Clarke County, IA — Planting Guide
June in Clarke County, Iowa — your action list
We've pulled the most time-sensitive tasks for Clarke County, Iowa this June and put them front and centre. Tackle them in order.
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Start basil, pole beans, and thai basil under lights
A seed-starting mix and a sunny window (or a grow light) are all you need. Keep soil warm — around 70°F — for fast germination.
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Collect carrots, green beans, and kale at their peak
Morning harvests are best — cooler temperatures mean crisper produce and longer fridge life.
A few tasks this June that'll pay off in July
- Starting indoors: peppers, begonias, and eggplant
- First harvests: basil, carrots, and cucumber
Clarke County is in USDA Zone 5b. The average last spring frost is April 24 and the first fall frost is October 11, giving you a growing season of approximately 170 days.
At an elevation of 1,182 ft, Clarke County receives approximately 35.9 in of rainfall annually. Summer highs average 87°F with winter lows around 15°F. The predominant soil type is Silt Loam.
Based on 31 years of NOAA climate station data, the last frost date here varies by 27 days year to year — ranging from April 12 in warm years to May 9 in cold years. Clarke County scores 71/100 (Good) on the Microclimate Index.
🌡️ Zone
5b (-15°F to -10°F min)
❄️ Last Frost
April 24
🍂 First Frost
October 11
📅 Growing Season
170 days
⛰️ Elevation
1,182 ft
🌧️ Annual Rainfall
35.9 in
Monthly Watering Calendar for Clarke County
When you'll need to water your garden — based on average monthly rainfall vs. the ~1 inch/week most gardens need.
Why this matters: In humid climates, watering is usually about timing (morning, not evening, to prevent disease) more than volume. In dry climates, it's about depth (water deep, less often) more than frequency. Clarke County's 36" annual tells you which side you're on.
View detailed monthly data
| Month | Avg Rainfall | Rainy Days | Extra Water Needed | Watering Effort |
|---|---|---|---|---|
| Jan | 1.6 in | 7 days | — | None |
| Feb | 1.7 in | 6 days | — | None |
| Mar | 2.2 in | 9 days | — | None |
| Apr | 3.5 in | 9 days | 0.8 in | Moderate |
| May | 4.5 in | 10 days | — | Low |
| Jun | 4 in | 10 days | 0.3 in | Low |
| Jul | 3.7 in | 10 days | 0.6 in | Moderate |
| Aug | 3.9 in | 10 days | 0.4 in | Low |
| Sep | 3.2 in | 9 days | 1.1 in | Moderate |
| Oct | 3.1 in | 8 days | 1.2 in | Moderate |
| Nov | 2.3 in | 8 days | — | None |
| Dec | 2.2 in | 7 days | — | None |
Annual total: 35.9 in. Water needs vary by crop — tomatoes need ~1.2"/week while herbs like rosemary need only 0.3"/week. Check individual plant pages for crop-specific water budgets that factor in your county's rainfall and soil drainage.
Clarke County Soil Profile
Soil Type
Silt Loam
Soil pH
6-6.9
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) | May 9 | Oct 24 | 168 days |
| Cautious | Apr 30 | Oct 15 | 168 days |
| Average year | Apr 24 | Oct 11 | 170 days |
| Optimistic | Apr 18 | Oct 5 | 170 days |
| Aggressive (risky) | Apr 12 | Sep 23 | 164 days |
Not very — frost dates can vary by ±27 days year-to-year. Use the "Conservative" row in the table below, and keep row covers handy for surprise late frosts.
Slightly — seasons are trending a bit shorter (0.4 days/decade). Stay conservative with planting dates.
Gardening Difficulty Score
Clarke County offers good growing conditions. A little planning around frost dates goes a long way.
Local Gardening Help in Clarke 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 Clarke County's climate and soil.
County Extension Office
Clarke 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.
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 Clarke County
Finding local nurseries & garden centers in Clarke County
Why Buy Local
Local nurseries carry plants that are proven to grow in your area. Staff can give you advice specific to Clarke 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 Clarke County IA" or "garden center Clarke 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 Clarke County IA" or check your extension office and local parks department. Facebook groups like "Clarke 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.
Show 6 more succession options
Sunlight & Day Length in Clarke County
Monthly daylight hours and peak sun — critical for onion varieties, photoperiod-sensitive plants, and solar garden planning.
Why it matters: The longest day at Clarke County's latitude gets longer the further north you go. Strawberries, garlic, onions all care. The shortest day gets shorter — which limits winter growing for greens without artificial light.
