Keweenaw County, MI — Planting Guide
Keweenaw County is in USDA Zone 4a. The average last spring frost is May 19 and the first fall frost is October 1, giving you a growing season of approximately 135 days.
At an elevation of 1,035 ft, Keweenaw County receives approximately 40.9 in of rainfall annually. Summer highs average 81°F with winter lows around 5°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 May 5 in warm years to June 4 in cold years. The growing season is trending shorter by about 1.59 days per decade. Keweenaw County scores 67/100 (Good) on the Microclimate Index.
🌡️ Zone
4a (-30°F to -25°F min)
❄️ Last Frost
May 19
🍂 First Frost
October 1
📅 Growing Season
135 days
⛰️ Elevation
1,035 ft
🌧️ Annual Rainfall
40.9 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 | 1.7 in | 7 days | — | None |
| Feb | 1.8 in | 6 days | — | None |
| Mar | 2.6 in | 9 days | — | None |
| Apr | 3.7 in | 10 days | 0.6 in | Moderate |
| May | 4.2 in | 12 days | 0.1 in | Low |
| Jun | 4.9 in | 9 days | — | Low |
| Jul | 5 in | 9 days | — | Low |
| Aug | 4.7 in | 9 days | — | Low |
| Sep | 3.7 in | 7 days | 0.6 in | Moderate |
| Oct | 3.2 in | 7 days | 1.1 in | Moderate |
| Nov | 2.9 in | 6 days | — | None |
| Dec | 2.4 in | 7 days | — | None |
Annual total: 40.8 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.
Keweenaw County Soil Profile
Soil Type
Silt Loam
Soil pH
6.1-6.9
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) | Jun 4 | Oct 16 | 134 days |
| Cautious | May 28 | Oct 8 | 133 days |
| Average year | May 19 | Oct 1 | 135 days |
| Optimistic | May 15 | Sep 27 | 135 days |
| Aggressive (risky) | May 5 | Sep 14 | 132 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.
Yes — growing seasons are getting shorter here (about 1.6 days per decade). Use the "Conservative" dates and choose fast-maturing varieties.
Gardening Difficulty Score
Keweenaw County offers good growing conditions. A little planning around frost dates goes a long way.
Local Gardening Help in Keweenaw 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 Keweenaw County's climate and soil.
County Extension Office
Keweenaw County Michigan State University Extension Extension Office
Phone: 517-355-0240
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 Keweenaw County
Finding local nurseries & garden centers in Keweenaw County
Why Buy Local
Local nurseries carry plants that are proven to grow in your area. Staff can give you advice specific to Keweenaw 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 Keweenaw County MI" or "garden center Keweenaw 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 Keweenaw County MI" or check your extension office and local parks department. Facebook groups like "Keweenaw County Gardeners" or "Michigan 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
10 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 | 3.6 hr | Short day |
| February | 10 hr | 4.3 hr | Short day |
| March | 11.6 hr | 5.7 hr | Short day |
| April | 13.4 hr | 6.7 hr | Neutral |
| May | 14.9 hr | 8.5 hr | Long day |
| June | 15.7 hr | 10 hr | Long day |
| July | 15.4 hr | 9.9 hr | Long day |
| August | 14.1 hr | 9 hr | Long day |
| September | 12.3 hr | 6.9 hr | Neutral |
| October | 10.6 hr | 5.8 hr | Short day |
| November | 9.1 hr | 3.6 hr | Short day |
| December | 8.3 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
6 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 | 15°F | 23°F | ❄️ Dormant | ~36 weeks |
| Feb | 17°F | 21°F | ❄️ Dormant | ~36 weeks |
| Mar | 25°F | 29°F | ❄️ Dormant | ~36 weeks |
| Apr | 40°F | 40°F | 🐢 Slow | ~24 weeks |
| May | 53°F | 51°F | ♻️ Active | ~14 weeks |
| Jun | 64°F | 58°F | ♻️ Active | ~14 weeks |
| Jul | 74°F | 66°F | 🔥 Peak | ~8 weeks |
| Aug | 75°F | 69°F | 🔥 Peak | ~8 weeks |
| Sep | 66°F | 63°F | 🔥 Peak | ~8 weeks |
| Oct | 53°F | 54°F | ♻️ Active | ~14 weeks |
| Nov | 38°F | 41°F | ❄️ Dormant | ~36 weeks |
| Dec | 24°F | 30°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 Keweenaw 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
Moderate — watch for mildew and blight during wet periods.
