Hamilton County, IA — Planting Guide
Your June gardening checklist
A quick June briefing for Hamilton County, Iowa gardeners — what's urgent, what's next, and what can wait.
-
Start basil, cucumber, and kale indoors
These need a head start before your last frost (May 1). Sow into cells now so you're ready to transplant in a few weeks.
-
Bring in the carrots, kale, and lettuce
This is the payoff month. Bring a basket, bring a friend, and get into the beds.
Before July arrives, get these ready
- Starting indoors: peppers, astilbe, and begonias
- First harvests: basil, carrots, and cucumber
- Fall sowing: carrots, kale, and lettuce
Hamilton County is in USDA Zone 5a. The average last spring frost is May 1 and the first fall frost is October 7, giving you a growing season of approximately 159 days.
At an elevation of 1,210 ft, Hamilton County receives approximately 35.8 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 27 days year to year — ranging from April 17 in warm years to May 14 in cold years. The growing season is trending shorter by about 2.89 days per decade. Hamilton County scores 57/100 (Moderate) on the Microclimate Index.
🌡️ Zone
5a (-20°F to -15°F min)
❄️ Last Frost
May 1
🍂 First Frost
October 7
📅 Growing Season
159 days
⛰️ Elevation
1,210 ft
🌧️ Annual Rainfall
35.8 in
Monthly Watering Calendar for Hamilton County
When you'll need to water your garden — based on average monthly rainfall vs. the ~1 inch/week most gardens need.
What this means for you: Over-watering kills more plants than under-watering. Hamilton County's 36" annual rainfall changes the gardening playbook — humid-region gardeners often water by the calendar when they should water by the soil moisture.
View detailed monthly data
| Month | Avg Rainfall | Rainy Days | Extra Water Needed | Watering Effort |
|---|---|---|---|---|
| Jan | 1.4 in | 7 days | — | None |
| Feb | 1.5 in | 5 days | — | None |
| Mar | 2.5 in | 9 days | — | None |
| Apr | 3.4 in | 9 days | 0.9 in | Moderate |
| May | 4.1 in | 10 days | 0.2 in | Low |
| Jun | 4.1 in | 9 days | 0.2 in | Low |
| Jul | 4 in | 8 days | 0.3 in | Low |
| Aug | 3.5 in | 8 days | 0.8 in | Moderate |
| Sep | 3.7 in | 7 days | 0.6 in | Moderate |
| Oct | 3.1 in | 7 days | 1.2 in | Moderate |
| Nov | 2.5 in | 7 days | — | None |
| Dec | 1.9 in | 6 days | — | None |
Annual total: 35.7 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.
Hamilton County Soil Profile
Soil Type
Silt Loam
Soil pH
5.8-6.8
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 14 | Oct 16 | 155 days |
| Cautious | May 4 | Oct 11 | 160 days |
| Average year | May 1 | Oct 7 | 159 days |
| Optimistic | Apr 24 | Oct 2 | 161 days |
| Aggressive (risky) | Apr 17 | Sep 21 | 157 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 2.9 days per decade). Use the "Conservative" dates and choose fast-maturing varieties.
Gardening Difficulty Score
Hamilton County presents some gardening challenges. Choose adapted varieties and plan around frost dates.
Local Gardening Help in Hamilton 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 Hamilton County's climate and soil.
County Extension Office
Hamilton 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 Hamilton County
Finding local nurseries & garden centers in Hamilton County
Why Buy Local
Local nurseries carry plants that are proven to grow in your area. Staff can give you advice specific to Hamilton 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 Hamilton County IA" or "garden center Hamilton 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 Hamilton County IA" or check your extension office and local parks department. Facebook groups like "Hamilton 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 Hamilton County
Monthly daylight hours and peak sun — critical for onion varieties, photoperiod-sensitive plants, and solar garden planning.
Why it matters: Onion varieties are sold by "short-day," "intermediate-day," and "long-day." Hamilton County's latitude determines which to buy — and getting it wrong is the difference between baseball-sized bulbs and marbles.
Longest Day
15.1 hours
Summer solstice daylight
Shortest Day
8.9 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 | 3.6 hr | Short day |
| February | 10.3 hr | 4.4 hr | Short day |
| March | 11.7 hr | 5.5 hr | Short day |
| April | 13.2 hr | 6.5 hr | Neutral |
| May | 14.4 hr | 8.4 hr | Long day |
| June | 15.1 hr | 9.6 hr | Long day |
| July | 14.8 hr | 9.5 hr | Long day |
| August | 13.7 hr | 8.5 hr | Neutral |
| September | 12.3 hr | 7 hr | Neutral |
| October | 10.8 hr | 5.6 hr | Short day |
| November | 9.5 hr | 3.7 hr | Short day |
| December | 8.9 hr | 3.3 hr | Short day |
Peak sun hours factor in typical cloud cover — use these for solar panel and shade-planning calculations.
