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Buchanan County, IA — Planting Guide

Buchanan County is in USDA Zone 4b. The average last spring frost is May 2 and the first fall frost is October 7, giving you a growing season of approximately 158 days.

At an elevation of 837 ft, Buchanan County receives approximately 41.4 in of rainfall annually. Summer highs average 83°F with winter lows around 4°F. The predominant soil type is Silt Loam.

Based on 31 years of NOAA climate station data, the last frost date here varies by 28 days year to year — ranging from April 17 in warm years to May 16 in cold years. The growing season is trending shorter by about 1.8 days per decade. Buchanan County scores 62/100 (Good) on the Microclimate Index.

🌡️ Zone

4b (-25°F to -20°F min)

❄️ Last Frost

May 2

🍂 First Frost

October 7

📅 Growing Season

158 days

⛰️ Elevation

837 ft

🌧️ Annual Rainfall

41.4 in

Buchanan County, IA Moderate season
158 days
Last Spring Frost May 2
158 growing days
First Fall Frost October 7

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" 2.6" 3.8" 5.1" Jan 1.8" Feb 1.7" Mar 2.9" Apr 4.4" May 4.2" Jun 4.7" Jul 5.1" Aug 5" Sep 4" +1.5" Oct 2.8" Nov 2.6" Dec 2.2"
Rainfall sufficient Supplemental water needed Heavy watering required - - - 1"/week garden need
View detailed monthly data
MonthAvg RainfallRainy DaysExtra Water NeededWatering Effort
Jan 1.8 in 8 days None
Feb 1.7 in 8 days None
Mar 2.9 in 9 days None
Apr 4.4 in 11 days Low
May 4.2 in 11 days 0.1 in Low
Jun 4.7 in 10 days Low
Jul 5.1 in 9 days Low
Aug 5 in 9 days Low
Sep 4 in 6 days 0.3 in Low
Oct 2.8 in 8 days 1.5 in Moderate
Nov 2.6 in 7 days None
Dec 2.2 in 8 days None

Annual total: 41.4 in. Water needs vary by crop — tomatoes need ~1.2"/week while herbs like rosemary need only 0.3"/week. Check individual plant pages for crop-specific water budgets that factor in your county's rainfall and soil drainage.

Buchanan County Soil Profile

Soil Type

Silt Loam

Soil pH

6.1-7

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 2 → Oct 7 158 frost-free days Protect crops frost returns Apr May Jun Jul Aug Sep Oct Nov Safe: May 16 Protect by: Oct 16

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) May 16 Oct 16 153 days
Cautious May 11 Oct 11 153 days
Average year May 2 Oct 7 158 days
Optimistic Apr 25 Sep 30 158 days
Aggressive (risky) Apr 17 Sep 21 157 days
📊
How predictable are frost dates here?

Not very — frost dates can vary by ±28 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 1.8 days per decade). Use the "Conservative" dates and choose fast-maturing varieties.

Gardening Difficulty Score

62 Good
Frost Timing Risk
10.0/10
Drought Risk
5.5/10
Soil Difficulty
0.0/10
Altitude Challenge
0.0/10
Climate Shift
7.2/10
Rainfall Challenge
0.0/10

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

Zone 4b Frost Countdown
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Last Frost: May 2 First Frost: Oct 7

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

County Extension Office

Buchanan County Iowa State University Extension Extension Office

Phone: 515-294-6675

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 IA →

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 Buchanan County

Soil testing Pest identification Gardening hotline
Finding local nurseries & garden centers in Buchanan County

Why Buy Local

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

After Zucchini (harvest ends Sep 5) 32 days until frost
After Lettuce (harvest ends Aug 15) 53 days until frost
After Green Beans (harvest ends Aug 22) 46 days until frost
After Sweet Corn (harvest ends Aug 15) 53 days until frost
Show 6 more succession options
After Beets (harvest ends Jul 25) 74 days until frost
After Carrots (harvest ends Aug 8) 60 days until frost
After Spinach (harvest ends Aug 8) 60 days until frost
After Corn (harvest ends Aug 29) 39 days until frost
After Cauliflower (harvest ends Aug 29) 39 days until frost
After Chard (harvest ends Aug 15) 53 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

15.1 hours

Summer solstice daylight

Shortest Day

8.9 hours

Winter solstice daylight

Peak Sun Hours

9.9 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 9.2 hr 3.7 hr Short day
February 10.3 hr 4.5 hr Short day
March 11.7 hr 5.5 hr Short day
April 13.2 hr 7.2 hr Neutral
May 14.4 hr 8.4 hr Long day
June 15.1 hr 9.7 hr Long day
July 14.8 hr 9.9 hr Long day
August 13.7 hr 8.9 hr Neutral
September 12.3 hr 6.8 hr Neutral
October 10.8 hr 5.7 hr Short day
November 9.5 hr 3.7 hr Short day
December 8.9 hr 3.4 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.