Seasonal Risk
View 5 common pests in your area
| Pest | Risk Level | Peak Months |
|---|---|---|
| Aphids | Moderate | May, Jun, Jul, Aug |
| Cabbage worms | Low | Jun, Jul, Aug |
| Colorado potato beetle | Low | Jun, Jul |
| Flea beetles | Moderate | May, Jun, Jul |
| Slugs | Low | May, Jun, Jul, Aug, Sep |
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 Keweenaw 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 26 | Jul 23 | — | Rapid growth, attracts pollinators, suppresses weeds |
| White clover | Apr 19 | Aug 6 | ✓ 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 11 | Sep 3 | — | Deep roots break compaction, attract pollinators and beneficial insects |
Fall Cover Crops (5 options) — Plant after harvest to protect soil over winter
| Crop | Plant By | Terminate | N-Fixing | Soil Benefit |
|---|---|---|---|---|
| Daikon radish | Aug 9 | Apr 28 | — | Deep taproot breaks compaction, excellent for clay soils |
| Hairy vetch | Jul 10 | May 5 | ✓ Yes | Excellent nitrogen fixer, good for depleted soils |
| Oats | Sep 1 | May 5 | — | Quick biomass, winterkills in cold zones — no spring tillage needed |
| Winter rye | Jun 27 | Apr 28 | — | Suppresses weeds, prevents erosion, breaks up compacted soil |
| Winter wheat | Jun 29 | Apr 28 | — | 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: 13 mph Summer: 9 mph
Fall: 11 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 (248 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
20,334 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
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 40.8 inches of rain per year
- A 1,000 sq ft roof can collect roughly 20,334 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 Keweenaw County
Soil Type
Silt Loam
Soil pH 6.1–6.9 · 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. (40.9 in. annual rainfall)
Season Tips
135-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 Keweenaw County
96 vegetables that grow well in Zone 4a with planting dates for Keweenaw County.
Show all 96 vegetables with planting dates
| Plant | Start Indoors | Direct Sow | Transplant | Harvest | Days to Maturity |
|---|---|---|---|---|---|
| Acorn Squash | Apr 7 | Jun 2 | Jun 9 | Sep 1 – Oct 6 | 80–100 |
| Amaranth | Mar 17 | Jun 2 | Jun 9 | Sep 8 – Oct 27 | 90–120 |
| Arugula | Apr 7 | May 12 | May 19 | Jun 23 – Aug 25 | 30–50 |
| Asparagus | — | — | Jun 2 | — | 730–1095 |