Soil Temperature & Composting in Hamilton County
Monthly soil temps tell you when to plant warm-season crops, and when your compost pile is actively working.
The practical takeaway: Air temperature lies. Your air can be 70°F in April but the soil 4 inches down is still 50°F — too cold for tomatoes or peppers to root properly. Hamilton County's soil temperature curve tells you the real planting window. A $5 soil thermometer pays for itself in one season.
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 | 13°F | 22°F | ❄️ Dormant | ~36 weeks |
| Feb | 15°F | 21°F | ❄️ Dormant | ~36 weeks |
| Mar | 26°F | 29°F | ❄️ Dormant | ~36 weeks |
| Apr | 40°F | 39°F | 🐢 Slow | ~24 weeks |
| May | 53°F | 50°F | ♻️ Active | ~14 weeks |
| Jun | 63°F | 58°F | ♻️ Active | ~14 weeks |
| Jul | 72°F | 65°F | 🔥 Peak | ~8 weeks |
| Aug | 72°F | 68°F | 🔥 Peak | ~8 weeks |
| Sep | 67°F | 63°F | 🔥 Peak | ~8 weeks |
| Oct | 53°F | 54°F | ♻️ Active | ~14 weeks |
| Nov | 37°F | 42°F | ❄️ Dormant | ~36 weeks |
| Dec | 21°F | 30°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 Hamilton County
Computed from local climate patterns — warmer, humid conditions increase pest generations and fungal disease risk.
What this means for you: Pest pressure scales with warmth and humidity. Hot humid Hamilton County sees year-round bugs and fungal disease; cold dry regions see almost none. A high pest score means crop rotation, resistant varieties, and a weekly pest-watch routine from day one.
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 |
| Cabbage worms | Low | Jun, Jul, Aug |
| Colorado potato beetle | Moderate | Jun, Jul |
| Flea beetles | Moderate | May, Jun, Jul |
| Slugs | Low | 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 Hamilton County
Cover crops protect bare soil, fix nitrogen, suppress weeds, and improve soil structure — with planting dates calibrated for your area.
Why this matters: Cover crops fix nitrogen by hosting bacteria that pull it from the air. A vigorous legume cover crop can deliver 50-150 lbs/acre of nitrogen — meaningful for the next vegetable season.
Spring Cover Crops (2 options) — Build soil before the main growing season
| Crop | Plant By | Terminate | N-Fixing | Soil Benefit |
|---|---|---|---|---|
| Buckwheat | May 9 | Aug 12 | — | Rapid growth, attracts pollinators, suppresses weeds |
| White clover | Apr 3 | Aug 12 | ✓ 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 19 | Apr 17 | — | Deep taproot breaks compaction, excellent for clay soils |
| Hairy vetch | Jul 28 | Apr 10 | ✓ Yes | Excellent nitrogen fixer, good for depleted soils |
| Oats | Sep 1 | Apr 17 | — | Quick biomass, winterkills in cold zones — no spring tillage needed |
| Winter rye | Jul 6 | Apr 10 | — | Suppresses weeds, prevents erosion, breaks up compacted soil |
| Winter wheat | Jul 4 | Apr 10 | — | Erosion control, weed suppression, good biomass |
Wind & Microclimate in Hamilton County
The practical takeaway: Pollinators avoid windy days. Hamilton County's 8.5 mph average wind isn't enough to stop bees and butterflies — but plant fruiting crops (tomatoes, peppers, squash) in protected microclimates and you'll see noticeably better fruit set.
Wind dries soil, stresses plants, and affects frost patterns. Understanding your exposure helps with garden placement.
Seasonal Wind Speed
Spring: 11 mph Summer: 9 mph
Fall: 9 mph Winter: 11 mph
Prevailing wind: SW. Moderate wind — consider a temporary windbreak for young seedlings.
Windbreak Benefit
5/10
Moderately beneficial — a simple fence or trellis can protect delicate crops from wind stress.
Frost Pocket Risk
Low
Relatively flat terrain (247 ft range). Frost pocket risk is minimal — garden placement is flexible.