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 15°F 24°F ❄️ Dormant ~36 weeks
Feb 16°F 25°F ❄️ Dormant ~36 weeks
Mar 27°F 30°F ❄️ Dormant ~36 weeks
Apr 43°F 41°F 🐢 Slow ~24 weeks
May 53°F 51°F ♻️ Active ~14 weeks
Jun 64°F 60°F ♻️ Active ~14 weeks
Jul 74°F 67°F 🔥 Peak ~8 weeks
Aug 76°F 70°F 🔥 Peak ~8 weeks
Sep 67°F 63°F 🔥 Peak ~8 weeks
Oct 51°F 56°F ♻️ Active ~14 weeks
Nov 36°F 43°F ❄️ Dormant ~36 weeks
Dec 22°F 32°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 Buchanan County

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

Insect Pest Pressure

5.4 / 10

Moderate — common pests appear but manageable with monitoring.

Disease Risk

5.5 / 10

Moderate — watch for mildew and blight during wet periods.

Seasonal Risk

Spring Low
Summer High
Fall Low
Winter Low
View 5 common pests in your area
PestRisk LevelPeak Months
Aphids Moderate May, Jun, Jul, Aug
Cabbage worms Moderate Jun, Jul, Aug
Colorado potato beetle Moderate Jun, Jul
Flea beetles Moderate May, Jun, Jul
Slugs Moderate 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 Buchanan 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 11 Jul 29 Rapid growth, attracts pollinators, suppresses weeds
White clover Apr 7 Jul 29 ✓ 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 May 13 Sep 23 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 12 Apr 11 Deep taproot breaks compaction, excellent for clay soils
Hairy vetch Jul 12 Apr 18 ✓ Yes Excellent nitrogen fixer, good for depleted soils
Oats Sep 7 Apr 18 Quick biomass, winterkills in cold zones — no spring tillage needed
Winter rye Jul 17 Apr 18 Suppresses weeds, prevents erosion, breaks up compacted soil
Winter wheat Jul 4 Apr 18 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: 9 mph   Winter: 13 mph

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

Windbreak Benefit

7/10

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 (265 ft range). Frost pocket risk is minimal — garden placement is flexible.

Rainwater Harvesting Potential

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

Annual Collection

20,633 gal

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

Recommended Setup

6 rain barrels (55 gal each)

For a typical 500 sq ft garden. Serious collectors: consider a 1,500 gal tank.

Legal Status

Unrestricted

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

Best Collection Months

Apr, 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 41.4 inches of rain per year
  • A 1,000 sq ft roof can collect roughly 20,633 gallons annually
  • Rainwater harvesting is fully legal in your state
  • Stock up on stored water before your dry season (Jan, Feb, Dec)
  • Use a first-flush diverter to keep roof debris out of your collection

Soil & Growing Conditions in Buchanan County

Soil Type

Silt Loam

Soil pH 6.1–7 · Moderately 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

158-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.

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 Buchanan County

96 vegetables that grow well in Zone 4b with planting dates for Buchanan County.

