1.1" Oct 0.9" Nov 0.7" Dec 0.6"
Rainfall sufficient Supplemental water needed Heavy watering required - - - 1"/week garden need
View detailed monthly data
MonthAvg RainfallRainy DaysExtra Water NeededWatering Effort
Jan 0.5 in 7 days None
Feb 0.6 in 7 days None
Mar 0.9 in 8 days None
Apr 1.1 in 8 days None
May 1.1 in 11 days 3.2 in Critical
Jun 1.4 in 9 days 2.9 in High
Jul 1.3 in 9 days 3 in High
Aug 1.1 in 9 days 3.2 in Critical
Sep 1.1 in 6 days 3.2 in Critical
Oct 0.9 in 7 days None
Nov 0.7 in 8 days None
Dec 0.6 in 8 days None

Annual total: 11.3 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.

Thompson Soil Profile

Soil Type

Black Chernozem

Soil pH

6.0-7.0

Drainage

Well Drained

Gardening Difficulty Score

82 Excellent
Frost Timing Risk
0.0/10
Drought Risk
0.0/10
Soil Difficulty
3.0/10
Altitude Challenge
0.0/10
Climate Shift
0.0/10
Rainfall Challenge
7.5/10

Thompson is a very forgiving place to garden. Most plants thrive here with minimal effort.

Zone 3b Frost Countdown
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Loading...
Last Frost: May 25 First Frost: Sep 29

Local Gardening Help in Thompson

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 Thompson's climate and soil.

County Extension Office

Thompson Extension Office

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 Thompson

Soil testing Pest identification
Finding local nurseries & garden centers in Thompson

Why Buy Local

Local nurseries carry plants that are proven to grow in your area. Staff can give you advice specific to Thompson'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 Thompson MB" or "garden center Thompson" 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 Thompson MB" or check your extension office and local parks department. Facebook groups like "Thompson Gardeners" or "Manitoba 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
After Carrots (harvest ends Jul 22) 85 days until frost
After Broccoli (harvest ends Jul 29) 78 days until frost
After Sweet Corn (harvest ends Jul 29) 78 days until frost
After Zucchini (harvest ends Aug 19) 57 days until frost
After Onion (harvest ends Aug 19) 57 days until frost
After Lettuce (harvest ends Jul 29) 78 days until frost

Sunlight & Day Length

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

Longest Day

17.2 hours

Summer solstice daylight

Shortest Day

6.8 hours

Winter solstice daylight

Peak Sun Hours

10.7 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 1h 6h 10h 15h 19h 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 7.4 hr 3 hr Short day
February 9.3 hr 4 hr Short day
March 11.4 hr 5.7 hr Short day
April 13.9 hr 7.3 hr Neutral
May 16 hr 9.6 hr Long day
June 17.2 hr 10.3 hr Long day
July 16.7 hr 10.7 hr Long day
August 14.8 hr 8.8 hr Long day
September 12.4 hr 6.8 hr Neutral
October 10.1 hr 5.3 hr Short day
November 7.9 hr 3.1 hr Short day
December 6.8 hr 2.6 hr Short day

Peak sun hours factor in typical cloud cover — use these for solar panel and shade-planning calculations.

Soil Temperature & Composting Calendar

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

Plant Warm Crops When

Soil reaches 60°F+

Soil warm enough from Jul through Sep.

Best Month to Compost

Jul

Microbial activity peaks when soil is warm.

Active Composting

4 months

Short season — insulate pile or use indoor vermicomposting.

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 15°F ❄️ Dormant ~36 weeks
Feb 9°F 15°F ❄️ Dormant ~36 weeks
Mar 20°F 20°F ❄️ Dormant ~36 weeks
Apr 34°F 31°F ❄️ Dormant ~36 weeks
May 47°F 45°F 🐢 Slow ~24 weeks
Jun 60°F 54°F ♻️ Active ~14 weeks
Jul 67°F 61°F 🔥 Peak ~8 weeks
Aug 66°F 64°F 🔥 Peak ~8 weeks
Sep 61°F 57°F ♻️ Active ~14 weeks
Oct 46°F 48°F 🐢 Slow ~24 weeks
Nov 29°F 38°F ❄️ Dormant ~36 weeks
Dec 13°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 Thompson

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

Insect Pest Pressure

4.6 / 10

Moderate — common pests appear but manageable with monitoring.

