Benton County, IA — Planting Guide
Benton County is in USDA Zone 5a. The average last spring frost is April 28 and the first fall frost is October 9, giving you a growing season of approximately 164 days.
At an elevation of 1,230 ft, Benton County receives approximately 36 in of rainfall annually. Summer highs average 85°F with winter lows around 11°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 14 in warm years to May 12 in cold years. The growing season is trending shorter by about 1.53 days per decade. Benton County scores 67/100 (Good) on the Microclimate Index.
🌡️ Zone
5a (-20°F to -15°F min)
❄️ Last Frost
April 28
🍂 First Frost
October 9
📅 Growing Season
164 days
⛰️ Elevation
1,230 ft
🌧️ Annual Rainfall
36 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 | 1.4 in | 7 days | — | None |
| Feb | 1.6 in | 7 days | — | None |
| Mar | 2.3 in | 10 days | — | None |
| Apr | 3.6 in | 9 days | 0.7 in | Moderate |
| May | 4.4 in | 12 days | — | Low |
| Jun | 4.3 in | 9 days | — | Low |
| Jul | 4.4 in | 8 days | — | Low |
| Aug | 4.1 in | 9 days | 0.2 in | Low |
| Sep | 2.7 in | 8 days | 1.6 in | High |
| Oct | 2.9 in | 7 days | 1.4 in | Moderate |
| Nov | 2.4 in | 7 days | — | None |
| Dec | 1.9 in | 8 days | — | None |
Annual total: 36 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.
Benton County Soil Profile
Soil Type
Silt Loam
Soil pH
5.9-7
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 18 | 159 days |
| Cautious | May 3 | Oct 13 | 163 days |
| Average year | Apr 28 | Oct 9 | 164 days |
| Optimistic | Apr 21 | Oct 4 | 166 days |
| Aggressive (risky) | Apr 14 | Sep 23 | 162 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.
Yes — growing seasons are getting shorter here (about 1.5 days per decade). Use the "Conservative" dates and choose fast-maturing varieties.
Gardening Difficulty Score
Benton County offers good growing conditions. A little planning around frost dates goes a long way.
Local Gardening Help in Benton 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 Benton County's climate and soil.
County Extension Office
Benton 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 Benton County
Finding local nurseries & garden centers in Benton County
Why Buy Local
Local nurseries carry plants that are proven to grow in your area. Staff can give you advice specific to Benton 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 Benton County IA" or "garden center Benton 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 Benton County IA" or check your extension office and local parks department. Facebook groups like "Benton 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
15.1 hours
Summer solstice daylight
Shortest Day
8.9 hours
Winter solstice daylight
Peak Sun Hours
9.8 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 | 9.3 hr | 3.7 hr | Short day |
| February | 10.4 hr | 4.6 hr | Short day |
| March | 11.7 hr | 5.7 hr | Short day |
| April | 13.1 hr | 7.1 hr | Neutral |
| May | 14.4 hr | 8.2 hr | Long day |
| June | 15.1 hr | 9.8 hr | Long day |
| July | 14.8 hr | 9.8 hr | Long day |
| August | 13.7 hr | 8.4 hr | Neutral |
| September | 12.3 hr | 7.3 hr | Neutral |
| October | 10.8 hr | 5.9 hr | Short day |
| November | 9.6 hr | 3.8 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
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 | 21°F | 30°F | ❄️ Dormant | ~36 weeks |
| Feb | 24°F | 30°F | ❄️ Dormant | ~36 weeks |
| Mar | 30°F | 35°F | ❄️ Dormant | ~36 weeks |
| Apr | 45°F | 43°F | 🐢 Slow | ~24 weeks |
| May | 59°F | 55°F | ♻️ Active | ~14 weeks |
| Jun | 68°F | 63°F | 🔥 Peak | ~8 weeks |
| Jul | 78°F | 69°F | 🔥 Peak | ~8 weeks |
| Aug | 79°F | 73°F | 🔥 Peak | ~8 weeks |
| Sep | 68°F | 70°F | 🔥 Peak | ~8 weeks |
| Oct | 58°F | 58°F | ♻️ Active | ~14 weeks |
| Nov | 42°F | 47°F | 🐢 Slow | ~24 weeks |
| Dec | 29°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 Benton County
Computed from local climate patterns — warmer, humid conditions increase pest generations and fungal disease risk.
Insect Pest Pressure
Moderate — common pests appear but manageable with monitoring.
Disease Risk
Moderate — watch for mildew and blight during wet periods.