Longest Day
14.9 hours
Summer solstice daylight
Shortest Day
9.1 hours
Winter solstice daylight
Peak Sun Hours
9.5 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 | 9.4 hr | 3.8 hr | Short day |
| February | 10.4 hr | 4.5 hr | Short day |
| March | 11.7 hr | 5.7 hr | Short day |
| April | 13.1 hr | 6.8 hr | Neutral |
| May | 14.3 hr | 7.9 hr | Long day |
| June | 14.9 hr | 9.5 hr | Long day |
| July | 14.7 hr | 9.4 hr | Long day |
| August | 13.6 hr | 8.4 hr | Neutral |
| September | 12.3 hr | 7.2 hr | Neutral |
| October | 10.9 hr | 5.7 hr | Short day |
| November | 9.7 hr | 3.7 hr | Short day |
| December | 9.1 hr | 3.6 hr | Short day |
Peak sun hours factor in typical cloud cover — use these for solar panel and shade-planning calculations.
Soil Temperature & Composting in Clarke County
Monthly soil temps tell you when to plant warm-season crops, and when your compost pile is actively working.
What this means for you: Most root crops germinate well at 50-60°F. Most fruit-bearing crops want 65-75°F. Clarke County's monthly soil curve maps these windows to actual months.
Plant Warm Crops When
Soil reaches 60°F+
Soil warm enough from Jun through Sep.
Best Month to Compost
Jun
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 | 23°F | 30°F | ❄️ Dormant | ~36 weeks |
| Feb | 23°F | 29°F | ❄️ Dormant | ~36 weeks |
| Mar | 30°F | 35°F | ❄️ Dormant | ~36 weeks |
| Apr | 44°F | 44°F | 🐢 Slow | ~24 weeks |
| May | 58°F | 54°F | ♻️ Active | ~14 weeks |
| Jun | 67°F | 65°F | 🔥 Peak | ~8 weeks |
| Jul | 75°F | 72°F | 🔥 Peak | ~8 weeks |
| Aug | 78°F | 74°F | 🔥 Peak | ~8 weeks |
| Sep | 70°F | 70°F | 🔥 Peak | ~8 weeks |
| Oct | 58°F | 60°F | ♻️ Active | ~14 weeks |
| Nov | 41°F | 49°F | 🐢 Slow | ~24 weeks |
| Dec | 30°F | 37°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 Clarke County
Computed from local climate patterns — warmer, humid conditions increase pest generations and fungal disease risk.
Quick context: The most successful gardeners in high-pressure regions don't spray more — they design around the problem. Crop rotation, companion planting, and resistant varieties beat reactive spraying.
Insect Pest Pressure
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 |
| Japanese beetles | Moderate | Jun, Jul, Aug |
| Squash bugs | Low | Jun, Jul, Aug |
| Tomato hornworms | Moderate | Jul, Aug |
| Cabbage loopers | Low | May, Jun, Jul, Aug |
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 Clarke County
Cover crops protect bare soil, fix nitrogen, suppress weeds, and improve soil structure — with planting dates calibrated for your area.
Quick context: In Clarke County, cover crops also crowd out weeds. The denser the cover, the less weed pressure next season. Pays for itself in saved weeding time.
Spring Cover Crops (3 options) — Build soil before the main growing season
| Crop | Plant By | Terminate | N-Fixing | Soil Benefit |
|---|---|---|---|---|
| Buckwheat | Apr 27 | Aug 2 | — | Rapid growth, attracts pollinators, suppresses weeds |
| Sorghum-sudan grass | May 1 | Aug 9 | — | Massive biomass, breaks compaction, suppresses nematodes |
| White clover | Mar 29 | Aug 9 | ✓ 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 22 | Sep 13 | — | Deep roots break compaction, attract pollinators and beneficial insects |
Fall Cover Crops (6 options) — Plant after harvest to protect soil over winter
| Crop | Plant By | Terminate | N-Fixing | Soil Benefit |
|---|---|---|---|---|
| Austrian winter peas | Aug 9 | Apr 3 | ✓ Yes | Fixes nitrogen, good for heavy clay soils |
| Daikon radish | Aug 18 | Apr 3 | — | Deep taproot breaks compaction, excellent for clay soils |
| Hairy vetch | Jul 20 | Apr 3 | ✓ Yes | Excellent nitrogen fixer, good for depleted soils |
| Oats | Aug 30 | Apr 10 | — | Quick biomass, winterkills in cold zones — no spring tillage needed |
| Winter rye | Jul 13 | Apr 10 | — | Suppresses weeds, prevents erosion, breaks up compacted soil |
| Winter wheat | Jul 18 | Apr 10 | — | Erosion control, weed suppression, good biomass |
Wind & Microclimate in Clarke County
What this means for you: Wind shapes the garden you don't think about: bee paths, evaporation, structural stress on tomato cages. Clarke County's 8.8 mph background level is a baseline you should know before placing the tallest crops (sunflowers, pole beans, sweet corn).
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: 10 mph Winter: 12 mph
Prevailing wind: SW. Moderate wind — consider a temporary windbreak for young seedlings.
Windbreak Benefit
4.5/10
Moderately beneficial — a simple fence or trellis can protect delicate crops from wind stress.
Frost Pocket Risk
Low
Relatively flat terrain (257 ft range). Frost pocket risk is minimal — garden placement is flexible.
