Clay County, IA — Planting Guide
Clay County is in USDA Zone 4b. 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 984 ft, Clay County receives approximately 34.6 in of rainfall annually. Summer highs average 80°F with winter lows around 1°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 April 12 in warm years to May 12 in cold years. The growing season is trending longer by about 0.8 days per decade. Clay County scores 72/100 (Good) on the Microclimate Index.
🌡️ Zone
4b (-25°F to -20°F min)
❄️ Last Frost
April 24
🍂 First Frost
October 11
📅 Growing Season
170 days
⛰️ Elevation
984 ft
🌧️ Annual Rainfall
34.6 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 | 1.6 in | 7 days | — | None |
| Feb | 1.4 in | 6 days | — | None |
| Mar | 2.5 in | 8 days | — | None |
| Apr | 3.3 in | 10 days | 1 in | Moderate |
| May | 4.1 in | 9 days | 0.2 in | Low |
| Jun | 3.9 in | 8 days | 0.4 in | Low |
| Jul | 3.4 in | 10 days | 0.9 in | Moderate |
| Aug | 3.6 in | 8 days | 0.7 in | Moderate |
| Sep | 3.2 in | 8 days | 1.1 in | Moderate |
| Oct | 2.8 in | 8 days | 1.5 in | Moderate |
| Nov | 2.6 in | 7 days | — | None |
| Dec | 2.2 in | 7 days | — | None |
Annual total: 34.6 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.
Clay County Soil Profile
Soil Type
Silt Loam
Soil pH
6.2-7
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 12 | Oct 27 | 168 days |
| Cautious | May 1 | Oct 16 | 168 days |
| Average year | Apr 24 | Oct 11 | 170 days |
| Optimistic | Apr 17 | Oct 5 | 171 days |
| Aggressive (risky) | Apr 12 | Sep 30 | 171 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.
Slightly — seasons are trending a bit longer (0.8 days/decade). Historical frost dates are still reliable for planning.
Gardening Difficulty Score
Clay County offers good growing conditions. A little planning around frost dates goes a long way.
Local Gardening Help in Clay 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 Clay County's climate and soil.
County Extension Office
Clay 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 Clay County
Finding local nurseries & garden centers in Clay County
Why Buy Local
Local nurseries carry plants that are proven to grow in your area. Staff can give you advice specific to Clay 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 Clay County IA" or "garden center Clay 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 Clay County IA" or check your extension office and local parks department. Facebook groups like "Clay 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
Monthly daylight hours and peak sun — critical for onion varieties, photoperiod-sensitive plants, and solar garden planning.
Longest Day
15.2 hours
Summer solstice daylight
Shortest Day
8.8 hours
Winter solstice daylight
Peak Sun Hours
9.6 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 | 9.2 hr | 3.8 hr | Short day |
| February | 10.3 hr | 4.5 hr | Short day |
| March | 11.6 hr | 5.4 hr | Short day |
| April | 13.2 hr | 6.9 hr | Neutral |
| May | 14.5 hr | 8.5 hr | Long day |
| June | 15.2 hr | 9.2 hr | Long day |
| July | 14.9 hr | 9.6 hr | Long day |
| August | 13.8 hr | 8.7 hr | Neutral |
| September | 12.3 hr | 7.1 hr | Neutral |
| October | 10.8 hr | 5.3 hr | Short day |
| November | 9.5 hr | 3.7 hr | Short day |
| December | 8.8 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
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 | 16°F | 24°F | ❄️ Dormant | ~36 weeks |
| Feb | 15°F | 23°F | ❄️ Dormant | ~36 weeks |
| Mar | 27°F | 28°F | ❄️ Dormant | ~36 weeks |
| Apr | 41°F | 40°F | 🐢 Slow | ~24 weeks |
| May | 55°F | 49°F | ♻️ Active | ~14 weeks |
| Jun | 64°F | 58°F | ♻️ Active | ~14 weeks |
| Jul | 71°F | 68°F | 🔥 Peak | ~8 weeks |
| Aug | 74°F | 69°F | 🔥 Peak | ~8 weeks |
| Sep | 66°F | 66°F | 🔥 Peak | ~8 weeks |
| Oct | 53°F | 56°F | ♻️ Active | ~14 weeks |
| Nov | 38°F | 43°F | ❄️ Dormant | ~36 weeks |
| Dec | 25°F | 31°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 Clay 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 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 | Moderate | Jun, Jul |
| Flea beetles | Low | May, Jun, Jul |
| Slugs | Low | May, Jun, Jul, Aug, Sep |
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 Clay 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 | Apr 25 | Aug 9 | — | Rapid growth, attracts pollinators, suppresses weeds |
| White clover | Mar 24 | Aug 2 | ✓ 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 5 | Sep 27 | — | 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 25 | Apr 3 | — | Deep taproot breaks compaction, excellent for clay soils |
| Hairy vetch | Jul 30 | Apr 3 | ✓ Yes | Excellent nitrogen fixer, good for depleted soils |
| Oats | Aug 31 | Apr 3 | — | Quick biomass, winterkills in cold zones — no spring tillage needed |
| Winter rye | Jul 15 | Apr 3 | — | Suppresses weeds, prevents erosion, breaks up compacted soil |
| Winter wheat | Jul 3 | Apr 3 | — | 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: 12 mph
Prevailing wind: SW. Moderate wind — consider a temporary windbreak for young seedlings.