Disease Risk

1.8 / 10

Low disease risk — dry conditions reduce fungal problems.

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 Moderate Jun, Jul, Aug
Flea beetles Low May, Jun, Jul
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 Thompson

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 Jun 4 Jul 28 Rapid growth, attracts pollinators, suppresses weeds
White clover Apr 24 Jul 21 ✓ 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 19 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 21 May 11 Quick biomass, winterkills in cold zones — no spring tillage needed
Winter rye Jun 24 May 4 Suppresses weeds, prevents erosion, breaks up compacted soil
Winter wheat Jun 20 May 11 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: 12 mph   Summer: 9 mph

Fall: 11 mph   Winter: 12 mph

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

Windbreak Benefit

7.4/10

Strongly recommended — a windbreak (fence, hedge, or row of tall crops like corn or sunflowers) will significantly improve garden yields.

Frost Pocket Risk

Low

Relatively flat terrain (104 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

5,631 gal

Per 1,000 sq ft of roof area (at 80% collection efficiency)

Recommended Setup

8 rain barrels (55 gal each)

For a typical 500 sq ft garden. Serious collectors: consider a 2,250 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, Mar, Oct, 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 11.3 inches of rain per year
  • A 1,000 sq ft roof can collect roughly 5,631 gallons annually
  • Rainwater harvesting is fully legal in your state
  • In your dry climate, every drop counts — consider a larger cistern system
  • Position collection tanks in shade to reduce evaporation and algae growth

Soil & Growing Conditions in Thompson

Soil Type

Black Chernozem

Amend with compost each season to maintain fertility and structure.

Watering Needs

With 11.2 inches annually, regular irrigation is essential. Drip systems and heavy mulching conserve water.

Season Tips

127-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 Thompson

87 vegetables that grow well in Zone 3b with planting dates for Thompson.

