Delaware County, IA — Planting Guide
Delaware County is in USDA Zone 4b. The average last spring frost is May 2 and the first fall frost is October 7, giving you a growing season of approximately 158 days.
At an elevation of 974 ft, Delaware County receives approximately 31.3 in of rainfall annually. Summer highs average 83°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 28 days year to year — ranging from April 17 in warm years to May 16 in cold years. The growing season is trending shorter by about 1.8 days per decade. Delaware County scores 66/100 (Good) on the Microclimate Index.
🌡️ Zone
4b (-25°F to -20°F min)
❄️ Last Frost
May 2
🍂 First Frost
October 7
📅 Growing Season
158 days
⛰️ Elevation
974 ft
🌧️ Annual Rainfall
31.3 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 | 1.2 in | 7 days | — | None |
| Feb | 1.4 in | 7 days | — | None |
| Mar | 2.2 in | 9 days | — | None |
| Apr | 3.4 in | 10 days | 0.9 in | Moderate |
| May | 3.2 in | 11 days | 1.1 in | Moderate |
| Jun | 4.2 in | 9 days | 0.1 in | Low |
| Jul | 3.9 in | 9 days | 0.4 in | Low |
| Aug | 3.5 in | 7 days | 0.8 in | Moderate |
| Sep | 2.6 in | 9 days | 1.7 in | High |
| Oct | 2.1 in | 8 days | 2.2 in | High |
| Nov | 1.8 in | 7 days | — | None |
| Dec | 1.7 in | 8 days | — | None |
Annual total: 31.2 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.
Delaware County Soil Profile
Soil Type
Silt Loam
Soil pH
6-6.8
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 16 | Oct 16 | 153 days |
| Cautious | May 11 | Oct 11 | 153 days |
| Average year | May 2 | Oct 7 | 158 days |
| Optimistic | Apr 25 | Sep 30 | 158 days |
| Aggressive (risky) | Apr 17 | Sep 21 | 157 days |
Not very — frost dates can vary by ±28 days year-to-year. Use the "Conservative" row in the table below, and keep row covers handy for surprise late frosts.
Yes — growing seasons are getting shorter here (about 1.8 days per decade). Use the "Conservative" dates and choose fast-maturing varieties.
Gardening Difficulty Score
Delaware County offers good growing conditions. A little planning around frost dates goes a long way.
Local Gardening Help in Delaware 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 Delaware County's climate and soil.
County Extension Office
Delaware 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 Delaware County
Finding local nurseries & garden centers in Delaware County
Why Buy Local
Local nurseries carry plants that are proven to grow in your area. Staff can give you advice specific to Delaware 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 Delaware County IA" or "garden center Delaware 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 Delaware County IA" or check your extension office and local parks department. Facebook groups like "Delaware 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
10 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 | 3.7 hr | Short day |
| February | 10.3 hr | 4.4 hr | Short day |
| March | 11.7 hr | 5.6 hr | Short day |
| April | 13.2 hr | 6.9 hr | Neutral |
| May | 14.4 hr | 8.5 hr | Long day |
| June | 15.1 hr | 9.4 hr | Long day |
| July | 14.8 hr | 10 hr | Long day |
| August | 13.7 hr | 8.7 hr | Neutral |
| September | 12.3 hr | 6.9 hr | Neutral |
| October | 10.8 hr | 5.8 hr | Short day |
| November | 9.5 hr | 3.9 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 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 | 15°F | 23°F | ❄️ Dormant | ~36 weeks |
| Feb | 17°F | 23°F | ❄️ Dormant | ~36 weeks |
| Mar | 27°F | 29°F | ❄️ Dormant | ~36 weeks |
| Apr | 43°F | 41°F | 🐢 Slow | ~24 weeks |
| May | 54°F | 52°F | ♻️ Active | ~14 weeks |
| Jun | 67°F | 59°F | 🔥 Peak | ~8 weeks |
| Jul | 75°F | 67°F | 🔥 Peak | ~8 weeks |
| Aug | 75°F | 68°F | 🔥 Peak | ~8 weeks |
| Sep | 66°F | 66°F | 🔥 Peak | ~8 weeks |
| Oct | 51°F | 56°F | ♻️ Active | ~14 weeks |
| Nov | 36°F | 43°F | ❄️ Dormant | ~36 weeks |
| Dec | 23°F | 32°F | ❄️ Dormant | ~36 weeks |
Highlighted rows = soil 60°F+ (safe for warm-season transplants). Compost finishes fastest during peak activity months.