| Beets | — | May 12 | — | Jul 7 – Aug 4 | 50–70 |
| Belgian Endive | Apr 7 | May 12 | May 19 | Sep 8 – Oct 13 | 110–150 |
| Black Beans | — | Jun 2 | — | Sep 1 – Oct 20 | 90–120 |
| Bok Choy | Apr 7 | May 12 | May 19 | Jun 30 – Aug 4 | 40–60 |
| Broccoli | Apr 7 | May 12 | May 19 | Jul 21 – Sep 1 | 60–90 |
| Broccoli Rabe | Apr 7 | May 12 | May 19 | Jun 30 – Aug 4 | 40–60 |
| Brussels Sprouts | Apr 7 | May 12 | May 19 | Aug 18 – Oct 13 | 90–130 |
| Butternut Squash | Apr 7 | Jun 2 | Jun 9 | Sep 8 – Oct 13 | 85–110 |
| Cabbage | Apr 7 | May 12 | May 19 | Jul 21 – Sep 15 | 60–100 |
| Carrots | — | May 12 | — | Jul 14 – Aug 18 | 60–80 |
| Cauliflower | Apr 7 | May 12 | May 19 | Jul 14 – Sep 15 | 55–100 |
| Celeriac | Apr 7 | May 12 | May 19 | Sep 1 – Oct 6 | 100–120 |
| Celery | Apr 7 | May 12 | May 19 | Aug 11 – Oct 6 | 80–120 |
| Celtuce | Apr 7 | May 12 | May 19 | Jul 21 – Sep 1 | 60–90 |
| Chard | Apr 7 | May 12 | May 19 | Jul 14 – Sep 1 | 50–60 |
| Chickpeas | Apr 7 | May 12 | May 19 | Aug 11 – Sep 22 | 80–110 |
| Chicory | Apr 7 | May 12 | May 19 | Jul 21 – Sep 1 | 60–85 |
| Chinese Cabbage | Apr 7 | May 12 | May 19 | Jul 14 – Aug 11 | 50–70 |
| Christmas Lima Beans | Mar 17 | Jun 2 | Jun 9 | Sep 1 – Oct 6 | 80–100 |
| Collard Greens | Apr 7 | May 12 | May 19 | Jul 14 – Sep 15 | 55–75 |
| Corn | — | Jun 2 | — | Aug 4 – Sep 29 | 60–100 |
| Cress | Apr 7 | May 12 | May 19 | Jun 2 – Jun 23 | 14–21 |
| Crookneck Squash | Apr 7 | Jun 2 | Jun 9 | Jul 28 – Aug 25 | 45–60 |
| Crosne | — | May 12 | — | Oct 13 – Oct 6 | 150–200 |
| Cucumber | Apr 7 | Jun 2 | Jun 9 | Aug 4 – Sep 29 | 50–70 |
| Daikon | — | May 12 | — | Jul 7 – Aug 4 | 50–70 |
| Delicata Squash | Apr 7 | Jun 2 | Jun 9 | Sep 1 – Oct 6 | 80–100 |
| Edamame | — | Jun 2 | — | Aug 18 – Sep 29 | 75–100 |
| Endive | Apr 7 | May 12 | May 19 | Jul 7 – Aug 11 | 45–65 |
| Escarole | Apr 7 | May 12 | May 19 | Jul 14 – Aug 11 | 50–70 |
| Fava Beans | Apr 7 | May 12 | May 19 | Aug 4 – Sep 15 | 75–100 |
| Fennel | Mar 17 | Jun 2 | Jun 9 | Aug 11 – Sep 22 | 60–90 |
| Garlic | — | — | — | — | 90–240 |
| Green Beans | — | Jun 2 | — | Jul 28 – Sep 22 | 50–65 |
| Horseradish | — | — | Jun 2 | Oct 6 – Oct 27 | 120–180 |
| Hubbard Squash | Apr 7 | Jun 2 | Jun 9 | Sep 22 – Oct 27 | 100–120 |
| Kabocha | Apr 7 | Jun 2 | Jun 9 | Sep 8 – Oct 6 | 85–100 |
| Kai Lan | Apr 7 | May 12 | May 19 | Jul 7 – Aug 4 | 45–60 |
| Kale | Apr 7 | May 12 | May 19 | Jul 14 – Sep 8 | 50–70 |