Seasonal Risk
View 5 common pests in your area
| Pest | Risk Level | Peak Months |
|---|---|---|
| Aphids | Moderate | May, Jun, Jul, Aug |
| Japanese beetles | Moderate | Jun, Jul, Aug |
| Squash bugs | Low | Jun, Jul, Aug |
| Tomato hornworms | Moderate | Jul, Aug |
| Cabbage loopers | Moderate | 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 Benton County
Cover crops protect bare soil, fix nitrogen, suppress weeds, and improve soil structure — with county-specific planting dates.
Spring Cover Crops (3 options) — Build soil before the main growing season
| Crop | Plant By | Terminate | N-Fixing | Soil Benefit |
|---|---|---|---|---|
| Buckwheat | May 4 | Aug 7 | — | Rapid growth, attracts pollinators, suppresses weeds |
| Sorghum-sudan grass | May 4 | Aug 14 | — | Massive biomass, breaks compaction, suppresses nematodes |
| White clover | Apr 3 | Aug 7 | ✓ 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 10 | Sep 18 | — | 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 14 | Apr 14 | ✓ Yes | Fixes nitrogen, good for heavy clay soils |
| Daikon radish | Aug 14 | Apr 7 | — | Deep taproot breaks compaction, excellent for clay soils |
| Hairy vetch | Jul 14 | Apr 7 | ✓ Yes | Excellent nitrogen fixer, good for depleted soils |
| Oats | Sep 8 | Apr 14 | — | Quick biomass, winterkills in cold zones — no spring tillage needed |
| Winter rye | Jul 9 | Apr 7 | — | Suppresses weeds, prevents erosion, breaks up compacted soil |
| Winter wheat | Jul 2 | Apr 14 | — | 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: 12 mph Summer: 9 mph
Fall: 11 mph Winter: 13 mph
Prevailing wind: SW. Moderate wind — consider a temporary windbreak for young seedlings.
Windbreak Benefit
6.8/10
Moderately beneficial — a simple fence or trellis can protect delicate crops from wind stress.
Frost Pocket Risk
Low
Relatively flat terrain (295 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
17,942 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 36.0 inches of rain per year
- A 1,000 sq ft roof can collect roughly 17,942 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 Benton County
Soil Type
Silt Loam
Soil pH 5.9–7 · 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. (36 in. annual rainfall)
Season Tips
164-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 Benton County
106 vegetables that grow well in Zone 5a with planting dates for Benton County.
Show all 106 vegetables with planting dates
| Plant | Start Indoors | Direct Sow | Transplant | Harvest | Days to Maturity |
|---|---|---|---|---|---|
| Acorn Squash | Mar 24 | May 5 | May 12 | Aug 4 – Sep 8 | 80–100 |
| Amaranth | Mar 3 | May 5 | May 12 | Aug 11 – Sep 29 | 90–120 |
| Arugula | Mar 24 | Apr 14 | Apr 28 | Jun 2 – Aug 4 | 30–50 |
| Asparagus | — | — | May 12 | — | 730–1095 |
| Beets | — | Apr 14 | — | Jun 9 – Jul 7 | 50–70 |
| Belgian Endive | Mar 24 | Apr 14 | Apr 28 | Aug 18 – Oct 13 | 110–150 |
| Bitter Melon | Mar 3 | May 5 | May 12 | Jul 14 – Aug 25 | 60–90 |
| Black Beans | — | May 5 | — | Aug 4 – Sep 22 | 90–120 |
| Bok Choy | Mar 24 | Apr 14 | Apr 28 | Jun 9 – Jul 14 | 40–60 |