Show all 96 vegetables with planting dates
Plant Start Indoors Direct Sow Transplant Harvest Days to Maturity
Acorn Squash Mar 21 May 16 May 23 Aug 15 – Sep 19 80–100
Amaranth Feb 28 May 16 May 23 Aug 22 – Oct 10 90–120
Arugula Mar 21 Apr 25 May 2 Jun 6 – Aug 8 30–50
Asparagus May 16 730–1095
Beets Apr 25 Jun 20 – Jul 18 50–70
Belgian Endive Mar 21 Apr 25 May 2 Aug 22 – Sep 26 110–150
Black Beans May 16 Aug 15 – Oct 3 90–120
Bok Choy Mar 21 Apr 25 May 2 Jun 13 – Jul 18 40–60
Broccoli Mar 21 Apr 25 May 2 Jul 4 – Aug 15 60–90
Broccoli Rabe Mar 21 Apr 25 May 2 Jun 13 – Jul 18 40–60
Brussels Sprouts Mar 21 Apr 25 May 2 Aug 1 – Sep 26 90–130
Butternut Squash Mar 21 May 16 May 23 Aug 22 – Sep 26 85–110
Cabbage Mar 21 Apr 25 May 2 Jul 4 – Aug 29 60–100
Carrots Apr 25 Jun 27 – Aug 1 60–80
Cauliflower Mar 21 Apr 25 May 2 Jun 27 – Aug 29 55–100
Celeriac Mar 21 Apr 25 May 2 Aug 15 – Sep 19 100–120
Celery Mar 21 Apr 25 May 2 Jul 25 – Sep 19 80–120
Celtuce Mar 21 Apr 25 May 2 Jul 4 – Aug 15 60–90
Chard Mar 21 Apr 25 May 2 Jun 27 – Aug 15 50–60
Chickpeas Mar 21 Apr 25 May 2 Jul 25 – Sep 5 80–110
Chicory Mar 21 Apr 25 May 2 Jul 4 – Aug 15 60–85
Chinese Cabbage Mar 21 Apr 25 May 2 Jun 27 – Jul 25 50–70
Christmas Lima Beans Feb 28 May 16 May 23 Aug 15 – Sep 19 80–100
Collard Greens Mar 21 Apr 25 May 2 Jun 27 – Aug 29 55–75
Corn May 16 Jul 18 – Sep 12 60–100
Cress Mar 21 Apr 25 May 2 May 16 – Jun 6 14–21
Crookneck Squash Mar 21 May 16 May 23 Jul 11 – Aug 8 45–60
Crosne Apr 25 Sep 26 – Sep 19 150–200
Cucumber Mar 21 May 16 May 23 Jul 18 – Sep 12 50–70
Daikon Apr 25 Jun 20 – Jul 18 50–70
Delicata Squash Mar 21 May 16 May 23 Aug 15 – Sep 19 80–100
Edamame May 16 Aug 1 – Sep 12 75–100
Endive Mar 21 Apr 25 May 2 Jun 20 – Jul 25 45–65
Escarole Mar 21 Apr 25 May 2 Jun 27 – Jul 25 50–70
Fava Beans Mar 21 Apr 25 May 2 Jul 18 – Aug 29 75–100
Fennel Feb 28 May 16 May 23 Jul 25 – Sep 5 60–90
Garlic 90–240
Green Beans May 16 Jul 11 – Sep 5 50–65
Horseradish May 16 Sep 19 – Oct 10 120–180
Hubbard Squash Mar 21 May 16 May 23 Sep 5 – Oct 10 100–120
Kabocha Mar 21 May 16 May 23 Aug 22 – Sep 19 85–100
Kai Lan Mar 21 Apr 25 May 2 Jun 20 – Jul 18 45–60
Kale Mar 21 Apr 25 May 2 Jun 27 – Aug 22 50–70
Kidney Beans May 16 Aug 15 – Sep 19 85–110
Kohlrabi Mar 21 Apr 25 May 2 Jun 20 – Jul 25 45–65
Komatsuna Mar 21 Apr 25 May 2 Jun 6 – Jul 11 35–50
Leeks Mar 21 Apr 25 May 2 Aug 1 – Sep 26 90–150
Lentils Mar 21 Apr 25 May 2 Jul 25 – Sep 5 80–110
Lettuce Mar 21 Apr 25 May 2 Jun 6 – Aug 15 30–60
Lima Beans May 16 Jul 18 – Aug 29 60–90
Mache Mar 21 Apr 25 May 2 Jun 13 – Jul 18 40–60
Melon Mar 21 May 16 May 23 Aug 1 – Sep 19 70–100
Microgreens Mar 21 Apr 25 May 2 May 9 – Jun 6 7–21
Mitsuba Mar 21 Apr 25 Apr 25 Jun 20 – Aug 15 50–70
Mizuna Mar 21 Apr 25 May 2 Jun 6 – Jul 4 30–45
Mustard Greens Mar 21 Apr 25 May 2 Jun 6 – Aug 8 30–50
Napa Cabbage Mar 21 Apr 25 May 2 Jun 27 – Aug 1 55–75
Onion Mar 21 Apr 25 May 2 Aug 1 – Sep 19 90–120
Pac Choi Mar 21 Apr 25 May 2 Jun 13 – Jul 11 40–55
Parsnip Apr 25 Aug 8 – Sep 19 100–130
Patty Pan Squash Mar 21 May 16 May 23 Jul 11 – Aug 8 45–60
Peas Mar 21 Apr 25 May 2 Jun 27 – Aug 22 55–70
Peppers Feb 14 May 16 May 23 Jul 25 – Oct 3 60–90
Pole Beans Feb 28 May 16 May 23 Jul 18 – Sep 12 55–70
Potatoes Feb 28 May 16 May 23 Aug 1 – Oct 10 70–120
Pumpkin Mar 21 May 16 May 23 Aug 22 – Oct 10 85–120
Purslane Mar 21 Apr 25 May 2 Jun 13 – Jul 18 40–60
Radicchio Mar 21 Apr 25 May 2 Jul 4 – Aug 8 60–80
Radish Apr 25 May 23 – Jun 13 22–35
Rhubarb May 30 365–730
Romanesco Mar 21 Apr 25 May 2 Jul 18 – Aug 29 75–100
Rutabaga Apr 25 Jul 18 – Aug 22 80–100
Salsify Apr 25 Aug 8 – Sep 19 100–130
Savoy Cabbage Mar 21 Apr 25 May 2 Jul 11 – Sep 5 70–110
Scallions Mar 21 Apr 25 May 2 Jun 27 – Jul 25 50–70
Scarlet Runner Beans Feb 28 May 16 May 23 Jul 25 – Aug 29 60–80
Shallot Mar 21 Apr 25 May 2 Aug 1 – Sep 19 90–120
Shiso Mar 7 May 9 May 23 Jul 18 – Sep 12 50–70
Snap Peas Feb 28 May 16 May 23 Jul 18 – Sep 12 55–70
Snow Peas Mar 21 Apr 25 May 2 Jun 27 – Aug 22 50–65
Soybeans May 16 Aug 8 – Oct 3 80–120
Spaghetti Squash Mar 21 May 16 May 23 Aug 22 – Sep 19 85–100
Spinach Mar 21 Apr 25 May 2 Jun 6 – Aug 8 35–50
Squash (Summer) Mar 21 May 16 May 23 Jul 11 – Sep 12 45–65
Squash (Winter) Mar 21 May 16 May 23 Aug 15 – Oct 10 80–120
Sunchoke May 16 Sep 5 – Oct 10 110–150
Sunflower Feb 28 May 16 May 23 Aug 1 – Sep 19 70–100
Sweet Corn May 16 Jul 18 – Aug 29 60–90
Tatsoi Mar 21 Apr 25 May 2 Jun 6 – Jul 11 35–50
Tomatillo Feb 28 May 16 May 23 Jul 25 – Oct 3 60–85
Tomatoes Feb 28 May 16 May 23 Jul 25 – Oct 3 60–85
Turnip Apr 25 Jun 6 – Jul 11 40–60
Watercress Mar 21 Apr 25 May 2 Jun 13 – Jul 18 40–60
Watermelon Mar 21 May 16 May 23 Aug 1 – Sep 19 70–100
Wax Beans May 16 Jul 11 – Sep 5 50–65
Zucchini Mar 21 May 16 May 23 Jul 11 – Sep 5 45–60