Rainwater Harvesting in Clarke County
How much water you can collect, when to collect it, and what size system you need for your garden.
The practical takeaway: The first inch of rain washes the roof clean — a first-flush diverter sends it to waste before the barrel fills. Worth the extra $20 for cleaner garden water. Clarke County gets 36" annually, so you'll fill and flush many times per year.
Annual Collection
17,892 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 35.9 inches of rain per year
- A 1,000 sq ft roof can collect roughly 17,892 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 Clarke County
Soil Type
Silt Loam
Soil pH 6–6.9 · 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
170-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.
Your Free Printable Garden Planner
Plan every bed, every planting, every harvest — in one place. This 22-page printable includes your zone's planting calendar, a month-by-month task list, a seed inventory tracker, a harvest log, and succession-planting charts. Built to print, write in, and actually use all season.
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 Clarke County
105 vegetables that grow well in Zone 5b with planting dates for Clarke County.
Show all 105 vegetables with planting dates
| Plant | Start Indoors | Direct Sow | Transplant | Fall Plant | Harvest | Days to Maturity |
|---|---|---|---|---|---|---|
| Acorn Squash | Mar 20 | May 1 | May 8 | — | Jul 31 – Sep 4 | 80–100 |
| Amaranth | Feb 27 | May 1 | May 8 | — | Aug 7 – Sep 25 | 90–120 |
| Arugula | Mar 20 | Apr 10 | Apr 24 | Aug 2 | May 29 – Jul 31 | 30–50 |
| Asparagus | — | — | May 8 | — | — | 730–1095 |
| Beets | — | Apr 10 | — | Aug 2 | Jun 5 – Jul 3 | 50–70 |
| Belgian Endive | Mar 20 | Apr 10 | Apr 24 | Aug 2 | Aug 14 – Oct 9 | 110–150 |
| Bitter Melon | Feb 27 | May 1 | May 8 | — | Jul 10 – Aug 21 | 60–90 |
| Black Beans | — | May 1 | — | — | Jul 31 – Sep 18 | 90–120 |
| Bok Choy | Mar 20 | Apr 10 | Apr 24 | Aug 2 | Jun 5 – Jul 10 | 40–60 |
| Broccoli | Mar 20 | Apr 10 | Apr 24 | Aug 2 | Jun 26 – Aug 7 | 60–90 |
| Broccoli Rabe | Mar 20 | Apr 10 | Apr 24 | Aug 2 | Jun 5 – Jul 10 | 40–60 |
| Brussels Sprouts | Mar 20 | Apr 10 | Apr 24 | Aug 2 | Jul 24 – Sep 18 | 90–130 |
| Butternut Squash | Mar 20 | May 1 | May 8 | — | Aug 7 – Sep 11 | 85–110 |
| Cabbage | Mar 20 | Apr 10 | Apr 24 | Aug 2 | Jun 26 – Aug 21 | 60–100 |
| Calabash | Feb 27 | May 1 | May 8 | — | Jul 31 – Sep 25 | 80–120 |
| Carrots | — | Apr 10 | — | Aug 2 | Jun 12 – Jul 17 | 60–80 |
| Cauliflower | Mar 20 | Apr 10 | Apr 24 | Aug 2 | Jun 19 – Aug 21 | 55–100 |
| Celeriac | Mar 20 | Apr 10 | Apr 24 | Aug 2 | Aug 7 – Sep 11 | 100–120 |
| Celery | Mar 20 | Apr 10 | Apr 24 | Aug 2 | Jul 17 – Sep 11 | 80–120 |
| Celtuce | Mar 20 | Apr 10 | Apr 24 | Aug 2 | Jun 26 – Aug 7 | 60–90 |
| Chard | Mar 20 | Apr 10 | Apr 24 | Aug 2 | Jun 19 – Aug 7 | 50–60 |
| Chickpeas | Mar 20 | Apr 10 | Apr 24 | Aug 2 | Jul 17 – Aug 28 | 80–110 |