| Broccoli | Mar 24 | Apr 14 | Apr 28 | Jun 30 – Aug 11 | 60–90 |
| Broccoli Rabe | Mar 24 | Apr 14 | Apr 28 | Jun 9 – Jul 14 | 40–60 |
| Brussels Sprouts | Mar 24 | Apr 14 | Apr 28 | Jul 28 – Sep 22 | 90–130 |
| Butternut Squash | Mar 24 | May 5 | May 12 | Aug 11 – Sep 15 | 85–110 |
| Cabbage | Mar 24 | Apr 14 | Apr 28 | Jun 30 – Aug 25 | 60–100 |
| Calabash | Mar 3 | May 5 | May 12 | Aug 4 – Sep 29 | 80–120 |
| Carrots | — | Apr 14 | — | Jun 16 – Jul 21 | 60–80 |
| Cauliflower | Mar 24 | Apr 14 | Apr 28 | Jun 23 – Aug 25 | 55–100 |
| Celeriac | Mar 24 | Apr 14 | Apr 28 | Aug 11 – Sep 15 | 100–120 |
| Celery | Mar 24 | Apr 14 | Apr 28 | Jul 21 – Sep 15 | 80–120 |
| Celtuce | Mar 24 | Apr 14 | Apr 28 | Jun 30 – Aug 11 | 60–90 |
| Chard | Mar 24 | Apr 14 | Apr 28 | Jun 23 – Aug 11 | 50–60 |
| Chickpeas | Mar 24 | Apr 14 | Apr 28 | Jul 21 – Sep 1 | 80–110 |
| Chicory | Mar 24 | Apr 14 | Apr 28 | Jun 30 – Aug 11 | 60–85 |
| Chinese Cabbage | Mar 24 | Apr 14 | Apr 28 | Jun 23 – Jul 21 | 50–70 |
| Christmas Lima Beans | Mar 3 | May 5 | May 12 | Aug 4 – Sep 8 | 80–100 |
| Collard Greens | Mar 24 | Apr 14 | Apr 28 | Jun 23 – Aug 25 | 55–75 |
| Corn | — | May 5 | — | Jul 7 – Sep 1 | 60–100 |
| Cowpeas | — | May 5 | — | Jul 7 – Aug 18 | 60–90 |
| Cress | Mar 24 | Apr 14 | Apr 28 | May 12 – Jun 2 | 14–21 |
| Crookneck Squash | Mar 24 | May 5 | May 12 | Jun 30 – Jul 28 | 45–60 |
| Crosne | — | Apr 14 | — | Sep 15 – Sep 29 | 150–200 |
| Cucumber | Mar 24 | May 5 | May 12 | Jul 7 – Sep 1 | 50–70 |
| Daikon | — | Apr 14 | — | Jun 9 – Jul 7 | 50–70 |
| Delicata Squash | Mar 24 | May 5 | May 12 | Aug 4 – Sep 8 | 80–100 |
| Edamame | — | May 5 | — | Jul 21 – Sep 1 | 75–100 |
| Eggplant | Feb 17 | May 5 | May 12 | Jul 21 – Sep 22 | 65–85 |
| Endive | Mar 24 | Apr 14 | Apr 28 | Jun 16 – Jul 21 | 45–65 |
| Escarole | Mar 24 | Apr 14 | Apr 28 | Jun 23 – Jul 21 | 50–70 |
| Fava Beans | Mar 24 | Apr 14 | Apr 28 | Jul 14 – Aug 25 | 75–100 |
| Fennel | Mar 3 | May 5 | May 12 | Jul 14 – Aug 25 | 60–90 |
| Garlic | — | — | — | — | 90–240 |
| Green Beans | — | May 5 | — | Jun 30 – Aug 25 | 50–65 |
| Horseradish | — | — | May 12 | Sep 15 – Oct 27 | 120–180 |
| Hot Peppers | Feb 17 | May 5 | May 12 | Jul 21 – Oct 27 | 70–120 |
| Hubbard Squash | Mar 24 | May 5 | May 12 | Aug 25 – Sep 29 | 100–120 |
| Kabocha | Mar 24 | May 5 | May 12 | Aug 11 – Sep 8 | 85–100 |
| Kai Lan | Mar 24 | Apr 14 | Apr 28 | Jun 16 – Jul 14 | 45–60 |
| Kale | Mar 24 | Apr 14 | Apr 28 | Jun 23 – Aug 18 | 50–70 |
| Kidney Beans | — | May 5 | — | Aug 4 – Sep 8 | 85–110 |
| Kohlrabi | Mar 24 | Apr 14 | Apr 28 | Jun 16 – Jul 21 | 45–65 |
| Komatsuna | Mar 24 | Apr 14 | Apr 28 | Jun 2 – Jul 7 | 35–50 |
| Leeks | Mar 24 | Apr 14 | Apr 28 | Jul 28 – Oct 13 | 90–150 |
| Lentils | Mar 24 | Apr 14 | Apr 28 | Jul 21 – Sep 1 | 80–110 |
| Lettuce | Mar 24 | Apr 14 | Apr 28 | Jun 2 – Aug 11 | 30–60 |
| Lima Beans | — | May 5 | — | Jul 7 – Aug 18 | 60–90 |
| Mache | Mar 24 | Apr 14 | Apr 28 | Jun 9 – Jul 14 | 40–60 |
| Melon | Mar 24 | May 5 | May 12 | Jul 21 – Sep 8 | 70–100 |
| Microgreens | Mar 24 | Apr 14 | Apr 28 | May 5 – Jun 2 | 7–21 |
| Mitsuba | Mar 24 | Apr 14 | Apr 21 | Jun 16 – Aug 11 | 50–70 |