| Kidney Beans | — | Jun 2 | — | Sep 1 – Oct 6 | 85–110 |
| Kohlrabi | Apr 7 | May 12 | May 19 | Jul 7 – Aug 11 | 45–65 |
| Komatsuna | Apr 7 | May 12 | May 19 | Jun 23 – Jul 28 | 35–50 |
| Leeks | Apr 7 | May 12 | May 19 | Aug 18 – Oct 13 | 90–150 |
| Lentils | Apr 7 | May 12 | May 19 | Aug 11 – Sep 22 | 80–110 |
| Lettuce | Apr 7 | May 12 | May 19 | Jun 23 – Sep 1 | 30–60 |
| Lima Beans | — | Jun 2 | — | Aug 4 – Sep 15 | 60–90 |
| Mache | Apr 7 | May 12 | May 19 | Jun 30 – Aug 4 | 40–60 |
| Melon | Apr 7 | Jun 2 | Jun 9 | Aug 18 – Oct 6 | 70–100 |
| Microgreens | Apr 7 | May 12 | May 19 | May 26 – Jun 23 | 7–21 |
| Mitsuba | Apr 7 | May 12 | May 12 | Jul 7 – Sep 1 | 50–70 |
| Mizuna | Apr 7 | May 12 | May 19 | Jun 23 – Jul 21 | 30–45 |
| Mustard Greens | Apr 7 | May 12 | May 19 | Jun 23 – Aug 25 | 30–50 |
| Napa Cabbage | Apr 7 | May 12 | May 19 | Jul 14 – Aug 18 | 55–75 |
| Onion | Apr 7 | May 12 | May 19 | Aug 18 – Oct 6 | 90–120 |
| Pac Choi | Apr 7 | May 12 | May 19 | Jun 30 – Jul 28 | 40–55 |
| Parsnip | — | May 12 | — | Aug 25 – Oct 6 | 100–130 |
| Patty Pan Squash | Apr 7 | Jun 2 | Jun 9 | Jul 28 – Aug 25 | 45–60 |
| Peas | Apr 7 | May 12 | May 19 | Jul 14 – Sep 8 | 55–70 |
| Peppers | Mar 3 | Jun 2 | Jun 9 | Aug 11 – Oct 20 | 60–90 |
| Pole Beans | Mar 17 | Jun 2 | Jun 9 | Aug 4 – Sep 29 | 55–70 |
| Potatoes | Mar 17 | Jun 2 | Jun 9 | Aug 18 – Oct 27 | 70–120 |
| Pumpkin | Apr 7 | Jun 2 | Jun 9 | Sep 8 – Oct 27 | 85–120 |
| Purslane | Apr 7 | May 12 | May 19 | Jun 30 – Aug 4 | 40–60 |
| Radicchio | Apr 7 | May 12 | May 19 | Jul 21 – Aug 25 | 60–80 |
| Radish | — | May 12 | — | Jun 9 – Jun 30 | 22–35 |
| Rhubarb | — | — | Jun 16 | — | 365–730 |
| Romanesco | Apr 7 | May 12 | May 19 | Aug 4 – Sep 15 | 75–100 |
| Rutabaga | — | May 12 | — | Aug 4 – Sep 8 | 80–100 |
| Salsify | — | May 12 | — | Aug 25 – Oct 6 | 100–130 |
| Savoy Cabbage | Apr 7 | May 12 | May 19 | Jul 28 – Sep 22 | 70–110 |
| Scallions | Apr 7 | May 12 | May 19 | Jul 14 – Aug 11 | 50–70 |
| Scarlet Runner Beans | Mar 17 | Jun 2 | Jun 9 | Aug 11 – Sep 15 | 60–80 |
| Shallot | Apr 7 | May 12 | May 19 | Aug 18 – Oct 6 | 90–120 |
| Shiso | Mar 24 | May 26 | Jun 9 | Aug 4 – Sep 29 | 50–70 |
| Snap Peas | Mar 17 | Jun 2 | Jun 9 | Aug 4 – Sep 29 | 55–70 |
| Snow Peas | Apr 7 | May 12 | May 19 | Jul 14 – Sep 8 | 50–65 |
| Soybeans | — | Jun 2 | — | Aug 25 – Oct 20 | 80–120 |