Rainwater Harvesting in Hamilton County
How much water you can collect, when to collect it, and what size system you need for your garden.
For new gardeners: A gravity-fed rain barrel ($75) is the easy entry. A larger cistern ($500-1500) covers a whole growing season. Hamilton County's 36" annual rainfall determines whether the larger system is overkill or essential.
Annual Collection
17,792 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, Sep
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 35.7 inches of rain per year
- A 1,000 sq ft roof can collect roughly 17,792 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 Hamilton County
Soil Type
Silt Loam
Soil pH 5.8–6.8 · 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
159-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 Hamilton County
105 vegetables that grow well in Zone 5a with planting dates for Hamilton County.
Show all 105 vegetables with planting dates
| Plant | Start Indoors | Direct Sow | Transplant | Fall Plant | Harvest | Days to Maturity |
|---|---|---|---|---|---|---|
| Acorn Squash | Mar 27 | May 8 | May 15 | — | Aug 7 – Sep 11 | 80–100 |
| Amaranth | Mar 6 | May 8 | May 15 | — | Aug 14 – Oct 2 | 90–120 |
| Arugula | Mar 27 | Apr 17 | May 1 | Jul 29 | Jun 5 – Aug 7 | 30–50 |
| Asparagus | — | — | May 15 | — | — | 730–1095 |
| Beets | — | Apr 17 | — | Jul 29 | Jun 12 – Jul 10 | 50–70 |
| Belgian Endive | Mar 27 | Apr 17 | May 1 | Jul 29 | Aug 21 – Oct 16 | 110–150 |
| Bitter Melon | Mar 6 | May 8 | May 15 | — | Jul 17 – Aug 28 | 60–90 |
| Black Beans | — | May 8 | — | — | Aug 7 – Sep 25 | 90–120 |
| Bok Choy | Mar 27 | Apr 17 | May 1 | Jul 29 | Jun 12 – Jul 17 | 40–60 |
| Broccoli | Mar 27 | Apr 17 | May 1 | Jul 29 | Jul 3 – Aug 14 | 60–90 |
| Broccoli Rabe | Mar 27 | Apr 17 | May 1 | Jul 29 | Jun 12 – Jul 17 | 40–60 |
| Brussels Sprouts | Mar 27 | Apr 17 | May 1 | Jul 29 | Jul 31 – Sep 25 | 90–130 |
| Butternut Squash | Mar 27 | May 8 | May 15 | — | Aug 14 – Sep 18 | 85–110 |
| Cabbage | Mar 27 | Apr 17 | May 1 | Jul 29 | Jul 3 – Aug 28 | 60–100 |
| Calabash | Mar 6 | May 8 | May 15 | — | Aug 7 – Oct 2 | 80–120 |
| Carrots | — | Apr 17 | — | Jul 29 | Jun 19 – Jul 24 | 60–80 |
| Cauliflower | Mar 27 | Apr 17 | May 1 | Jul 29 | Jun 26 – Aug 28 | 55–100 |
| Celeriac | Mar 27 | Apr 17 | May 1 | Jul 29 | Aug 14 – Sep 18 | 100–120 |
| Celery | Mar 27 | Apr 17 | May 1 | Jul 29 | Jul 24 – Sep 18 | 80–120 |
| Celtuce | Mar 27 | Apr 17 | May 1 | Jul 29 | Jul 3 – Aug 14 | 60–90 |
| Chard | Mar 27 | Apr 17 | May 1 | Jul 29 | Jun 26 – Aug 14 | 50–60 |
| Chickpeas | Mar 27 | Apr 17 | May 1 | Jul 29 | Jul 24 – Sep 4 | 80–110 |
| Chicory | Mar 27 | Apr 17 | May 1 | Jul 29 | Jul 3 – Aug 14 | 60–85 |
| Chinese Cabbage | Mar 27 | Apr 17 | May 1 | Jul 29 | Jun 26 – Jul 24 | 50–70 |
| Christmas Lima Beans | Mar 6 | May 8 | May 15 | — | Aug 7 – Sep 11 | 80–100 |