| Mizuna | Mar 24 | Apr 14 | Apr 28 | Jun 2 – Jun 30 | 30–45 |
| Mustard Greens | Mar 24 | Apr 14 | Apr 28 | Jun 2 – Aug 4 | 30–50 |
| Napa Cabbage | Mar 24 | Apr 14 | Apr 28 | Jun 23 – Jul 28 | 55–75 |
| New Zealand Spinach | Mar 3 | May 5 | May 12 | Jul 7 – Aug 4 | 55–70 |
| Okra | Mar 3 | May 5 | May 12 | Jul 7 – Sep 1 | 50–65 |
| Onion | Mar 24 | Apr 14 | Apr 28 | Jul 28 – Sep 15 | 90–120 |
| Pac Choi | Mar 24 | Apr 14 | Apr 28 | Jun 9 – Jul 7 | 40–55 |
| Parsnip | — | Apr 14 | — | Jul 28 – Sep 8 | 100–130 |
| Patty Pan Squash | Mar 24 | May 5 | May 12 | Jun 30 – Jul 28 | 45–60 |
| Peas | Mar 24 | Apr 14 | Apr 28 | Jun 23 – Aug 18 | 55–70 |
| Peppers | Feb 17 | May 5 | May 12 | Jul 14 – Sep 22 | 60–90 |
| Pole Beans | Mar 3 | May 5 | May 12 | Jul 7 – Sep 1 | 55–70 |
| Potatoes | Mar 3 | May 5 | May 12 | Jul 21 – Sep 29 | 70–120 |
| Pumpkin | Mar 24 | May 5 | May 12 | Aug 11 – Sep 29 | 85–120 |
| Purslane | Mar 24 | Apr 14 | Apr 28 | Jun 9 – Jul 14 | 40–60 |
| Radicchio | Mar 24 | Apr 14 | Apr 28 | Jun 30 – Aug 4 | 60–80 |
| Radish | — | Apr 14 | — | May 12 – Jun 2 | 22–35 |
| Rhubarb | — | — | May 19 | — | 365–730 |
| Romanesco | Mar 24 | Apr 14 | Apr 28 | Jul 14 – Aug 25 | 75–100 |
| Rutabaga | — | Apr 14 | — | Jul 7 – Aug 11 | 80–100 |
| Salsify | — | Apr 14 | — | Jul 28 – Sep 8 | 100–130 |
| Savoy Cabbage | Mar 24 | Apr 14 | Apr 28 | Jul 7 – Sep 1 | 70–110 |
| Scallions | Mar 24 | Apr 14 | Apr 28 | Jun 23 – Jul 21 | 50–70 |
| Scarlet Runner Beans | Mar 3 | May 5 | May 12 | Jul 14 – Aug 18 | 60–80 |
| Shallot | Mar 24 | Apr 14 | Apr 28 | Jul 28 – Sep 15 | 90–120 |
| Shiso | Mar 10 | May 5 | May 12 | Jul 7 – Sep 1 | 50–70 |
| Snap Peas | Mar 3 | May 5 | May 12 | Jul 7 – Sep 1 | 55–70 |
| Snow Peas | Mar 24 | Apr 14 | Apr 28 | Jun 23 – Aug 18 | 50–65 |
| Soybeans | — | May 5 | — | Jul 28 – Sep 22 | 80–120 |
| Spaghetti Squash | Mar 24 | May 5 | May 12 | Aug 11 – Sep 8 | 85–100 |
| Spinach | Mar 24 | Apr 14 | Apr 28 | Jun 2 – Aug 4 | 35–50 |
| Squash (Summer) | Mar 24 | May 5 | May 12 | Jun 30 – Sep 1 | 45–65 |
| Squash (Winter) | Mar 24 | May 5 | May 12 | Aug 4 – Sep 29 | 80–120 |
| Sunchoke | — | — | May 12 | Sep 1 – Oct 27 | 110–150 |
| Sunflower | Mar 3 | May 5 | May 12 | Jul 21 – Sep 8 | 70–100 |
| Sweet Corn | — | May 5 | — | Jul 7 – Aug 18 | 60–90 |
| Sweet Potatoes | Mar 3 | May 5 | May 12 | Aug 11 – Sep 29 | 90–120 |
| Tatsoi | Mar 24 | Apr 14 | Apr 28 | Jun 2 – Jul 7 | 35–50 |
| Tomatillo | Mar 3 | May 5 | May 12 | Jul 14 – Sep 22 | 60–85 |
| Tomatoes | Mar 3 | May 5 | May 12 | Jul 14 – Sep 22 | 60–85 |
| Turnip | — | Apr 14 | — | May 26 – Jun 30 | 40–60 |
| Watercress | Mar 24 | Apr 14 | Apr 28 | Jun 9 – Jul 14 | 40–60 |
| Watermelon | Mar 24 | May 5 | May 12 | Jul 21 – Sep 8 | 70–100 |
| Wax Beans | — | May 5 | — | Jun 30 – Aug 25 | 50–65 |
| Winter Melon | Mar 3 | May 5 | May 12 | Aug 11 – Sep 29 | 90–120 |
| Yard Long Beans | Mar 3 | May 5 | May 12 | Jul 7 – Aug 18 | 55–80 |
| Zucchini | Mar 24 | May 5 | May 12 | Jun 30 – Aug 25 | 45–60 |
🍓 Fruits to Grow in Benton County
27 fruits that grow well in Zone 5a with planting dates for Benton County.