| Spaghetti Squash | Apr 7 | Jun 2 | Jun 9 | Sep 8 – Oct 6 | 85–100 |
| Spinach | Apr 7 | May 12 | May 19 | Jun 23 – Aug 25 | 35–50 |
| Squash (Summer) | Apr 7 | Jun 2 | Jun 9 | Jul 28 – Sep 29 | 45–65 |
| Squash (Winter) | Apr 7 | Jun 2 | Jun 9 | Sep 1 – Oct 27 | 80–120 |
| Sunchoke | — | — | Jun 2 | Sep 22 – Oct 27 | 110–150 |
| Sunflower | Mar 17 | Jun 2 | Jun 9 | Aug 18 – Oct 6 | 70–100 |
| Sweet Corn | — | Jun 2 | — | Aug 4 – Sep 15 | 60–90 |
| Tatsoi | Apr 7 | May 12 | May 19 | Jun 23 – Jul 28 | 35–50 |
| Tomatillo | Mar 17 | Jun 2 | Jun 9 | Aug 11 – Oct 20 | 60–85 |
| Tomatoes | Mar 17 | Jun 2 | Jun 9 | Aug 11 – Oct 20 | 60–85 |
| Turnip | — | May 12 | — | Jun 23 – Jul 28 | 40–60 |
| Watercress | Apr 7 | May 12 | May 19 | Jun 30 – Aug 4 | 40–60 |
| Watermelon | Apr 7 | Jun 2 | Jun 9 | Aug 18 – Oct 6 | 70–100 |
| Wax Beans | — | Jun 2 | — | Jul 28 – Sep 22 | 50–65 |
| Zucchini | Apr 7 | Jun 2 | Jun 9 | Jul 28 – Sep 22 | 45–60 |
🍓 Fruits to Grow in Keweenaw County
22 fruits that grow well in Zone 4a with planting dates for Keweenaw County.
Show all 22 fruits with planting dates
| Plant | Start Indoors | Direct Sow | Transplant | Harvest | Days to Maturity |
|---|---|---|---|---|---|
| Alpine Strawberries | — | — | Jun 16 | Sep 15 – Nov 10 | 90–180 |
| Aronia | — | — | Jun 16 | — | 730–1095 |
| Blueberries | — | — | Jun 16 | — | 730–1095 |
| Cantaloupe | — | — | Jun 16 | Aug 25 – Sep 29 | 70–90 |
| Cranberries | — | — | Jun 16 | — | 730–1095 |
| Currants | — | — | Jun 16 | — | 730–1095 |
| Elderberries | — | — | Jun 16 | — | 730–1095 |
| Goji Berries | — | — | Jun 16 | — | 730–1095 |
| Gooseberries | — | — | Jun 16 | — | 730–1095 |
| Grapes | — | — | Jun 16 | — | 730–1095 |
| Ground Cherry | — | — | Jun 16 | Aug 25 – Oct 20 | 65–80 |
| Hardy Kiwi | — | — | Jun 16 | — | 1095–1825 |
| Haskaps | — | — | Jun 16 | — | 730–1095 |
| Honeydew | — | — | Jun 16 | Sep 8 – Oct 20 | 80–110 |
| Jostaberry | — | — | Jun 16 | — | 730–1095 |
| Lingonberries | — | — | Jun 16 | — | 730–1095 |
| Medlar | — | — | Jun 16 | — | 1095–1825 |
| Mulberries | — | — | Jun 16 | — | 730–1825 |
| Persimmon | — | — | Jun 16 | — | 1095–2555 |
| Raspberries | — | — | Jun 16 | — | 365–730 |
| Serviceberries | — | — | Jun 16 | — | 730–1095 |
| Strawberries | — | — | Jun 16 | Sep 15 – Nov 10 | 90–365 |
🌿 Herbs to Grow in Keweenaw County
32 herbs that grow well in Zone 4a with planting dates for Keweenaw County.