Show all 87 vegetables with planting dates
Plant Start Indoors Direct Sow Transplant Harvest Days to Maturity
Acorn Squash Apr 13 Jun 8 Jun 15 Sep 7 – Oct 12 80–100
Amaranth Mar 23 Jun 8 Jun 15 Sep 14 – Oct 19 90–120
Arugula Apr 13 May 18 May 25 Jun 29 – Aug 31 30–50
Asparagus Jun 8 730–1095
Beets May 18 Jul 13 – Aug 10 50–70
Belgian Endive Apr 13 May 18 May 25 Sep 14 – Sep 28 110–150
Black Beans Jun 8 Sep 7 – Oct 12 90–120
Bok Choy Apr 13 May 18 May 25 Jul 6 – Aug 10 40–60
Broccoli Apr 13 May 18 May 25 Jul 27 – Sep 7 60–90
Broccoli Rabe Apr 13 May 18 May 25 Jul 6 – Aug 10 40–60
Brussels Sprouts Apr 13 May 18 May 25 Aug 24 – Sep 28 90–130
Butternut Squash Apr 13 Jun 8 Jun 15 Sep 14 – Oct 19 85–110
Cabbage Apr 13 May 18 May 25 Jul 27 – Sep 21 60–100
Carrots May 18 Jul 20 – Aug 24 60–80
Cauliflower Apr 13 May 18 May 25 Jul 20 – Sep 21 55–100
Celeriac Apr 13 May 18 May 25 Sep 7 – Sep 28 100–120
Celery Apr 13 May 18 May 25 Aug 17 – Sep 28 80–120
Celtuce Apr 13 May 18 May 25 Jul 27 – Sep 7 60–90
Chard Apr 13 May 18 May 25 Jul 20 – Sep 7 50–60
Chickpeas Apr 13 May 18 May 25 Aug 17 – Sep 28 80–110
Chicory Apr 13 May 18 May 25 Jul 27 – Sep 7 60–85
Chinese Cabbage Apr 13 May 18 May 25 Jul 20 – Aug 17 50–70
Collard Greens Apr 13 May 18 May 25 Jul 20 – Sep 21 55–75
Corn Jun 8 Aug 10 – Oct 5 60–100
Cress Apr 13 May 18 May 25 Jun 8 – Jun 29 14–21
Crookneck Squash Apr 13 Jun 8 Jun 15 Aug 3 – Aug 31 45–60
Cucumber Apr 13 Jun 8 Jun 15 Aug 10 – Oct 5 50–70
Daikon May 18 Jul 13 – Aug 10 50–70
Delicata Squash Apr 13 Jun 8 Jun 15 Sep 7 – Oct 12 80–100
Edamame Jun 8 Aug 24 – Oct 5 75–100
Endive Apr 13 May 18 May 25 Jul 13 – Aug 17 45–65
Escarole Apr 13 May 18 May 25 Jul 20 – Aug 17 50–70
Fava Beans Apr 13 May 18 May 25 Aug 10 – Sep 21 75–100
Garlic 90–240
Green Beans Jun 8 Aug 3 – Sep 28 50–65
Horseradish Jun 8 Oct 12 120–180
Hubbard Squash Apr 13 Jun 8 Jun 15 Sep 28 – Oct 19 100–120
Kabocha Apr 13 Jun 8 Jun 15 Sep 14 – Oct 12 85–100
Kai Lan Apr 13 May 18 May 25 Jul 13 – Aug 10 45–60
Kale Apr 13 May 18 May 25 Jul 20 – Sep 14 50–70
Kidney Beans Jun 8 Sep 7 – Oct 12 85–110
Kohlrabi Apr 13 May 18 May 25 Jul 13 – Aug 17 45–65
Komatsuna Apr 13 May 18 May 25 Jun 29 – Aug 3 35–50
Leeks Apr 13 May 18 May 25 Aug 24 – Sep 28 90–150
Lentils Apr 13 May 18 May 25 Aug 17 – Sep 28 80–110
Lettuce Apr 13 May 18 May 25 Jun 29 – Sep 7 30–60
Lima Beans Jun 8 Aug 10 – Sep 21 60–90
Mache Apr 13 May 18 May 25 Jul 6 – Aug 10 40–60
Microgreens Apr 13 May 18 May 25 Jun 1 – Jun 29 7–21
Mizuna Apr 13 May 18 May 25 Jun 29 – Jul 27 30–45
Mustard Greens Apr 13 May 18 May 25 Jun 29 – Aug 31 30–50
Napa Cabbage Apr 13 May 18 May 25 Jul 20 – Aug 24 55–75
Onion Apr 13 May 18 May 25 Aug 24 – Sep 28 90–120
Pac Choi Apr 13 May 18 May 25 Jul 6 – Aug 3 40–55
Parsnip May 18 Aug 31 – Sep 21 100–130
Patty Pan Squash Apr 13 Jun 8 Jun 15 Aug 3 – Aug 31 45–60
Peas Apr 13 May 18 May 25 Jul 20 – Sep 14 55–70
Peppers Mar 9 Jun 8 Jun 15 Aug 17 – Oct 19 60–90
Pole Beans Mar 23 Jun 8 Jun 15 Aug 10 – Oct 5 55–70
Potatoes Mar 23 Jun 8 Jun 15 Aug 24 – Oct 19 70–120
Pumpkin Apr 13 Jun 8 Jun 15 Sep 14 – Oct 19 85–120
Purslane Apr 13 May 18 May 25 Jul 6 – Aug 10 40–60
Radish May 18 Jun 15 – Jul 6 22–35
Rhubarb Jun 22 365–730
Romanesco Apr 13 May 18 May 25 Aug 10 – Sep 21 75–100
Rutabaga May 18 Aug 10 – Sep 14 80–100
Salsify May 18 Aug 31 – Sep 21 100–130
Savoy Cabbage Apr 13 May 18 May 25 Aug 3 – Sep 28 70–110
Scallions Apr 13 May 18 May 25 Jul 20 – Aug 17 50–70
Scarlet Runner Beans Mar 23 Jun 8 Jun 15 Aug 17 – Sep 21 60–80
Shiso Mar 30 Jun 1 Jun 15 Aug 10 – Oct 5 50–70
Snap Peas Mar 23 Jun 8 Jun 15 Aug 10 – Oct 5 55–70
Snow Peas Apr 13 May 18 May 25 Jul 20 – Sep 14 50–65
Soybeans Jun 8 Aug 31 – Oct 12 80–120
Spaghetti Squash Apr 13 Jun 8 Jun 15 Sep 14 – Oct 12 85–100
Spinach Apr 13 May 18 May 25 Jun 29 – Aug 31 35–50
Squash (Summer) Apr 13 Jun 8 Jun 15 Aug 3 – Oct 5 45–65
Squash (Winter) Apr 13 Jun 8 Jun 15 Sep 7 – Oct 19 80–120
Sunchoke Jun 8 Sep 28 – Oct 12 110–150
Sunflower Mar 23 Jun 8 Jun 15 Aug 24 – Oct 12 70–100
Sweet Corn Jun 8 Aug 10 – Sep 21 60–90
Tatsoi Apr 13 May 18 May 25 Jun 29 – Aug 3 35–50
Tomatoes Mar 23 Jun 8 Jun 15 Aug 17 – Oct 19 60–85
Turnip May 18 Jun 29 – Aug 3 40–60
Watercress Apr 13 May 18 May 25 Jul 6 – Aug 10 40–60
Wax Beans Jun 8 Aug 3 – Sep 28 50–65
Zucchini Apr 13 Jun 8 Jun 15 Aug 3 – Sep 28 45–60