| Chicory | Mar 20 | Apr 10 | Apr 24 | Aug 2 | Jun 26 – Aug 7 | 60–85 |
| Chinese Cabbage | Mar 20 | Apr 10 | Apr 24 | Aug 2 | Jun 19 – Jul 17 | 50–70 |
| Christmas Lima Beans | Feb 27 | May 1 | May 8 | — | Jul 31 – Sep 4 | 80–100 |
| Collard Greens | Mar 20 | Apr 10 | Apr 24 | Aug 2 | Jun 19 – Aug 21 | 55–75 |
| Corn | — | May 1 | — | — | Jul 3 – Aug 28 | 60–100 |
| Cowpeas | — | May 1 | — | — | Jul 3 – Aug 14 | 60–90 |
| Cress | Mar 20 | Apr 10 | Apr 24 | Aug 2 | May 8 – May 29 | 14–21 |
| Crookneck Squash | Mar 20 | May 1 | May 8 | — | Jun 26 – Jul 24 | 45–60 |
| Crosne | — | Apr 10 | — | Aug 2 | Sep 11 – Sep 25 | 150–200 |
| Cucumber | Mar 20 | May 1 | May 8 | — | Jul 3 – Aug 28 | 50–70 |
| Daikon | — | Apr 10 | — | Aug 2 | Jun 5 – Jul 3 | 50–70 |
| Delicata Squash | Mar 20 | May 1 | May 8 | — | Jul 31 – Sep 4 | 80–100 |
| Edamame | — | May 1 | — | — | Jul 17 – Aug 28 | 75–100 |
| Eggplant | Feb 13 | May 1 | May 8 | — | Jul 17 – Sep 18 | 65–85 |
| Endive | Mar 20 | Apr 10 | Apr 24 | Aug 2 | Jun 12 – Jul 17 | 45–65 |
| Escarole | Mar 20 | Apr 10 | Apr 24 | Aug 2 | Jun 19 – Jul 17 | 50–70 |
| Fava Beans | Mar 20 | Apr 10 | Apr 24 | Aug 2 | Jul 10 – Aug 21 | 75–100 |
| Fennel | Feb 27 | May 1 | May 8 | — | Jul 10 – Aug 21 | 60–90 |
| Garlic | — | — | — | Aug 30 | Nov 29 – Feb 14 | 90–240 |
| Green Beans | — | May 1 | — | — | Jun 26 – Aug 21 | 50–65 |
| Horseradish | — | — | May 8 | — | Sep 11 – Oct 23 | 120–180 |
| Hot Peppers | Feb 13 | May 1 | May 8 | — | Jul 17 – Oct 23 | 70–120 |
| Hubbard Squash | Mar 20 | May 1 | May 8 | — | Aug 21 – Sep 25 | 100–120 |
| Kabocha | Mar 20 | May 1 | May 8 | — | Aug 7 – Sep 4 | 85–100 |
| Kai Lan | Mar 20 | Apr 10 | Apr 24 | Aug 2 | Jun 12 – Jul 10 | 45–60 |
| Kale | Mar 20 | Apr 10 | Apr 24 | Aug 2 | Jun 19 – Aug 14 | 50–70 |
| Kidney Beans | — | May 1 | — | — | Jul 31 – Sep 4 | 85–110 |
| Kohlrabi | Mar 20 | Apr 10 | Apr 24 | Aug 2 | Jun 12 – Jul 17 | 45–65 |
| Komatsuna | Mar 20 | Apr 10 | Apr 24 | Aug 2 | May 29 – Jul 3 | 35–50 |
| Leeks | Mar 20 | Apr 10 | Apr 24 | Aug 2 | Jul 24 – Oct 9 | 90–150 |
| Lentils | Mar 20 | Apr 10 | Apr 24 | Aug 2 | Jul 17 – Aug 28 | 80–110 |
| Lettuce | Mar 20 | Apr 10 | Apr 24 | Aug 2 | May 29 – Aug 7 | 30–60 |
| Lima Beans | — | May 1 | — | — | Jul 3 – Aug 14 | 60–90 |
| Mache | Mar 20 | Apr 10 | Apr 24 | Aug 2 | Jun 5 – Jul 10 | 40–60 |
| Melon | Mar 20 | May 1 | May 8 | — | Jul 17 – Sep 4 | 70–100 |
| Microgreens | Mar 20 | Apr 10 | Apr 24 | Aug 2 | May 1 – May 29 | 7–21 |
| Mitsuba | Mar 20 | Apr 10 | Apr 17 | Aug 2 | Jun 12 – Aug 7 | 50–70 |
| Mizuna | Mar 20 | Apr 10 | Apr 24 | Aug 2 | May 29 – Jun 26 | 30–45 |
| Mustard Greens | Mar 20 | Apr 10 | Apr 24 | Aug 2 | May 29 – Jul 31 | 30–50 |
| Napa Cabbage | Mar 20 | Apr 10 | Apr 24 | Aug 2 | Jun 19 – Jul 24 | 55–75 |
| New Zealand Spinach | Feb 27 | May 1 | May 8 | — | Jul 3 – Jul 31 | 55–70 |
| Okra | Feb 27 | May 1 | May 8 | — | Jul 3 – Aug 28 | 50–65 |
