Iron County, WI — Planting Guide
Iron County is in USDA Zone 3b. The average last spring frost is May 22 and the first fall frost is September 25, giving you a growing season of approximately 126 days.
At an elevation of 841 ft, Iron County receives approximately 32.4 in of rainfall annually. Summer highs average 78°F with winter lows around -2°F. The predominant soil type is Silt Loam.
Based on 31 years of NOAA climate station data, the last frost date here varies by 25 days year to year — ranging from May 12 in warm years to June 6 in cold years. The growing season is trending longer by about 1.19 days per decade. Iron County scores 70/100 (Good) on the Microclimate Index.
🌡️ Zone
3b (-35°F to -30°F min)
❄️ Last Frost
May 22
🍂 First Frost
September 25
📅 Growing Season
126 days
⛰️ Elevation
841 ft
🌧️ Annual Rainfall
32.4 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 | 1.2 in | 7 days | — | None |
| Feb | 1.4 in | 7 days | — | None |
| Mar | 2.4 in | 9 days | — | None |
| Apr | 3 in | 9 days | — | None |
| May | 3.7 in | 9 days | 0.6 in | Moderate |
| Jun | 3.6 in | 9 days | 0.7 in | Moderate |
| Jul | 3.6 in | 8 days | 0.7 in | Moderate |
| Aug | 3.7 in | 9 days | 0.6 in | Moderate |
| Sep | 3.2 in | 7 days | 1.1 in | Moderate |
| Oct | 2.5 in | 7 days | — | None |
| Nov | 2.3 in | 8 days | — | None |
| Dec | 1.8 in | 7 days | — | None |
Annual total: 32.4 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.
Iron County Soil Profile
Soil Type
Silt Loam
Soil pH
5.7-6.9
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 6 | Oct 9 | 125 days |
| Cautious | May 30 | Sep 30 | 123 days |
| Average year | May 22 | Sep 25 | 126 days |
| Optimistic | May 18 | Sep 18 | 123 days |
| Aggressive (risky) | May 12 | Sep 11 | 122 days |
Not very — frost dates can vary by ±25 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 longer here (about 1.2 days per decade). Spring is arriving earlier than it used to. Good news for gardeners.
Gardening Difficulty Score
Iron County offers good growing conditions. A little planning around frost dates goes a long way.
Local Gardening Help in Iron 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 Iron County's climate and soil.
County Extension Office
Iron County University of Wisconsin-Madison Division of Extension Extension Office
Phone: 608-263-7779
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 Iron County
Finding local nurseries & garden centers in Iron County
Why Buy Local
Local nurseries carry plants that are proven to grow in your area. Staff can give you advice specific to Iron 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 Iron County WI" or "garden center Iron 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 Iron County WI" or check your extension office and local parks department. Facebook groups like "Iron County Gardeners" or "Wisconsin 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
15.6 hours
Summer solstice daylight
Shortest Day
8.4 hours
Winter solstice daylight
Peak Sun Hours
9.7 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.
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 | 8.8 hr | 3.4 hr | Short day |
| February | 10.1 hr | 4.4 hr | Short day |
| March | 11.6 hr | 5.5 hr | Short day |
| April | 13.3 hr | 7 hr | Neutral |
| May | 14.8 hr | 8.9 hr | Long day |
| June | 15.6 hr | 9.7 hr | Long day |
| July | 15.2 hr | 9.7 hr | Long day |
| August | 14 hr | 8.4 hr | Long day |
| September | 12.3 hr | 7.1 hr | Neutral |
| October | 10.6 hr | 5.3 hr | Short day |
| November | 9.2 hr | 3.5 hr | Short day |
| December | 8.4 hr | 3.2 hr | Short day |
Peak sun hours factor in typical cloud cover — use these for solar panel and shade-planning calculations.
Soil Temperature & Composting Calendar
Monthly soil temps tell you when to plant warm-season crops, and when your compost pile is actively working.
Plant Warm Crops When
Soil reaches 60°F+
Soil warm enough from 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.