Show all 32 herbs with planting dates
| Plant | Start Indoors | Direct Sow | Transplant | Harvest | Days to Maturity |
|---|---|---|---|---|---|
| Angelica | Apr 7 | May 12 | May 12 | — | 365–730 |
| Anise | Apr 7 | May 12 | May 12 | Aug 11 – Oct 6 | 90–120 |
| Basil | Mar 24 | May 26 | Jun 9 | Aug 4 – Oct 6 | 50–75 |
| Bee Balm | — | — | May 26 | Aug 25 – Oct 20 | 90–120 |
| Borage | Apr 7 | May 12 | May 12 | Jul 7 – Aug 25 | 50–60 |
| Caraway | Apr 7 | May 12 | May 12 | — | 365–450 |
| Catnip | — | — | May 26 | Jul 28 – Sep 29 | 60–80 |
| Chamomile | Apr 7 | May 12 | May 12 | Jul 14 – Sep 22 | 60–90 |
| Chervil | Apr 7 | May 12 | May 12 | Jun 23 – Aug 25 | 40–60 |
| Chives | — | — | May 26 | Jul 28 – Oct 6 | 60–90 |
| Cilantro | Apr 7 | May 12 | May 12 | Jun 23 – Aug 25 | 40–60 |
| Comfrey | — | — | May 26 | Jul 28 – Oct 6 | 60–90 |
| Dill | Apr 7 | May 12 | May 12 | Jun 23 – Aug 25 | 40–60 |
| Echinacea | — | — | May 26 | Sep 29 – Oct 20 | 120–180 |
| Fennel (herb) | Apr 7 | May 12 | May 12 | Jul 14 – Sep 22 | 60–90 |
| Garlic Chives | — | — | May 26 | Jul 28 – Oct 6 | 60–90 |
| Horehound | — | — | May 26 | Aug 11 – Oct 6 | 75–90 |
| Hyssop | — | — | May 26 | Aug 4 – Oct 6 | 70–90 |
| Lemon Balm | — | — | May 26 | Jul 28 – Sep 15 | 60–70 |
| Lovage | — | — | May 26 | Aug 4 – Oct 6 | 70–90 |
| Mint | — | — | May 26 | Jul 28 – Oct 6 | 60–90 |
| Oregano | — | — | May 26 | Jul 28 – Oct 6 | 60–90 |
| Parsley | Apr 7 | May 12 | May 12 | Jul 14 – Sep 15 | 60–80 |
| Rue | — | — | May 26 | Aug 4 – Oct 6 | 70–90 |
| Sage | — | — | May 26 | Aug 11 – Oct 6 | 75–90 |
| Savory | — | — | May 26 | Jul 21 – Sep 15 | 50–70 |
| Sorrel | Apr 7 | May 12 | May 12 | Jun 23 – Aug 25 | 40–60 |
| Tarragon | — | — | May 26 | Jul 28 – Oct 6 | 60–90 |
| Thai Basil | Mar 24 | May 26 | Jun 9 | Aug 4 – Oct 6 | 50–75 |
| Thyme | — | — | May 26 | Aug 4 – Oct 6 | 70–90 |
| Valerian | — | — | May 26 | Sep 29 – Oct 20 | 120–180 |
| Yarrow | — | — | May 26 | Aug 25 – Oct 20 | 90–120 |
Monthly Planting Guide for Keweenaw County
Gardening Guides & Resources
Helpful guides from The Ultimate Homestead to improve your garden in Keweenaw County.
Frequently Asked Questions
What planting zone is Keweenaw County, MI?
Keweenaw County is in USDA Hardiness Zone 4a. 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 Keweenaw County, MI?
Based on 31 years of NOAA weather station data, the median last spring frost in Keweenaw County falls around May 19. In 8 out of 10 years, last frost lands between May 5 and June 4 — a 30-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 Keweenaw County, MI?
The median first fall frost in Keweenaw County arrives around October 1. In cold years it can arrive as early as September 14; in mild years as late as October 16. Harvest or protect frost-sensitive crops — tomatoes, peppers, basil, squash — before this date.
How long is the growing season in Keweenaw County?
Keweenaw County has a frost-free growing season of approximately 135 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 1.59 days per decade.
What is the soil like in Keweenaw County for gardening?
Keweenaw County has predominantly Silt Loam soil with a pH range of 6.1–6.9 and Well Drained drainage. Most vegetables and herbs grow well with standard composting and seasonal soil amendment.
What is grown commercially in Keweenaw County?
Keweenaw County has commercial agriculture that includes Soybeans, Corn, Dairy, Hay, Oats. These crops reflect the local climate and soil conditions — what succeeds commercially often translates well to home gardens in the same area.
Is Keweenaw County a good location for home gardening?
Keweenaw County scores 67/100 (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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