| Collard Greens | Mar 27 | Apr 17 | May 1 | Jul 29 | Jun 26 – Aug 28 | 55–75 |
| Corn | — | May 8 | — | — | Jul 10 – Sep 4 | 60–100 |
| Cowpeas | — | May 8 | — | — | Jul 10 – Aug 21 | 60–90 |
| Cress | Mar 27 | Apr 17 | May 1 | Jul 29 | May 15 – Jun 5 | 14–21 |
| Crookneck Squash | Mar 27 | May 8 | May 15 | — | Jul 3 – Jul 31 | 45–60 |
| Crosne | — | Apr 17 | — | Jul 29 | Sep 18 – Oct 2 | 150–200 |
| Cucumber | Mar 27 | May 8 | May 15 | — | Jul 10 – Sep 4 | 50–70 |
| Daikon | — | Apr 17 | — | Jul 29 | Jun 12 – Jul 10 | 50–70 |
| Delicata Squash | Mar 27 | May 8 | May 15 | — | Aug 7 – Sep 11 | 80–100 |
| Edamame | — | May 8 | — | — | Jul 24 – Sep 4 | 75–100 |
| Eggplant | Feb 20 | May 8 | May 15 | — | Jul 24 – Sep 25 | 65–85 |
| Endive | Mar 27 | Apr 17 | May 1 | Jul 29 | Jun 19 – Jul 24 | 45–65 |
| Escarole | Mar 27 | Apr 17 | May 1 | Jul 29 | Jun 26 – Jul 24 | 50–70 |
| Fava Beans | Mar 27 | Apr 17 | May 1 | Jul 29 | Jul 17 – Aug 28 | 75–100 |
| Fennel | Mar 6 | May 8 | May 15 | — | Jul 17 – Aug 28 | 60–90 |
| Garlic | — | — | — | Aug 26 | Nov 25 – Feb 10 | 90–240 |
| Green Beans | — | May 8 | — | — | Jul 3 – Aug 28 | 50–65 |
| Horseradish | — | — | May 15 | — | Sep 18 – Oct 30 | 120–180 |
| Hot Peppers | Feb 20 | May 8 | May 15 | — | Jul 24 – Oct 30 | 70–120 |
| Hubbard Squash | Mar 27 | May 8 | May 15 | — | Aug 28 – Oct 2 | 100–120 |
| Kabocha | Mar 27 | May 8 | May 15 | — | Aug 14 – Sep 11 | 85–100 |
| Kai Lan | Mar 27 | Apr 17 | May 1 | Jul 29 | Jun 19 – Jul 17 | 45–60 |
| Kale | Mar 27 | Apr 17 | May 1 | Jul 29 | Jun 26 – Aug 21 | 50–70 |
| Kidney Beans | — | May 8 | — | — | Aug 7 – Sep 11 | 85–110 |
| Kohlrabi | Mar 27 | Apr 17 | May 1 | Jul 29 | Jun 19 – Jul 24 | 45–65 |
| Komatsuna | Mar 27 | Apr 17 | May 1 | Jul 29 | Jun 5 – Jul 10 | 35–50 |
| Leeks | Mar 27 | Apr 17 | May 1 | Jul 29 | Jul 31 – Oct 16 | 90–150 |
| Lentils | Mar 27 | Apr 17 | May 1 | Jul 29 | Jul 24 – Sep 4 | 80–110 |
| Lettuce | Mar 27 | Apr 17 | May 1 | Jul 29 | Jun 5 – Aug 14 | 30–60 |
| Lima Beans | — | May 8 | — | — | Jul 10 – Aug 21 | 60–90 |
| Mache | Mar 27 | Apr 17 | May 1 | Jul 29 | Jun 12 – Jul 17 | 40–60 |
| Melon | Mar 27 | May 8 | May 15 | — | Jul 24 – Sep 11 | 70–100 |
| Microgreens | Mar 27 | Apr 17 | May 1 | Jul 29 | May 8 – Jun 5 | 7–21 |
| Mitsuba | Mar 27 | Apr 17 | Apr 24 | Jul 29 | Jun 19 – Aug 14 | 50–70 |
| Mizuna | Mar 27 | Apr 17 | May 1 | Jul 29 | Jun 5 – Jul 3 | 30–45 |
| Mustard Greens | Mar 27 | Apr 17 | May 1 | Jul 29 | Jun 5 – Aug 7 | 30–50 |
| Napa Cabbage | Mar 27 | Apr 17 | May 1 | Jul 29 | Jun 26 – Jul 31 | 55–75 |
| New Zealand Spinach | Mar 6 | May 8 | May 15 | — | Jul 10 – Aug 7 | 55–70 |
| Okra | Mar 6 | May 8 | May 15 | — | Jul 10 – Sep 4 | 50–65 |
| Onion | Mar 27 | Apr 17 | May 1 | Jul 29 | Jul 31 – Sep 18 | 90–120 |
| Pac Choi | Mar 27 | Apr 17 | May 1 | Jul 29 | Jun 12 – Jul 10 | 40–55 |