Pest & Disease Pressure in Delaware 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 | Moderate | Jun, Jul, Aug |
| Colorado potato beetle | Moderate | Jun, Jul |
| Flea beetles | Moderate | May, Jun, Jul |
| Slugs | Moderate | May, Jun, Jul, Aug, Sep |
Organic pest management tips
- 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 Delaware County
Cover crops protect bare soil, fix nitrogen, suppress weeds, and improve soil structure — with county-specific planting dates.
Spring Cover Crops (2 options) — Build soil before the main growing season
| Crop | Plant By | Terminate | N-Fixing | Soil Benefit |
|---|---|---|---|---|
| Buckwheat | May 10 | Jul 29 | — | Rapid growth, attracts pollinators, suppresses weeds |
| White clover | Apr 3 | Jul 29 | ✓ Yes | Living mulch, fixes nitrogen, permanent ground cover |
Summer Cover Crops (1 options) — Fill gaps and suppress weeds between plantings
| Crop | Plant By | Terminate | N-Fixing | Soil Benefit |
|---|---|---|---|---|
| Sunflowers | May 20 | Sep 16 | — | 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 21 | Apr 18 | — | Deep taproot breaks compaction, excellent for clay soils |
| Hairy vetch | Jul 14 | Apr 18 | ✓ Yes | Excellent nitrogen fixer, good for depleted soils |
| Oats | Sep 6 | Apr 11 | — | Quick biomass, winterkills in cold zones — no spring tillage needed |
| Winter rye | Jul 15 | Apr 18 | — | Suppresses weeds, prevents erosion, breaks up compacted soil |
| Winter wheat | Jul 16 | Apr 11 | — | 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: 8 mph
Fall: 10 mph Winter: 12 mph
Prevailing wind: SW. Moderate wind — consider a temporary windbreak for young seedlings.
Windbreak Benefit
5.2/10
Moderately beneficial — a simple fence or trellis can protect delicate crops from wind stress.
Frost Pocket Risk
Low
Relatively flat terrain (195 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
15,550 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
Apr, Jun, Jul, Aug
Highest rainfall months — your barrels will fill up quickly during these months.
Months to Draw From Storage
Jan, Feb, Dec
Dry months when you'll rely on stored water — size your storage for this gap.
Rainwater collection tips for your area
- Your county receives approximately 31.2 inches of rain per year
- A 1,000 sq ft roof can collect roughly 15,550 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 Delaware County
Soil Type
Silt Loam
Soil pH 6–6.8 · Moderately 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. (31.3 in. annual rainfall)
Season Tips
158-day frost-free season
Start warm-season crops indoors and focus on short-season varieties. Cold frames extend your season by 3–4 weeks in fall.
Free Garden Planner
Plan your entire garden season — organize planting dates, track what you're growing, and know exactly when to start seeds, transplant, and harvest.
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 Delaware County
96 vegetables that grow well in Zone 4b with planting dates for Delaware County.