Windbreak Benefit
5.1/10
Moderately beneficial — a simple fence or trellis can protect delicate crops from wind stress.
Frost Pocket Risk
Low
Relatively flat terrain (139 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
17,244 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 34.6 inches of rain per year
- A 1,000 sq ft roof can collect roughly 17,244 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 Clay County
Soil Type
Silt Loam
Soil pH 6.2–7 · 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. (34.6 in. annual rainfall)
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.
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 Clay County
96 vegetables that grow well in Zone 4b with planting dates for Clay County.
Show all 96 vegetables with planting dates
| Plant | Start Indoors | Direct Sow | Transplant | Harvest | Days to Maturity |
|---|---|---|---|---|---|
| Acorn Squash | Mar 13 | May 8 | May 15 | Aug 7 – Sep 11 | 80–100 |
| Amaranth | Feb 20 | May 8 | May 15 | Aug 14 – Oct 2 | 90–120 |
| Arugula | Mar 13 | Apr 17 | Apr 24 | May 29 – Jul 31 | 30–50 |
| Asparagus | — | — | May 8 | — | 730–1095 |
| Beets | — | Apr 17 | — | Jun 12 – Jul 10 | 50–70 |
| Belgian Endive | Mar 13 | Apr 17 | Apr 24 | Aug 14 – Sep 18 | 110–150 |
| Black Beans | — | May 8 | — | Aug 7 – Sep 25 | 90–120 |
| Bok Choy | Mar 13 | Apr 17 | Apr 24 | Jun 5 – Jul 10 | 40–60 |
| Broccoli | Mar 13 | Apr 17 | Apr 24 | Jun 26 – Aug 7 | 60–90 |
| Broccoli Rabe | Mar 13 | Apr 17 | Apr 24 | Jun 5 – Jul 10 | 40–60 |
| Brussels Sprouts | Mar 13 | Apr 17 | Apr 24 | Jul 24 – Sep 18 | 90–130 |
| Butternut Squash | Mar 13 | May 8 | May 15 | Aug 14 – Sep 18 | 85–110 |
| Cabbage | Mar 13 | Apr 17 | Apr 24 | Jun 26 – Aug 21 | 60–100 |
| Carrots | — | Apr 17 | — | Jun 19 – Jul 24 | 60–80 |
| Cauliflower | Mar 13 | Apr 17 | Apr 24 | Jun 19 – Aug 21 | 55–100 |
| Celeriac | Mar 13 | Apr 17 | Apr 24 | Aug 7 – Sep 11 | 100–120 |
| Celery | Mar 13 | Apr 17 | Apr 24 | Jul 17 – Sep 11 | 80–120 |
| Celtuce | Mar 13 | Apr 17 | Apr 24 | Jun 26 – Aug 7 | 60–90 |
| Chard | Mar 13 | Apr 17 | Apr 24 | Jun 19 – Aug 7 | 50–60 |
| Chickpeas | Mar 13 | Apr 17 | Apr 24 | Jul 17 – Aug 28 | 80–110 |
| Chicory | Mar 13 | Apr 17 | Apr 24 | Jun 26 – Aug 7 | 60–85 |
| Chinese Cabbage | Mar 13 | Apr 17 | Apr 24 | Jun 19 – Jul 17 | 50–70 |
| Christmas Lima Beans | Feb 20 | May 8 | May 15 | Aug 7 – Sep 11 | 80–100 |
| Collard Greens | Mar 13 | Apr 17 | Apr 24 | Jun 19 – Aug 21 | 55–75 |
| Corn | — | May 8 | — | Jul 10 – Sep 4 | 60–100 |
| Cress | Mar 13 | Apr 17 | Apr 24 | May 8 – May 29 | 14–21 |
| Crookneck Squash | Mar 13 | May 8 | May 15 | Jul 3 – Jul 31 | 45–60 |
| Crosne | — | Apr 17 | — | Sep 18 – Sep 11 | 150–200 |
| Cucumber | Mar 13 | May 8 | May 15 | Jul 10 – Sep 4 | 50–70 |
| Daikon | — | Apr 17 | — | Jun 12 – Jul 10 | 50–70 |