| Parsnip | — | Apr 17 | — | Jul 29 | Jul 31 – Sep 11 | 100–130 |
| Patty Pan Squash | Mar 27 | May 8 | May 15 | — | Jul 3 – Jul 31 | 45–60 |
| Peas | Mar 27 | Apr 17 | May 1 | Jul 29 | Jun 26 – Aug 21 | 55–70 |
| Peppers | Feb 20 | May 8 | May 15 | — | Jul 17 – Sep 25 | 60–90 |
| Pole Beans | Mar 6 | May 8 | May 15 | — | Jul 10 – Sep 4 | 55–70 |
| Potatoes | Mar 6 | May 8 | May 15 | — | Jul 24 – Oct 2 | 70–120 |
| Pumpkin | Mar 27 | May 8 | May 15 | — | Aug 14 – Oct 2 | 85–120 |
| Purslane | Mar 27 | Apr 17 | May 1 | Jul 29 | Jun 12 – Jul 17 | 40–60 |
| Radicchio | Mar 27 | Apr 17 | May 1 | Jul 29 | Jul 3 – Aug 7 | 60–80 |
| Radish | — | Apr 17 | — | Jul 29 | May 15 – Jun 5 | 22–35 |
| Rhubarb | — | — | May 22 | — | — | 365–730 |
| Romanesco | Mar 27 | Apr 17 | May 1 | Jul 29 | Jul 17 – Aug 28 | 75–100 |
| Rutabaga | — | Apr 17 | — | Jul 29 | Jul 10 – Aug 14 | 80–100 |
| Salsify | — | Apr 17 | — | Jul 29 | Jul 31 – Sep 11 | 100–130 |
| Savoy Cabbage | Mar 27 | Apr 17 | May 1 | Jul 29 | Jul 10 – Sep 4 | 70–110 |
| Scallions | Mar 27 | Apr 17 | May 1 | Jul 29 | Jun 26 – Jul 24 | 50–70 |
| Scarlet Runner Beans | Mar 6 | May 8 | May 15 | — | Jul 17 – Aug 21 | 60–80 |
| Shallot | Mar 27 | Apr 17 | May 1 | Jul 29 | Jul 31 – Sep 18 | 90–120 |
| Shiso | Mar 13 | May 8 | May 15 | — | Jul 10 – Sep 4 | 50–70 |
| Snap Peas | Mar 6 | May 8 | May 15 | — | Jul 10 – Sep 4 | 55–70 |
| Snow Peas | Mar 27 | Apr 17 | May 1 | Jul 29 | Jun 26 – Aug 21 | 50–65 |
| Soybeans | — | May 8 | — | — | Jul 31 – Sep 25 | 80–120 |
| Spaghetti Squash | Mar 27 | May 8 | May 15 | — | Aug 14 – Sep 11 | 85–100 |
| Spinach | Mar 27 | Apr 17 | May 1 | Jul 29 | Jun 5 – Aug 7 | 35–50 |
| Squash (Summer) | Mar 27 | May 8 | May 15 | — | Jul 3 – Sep 4 | 45–65 |
| Squash (Winter) | Mar 27 | May 8 | May 15 | — | Aug 7 – Oct 2 | 80–120 |
| Sunchoke | — | — | May 15 | — | Sep 4 – Oct 30 | 110–150 |
| Sweet Corn | — | May 8 | — | — | Jul 10 – Aug 21 | 60–90 |
| Sweet Potatoes | Mar 6 | May 8 | May 15 | — | Aug 14 – Oct 2 | 90–120 |
| Tatsoi | Mar 27 | Apr 17 | May 1 | Jul 29 | Jun 5 – Jul 10 | 35–50 |
| Tomatillo | Mar 6 | May 8 | May 15 | — | Jul 17 – Sep 25 | 60–85 |
| Tomatoes | Mar 6 | May 8 | May 15 | — | Jul 17 – Sep 25 | 60–85 |
| Turnip | — | Apr 17 | — | Jul 29 | May 29 – Jul 3 | 40–60 |
| Watercress | Mar 27 | Apr 17 | May 1 | Jul 29 | Jun 12 – Jul 17 | 40–60 |
| Watermelon | Mar 27 | May 8 | May 15 | — | Jul 24 – Sep 11 | 70–100 |
| Wax Beans | — | May 8 | — | — | Jul 3 – Aug 28 | 50–65 |
| Winter Melon | Mar 6 | May 8 | May 15 | — | Aug 14 – Oct 2 | 90–120 |
| Yard Long Beans | Mar 6 | May 8 | May 15 | — | Jul 10 – Aug 21 | 55–80 |
| Zucchini | Mar 27 | May 8 | May 15 | — | Jul 3 – Aug 28 | 45–60 |
🍓 Fruits to Grow in Hamilton County
27 fruits that grow well in Zone 5a with planting dates for Hamilton County.