🍓 Fruits to Grow in Thompson

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

Show all 15 fruits with planting dates
Plant Start Indoors Direct Sow Transplant Harvest Days to Maturity
Alpine Strawberries Jun 22 Sep 21 – Oct 26 90–180
Aronia Jun 22 730–1095
Blueberries Jun 22 730–1095
Cranberries Jun 22 730–1095
Currants Jun 22 730–1095
Elderberries Jun 22 730–1095
Goji Berries Jun 22 730–1095
Gooseberries Jun 22 730–1095
Hardy Kiwi Jun 22 1095–1825
Haskaps Jun 22 730–1095
Jostaberry Jun 22 730–1095
Lingonberries Jun 22 730–1095
Raspberries Jun 22 365–730
Serviceberries Jun 22 730–1095
Strawberries Jun 22 Sep 21 – Oct 26 90–365

🌿 Herbs to Grow in Thompson

22 herbs that grow well in Zone 3b with planting dates for Thompson.

Show all 22 herbs with planting dates
Plant Start Indoors Direct Sow Transplant Harvest Days to Maturity
Angelica Apr 13 May 18 May 18 365–730
Bee Balm Jun 1 Aug 31 – Oct 5 90–120
Borage Apr 13 May 18 May 18 Jul 13 – Aug 31 50–60
Caraway Apr 13 May 18 May 18 365–450
Catnip Jun 1 Aug 3 – Oct 5 60–80
Chamomile Apr 13 May 18 May 18 Jul 20 – Sep 21 60–90
Chervil Apr 13 May 18 May 18 Jun 29 – Aug 31 40–60
Chives Jun 1 Aug 3 – Oct 5 60–90
Cilantro Apr 13 May 18 May 18 Jun 29 – Aug 31 40–60
Comfrey Jun 1 Aug 3 – Oct 5 60–90
Dill Apr 13 May 18 May 18 Jun 29 – Aug 31 40–60
Echinacea Jun 1 Oct 5 120–180
Garlic Chives Jun 1 Aug 3 – Oct 5 60–90
Horehound Jun 1 Aug 17 – Oct 5 75–90
Hyssop Jun 1 Aug 10 – Oct 5 70–90
Lemon Balm Jun 1 Aug 3 – Sep 21 60–70
Lovage Jun 1 Aug 10 – Oct 5 70–90
Mint Jun 1 Aug 3 – Oct 5 60–90
Parsley Apr 13 May 18 May 18 Jul 20 – Sep 21 60–80
Sorrel Apr 13 May 18 May 18 Jun 29 – Aug 31 40–60
Valerian Jun 1 Oct 5 120–180
Yarrow Jun 1 Aug 31 – Oct 5 90–120

Monthly Planting Guide for Thompson

Gardening Guides & Resources

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

Frequently Asked Questions

What planting zone is Thompson, MB?

Thompson 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 Thompson, MB?

Based on 30 years of NOAA weather station data, the median last spring frost in Thompson falls around May 25. Plan transplants and direct-sow dates relative to this date.

When is the first fall frost in Thompson, MB?

The median first fall frost in Thompson arrives around September 29. Harvest or protect frost-sensitive crops — tomatoes, peppers, basil, squash — before this date.

Is Thompson a good location for home gardening?

Thompson scores 82/100 (Excellent) 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 Thompson 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.

Level Up Your Garden

Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates represent 50% probability averages; local conditions vary by elevation and microclimate. Last updated: April 2026.