| Delicata Squash | Mar 13 | May 8 | May 15 | Aug 7 – Sep 11 | 80–100 |
| Edamame | — | May 8 | — | Jul 24 – Sep 4 | 75–100 |
| Endive | Mar 13 | Apr 17 | Apr 24 | Jun 12 – Jul 17 | 45–65 |
| Escarole | Mar 13 | Apr 17 | Apr 24 | Jun 19 – Jul 17 | 50–70 |
| Fava Beans | Mar 13 | Apr 17 | Apr 24 | Jul 10 – Aug 21 | 75–100 |
| Fennel | Feb 20 | May 8 | May 15 | Jul 17 – Aug 28 | 60–90 |
| Garlic | — | — | — | — | 90–240 |
| Green Beans | — | May 8 | — | Jul 3 – Aug 28 | 50–65 |
| Horseradish | — | — | May 8 | Sep 11 – Oct 2 | 120–180 |
| Hubbard Squash | Mar 13 | May 8 | May 15 | Aug 28 – Oct 2 | 100–120 |
| Kabocha | Mar 13 | May 8 | May 15 | Aug 14 – Sep 11 | 85–100 |
| Kai Lan | Mar 13 | Apr 17 | Apr 24 | Jun 12 – Jul 10 | 45–60 |
| Kale | Mar 13 | Apr 17 | Apr 24 | Jun 19 – Aug 14 | 50–70 |
| Kidney Beans | — | May 8 | — | Aug 7 – Sep 11 | 85–110 |
| Kohlrabi | Mar 13 | Apr 17 | Apr 24 | Jun 12 – Jul 17 | 45–65 |
| Komatsuna | Mar 13 | Apr 17 | Apr 24 | May 29 – Jul 3 | 35–50 |
| Leeks | Mar 13 | Apr 17 | Apr 24 | Jul 24 – Sep 18 | 90–150 |
| Lentils | Mar 13 | Apr 17 | Apr 24 | Jul 17 – Aug 28 | 80–110 |
| Lettuce | Mar 13 | Apr 17 | Apr 24 | May 29 – Aug 7 | 30–60 |
| Lima Beans | — | May 8 | — | Jul 10 – Aug 21 | 60–90 |
| Mache | Mar 13 | Apr 17 | Apr 24 | Jun 5 – Jul 10 | 40–60 |
| Melon | Mar 13 | May 8 | May 15 | Jul 24 – Sep 11 | 70–100 |
| Microgreens | Mar 13 | Apr 17 | Apr 24 | May 1 – May 29 | 7–21 |
| Mitsuba | Mar 13 | Apr 17 | Apr 17 | Jun 12 – Aug 7 | 50–70 |
| Mizuna | Mar 13 | Apr 17 | Apr 24 | May 29 – Jun 26 | 30–45 |
| Mustard Greens | Mar 13 | Apr 17 | Apr 24 | May 29 – Jul 31 | 30–50 |
| Napa Cabbage | Mar 13 | Apr 17 | Apr 24 | Jun 19 – Jul 24 | 55–75 |
| Onion | Mar 13 | Apr 17 | Apr 24 | Jul 24 – Sep 11 | 90–120 |
| Pac Choi | Mar 13 | Apr 17 | Apr 24 | Jun 5 – Jul 3 | 40–55 |
| Parsnip | — | Apr 17 | — | Jul 31 – Sep 11 | 100–130 |
| Patty Pan Squash | Mar 13 | May 8 | May 15 | Jul 3 – Jul 31 | 45–60 |
| Peas | Mar 13 | Apr 17 | Apr 24 | Jun 19 – Aug 14 | 55–70 |
| Peppers | Feb 6 | May 8 | May 15 | Jul 17 – Sep 25 | 60–90 |
| Pole Beans | Feb 20 | May 8 | May 15 | Jul 10 – Sep 4 | 55–70 |
| Potatoes | Feb 20 | May 8 | May 15 | Jul 24 – Oct 2 | 70–120 |
| Pumpkin | Mar 13 | May 8 | May 15 | Aug 14 – Oct 2 | 85–120 |
| Purslane | Mar 13 | Apr 17 | Apr 24 | Jun 5 – Jul 10 | 40–60 |
| Radicchio | Mar 13 | Apr 17 | Apr 24 | Jun 26 – Jul 31 | 60–80 |
| Radish | — | Apr 17 | — | May 15 – Jun 5 | 22–35 |
| Rhubarb | — | — | May 22 | — | 365–730 |
| Romanesco | Mar 13 | Apr 17 | Apr 24 | Jul 10 – Aug 21 | 75–100 |
| Rutabaga | — | Apr 17 | — | Jul 10 – Aug 14 | 80–100 |
| Salsify | — | Apr 17 | — | Jul 31 – Sep 11 | 100–130 |
| Savoy Cabbage | Mar 13 | Apr 17 | Apr 24 | Jul 3 – Aug 28 | 70–110 |
| Scallions | Mar 13 | Apr 17 | Apr 24 | Jun 19 – Jul 17 | 50–70 |