Show all 96 vegetables with planting dates
| Plant | Start Indoors | Direct Sow | Transplant | Harvest | Days to Maturity |
|---|---|---|---|---|---|
| Acorn Squash | Mar 21 | May 16 | May 23 | Aug 15 – Sep 19 | 80–100 |
| Amaranth | Feb 28 | May 16 | May 23 | Aug 22 – Oct 10 | 90–120 |
| Arugula | Mar 21 | Apr 25 | May 2 | Jun 6 – Aug 8 | 30–50 |
| Asparagus | — | — | May 16 | — | 730–1095 |
| Beets | — | Apr 25 | — | Jun 20 – Jul 18 | 50–70 |
| Belgian Endive | Mar 21 | Apr 25 | May 2 | Aug 22 – Sep 26 | 110–150 |
| Black Beans | — | May 16 | — | Aug 15 – Oct 3 | 90–120 |
| Bok Choy | Mar 21 | Apr 25 | May 2 | Jun 13 – Jul 18 | 40–60 |
| Broccoli | Mar 21 | Apr 25 | May 2 | Jul 4 – Aug 15 | 60–90 |
| Broccoli Rabe | Mar 21 | Apr 25 | May 2 | Jun 13 – Jul 18 | 40–60 |
| Brussels Sprouts | Mar 21 | Apr 25 | May 2 | Aug 1 – Sep 26 | 90–130 |
| Butternut Squash | Mar 21 | May 16 | May 23 | Aug 22 – Sep 26 | 85–110 |
| Cabbage | Mar 21 | Apr 25 | May 2 | Jul 4 – Aug 29 | 60–100 |
| Carrots | — | Apr 25 | — | Jun 27 – Aug 1 | 60–80 |
| Cauliflower | Mar 21 | Apr 25 | May 2 | Jun 27 – Aug 29 | 55–100 |
| Celeriac | Mar 21 | Apr 25 | May 2 | Aug 15 – Sep 19 | 100–120 |
| Celery | Mar 21 | Apr 25 | May 2 | Jul 25 – Sep 19 | 80–120 |
| Celtuce | Mar 21 | Apr 25 | May 2 | Jul 4 – Aug 15 | 60–90 |
| Chard | Mar 21 | Apr 25 | May 2 | Jun 27 – Aug 15 | 50–60 |
| Chickpeas | Mar 21 | Apr 25 | May 2 | Jul 25 – Sep 5 | 80–110 |
| Chicory | Mar 21 | Apr 25 | May 2 | Jul 4 – Aug 15 | 60–85 |
| Chinese Cabbage | Mar 21 | Apr 25 | May 2 | Jun 27 – Jul 25 | 50–70 |
| Christmas Lima Beans | Feb 28 | May 16 | May 23 | Aug 15 – Sep 19 | 80–100 |
| Collard Greens | Mar 21 | Apr 25 | May 2 | Jun 27 – Aug 29 | 55–75 |
| Corn | — | May 16 | — | Jul 18 – Sep 12 | 60–100 |
| Cress | Mar 21 | Apr 25 | May 2 | May 16 – Jun 6 | 14–21 |
| Crookneck Squash | Mar 21 | May 16 | May 23 | Jul 11 – Aug 8 | 45–60 |
| Crosne | — | Apr 25 | — | Sep 26 – Sep 19 | 150–200 |
| Cucumber | Mar 21 | May 16 | May 23 | Jul 18 – Sep 12 | 50–70 |
| Daikon | — | Apr 25 | — | Jun 20 – Jul 18 | 50–70 |
| Delicata Squash | Mar 21 | May 16 | May 23 | Aug 15 – Sep 19 | 80–100 |
| Edamame | — | May 16 | — | Aug 1 – Sep 12 | 75–100 |
| Endive | Mar 21 | Apr 25 | May 2 | Jun 20 – Jul 25 | 45–65 |
| Escarole | Mar 21 | Apr 25 | May 2 | Jun 27 – Jul 25 | 50–70 |
| Fava Beans | Mar 21 | Apr 25 | May 2 | Jul 18 – Aug 29 | 75–100 |
| Fennel | Feb 28 | May 16 | May 23 | Jul 25 – Sep 5 | 60–90 |
| Garlic | — | — | — | — | 90–240 |
| Green Beans | — | May 16 | — | Jul 11 – Sep 5 | 50–65 |