Show all 27 fruits with planting dates
| Plant | Start Indoors | Direct Sow | Transplant | Fall Plant | Harvest | Days to Maturity |
|---|---|---|---|---|---|---|
| Alpine Strawberries | — | — | May 22 | — | Aug 21 – Nov 6 | 90–180 |
| Aronia | — | — | May 22 | — | — | 730–1095 |
| Blackberries | — | — | May 22 | — | — | 365–730 |
| Blueberries | — | — | May 22 | — | — | 730–1095 |
| Boysenberries | — | — | May 22 | — | — | 365–730 |
| Cantaloupe | — | — | May 22 | — | Jul 31 – Sep 4 | 70–90 |
| Che Fruit | — | — | May 22 | — | — | 1095–1825 |
| 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 |
| Pawpaw | — | — | May 22 | — | — | 1095–2555 |
| Persimmon | — | — | May 22 | — | — | 1095–2555 |
| Quince | — | — | May 22 | — | — | 1095–1825 |
| Raspberries | — | — | May 22 | — | — | 365–730 |
| Serviceberries | — | — | May 22 | — | — | 730–1095 |
| Strawberries | — | — | May 22 | — | Aug 21 – Nov 6 | 90–365 |
🌿 Herbs to Grow in Hamilton County
34 herbs that grow well in Zone 5a with planting dates for Hamilton County.
Show all 34 herbs with planting dates
| Plant | Start Indoors | Direct Sow | Transplant | Fall Plant | Harvest | Days to Maturity |
|---|---|---|---|---|---|---|
| Angelica | Mar 27 | Apr 17 | Apr 24 | Jul 29 | — | 365–730 |
| Anise | Mar 27 | Apr 17 | Apr 24 | Jul 29 | Jul 24 – Oct 9 | 90–120 |
| Basil | Mar 13 | May 8 | May 15 | — | Jul 10 – Sep 11 | 50–75 |
| Bee Balm | — | — | May 8 | — | Aug 7 – Oct 23 | 90–120 |
| Borage | Mar 27 | Apr 17 | Apr 24 | Jul 29 | Jun 19 – Aug 7 | 50–60 |
| Caraway | Mar 27 | Apr 17 | Apr 24 | Jul 29 | — | 365–450 |
| Catnip | — | — | May 8 | — | Jul 10 – Sep 11 | 60–80 |
| Chamomile | Mar 27 | Apr 17 | Apr 24 | Jul 29 | Jun 26 – Sep 4 | 60–90 |
| Chervil | Mar 27 | Apr 17 | Apr 24 | Jul 29 | Jun 5 – Aug 7 | 40–60 |
| Chives | — | — | May 8 | — | Jul 10 – Sep 18 | 60–90 |
| Cilantro | Mar 27 | Apr 17 | Apr 24 | Jul 29 | Jun 5 – Aug 7 | 40–60 |
| Comfrey | — | — | May 8 | — | Jul 10 – Sep 18 | 60–90 |
| Cumin | Mar 27 | Apr 17 | Apr 24 | Jul 29 | Aug 7 – Oct 9 | 100–120 |
| Dill | Mar 27 | Apr 17 | Apr 24 | Jul 29 | Jun 5 – Aug 7 | 40–60 |
| Epazote | Mar 13 | May 8 | May 15 | — | Jul 3 – Aug 28 | 45–60 |
| Fennel (herb) | Mar 27 | Apr 17 | Apr 24 | Jul 29 | Jun 26 – Sep 4 | 60–90 |
| Feverfew | — | — | May 8 | — | Aug 7 – Oct 23 | 90–120 |
| Garlic Chives | — | — | May 8 | — | Jul 10 – Sep 18 | 60–90 |
| Horehound | — | — | May 8 | — | Jul 24 – Sep 18 | 75–90 |
| Hyssop | — | — | May 8 | — | Jul 17 – Sep 18 | 70–90 |
| Lemon Balm | — | — | May 8 | — | Jul 10 – Aug 28 | 60–70 |
| Lemon Thyme | — | — | May 8 | — | Jul 17 – Sep 18 | 70–90 |
| Lovage | — | — | May 8 | — | Jul 17 – Sep 18 | 70–90 |
| Mint | — | — | May 8 | — | Jul 10 – Sep 18 | 60–90 |
| Oregano | — | — | May 8 | — | Jul 10 – Sep 18 | 60–90 |
| Parsley | Mar 27 | Apr 17 | Apr 24 | Jul 29 | Jun 26 – Aug 28 | 60–80 |
| Rue | — | — | May 8 | — | Jul 17 – Sep 18 | 70–90 |