| Onion | Mar 20 | Apr 10 | Apr 24 | Aug 2 | Jul 24 – Sep 11 | 90–120 |
| Pac Choi | Mar 20 | Apr 10 | Apr 24 | Aug 2 | Jun 5 – Jul 3 | 40–55 |
| Parsnip | — | Apr 10 | — | Aug 2 | Jul 24 – Sep 4 | 100–130 |
| Patty Pan Squash | Mar 20 | May 1 | May 8 | — | Jun 26 – Jul 24 | 45–60 |
| Peas | Mar 20 | Apr 10 | Apr 24 | Aug 2 | Jun 19 – Aug 14 | 55–70 |
| Peppers | Feb 13 | May 1 | May 8 | — | Jul 10 – Sep 18 | 60–90 |
| Pole Beans | Feb 27 | May 1 | May 8 | — | Jul 3 – Aug 28 | 55–70 |
| Potatoes | Feb 27 | May 1 | May 8 | — | Jul 17 – Sep 25 | 70–120 |
| Pumpkin | Mar 20 | May 1 | May 8 | — | Aug 7 – Sep 25 | 85–120 |
| Purslane | Mar 20 | Apr 10 | Apr 24 | Aug 2 | Jun 5 – Jul 10 | 40–60 |
| Radicchio | Mar 20 | Apr 10 | Apr 24 | Aug 2 | Jun 26 – Jul 31 | 60–80 |
| Radish | — | Apr 10 | — | Aug 2 | May 8 – May 29 | 22–35 |
| Rhubarb | — | — | May 15 | — | — | 365–730 |
| Romanesco | Mar 20 | Apr 10 | Apr 24 | Aug 2 | Jul 10 – Aug 21 | 75–100 |
| Rutabaga | — | Apr 10 | — | Aug 2 | Jul 3 – Aug 7 | 80–100 |
| Salsify | — | Apr 10 | — | Aug 2 | Jul 24 – Sep 4 | 100–130 |
| Savoy Cabbage | Mar 20 | Apr 10 | Apr 24 | Aug 2 | Jul 3 – Aug 28 | 70–110 |
| Scallions | Mar 20 | Apr 10 | Apr 24 | Aug 2 | Jun 19 – Jul 17 | 50–70 |
| Scarlet Runner Beans | Feb 27 | May 1 | May 8 | — | Jul 10 – Aug 14 | 60–80 |
| Shallot | Mar 20 | Apr 10 | Apr 24 | Aug 2 | Jul 24 – Sep 11 | 90–120 |
| Shiso | Mar 6 | May 1 | May 8 | — | Jul 3 – Aug 28 | 50–70 |
| Snap Peas | Feb 27 | May 1 | May 8 | — | Jul 3 – Aug 28 | 55–70 |
| Snow Peas | Mar 20 | Apr 10 | Apr 24 | Aug 2 | Jun 19 – Aug 14 | 50–65 |
| Soybeans | — | May 1 | — | — | Jul 24 – Sep 18 | 80–120 |
| Spaghetti Squash | Mar 20 | May 1 | May 8 | — | Aug 7 – Sep 4 | 85–100 |
| Spinach | Mar 20 | Apr 10 | Apr 24 | Aug 2 | May 29 – Jul 31 | 35–50 |
| Squash (Summer) | Mar 20 | May 1 | May 8 | — | Jun 26 – Aug 28 | 45–65 |
| Squash (Winter) | Mar 20 | May 1 | May 8 | — | Jul 31 – Sep 25 | 80–120 |
| Sunchoke | — | — | May 8 | — | Aug 28 – Oct 23 | 110–150 |
| Sweet Corn | — | May 1 | — | — | Jul 3 – Aug 14 | 60–90 |
| Sweet Potatoes | Feb 27 | May 1 | May 8 | — | Aug 7 – Sep 25 | 90–120 |
| Tatsoi | Mar 20 | Apr 10 | Apr 24 | Aug 2 | May 29 – Jul 3 | 35–50 |
| Tomatillo | Feb 27 | May 1 | May 8 | — | Jul 10 – Sep 18 | 60–85 |
| Tomatoes | Feb 27 | May 1 | May 8 | — | Jul 10 – Sep 18 | 60–85 |
| Turnip | — | Apr 10 | — | Aug 2 | May 22 – Jun 26 | 40–60 |
| Watercress | Mar 20 | Apr 10 | Apr 24 | Aug 2 | Jun 5 – Jul 10 | 40–60 |
| Watermelon | Mar 20 | May 1 | May 8 | — | Jul 17 – Sep 4 | 70–100 |
| Wax Beans | — | May 1 | — | — | Jun 26 – Aug 21 | 50–65 |
| Winter Melon | Feb 27 | May 1 | May 8 | — | Aug 7 – Sep 25 | 90–120 |
| Yard Long Beans | Feb 27 | May 1 | May 8 | — | Jul 3 – Aug 14 | 55–80 |
| Zucchini | Mar 20 | May 1 | May 8 | — | Jun 26 – Aug 21 | 45–60 |
🍓 Fruits to Grow in Clarke County
27 fruits that grow well in Zone 5b with planting dates for Clarke County.