| Horseradish | — | — | May 16 | Sep 19 – Oct 10 | 120–180 |
| Hubbard Squash | Mar 21 | May 16 | May 23 | Sep 5 – Oct 10 | 100–120 |
| Kabocha | Mar 21 | May 16 | May 23 | Aug 22 – Sep 19 | 85–100 |
| Kai Lan | Mar 21 | Apr 25 | May 2 | Jun 20 – Jul 18 | 45–60 |
| Kale | Mar 21 | Apr 25 | May 2 | Jun 27 – Aug 22 | 50–70 |
| Kidney Beans | — | May 16 | — | Aug 15 – Sep 19 | 85–110 |
| Kohlrabi | Mar 21 | Apr 25 | May 2 | Jun 20 – Jul 25 | 45–65 |
| Komatsuna | Mar 21 | Apr 25 | May 2 | Jun 6 – Jul 11 | 35–50 |
| Leeks | Mar 21 | Apr 25 | May 2 | Aug 1 – Sep 26 | 90–150 |
| Lentils | Mar 21 | Apr 25 | May 2 | Jul 25 – Sep 5 | 80–110 |
| Lettuce | Mar 21 | Apr 25 | May 2 | Jun 6 – Aug 15 | 30–60 |
| Lima Beans | — | May 16 | — | Jul 18 – Aug 29 | 60–90 |
| Mache | Mar 21 | Apr 25 | May 2 | Jun 13 – Jul 18 | 40–60 |
| Melon | Mar 21 | May 16 | May 23 | Aug 1 – Sep 19 | 70–100 |
| Microgreens | Mar 21 | Apr 25 | May 2 | May 9 – Jun 6 | 7–21 |
| Mitsuba | Mar 21 | Apr 25 | Apr 25 | Jun 20 – Aug 15 | 50–70 |
| Mizuna | Mar 21 | Apr 25 | May 2 | Jun 6 – Jul 4 | 30–45 |
| Mustard Greens | Mar 21 | Apr 25 | May 2 | Jun 6 – Aug 8 | 30–50 |
| Napa Cabbage | Mar 21 | Apr 25 | May 2 | Jun 27 – Aug 1 | 55–75 |
| Onion | Mar 21 | Apr 25 | May 2 | Aug 1 – Sep 19 | 90–120 |
| Pac Choi | Mar 21 | Apr 25 | May 2 | Jun 13 – Jul 11 | 40–55 |
| Parsnip | — | Apr 25 | — | Aug 8 – Sep 19 | 100–130 |
| Patty Pan Squash | Mar 21 | May 16 | May 23 | Jul 11 – Aug 8 | 45–60 |
| Peas | Mar 21 | Apr 25 | May 2 | Jun 27 – Aug 22 | 55–70 |
| Peppers | Feb 14 | May 16 | May 23 | Jul 25 – Oct 3 | 60–90 |
| Pole Beans | Feb 28 | May 16 | May 23 | Jul 18 – Sep 12 | 55–70 |
| Potatoes | Feb 28 | May 16 | May 23 | Aug 1 – Oct 10 | 70–120 |
| Pumpkin | Mar 21 | May 16 | May 23 | Aug 22 – Oct 10 | 85–120 |
| Purslane | Mar 21 | Apr 25 | May 2 | Jun 13 – Jul 18 | 40–60 |
| Radicchio | Mar 21 | Apr 25 | May 2 | Jul 4 – Aug 8 | 60–80 |
| Radish | — | Apr 25 | — | May 23 – Jun 13 | 22–35 |
| Rhubarb | — | — | May 30 | — | 365–730 |
| Romanesco | Mar 21 | Apr 25 | May 2 | Jul 18 – Aug 29 | 75–100 |
| Rutabaga | — | Apr 25 | — | Jul 18 – Aug 22 | 80–100 |
| Salsify | — | Apr 25 | — | Aug 8 – Sep 19 | 100–130 |
| Savoy Cabbage | Mar 21 | Apr 25 | May 2 | Jul 11 – Sep 5 | 70–110 |
| Scallions | Mar 21 | Apr 25 | May 2 | Jun 27 – Jul 25 | 50–70 |
| Scarlet Runner Beans | Feb 28 | May 16 | May 23 | Jul 25 – Aug 29 | 60–80 |
| Shallot | Mar 21 | Apr 25 | May 2 | Aug 1 – Sep 19 | 90–120 |
| Shiso | Mar 7 | May 9 | May 23 | Jul 18 – Sep 12 | 50–70 |
| Snap Peas | Feb 28 | May 16 | May 23 | Jul 18 – Sep 12 | 55–70 |