| Sage | — | — | May 8 | — | Jul 24 – Sep 18 | 75–90 |
| Savory | — | — | May 8 | — | Jul 3 – Aug 28 | 50–70 |
| Sorrel | Mar 27 | Apr 17 | Apr 24 | Jul 29 | Jun 5 – Aug 7 | 40–60 |
| Tarragon | — | — | May 8 | — | Jul 10 – Sep 18 | 60–90 |
| Thai Basil | Mar 13 | May 8 | May 15 | — | Jul 10 – Sep 11 | 50–75 |
| Thyme | — | — | May 8 | — | Jul 17 – Sep 18 | 70–90 |
| Valerian | — | — | May 8 | — | Sep 11 – Oct 23 | 120–180 |
🌸 Flowers to Grow in Hamilton County
51 flowers that grow well in Zone 5a with planting dates for Hamilton County.
Show all 51 flowers with planting dates
| Plant | Start Indoors | Direct Sow | Transplant | Fall Plant | Bloom | Days to Maturity |
|---|---|---|---|---|---|---|
| Ageratum | Mar 13 | May 8 | May 8 | — | Jul 3 – Sep 25 | 60–75 |
| Alliums | — | — | — | Aug 26 | Sep 30 – Oct 28 | 28–42 |
| Anemones | Apr 3 | — | May 1 | — | Jun 12 – Jul 10 | 90–120 |
| Astilbe | Feb 27 | — | May 15 | — | Jul 31 – Oct 2 | 70–100 |
| Bachelor's Button | Mar 20 | Apr 10 | May 1 | — | Jul 3 – Sep 11 | 60–90 |
| Begonias | Feb 20 | — | May 8 | — | Jul 17 – Oct 9 | 70–90 |
| Black-eyed Susan | Feb 27 | May 1 | May 15 | — | Jul 31 – Oct 30 | 60–80 |
| Bleeding Hearts | Feb 27 | — | May 15 | — | Jul 10 – Aug 21 | 60–90 |
| Calendula | Mar 20 | Apr 10 | May 1 | — | Jun 19 – Sep 11 | 50–70 |
| Celosia | Mar 27 | May 15 | May 15 | — | Jul 17 – Oct 16 | 60–90 |
| Columbine | Feb 27 | May 15 | May 15 | — | Jul 10 – Aug 21 | 70–100 |
| Coreopsis | Feb 27 | May 8 | May 15 | — | Jul 24 – Oct 30 | 60–80 |
| Cosmos | Apr 3 | May 8 | May 8 | — | Jul 17 – Oct 9 | 60–90 |
| Crocus | — | — | — | Aug 26 | Jul 8 – Jul 29 | 10–20 |
| Daffodils | — | — | — | Aug 26 | Jul 15 – Aug 5 | 20–40 |
| Dahlias | Apr 3 | May 8 | May 8 | — | Jul 31 – Oct 23 | 70–120 |
| Daylily | Feb 27 | — | May 15 | — | Aug 7 – Oct 30 | 60–90 |
| Dianthus | Feb 27 | Apr 3 | Apr 17 | — | Jun 5 – Aug 21 | 60–80 |
| Echinacea (Purple Coneflower) | Feb 27 | May 15 | May 15 | — | Aug 7 – Oct 30 | 70–90 |
| Foxglove | Feb 27 | May 15 | May 15 | — | Jul 10 – Aug 21 | 80–120 |
| Gaillardia (Blanket Flower) | Mar 6 | May 15 | May 15 | — | Jul 24 – Nov 13 | 70–100 |
| Geraniums | Feb 20 | — | May 8 | — | Jul 17 – Oct 9 | 70–100 |
| Gladiolus | — | May 8 | May 8 | — | Jul 31 – Oct 23 | 70–100 |
| Hostas | Feb 20 | — | May 15 | — | Aug 7 – Oct 30 | 60–90 |
| Hyacinths | — | — | — | Aug 26 | Aug 5 – Sep 2 | 14–28 |
| Hydrangeas | Feb 20 | — | May 15 | — | Jul 31 – Oct 16 | 90–150 |
| Impatiens | Mar 6 | — | May 8 | — | Jul 17 – Oct 9 | 60–75 |
| Irises | — | Division | May 15 | — | Jul 10 – Aug 14 | 60–100 |
| Larkspur | — | Apr 3 | — | — | Jun 12 – Aug 7 | 60–90 |
| Lavender | Feb 20 | — | May 22 | — | Jul 31 – Sep 11 | 90–120 |
| Lilies | — | Division | May 15 | — | Jul 24 – Oct 16 | 70–120 |
| Lobelia | Feb 20 | — | Apr 24 | — | Jun 19 – Aug 28 | 70–80 |
| Lupine | Feb 27 | May 15 | May 15 | — | Jul 10 – Aug 21 | 75–100 |