| Scarlet Runner Beans | Feb 20 | May 8 | May 15 | Jul 17 – Aug 21 | 60–80 |
| Shallot | Mar 13 | Apr 17 | Apr 24 | Jul 24 – Sep 11 | 90–120 |
| Shiso | Feb 27 | May 1 | May 15 | Jul 10 – Sep 4 | 50–70 |
| Snap Peas | Feb 20 | May 8 | May 15 | Jul 10 – Sep 4 | 55–70 |
| Snow Peas | Mar 13 | Apr 17 | Apr 24 | Jun 19 – Aug 14 | 50–65 |
| Soybeans | — | May 8 | — | Jul 31 – Sep 25 | 80–120 |
| Spaghetti Squash | Mar 13 | May 8 | May 15 | Aug 14 – Sep 11 | 85–100 |
| Spinach | Mar 13 | Apr 17 | Apr 24 | May 29 – Jul 31 | 35–50 |
| Squash (Summer) | Mar 13 | May 8 | May 15 | Jul 3 – Sep 4 | 45–65 |
| Squash (Winter) | Mar 13 | May 8 | May 15 | Aug 7 – Oct 2 | 80–120 |
| Sunchoke | — | — | May 8 | Aug 28 – Oct 2 | 110–150 |
| Sunflower | Feb 20 | May 8 | May 15 | Jul 24 – Sep 11 | 70–100 |
| Sweet Corn | — | May 8 | — | Jul 10 – Aug 21 | 60–90 |
| Tatsoi | Mar 13 | Apr 17 | Apr 24 | May 29 – Jul 3 | 35–50 |
| Tomatillo | Feb 20 | May 8 | May 15 | Jul 17 – Sep 25 | 60–85 |
| Tomatoes | Feb 20 | May 8 | May 15 | Jul 17 – Sep 25 | 60–85 |
| Turnip | — | Apr 17 | — | May 29 – Jul 3 | 40–60 |
| Watercress | Mar 13 | Apr 17 | Apr 24 | Jun 5 – Jul 10 | 40–60 |
| Watermelon | Mar 13 | May 8 | May 15 | Jul 24 – Sep 11 | 70–100 |
| Wax Beans | — | May 8 | — | Jul 3 – Aug 28 | 50–65 |
| Zucchini | Mar 13 | May 8 | May 15 | Jul 3 – Aug 28 | 45–60 |
🍓 Fruits to Grow in Clay County
22 fruits that grow well in Zone 4b with planting dates for Clay County.
Show all 22 fruits with planting dates
| Plant | Start Indoors | Direct Sow | Transplant | Harvest | Days to Maturity |
|---|---|---|---|---|---|
| Alpine Strawberries | — | — | May 22 | Aug 21 – Oct 16 | 90–180 |
| Aronia | — | — | May 22 | — | 730–1095 |
| Blueberries | — | — | May 22 | — | 730–1095 |
| Cantaloupe | — | — | May 22 | Jul 31 – Sep 4 | 70–90 |
| Cranberries | — | — | May 22 | — | 730–1095 |
| Currants | — | — | May 22 | — | 730–1095 |
| Elderberries | — | — | May 22 | — | 730–1095 |
| Goji Berries | — | — | May 22 | — | 730–1095 |
| Gooseberries | — | — | May 22 | — | 730–1095 |
| Grapes | — | — | May 22 | — | 730–1095 |
| Ground Cherry | — | — | May 22 | Jul 31 – Sep 25 | 65–80 |
| Hardy Kiwi | — | — | May 22 | — | 1095–1825 |
| Haskaps | — | — | May 22 | — | 730–1095 |
| Honeydew | — | — | May 22 | Aug 14 – Sep 25 | 80–110 |
| Jostaberry | — | — | May 22 | — | 730–1095 |
| Lingonberries | — | — | May 22 | — | 730–1095 |
| Medlar | — | — | May 22 | — | 1095–1825 |
| Mulberries | — | — | May 22 | — | 730–1825 |
| Persimmon | — | — | May 22 | — | 1095–2555 |
| Raspberries | — | — | May 22 | — | 365–730 |
| Serviceberries | — | — | May 22 | — | 730–1095 |
| Strawberries | — | — | May 22 | Aug 21 – Oct 16 | 90–365 |
🌿 Herbs to Grow in Clay County
32 herbs that grow well in Zone 4b with planting dates for Clay County.