🍓 Fruits to Grow in Buchanan County

22 fruits that grow well in Zone 4b with planting dates for Buchanan County.

Show all 22 fruits with planting dates
Plant Start Indoors Direct Sow Transplant Harvest Days to Maturity
Alpine Strawberries May 30 Aug 29 – Oct 24 90–180
Aronia May 30 730–1095
Blueberries May 30 730–1095
Cantaloupe May 30 Aug 8 – Sep 12 70–90
Cranberries May 30 730–1095
Currants May 30 730–1095
Elderberries May 30 730–1095
Goji Berries May 30 730–1095
Gooseberries May 30 730–1095
Grapes May 30 730–1095
Ground Cherry May 30 Aug 8 – Oct 3 65–80
Hardy Kiwi May 30 1095–1825
Haskaps May 30 730–1095
Honeydew May 30 Aug 22 – Oct 3 80–110
Jostaberry May 30 730–1095
Lingonberries May 30 730–1095
Medlar May 30 1095–1825
Mulberries May 30 730–1825
Persimmon May 30 1095–2555
Raspberries May 30 365–730
Serviceberries May 30 730–1095
Strawberries May 30 Aug 29 – Oct 24 90–365

🌿 Herbs to Grow in Buchanan County

32 herbs that grow well in Zone 4b with planting dates for Buchanan County.

