Union County, OH — Planting Guide
Union County is in USDA Zone 5b. The average last spring frost is April 25 and the first fall frost is October 19, giving you a growing season of approximately 177 days.
At an elevation of 1,227 ft, Union County receives approximately 34.6 in of rainfall annually. Summer highs average 86°F with winter lows around 15°F. The predominant soil type is Silt Loam.
Based on 31 years of NOAA climate station data, the last frost date here varies by 31 days year to year — ranging from April 10 in warm years to May 11 in cold years. The growing season is trending shorter by about 0.76 days per decade. Union County scores 68/100 (Good) on the Microclimate Index.
🌡️ Zone
5b (-15°F to -10°F min)
❄️ Last Frost
April 25
🍂 First Frost
October 19
📅 Growing Season
177 days
⛰️ Elevation
1,227 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 | 1.3 in | 8 days | — | None |
| Feb | 1.5 in | 5 days | — | None |
| Mar | 2.6 in | 9 days | — | None |
| Apr | 3.7 in | 11 days | 0.6 in | Moderate |
| May | 3.9 in | 9 days | 0.4 in | Low |
| Jun | 4.2 in | 8 days | 0.1 in | Low |
| Jul | 3.5 in | 7 days | 0.8 in | Moderate |
| Aug | 4 in | 8 days | 0.3 in | Low |
| Sep | 2.6 in | 7 days | 1.7 in | High |
| Oct | 2.8 in | 8 days | 1.5 in | Moderate |
| Nov | 2.7 in | 9 days | — | None |
| Dec | 1.8 in | 9 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.
Union County Soil Profile
Soil Type
Silt Loam
Soil pH
5.8-7.2
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 11 | Oct 31 | 173 days |
| Cautious | Apr 28 | Oct 24 | 179 days |
| Average year | Apr 25 | Oct 19 | 177 days |
| Optimistic | Apr 17 | Oct 15 | 181 days |
| Aggressive (risky) | Apr 10 | Oct 7 | 180 days |
Not very — frost dates can vary by ±31 days year-to-year. Use the "Conservative" row in the table below, and keep row covers handy for surprise late frosts.
Slightly — seasons are trending a bit shorter (0.8 days/decade). Stay conservative with planting dates.
Gardening Difficulty Score
Union County offers good growing conditions. A little planning around frost dates goes a long way.
Local Gardening Help in Union 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 Union County's climate and soil.
County Extension Office
Union County Ohio State University Extension Extension Office
Phone: 614-292-6181
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 Union County
Finding local nurseries & garden centers in Union County
Why Buy Local
Local nurseries carry plants that are proven to grow in your area. Staff can give you advice specific to Union 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 Union County OH" or "garden center Union 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 Union County OH" or check your extension office and local parks department. Facebook groups like "Union County Gardeners" or "Ohio 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
14.9 hours
Summer solstice daylight
Shortest Day
9.1 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 | 9.4 hr | 3.7 hr | Short day |
| February | 10.5 hr | 4.8 hr | Short day |
| March | 11.7 hr | 5.6 hr | Short day |
| April | 13.1 hr | 6.5 hr | Neutral |
| May | 14.2 hr | 8.4 hr | Long day |
| June | 14.9 hr | 9.4 hr | Long day |
| July | 14.6 hr | 9.8 hr | Long day |
| August | 13.6 hr | 8.8 hr | Neutral |
| September | 12.3 hr | 7.1 hr | Neutral |
| October | 10.9 hr | 5.5 hr | Short day |
| November | 9.7 hr | 3.8 hr | Short day |
| December | 9.1 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 | 21°F | 32°F | ❄️ Dormant | ~36 weeks |