| Marigolds | Mar 20 | May 8 | May 8 | — | Jul 3 – Sep 25 | 50–70 |
| Nasturtium | Apr 3 | May 8 | May 8 | — | Jul 3 – Oct 9 | 55–65 |
| Pansy | Feb 20 | — | May 1 | — | Jun 26 – Aug 21 | 70–90 |
| Peonies | — | Division | May 15 | — | Jul 24 – Sep 4 | 90–120 |
| Petunia | Mar 6 | — | May 8 | — | Jul 17 – Oct 9 | 70–90 |
| Phlox | Feb 27 | May 15 | May 15 | — | Jul 31 – Oct 16 | 80–110 |
| Portulaca | Mar 27 | May 15 | May 15 | — | Jul 3 – Oct 2 | 50–70 |
| Roses | Feb 20 | — | May 15 | — | Jul 31 – Oct 30 | 90–180 |
| Salvia | Feb 27 | — | May 8 | — | Jul 17 – Oct 9 | 70–90 |
| Sedum (Stonecrop) | Feb 27 | — | May 15 | — | Sep 11 – Nov 13 | 60–90 |
| Snapdragon | Feb 20 | Apr 17 | May 1 | — | Jul 10 – Sep 11 | 70–100 |
| Sunflower | Apr 10 | May 8 | May 8 | — | Jul 31 – Oct 9 | 70–100 |
| Sweet Alyssum | Mar 13 | Apr 17 | May 1 | — | Jun 12 – Aug 21 | 45–60 |
| Sweet Pea | Mar 20 | Mar 27 | May 1 | — | Jul 17 – Sep 18 | 65–85 |
| Tulips | — | — | — | Aug 26 | Jul 29 – Aug 19 | 15–30 |
| Vinca (Annual) | Feb 13 | — | May 15 | — | Jul 24 – Oct 9 | 70–90 |
| Yarrow | Feb 27 | May 1 | May 15 | — | Jul 24 – Oct 30 | 60–90 |
| Zinnia | Apr 3 | May 8 | May 8 | — | Jul 17 – Oct 9 | 60–70 |
Monthly Planting Guide for Hamilton County
Gardening Guides & Resources
Helpful guides from The Ultimate Homestead to improve your garden in Hamilton County.
Frequently Asked Questions
What planting zone is Hamilton County, IA?
Hamilton 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 Hamilton County, IA?
Based on 31 years of NOAA weather station data, the median last spring frost in Hamilton County falls around May 1. In 8 out of 10 years, last frost lands between April 17 and May 14 — a 27-day window of variability. Use May 14 as your conservative safe-to-plant date for frost-sensitive crops.
When is the first fall frost in Hamilton County, IA?
The median first fall frost in Hamilton 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 Hamilton County?
Hamilton County has a frost-free growing season of approximately 159 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 2.89 days per decade.
What is the soil like in Hamilton County for gardening?
Hamilton County has predominantly Silt Loam soil with a pH range of 5.8–6.8 and Well Drained drainage. Most vegetables and herbs grow well with standard composting and seasonal soil amendment.
What is grown commercially in Hamilton County?
Hamilton County has commercial agriculture that includes Corn, Soybeans, Hay, Wheat. These crops reflect the local climate and soil conditions — what succeeds commercially often translates well to home gardens in the same area.
Is Hamilton County a good location for home gardening?
Hamilton County scores 57/100 (Moderate) 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.
Your Hamilton County Garden Planner — Free
A 22-page printable planner built for Hamilton County (Zone 5a). 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