Show all 27 fruits with planting dates
| Plant | Start Indoors | Direct Sow | Transplant | Fall Plant | Harvest | Days to Maturity |
|---|---|---|---|---|---|---|
| Alpine Strawberries | — | — | May 15 | — | Aug 14 – Oct 30 | 90–180 |
| Aronia | — | — | May 15 | — | — | 730–1095 |
| Blackberries | — | — | May 15 | — | — | 365–730 |
| Blueberries | — | — | May 15 | — | — | 730–1095 |
| Boysenberries | — | — | May 15 | — | — | 365–730 |
| Cantaloupe | — | — | May 15 | — | Jul 24 – Aug 28 | 70–90 |
| Che Fruit | — | — | May 15 | — | — | 1095–1825 |
| Cranberries | — | — | May 15 | — | — | 730–1095 |
| Currants | — | — | May 15 | — | — | 730–1095 |
| Elderberries | — | — | May 15 | — | — | 730–1095 |
| Goji Berries | — | — | May 15 | — | — | 730–1095 |
| Gooseberries | — | — | May 15 | — | — | 730–1095 |
| Grapes | — | — | May 15 | — | — | 730–1095 |
| Ground Cherry | — | — | May 15 | — | Jul 24 – Sep 18 | 65–80 |
| Hardy Kiwi | — | — | May 15 | — | — | 1095–1825 |
| Haskaps | — | — | May 15 | — | — | 730–1095 |
| Honeydew | — | — | May 15 | — | Aug 7 – Sep 18 | 80–110 |
| Jostaberry | — | — | May 15 | — | — | 730–1095 |
| Lingonberries | — | — | May 15 | — | — | 730–1095 |
| Medlar | — | — | May 15 | — | — | 1095–1825 |
| Mulberries | — | — | May 15 | — | — | 730–1825 |
| Pawpaw | — | — | May 15 | — | — | 1095–2555 |
| Persimmon | — | — | May 15 | — | — | 1095–2555 |
| Quince | — | — | May 15 | — | — | 1095–1825 |
| Raspberries | — | — | May 15 | — | — | 365–730 |
| Serviceberries | — | — | May 15 | — | — | 730–1095 |
| Strawberries | — | — | May 15 | — | Aug 14 – Oct 30 | 90–365 |
🌿 Herbs to Grow in Clarke County
34 herbs that grow well in Zone 5b with planting dates for Clarke County.
Show all 34 herbs with planting dates
| Plant | Start Indoors | Direct Sow | Transplant | Fall Plant | Harvest | Days to Maturity |
|---|---|---|---|---|---|---|
| Angelica | Mar 20 | Apr 10 | Apr 17 | Aug 2 | — | 365–730 |
| Anise | Mar 20 | Apr 10 | Apr 17 | Aug 2 | Jul 17 – Oct 2 | 90–120 |
| Basil | Mar 6 | May 1 | May 8 | — | Jul 3 – Sep 4 | 50–75 |
| Bee Balm | — | — | May 1 | — | Jul 31 – Oct 16 | 90–120 |
| Borage | Mar 20 | Apr 10 | Apr 17 | Aug 2 | Jun 12 – Jul 31 | 50–60 |
| Caraway | Mar 20 | Apr 10 | Apr 17 | Aug 2 | — | 365–450 |
| Catnip | — | — | May 1 | — | Jul 3 – Sep 4 | 60–80 |
| Chamomile | Mar 20 | Apr 10 | Apr 17 | Aug 2 | Jun 19 – Aug 28 | 60–90 |
| Chervil | Mar 20 | Apr 10 | Apr 17 | Aug 2 | May 29 – Jul 31 | 40–60 |
| Chives | — | — | May 1 | — | Jul 3 – Sep 11 | 60–90 |
| Cilantro | Mar 20 | Apr 10 | Apr 17 | Aug 2 | May 29 – Jul 31 | 40–60 |
| Comfrey | — | — | May 1 | — | Jul 3 – Sep 11 | 60–90 |
| Cumin | Mar 20 | Apr 10 | Apr 17 | Aug 2 | Jul 31 – Oct 2 | 100–120 |
| Dill | Mar 20 | Apr 10 | Apr 17 | Aug 2 | May 29 – Jul 31 | 40–60 |
| Epazote | Mar 6 | May 1 | May 8 | — | Jun 26 – Aug 21 | 45–60 |
| Fennel (herb) | Mar 20 | Apr 10 | Apr 17 | Aug 2 | Jun 19 – Aug 28 | 60–90 |
| Feverfew | — | — | May 1 | — | Jul 31 – Oct 16 | 90–120 |
| Garlic Chives | — | — | May 1 | — | Jul 3 – Sep 11 | 60–90 |
| Horehound | — | — | May 1 | — | Jul 17 – Sep 11 | 75–90 |
| Hyssop | — | — | May 1 | — | Jul 10 – Sep 11 | 70–90 |
| Lemon Balm | — | — | May 1 | — | Jul 3 – Aug 21 | 60–70 |
| Lemon Thyme | — | — | May 1 | — | Jul 10 – Sep 11 | 70–90 |
| Lovage | — | — | May 1 | — | Jul 10 – Sep 11 | 70–90 |
| Mint | — | — | May 1 | — | Jul 3 – Sep 11 | 60–90 |
| Oregano | — | — | May 1 | — | Jul 3 – Sep 11 | 60–90 |
| Parsley | Mar 20 | Apr 10 | Apr 17 | Aug 2 | Jun 19 – Aug 21 | 60–80 |
| Rue | — | — | May 1 | — | Jul 10 – Sep 11 | 70–90 |
| Sage | — | — | May 1 | — | Jul 17 – Sep 11 | 75–90 |
| Savory | — | — | May 1 | — | Jun 26 – Aug 21 | 50–70 |
| Sorrel | Mar 20 | Apr 10 | Apr 17 | Aug 2 | May 29 – Jul 31 | 40–60 |
| Tarragon | — | — | May 1 | — | Jul 3 – Sep 11 | 60–90 |
| Thai Basil | Mar 6 | May 1 | May 8 | — | Jul 3 – Sep 4 | 50–75 |
| Thyme | — | — | May 1 | — | Jul 10 – Sep 11 | 70–90 |
| Valerian | — | — | May 1 | — | Sep 4 – Oct 16 | 120–180 |
🌸 Flowers to Grow in Clarke County
51 flowers that grow well in Zone 5b with planting dates for Clarke County.