View detailed monthly data
| Month | Soil 4" Deep | Soil 8" Deep | Compost Activity | Time to Finish |
|---|---|---|---|---|
| Jan | 6°F | 17°F | ❄️ Dormant | ~36 weeks |
| Feb | 8°F | 16°F | ❄️ Dormant | ~36 weeks |
| Mar | 21°F | 22°F | ❄️ Dormant | ~36 weeks |
| Apr | 35°F | 33°F | ❄️ Dormant | ~36 weeks |
| May | 50°F | 45°F | ♻️ Active | ~14 weeks |
| Jun | 60°F | 56°F | ♻️ Active | ~14 weeks |
| Jul | 69°F | 62°F | 🔥 Peak | ~8 weeks |
| Aug | 71°F | 65°F | 🔥 Peak | ~8 weeks |
| Sep | 62°F | 59°F | ♻️ Active | ~14 weeks |
| Oct | 47°F | 49°F | 🐢 Slow | ~24 weeks |
| Nov | 32°F | 38°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 Iron County
Computed from local climate patterns — warmer, humid conditions increase pest generations and fungal disease risk.
Insect Pest Pressure
Moderate — common pests appear but manageable with monitoring.
Disease Risk
Low disease risk — dry conditions reduce fungal problems.
Seasonal Risk
View 4 common pests in your area
| Pest | Risk Level | Peak Months |
|---|---|---|
| Aphids | Low | Jun, Jul, Aug |
| Cabbage worms | Moderate | Jun, Jul, Aug |
| Flea beetles | Low | May, Jun, Jul |
| Slugs | Moderate | May, Jun, Jul, Aug |
Organic pest management tips
- Maintain healthy soil with regular compost additions to build natural pest resistance
- Practice crop rotation annually to break pest cycles
- Encourage beneficial insects with flowering herbs like dill, fennel, and yarrow
Cover Crops for Iron 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 22 | Jul 17 | ✓ 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 29 | May 1 | — | Quick biomass, winterkills in cold zones — no spring tillage needed |
| Winter rye | Jun 30 | May 1 | — | Suppresses weeds, prevents erosion, breaks up compacted soil |
| Winter wheat | Jun 24 | 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: 9 mph
Fall: 10 mph Winter: 12 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 (194 ft range). Frost pocket risk is minimal — garden placement is flexible.
Rainwater Harvesting Potential
How much water you can collect, when to collect it, and what size system you need for your garden.
Annual Collection
16,148 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 32.4 inches of rain per year
- A 1,000 sq ft roof can collect roughly 16,148 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 Iron County
Soil Type
Silt Loam
Soil pH 5.7–6.9 · 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. (32.4 in. annual rainfall)
Season Tips
126-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.
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 Iron County
87 vegetables that grow well in Zone 3b with planting dates for Iron 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 Iron County
15 fruits that grow well in Zone 3b with planting dates for Iron 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 Iron County
22 herbs that grow well in Zone 3b with planting dates for Iron 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 Iron County
Gardening Guides & Resources
Helpful guides from The Ultimate Homestead to improve your garden in Iron County.
Frequently Asked Questions
What planting zone is Iron County, WI?
Iron 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 Iron County, WI?
Based on 31 years of NOAA weather station data, the median last spring frost in Iron County falls around May 22. In 8 out of 10 years, last frost lands between May 12 and June 6 — a 25-day window of variability. Use June 6 as your conservative safe-to-plant date for frost-sensitive crops.
When is the first fall frost in Iron County, WI?
The median first fall frost in Iron County arrives around September 25. In cold years it can arrive as early as September 11; in mild years as late as October 9. Harvest or protect frost-sensitive crops — tomatoes, peppers, basil, squash — before this date.
How long is the growing season in Iron County?
Iron County has a frost-free growing season of approximately 126 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 1.19 days per decade.
What is the soil like in Iron County for gardening?
Iron County has predominantly Silt Loam soil with a pH range of 5.7–6.9 and Well Drained drainage. Most vegetables and herbs grow well with standard composting and seasonal soil amendment.
What is grown commercially in Iron County?
Iron County has commercial agriculture that includes Soybeans, Corn, Hay. These crops reflect the local climate and soil conditions — what succeeds commercially often translates well to home gardens in the same area.
Is Iron County a good location for home gardening?
Iron County scores 70/100 (Good) on our Microclimate Index, which combines frost reliability, drought pressure, soil challenge, elevation risk, and long-term climate trend. This is an above-average location for home gardening with relatively predictable growing conditions.
Plan Your Garden with Confidence
Get our free Garden Planner — designed to help Iron County gardeners in Zone 3b organize planting dates, track what's growing, and never miss a planting window.
Get Your Free Garden Planner →Free download. Plan your entire garden season in minutes.