| Snow Peas | Mar 21 | Apr 25 | May 2 | Jun 27 – Aug 22 | 50–65 |
| Soybeans | — | May 16 | — | Aug 8 – Oct 3 | 80–120 |
| Spaghetti Squash | Mar 21 | May 16 | May 23 | Aug 22 – Sep 19 | 85–100 |
| Spinach | Mar 21 | Apr 25 | May 2 | Jun 6 – Aug 8 | 35–50 |
| Squash (Summer) | Mar 21 | May 16 | May 23 | Jul 11 – Sep 12 | 45–65 |
| Squash (Winter) | Mar 21 | May 16 | May 23 | Aug 15 – Oct 10 | 80–120 |
| Sunchoke | — | — | May 16 | Sep 5 – Oct 10 | 110–150 |
| Sunflower | Feb 28 | May 16 | May 23 | Aug 1 – Sep 19 | 70–100 |
| Sweet Corn | — | May 16 | — | Jul 18 – Aug 29 | 60–90 |
| Tatsoi | Mar 21 | Apr 25 | May 2 | Jun 6 – Jul 11 | 35–50 |
| Tomatillo | Feb 28 | May 16 | May 23 | Jul 25 – Oct 3 | 60–85 |
| Tomatoes | Feb 28 | May 16 | May 23 | Jul 25 – Oct 3 | 60–85 |
| Turnip | — | Apr 25 | — | Jun 6 – Jul 11 | 40–60 |
| Watercress | Mar 21 | Apr 25 | May 2 | Jun 13 – Jul 18 | 40–60 |
| Watermelon | Mar 21 | May 16 | May 23 | Aug 1 – Sep 19 | 70–100 |
| Wax Beans | — | May 16 | — | Jul 11 – Sep 5 | 50–65 |
| Zucchini | Mar 21 | May 16 | May 23 | Jul 11 – Sep 5 | 45–60 |
🍓 Fruits to Grow in Delaware County
22 fruits that grow well in Zone 4b with planting dates for Delaware County.
Show all 22 fruits with planting dates
| Plant | Start Indoors | Direct Sow | Transplant | Harvest | Days to Maturity |
|---|---|---|---|---|---|
| Alpine Strawberries | — | — | May 30 | Aug 29 – Oct 24 | 90–180 |
| Aronia | — | — | May 30 | — | 730–1095 |
| Blueberries | — | — | May 30 | — | 730–1095 |
| Cantaloupe | — | — | May 30 | Aug 8 – Sep 12 | 70–90 |
| Cranberries | — | — | May 30 | — | 730–1095 |
| Currants | — | — | May 30 | — | 730–1095 |
| Elderberries | — | — | May 30 | — | 730–1095 |
| Goji Berries | — | — | May 30 | — | 730–1095 |
| Gooseberries | — | — | May 30 | — | 730–1095 |
| Grapes | — | — | May 30 | — | 730–1095 |
| Ground Cherry | — | — | May 30 | Aug 8 – Oct 3 | 65–80 |
| Hardy Kiwi | — | — | May 30 | — | 1095–1825 |
| Haskaps | — | — | May 30 | — | 730–1095 |
| Honeydew | — | — | May 30 | Aug 22 – Oct 3 | 80–110 |
| Jostaberry | — | — | May 30 | — | 730–1095 |
| Lingonberries | — | — | May 30 | — | 730–1095 |
| Medlar | — | — | May 30 | — | 1095–1825 |
| Mulberries | — | — | May 30 | — | 730–1825 |
| Persimmon | — | — | May 30 | — | 1095–2555 |
| Raspberries | — | — | May 30 | — | 365–730 |
| Serviceberries | — | — | May 30 | — | 730–1095 |
| Strawberries | — | — | May 30 | Aug 29 – Oct 24 | 90–365 |
🌿 Herbs to Grow in Delaware County
32 herbs that grow well in Zone 4b with planting dates for Delaware County.