Show all 32 herbs with planting dates
| Plant | Start Indoors | Direct Sow | Transplant | Harvest | Days to Maturity |
|---|---|---|---|---|---|
| Angelica | Mar 13 | Apr 17 | Apr 17 | — | 365–730 |
| Anise | Mar 13 | Apr 17 | Apr 17 | Jul 17 – Sep 11 | 90–120 |
| Basil | Feb 27 | May 1 | May 15 | Jul 10 – Sep 11 | 50–75 |
| Bee Balm | — | — | May 1 | Jul 31 – Sep 25 | 90–120 |
| Borage | Mar 13 | Apr 17 | Apr 17 | Jun 12 – Jul 31 | 50–60 |
| Caraway | Mar 13 | Apr 17 | Apr 17 | — | 365–450 |
| Catnip | — | — | May 1 | Jul 3 – Sep 4 | 60–80 |
| Chamomile | Mar 13 | Apr 17 | Apr 17 | Jun 19 – Aug 28 | 60–90 |
| Chervil | Mar 13 | Apr 17 | Apr 17 | May 29 – Jul 31 | 40–60 |
| Chives | — | — | May 1 | Jul 3 – Sep 11 | 60–90 |
| Cilantro | Mar 13 | Apr 17 | Apr 17 | May 29 – Jul 31 | 40–60 |
| Comfrey | — | — | May 1 | Jul 3 – Sep 11 | 60–90 |
| Dill | Mar 13 | Apr 17 | Apr 17 | May 29 – Jul 31 | 40–60 |
| Echinacea | — | — | May 1 | Sep 4 – Sep 25 | 120–180 |
| Fennel (herb) | Mar 13 | Apr 17 | Apr 17 | Jun 19 – Aug 28 | 60–90 |
| 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 |
| 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 13 | Apr 17 | Apr 17 | 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 13 | Apr 17 | Apr 17 | May 29 – Jul 31 | 40–60 |
| Tarragon | — | — | May 1 | Jul 3 – Sep 11 | 60–90 |
| Thai Basil | Feb 27 | May 1 | May 15 | Jul 10 – Sep 11 | 50–75 |
| Thyme | — | — | May 1 | Jul 10 – Sep 11 | 70–90 |
| Valerian | — | — | May 1 | Sep 4 – Sep 25 | 120–180 |
| Yarrow | — | — | May 1 | Jul 31 – Sep 25 | 90–120 |
Monthly Planting Guide for Clay County
Gardening Guides & Resources
Helpful guides from The Ultimate Homestead to improve your garden in Clay County.
Frequently Asked Questions
What planting zone is Clay County, IA?
Clay 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 Clay County, IA?
Based on 31 years of NOAA weather station data, the median last spring frost in Clay County falls around April 24. In 8 out of 10 years, last frost lands between April 12 and May 12 — a 30-day window of variability. Use May 12 as your conservative safe-to-plant date for frost-sensitive crops.
When is the first fall frost in Clay County, IA?
The median first fall frost in Clay County arrives around October 11. In cold years it can arrive as early as September 30; in mild years as late as October 27. Harvest or protect frost-sensitive crops — tomatoes, peppers, basil, squash — before this date.
How long is the growing season in Clay County?
Clay 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. Climate records show the growing season is trending longer by about 0.8 days per decade.
What is the soil like in Clay County for gardening?
Clay County has predominantly Silt Loam soil with a pH range of 6.2–7 and Well Drained drainage. Most vegetables and herbs grow well with standard composting and seasonal soil amendment.
What is grown commercially in Clay County?
Clay County has commercial agriculture that includes Soybeans, Corn, 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 Clay County a good location for home gardening?
Clay County scores 72/100 (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 Clay County gardeners in Zone 4b organize planting dates, track what's growing, and never miss a planting window.
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