Show all 51 flowers with planting dates
| Plant | Start Indoors | Direct Sow | Transplant | Fall Plant | Bloom | Days to Maturity |
|---|---|---|---|---|---|---|
| Ageratum | Mar 6 | May 1 | May 1 | — | Jun 26 – Sep 25 | 60–75 |
| Alliums | — | — | — | Aug 30 | Oct 4 – Oct 25 | 28–42 |
| Anemones | Mar 27 | — | Apr 24 | — | May 29 – Jun 26 | 90–120 |
| Astilbe | Feb 20 | — | May 8 | — | Jul 24 – Oct 2 | 70–100 |
| Bachelor's Button | Mar 13 | Apr 3 | Apr 24 | — | Jun 26 – Sep 11 | 60–90 |
| Begonias | Feb 13 | — | May 1 | — | Jul 10 – Oct 2 | 70–90 |
| Black-eyed Susan | Feb 20 | Apr 24 | May 8 | — | Jul 24 – Oct 30 | 60–80 |
| Bleeding Hearts | Feb 20 | — | May 8 | — | Jul 3 – Aug 14 | 60–90 |
| Calendula | Mar 13 | Apr 3 | Apr 24 | — | Jun 12 – Sep 11 | 50–70 |
| Celosia | Mar 20 | May 1 | May 1 | — | Jul 3 – Oct 9 | 60–90 |
| Columbine | Feb 20 | May 8 | May 8 | — | Jul 3 – Aug 14 | 70–100 |
| Coreopsis | Feb 20 | May 1 | May 8 | — | Jul 17 – Oct 30 | 60–80 |
| Cosmos | Mar 27 | Apr 24 | Apr 24 | — | Jul 3 – Oct 2 | 60–90 |
| Crocus | — | — | — | Aug 30 | Jul 12 – Aug 2 | 10–20 |
| Daffodils | — | — | — | Aug 30 | Jul 19 – Aug 9 | 20–40 |
| Dahlias | Mar 27 | May 1 | May 1 | — | Jul 24 – Oct 23 | 70–120 |
| Daylily | Feb 20 | — | May 8 | — | Jul 31 – Oct 30 | 60–90 |
| Dianthus | Feb 20 | Mar 27 | Apr 10 | — | May 29 – Aug 21 | 60–80 |
| Echinacea (Purple Coneflower) | Feb 20 | May 8 | May 8 | — | Jul 31 – Oct 30 | 70–90 |
| Foxglove | Feb 20 | May 8 | May 8 | — | Jul 3 – Aug 14 | 80–120 |
| Gaillardia (Blanket Flower) | Feb 27 | May 1 | May 1 | — | Jul 10 – Oct 30 | 70–100 |
| Geraniums | Feb 13 | — | May 1 | — | Jul 10 – Oct 2 | 70–100 |
| Gladiolus | — | May 1 | May 1 | — | Jul 24 – Oct 23 | 70–100 |
| Hostas | Feb 13 | — | May 8 | — | Jul 31 – Oct 30 | 60–90 |
| Hyacinths | — | — | — | Aug 30 | Aug 9 – Sep 6 | 14–28 |
| Hydrangeas | Feb 13 | — | May 8 | — | Jul 24 – Oct 16 | 90–150 |
| Impatiens | Feb 27 | — | May 1 | — | Jul 10 – Oct 9 | 60–75 |
| Irises | — | Division | May 8 | — | Jul 3 – Aug 7 | 60–100 |
| Larkspur | — | Mar 27 | — | — | Jun 5 – Jul 31 | 60–90 |
| Lavender | Feb 13 | — | May 15 | — | Jul 24 – Sep 11 | 90–120 |
| Lilies | — | Division | May 8 | — | Jul 17 – Oct 16 | 70–120 |
| Lobelia | Feb 13 | — | Apr 17 | — | Jun 12 – Aug 28 | 70–80 |
| Lupine | Feb 20 | May 8 | May 8 | — | Jul 3 – Aug 14 | 75–100 |
| Marigolds | Mar 13 | May 1 | May 1 | — | Jun 26 – Sep 25 | 50–70 |
| Nasturtium | Mar 27 | May 1 | May 1 | — | Jun 26 – Oct 9 | 55–65 |
| Pansy | Feb 13 | — | Apr 24 | — | Jun 19 – Aug 21 | 70–90 |
| Peonies | — | Division | May 8 | — | Jul 17 – Aug 28 | 90–120 |
| Petunia | Feb 27 | — | May 1 | — | Jul 10 – Oct 9 | 70–90 |
| Phlox | Feb 20 | May 8 | May 8 | — | Jul 24 – Oct 16 | 80–110 |
| Portulaca | Mar 20 | May 1 | May 1 | — | Jun 19 – Sep 25 | 50–70 |
| Roses | Feb 13 | — | May 8 | — | Jul 24 – Oct 30 | 90–180 |
| Salvia | Feb 20 | — | May 1 | — | Jul 10 – Oct 9 | 70–90 |
| Sedum (Stonecrop) | Feb 20 | — | May 8 | — | Sep 4 – Nov 13 | 60–90 |
| Snapdragon | Feb 13 | Apr 10 | Apr 24 | — | Jul 3 – Sep 11 | 70–100 |
| Sunflower | Apr 3 | May 1 | May 1 | — | Jul 24 – Oct 9 | 70–100 |
| Sweet Alyssum | Mar 6 | Apr 10 | Apr 24 | — | Jun 5 – Aug 14 | 45–60 |
| Sweet Pea | Mar 13 | Mar 20 | Apr 24 | — | Jul 10 – Sep 11 | 65–85 |