Show all 27 fruits with planting dates
| Plant | Start Indoors | Direct Sow | Transplant | Harvest | Days to Maturity |
|---|---|---|---|---|---|
| Alpine Strawberries | — | — | May 19 | Aug 18 – Nov 3 | 90–180 |
| Aronia | — | — | May 19 | — | 730–1095 |
| Blackberries | — | — | May 19 | — | 365–730 |
| Blueberries | — | — | May 19 | — | 730–1095 |
| Boysenberries | — | — | May 19 | — | 365–730 |
| Cantaloupe | — | — | May 19 | Jul 28 – Sep 1 | 70–90 |
| Che Fruit | — | — | May 19 | — | 1095–1825 |
| Cranberries | — | — | May 19 | — | 730–1095 |
| Currants | — | — | May 19 | — | 730–1095 |
| Elderberries | — | — | May 19 | — | 730–1095 |
| Goji Berries | — | — | May 19 | — | 730–1095 |
| Gooseberries | — | — | May 19 | — | 730–1095 |
| Grapes | — | — | May 19 | — | 730–1095 |
| Ground Cherry | — | — | May 19 | Jul 28 – Sep 22 | 65–80 |
| Hardy Kiwi | — | — | May 19 | — | 1095–1825 |
| Haskaps | — | — | May 19 | — | 730–1095 |
| Honeydew | — | — | May 19 | Aug 11 – Sep 22 | 80–110 |
| Jostaberry | — | — | May 19 | — | 730–1095 |
| Lingonberries | — | — | May 19 | — | 730–1095 |
| Medlar | — | — | May 19 | — | 1095–1825 |
| Mulberries | — | — | May 19 | — | 730–1825 |
| Pawpaw | — | — | May 19 | — | 1095–2555 |
| Persimmon | — | — | May 19 | — | 1095–2555 |
| Quince | — | — | May 19 | — | 1095–1825 |
| Raspberries | — | — | May 19 | — | 365–730 |
| Serviceberries | — | — | May 19 | — | 730–1095 |
| Strawberries | — | — | May 19 | Aug 18 – Nov 3 | 90–365 |
🌿 Herbs to Grow in Benton County
37 herbs that grow well in Zone 5a with planting dates for Benton County.