Show all 32 herbs with planting dates
Plant Start Indoors Direct Sow Transplant Harvest Days to Maturity
Angelica Mar 21 Apr 25 Apr 25 365–730
Anise Mar 21 Apr 25 Apr 25 Jul 25 – Sep 19 90–120
Basil Mar 7 May 9 May 23 Jul 18 – Sep 19 50–75
Bee Balm May 9 Aug 8 – Oct 3 90–120
Borage Mar 21 Apr 25 Apr 25 Jun 20 – Aug 8 50–60
Caraway Mar 21 Apr 25 Apr 25 365–450
Catnip May 9 Jul 11 – Sep 12 60–80
Chamomile Mar 21 Apr 25 Apr 25 Jun 27 – Sep 5 60–90
Chervil Mar 21 Apr 25 Apr 25 Jun 6 – Aug 8 40–60
Chives May 9 Jul 11 – Sep 19 60–90
Cilantro Mar 21 Apr 25 Apr 25 Jun 6 – Aug 8 40–60
Comfrey May 9 Jul 11 – Sep 19 60–90
Dill Mar 21 Apr 25 Apr 25 Jun 6 – Aug 8 40–60
Echinacea May 9 Sep 12 – Oct 3 120–180
Fennel (herb) Mar 21 Apr 25 Apr 25 Jun 27 – Sep 5 60–90
Garlic Chives May 9 Jul 11 – Sep 19 60–90
Horehound May 9 Jul 25 – Sep 19 75–90
Hyssop May 9 Jul 18 – Sep 19 70–90
Lemon Balm May 9 Jul 11 – Aug 29 60–70
Lovage May 9 Jul 18 – Sep 19 70–90
Mint May 9 Jul 11 – Sep 19 60–90
Oregano May 9 Jul 11 – Sep 19 60–90
Parsley Mar 21 Apr 25 Apr 25 Jun 27 – Aug 29 60–80
Rue May 9 Jul 18 – Sep 19 70–90
Sage May 9 Jul 25 – Sep 19 75–90
Savory May 9 Jul 4 – Aug 29 50–70
Sorrel Mar 21 Apr 25 Apr 25 Jun 6 – Aug 8 40–60
Tarragon May 9 Jul 11 – Sep 19 60–90
Thai Basil Mar 7 May 9 May 23 Jul 18 – Sep 19 50–75
Thyme May 9 Jul 18 – Sep 19 70–90
Valerian May 9 Sep 12 – Oct 3 120–180
Yarrow May 9 Aug 8 – Oct 3 90–120

Monthly Planting Guide for Buchanan County

Gardening Guides & Resources

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

Frequently Asked Questions

What planting zone is Buchanan County, IA?

Buchanan County is in USDA Hardiness Zone 4b. 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 Buchanan County, IA?

Based on 31 years of NOAA weather station data, the median last spring frost in Buchanan County falls around May 2. In 8 out of 10 years, last frost lands between April 17 and May 16 — a 28-day window of variability. Use May 16 as your conservative safe-to-plant date for frost-sensitive crops.

When is the first fall frost in Buchanan County, IA?

The median first fall frost in Buchanan County arrives around October 7. In cold years it can arrive as early as September 21; 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 Buchanan County?

Buchanan County has a frost-free growing season of approximately 158 days. This is enough time for most warm-season crops including tomatoes, peppers, and squash with proper timing. Climate records show the growing season is trending shorter by about 1.8 days per decade.

What is the soil like in Buchanan County for gardening?

Buchanan County has predominantly Silt Loam soil with a pH range of 6.1–7 and Moderately Well Drained drainage. Most vegetables and herbs grow well with standard composting and seasonal soil amendment.

What is grown commercially in Buchanan County?

Buchanan 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 Buchanan County a good location for home gardening?

Buchanan County scores 62/100 (Good) on our Microclimate Index, which combines frost reliability, drought pressure, soil challenge, elevation risk, and long-term climate trend. Conditions here are moderate — most common crops grow well with standard timing and care.

🌱

Plan Your Garden with Confidence

Get our free Garden Planner — designed to help Buchanan County gardeners in Zone 4b organize planting dates, track what's growing, and never miss a planting window.

Get Your Free Garden Planner →

Free download. Plan your entire garden season in minutes.

Level Up Your Garden

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