Show all 32 herbs with planting dates
| Plant | Start Indoors | Direct Sow | Transplant | Harvest | Days to Maturity |
|---|---|---|---|---|---|
| Angelica | Mar 21 | Apr 25 | Apr 25 | — | 365–730 |
| Anise | Mar 21 | Apr 25 | Apr 25 | Jul 25 – Sep 19 | 90–120 |
| Basil | Mar 7 | May 9 | May 23 | Jul 18 – Sep 19 | 50–75 |
| Bee Balm | — | — | May 9 | Aug 8 – Oct 3 | 90–120 |
| Borage | Mar 21 | Apr 25 | Apr 25 | Jun 20 – Aug 8 | 50–60 |
| Caraway | Mar 21 | Apr 25 | Apr 25 | — | 365–450 |
| Catnip | — | — | May 9 | Jul 11 – Sep 12 | 60–80 |
| Chamomile | Mar 21 | Apr 25 | Apr 25 | Jun 27 – Sep 5 | 60–90 |
| Chervil | Mar 21 | Apr 25 | Apr 25 | Jun 6 – Aug 8 | 40–60 |
| Chives | — | — | May 9 | Jul 11 – Sep 19 | 60–90 |
| Cilantro | Mar 21 | Apr 25 | Apr 25 | Jun 6 – Aug 8 | 40–60 |
| Comfrey | — | — | May 9 | Jul 11 – Sep 19 | 60–90 |
| Dill | Mar 21 | Apr 25 | Apr 25 | Jun 6 – Aug 8 | 40–60 |
| Echinacea | — | — | May 9 | Sep 12 – Oct 3 | 120–180 |
| Fennel (herb) | Mar 21 | Apr 25 | Apr 25 | Jun 27 – Sep 5 | 60–90 |
| Garlic Chives | — | — | May 9 | Jul 11 – Sep 19 | 60–90 |
| Horehound | — | — | May 9 | Jul 25 – Sep 19 | 75–90 |
| Hyssop | — | — | May 9 | Jul 18 – Sep 19 | 70–90 |
| Lemon Balm | — | — | May 9 | Jul 11 – Aug 29 | 60–70 |
| Lovage | — | — | May 9 | Jul 18 – Sep 19 | 70–90 |
| Mint | — | — | May 9 | Jul 11 – Sep 19 | 60–90 |
| Oregano | — | — | May 9 | Jul 11 – Sep 19 | 60–90 |
| Parsley | Mar 21 | Apr 25 | Apr 25 | Jun 27 – Aug 29 | 60–80 |
| Rue | — | — | May 9 | Jul 18 – Sep 19 | 70–90 |
| Sage | — | — | May 9 | Jul 25 – Sep 19 | 75–90 |
| Savory | — | — | May 9 | Jul 4 – Aug 29 | 50–70 |
| Sorrel | Mar 21 | Apr 25 | Apr 25 | Jun 6 – Aug 8 | 40–60 |
| Tarragon | — | — | May 9 | Jul 11 – Sep 19 | 60–90 |
| Thai Basil | Mar 7 | May 9 | May 23 | Jul 18 – Sep 19 | 50–75 |
| Thyme | — | — | May 9 | Jul 18 – Sep 19 | 70–90 |
| Valerian | — | — | May 9 | Sep 12 – Oct 3 | 120–180 |
| Yarrow | — | — | May 9 | Aug 8 – Oct 3 | 90–120 |
Monthly Planting Guide for Delaware County
Gardening Guides & Resources
Helpful guides from The Ultimate Homestead to improve your garden in Delaware County.
Frequently Asked Questions
What planting zone is Delaware County, IA?
Delaware 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 Delaware County, IA?
Based on 31 years of NOAA weather station data, the median last spring frost in Delaware County falls around May 2. In 8 out of 10 years, last frost lands between April 17 and May 16 — a 28-day window of variability. Use May 16 as your conservative safe-to-plant date for frost-sensitive crops.
When is the first fall frost in Delaware County, IA?
The median first fall frost in Delaware 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 Delaware County?
Delaware County has a frost-free growing season of approximately 158 days. This is enough time for most warm-season crops including tomatoes, peppers, and squash with proper timing. Climate records show the growing season is trending shorter by about 1.8 days per decade.
What is the soil like in Delaware County for gardening?
Delaware County has predominantly Silt Loam soil with a pH range of 6–6.8 and Moderately Well Drained drainage. Most vegetables and herbs grow well with standard composting and seasonal soil amendment.
What is grown commercially in Delaware County?
Delaware 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 Delaware County a good location for home gardening?
Delaware County scores 66/100 (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
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