Show all 37 herbs with planting dates
| Plant | Start Indoors | Direct Sow | Transplant | Harvest | Days to Maturity |
|---|---|---|---|---|---|
| Angelica | Mar 24 | Apr 14 | Apr 21 | — | 365–730 |
| Anise | Mar 24 | Apr 14 | Apr 21 | Jul 21 – Oct 6 | 90–120 |
| Basil | Mar 10 | May 5 | May 12 | Jul 7 – Sep 8 | 50–75 |
| Bee Balm | — | — | May 5 | Aug 4 – Oct 20 | 90–120 |
| Borage | Mar 24 | Apr 14 | Apr 21 | Jun 16 – Aug 4 | 50–60 |
| Caraway | Mar 24 | Apr 14 | Apr 21 | — | 365–450 |
| Catnip | — | — | May 5 | Jul 7 – Sep 8 | 60–80 |
| Chamomile | Mar 24 | Apr 14 | Apr 21 | Jun 23 – Sep 1 | 60–90 |
| Chervil | Mar 24 | Apr 14 | Apr 21 | Jun 2 – Aug 4 | 40–60 |
| Chives | — | — | May 5 | Jul 7 – Sep 15 | 60–90 |
| Cilantro | Mar 24 | Apr 14 | Apr 21 | Jun 2 – Aug 4 | 40–60 |
| Comfrey | — | — | May 5 | Jul 7 – Sep 15 | 60–90 |
| Cumin | Mar 24 | Apr 14 | Apr 21 | Aug 4 – Oct 6 | 100–120 |
| Dill | Mar 24 | Apr 14 | Apr 21 | Jun 2 – Aug 4 | 40–60 |
| Echinacea | — | — | May 5 | Sep 8 – Oct 20 | 120–180 |
| Epazote | Mar 10 | May 5 | May 12 | Jun 30 – Aug 25 | 45–60 |
| Fennel (herb) | Mar 24 | Apr 14 | Apr 21 | Jun 23 – Sep 1 | 60–90 |
| Feverfew | — | — | May 5 | Aug 4 – Oct 20 | 90–120 |
| Garlic Chives | — | — | May 5 | Jul 7 – Sep 15 | 60–90 |
| Horehound | — | — | May 5 | Jul 21 – Sep 15 | 75–90 |
| Hyssop | — | — | May 5 | Jul 14 – Sep 15 | 70–90 |
| Lavender | — | — | May 5 | Aug 4 – Oct 20 | 90–200 |
| Lemon Balm | — | — | May 5 | Jul 7 – Aug 25 | 60–70 |
| Lemon Thyme | — | — | May 5 | Jul 14 – Sep 15 | 70–90 |
| Lovage | — | — | May 5 | Jul 14 – Sep 15 | 70–90 |
| Mint | — | — | May 5 | Jul 7 – Sep 15 | 60–90 |
| Oregano | — | — | May 5 | Jul 7 – Sep 15 | 60–90 |
| Parsley | Mar 24 | Apr 14 | Apr 21 | Jun 23 – Aug 25 | 60–80 |
| Rue | — | — | May 5 | Jul 14 – Sep 15 | 70–90 |
| Sage | — | — | May 5 | Jul 21 – Sep 15 | 75–90 |
| Savory | — | — | May 5 | Jun 30 – Aug 25 | 50–70 |
| Sorrel | Mar 24 | Apr 14 | Apr 21 | Jun 2 – Aug 4 | 40–60 |
| Tarragon | — | — | May 5 | Jul 7 – Sep 15 | 60–90 |
| Thai Basil | Mar 10 | May 5 | May 12 | Jul 7 – Sep 8 | 50–75 |
| Thyme | — | — | May 5 | Jul 14 – Sep 15 | 70–90 |
| Valerian | — | — | May 5 | Sep 8 – Oct 20 | 120–180 |
| Yarrow | — | — | May 5 | Aug 4 – Oct 20 | 90–120 |
Monthly Planting Guide for Benton County
Gardening Guides & Resources
Helpful guides from The Ultimate Homestead to improve your garden in Benton County.
Frequently Asked Questions
What planting zone is Benton County, IA?
Benton County is in USDA Hardiness Zone 5a. 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 Benton County, IA?
Based on 31 years of NOAA weather station data, the median last spring frost in Benton County falls around April 28. In 8 out of 10 years, last frost lands between April 14 and May 12 — a 27-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 Benton County, IA?
The median first fall frost in Benton County arrives around October 9. In cold years it can arrive as early as September 23; in mild years as late as October 18. Harvest or protect frost-sensitive crops — tomatoes, peppers, basil, squash — before this date.
How long is the growing season in Benton County?
Benton County has a frost-free growing season of approximately 164 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 1.53 days per decade.
What is the soil like in Benton County for gardening?
Benton County has predominantly Silt Loam soil with a pH range of 5.9–7 and Well Drained drainage. Most vegetables and herbs grow well with standard composting and seasonal soil amendment.
What is grown commercially in Benton County?
Benton 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 Benton County a good location for home gardening?
Benton County scores 67/100 (Good) on our Microclimate Index, which combines frost reliability, drought pressure, soil challenge, elevation risk, and long-term climate trend. Conditions here are moderate — most common crops grow well with standard timing and care.
Plan Your Garden with Confidence
Get our free Garden Planner — designed to help Benton County gardeners in Zone 5a 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.