| Tulips | — | — | — | Aug 30 | Aug 2 – Aug 23 | 15–30 |
| Vinca (Annual) | Feb 6 | — | May 1 | — | Jul 10 – Oct 2 | 70–90 |
| Yarrow | Feb 20 | Apr 24 | May 8 | — | Jul 17 – Oct 30 | 60–90 |
| Zinnia | Mar 27 | May 1 | May 1 | — | Jul 10 – Oct 9 | 60–70 |
Monthly Planting Guide for Clarke County
Gardening Guides & Resources
Helpful guides from The Ultimate Homestead to improve your garden in Clarke County.
Frequently Asked Questions
What planting zone is Clarke County, IA?
Clarke County is in USDA Hardiness Zone 5b. 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 Clarke County, IA?
Based on 31 years of NOAA weather station data, the median last spring frost in Clarke County falls around April 24. In 8 out of 10 years, last frost lands between April 12 and May 9 — a 27-day window of variability. Use May 9 as your conservative safe-to-plant date for frost-sensitive crops.
When is the first fall frost in Clarke County, IA?
The median first fall frost in Clarke County arrives around October 11. In cold years it can arrive as early as September 23; in mild years as late as October 24. Harvest or protect frost-sensitive crops — tomatoes, peppers, basil, squash — before this date.
How long is the growing season in Clarke County?
Clarke County has a frost-free growing season of approximately 170 days. This is enough time for most warm-season crops including tomatoes, peppers, and squash with proper timing.
What is the soil like in Clarke County for gardening?
Clarke County has predominantly Silt Loam soil with a pH range of 6–6.9 and Well Drained drainage. Most vegetables and herbs grow well with standard composting and seasonal soil amendment.
What is grown commercially in Clarke County?
Clarke County has commercial agriculture that includes Corn, Soybeans, Hay, Wheat, Hogs. These crops reflect the local climate and soil conditions — what succeeds commercially often translates well to home gardens in the same area.
Is Clarke County a good location for home gardening?
Clarke County scores 71/100 (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.
Your Clarke County Garden Planner — Free
A 22-page printable planner built for Clarke County (Zone 5b). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.
The Gardener's Encyclopedia to Companion Planting
The pairings that make vegetables, herbs, and flowers grow better — and the ones that quietly wreck a bed.
- Proven pairings for 200+ vegetables, herbs, flowers, and fruits
- Full seed-starting + planting schedule with timing and spacing
- Bonus: square-foot gardening guide + printable seasonal planners
Seed Saving & Storage Guide
Most saved seeds go bad before next season. This shows exactly when to pick, how to dry, and where to store seeds from 200 plants so yours don't.
- 200 plants, step-by-step: life cycle, pollination type, isolation
- Exact temperature + humidity ranges that keep seeds viable
- Bonus: searchable Google Sheets tracker + custom GPT assistant
Composting Guide for Homesteaders
Turn kitchen scraps and yard waste into compost that actually feeds the garden — instead of a pile that smells, attracts pests, and never breaks down.
- 14 sections on composting methods, soil science, and troubleshooting
- The 7-step hot-compost system from start to finish
- Bonus tools: troubleshooting chart, safety guide, monitoring log