| Feb | 23°F | 28°F | ❄️ Dormant | ~36 weeks |
| Mar | 32°F | 35°F | ❄️ Dormant | ~36 weeks |
| Apr | 46°F | 45°F | 🐢 Slow | ~24 weeks |
| May | 58°F | 53°F | ♻️ Active | ~14 weeks |
| Jun | 68°F | 62°F | 🔥 Peak | ~8 weeks |
| Jul | 75°F | 69°F | 🔥 Peak | ~8 weeks |
| Aug | 79°F | 72°F | 🔥 Peak | ~8 weeks |
| Sep | 68°F | 68°F | 🔥 Peak | ~8 weeks |
| Oct | 57°F | 60°F | ♻️ Active | ~14 weeks |
| Nov | 44°F | 50°F | 🐢 Slow | ~24 weeks |
| Dec | 29°F | 39°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 Union 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 6 common pests in your area
| Pest | Risk Level | Peak Months |
|---|---|---|
| Aphids | Moderate | May, Jun, Jul, Aug |
| Japanese beetles | Moderate | Jun, Jul, Aug |
| Squash bugs | Moderate | Jun, Jul, Aug |
| Tomato hornworms | Moderate | Jul, Aug |
| Cabbage loopers | Moderate | May, Jun, Jul, Aug |
| Slugs | Low | Apr, May, Jun |
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 Union 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 | Apr 26 | Aug 10 | — | Rapid growth, attracts pollinators, suppresses weeds |
| Sorghum-sudan grass | Apr 27 | Aug 17 | — | Massive biomass, breaks compaction, suppresses nematodes |
| White clover | Mar 27 | Aug 17 | ✓ 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 24 | Sep 28 | — | 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 10 | Apr 11 | ✓ Yes | Fixes nitrogen, good for heavy clay soils |
| Daikon radish | Sep 1 | Apr 11 | — | Deep taproot breaks compaction, excellent for clay soils |
| Hairy vetch | Aug 7 | Apr 11 | ✓ Yes | Excellent nitrogen fixer, good for depleted soils |
| Oats | Sep 12 | Apr 11 | — | Quick biomass, winterkills in cold zones — no spring tillage needed |
| Winter rye | Jul 18 | Apr 4 | — | Suppresses weeds, prevents erosion, breaks up compacted soil |
| Winter wheat | Jul 15 | Apr 4 | — | 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: 11 mph Summer: 10 mph
Fall: 10 mph Winter: 11 mph
Prevailing wind: SW. Moderate wind — consider a temporary windbreak for young seedlings.
Windbreak Benefit
5.3/10
Moderately beneficial — a simple fence or trellis can protect delicate crops from wind stress.
Frost Pocket Risk
Low
Relatively flat terrain (226 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
Apr, May, Jun, 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 Union County
Soil Type
Silt Loam
Soil pH 5.8–7.2 · Moderately 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
177-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 Union County
106 vegetables that grow well in Zone 5b with planting dates for Union County.
Show all 106 vegetables with planting dates
| Plant | Start Indoors | Direct Sow | Transplant | Harvest | Days to Maturity |
|---|---|---|---|---|---|
| Acorn Squash | Mar 21 | May 2 | May 9 | Aug 1 – Sep 5 | 80–100 |
| Amaranth | Feb 28 | May 2 | May 9 | Aug 8 – Sep 26 | 90–120 |
| Arugula | Mar 21 | Apr 11 | Apr 25 | May 30 – Aug 1 | 30–50 |
| Asparagus | — | — | May 9 | — | 730–1095 |
| Beets | — | Apr 11 | — | Jun 6 – Jul 4 | 50–70 |
| Belgian Endive | Mar 21 | Apr 11 | Apr 25 | Aug 15 – Oct 10 | 110–150 |
| Bitter Melon | Feb 28 | May 2 | May 9 | Jul 11 – Aug 22 | 60–90 |
| Black Beans | — | May 2 | — | Aug 1 – Sep 19 | 90–120 |
| Bok Choy | Mar 21 | Apr 11 | Apr 25 | Jun 6 – Jul 11 | 40–60 |
| Broccoli | Mar 21 | Apr 11 | Apr 25 | Jun 27 – Aug 8 | 60–90 |
| Broccoli Rabe | Mar 21 | Apr 11 | Apr 25 | Jun 6 – Jul 11 | 40–60 |
| Brussels Sprouts | Mar 21 | Apr 11 | Apr 25 | Jul 25 – Sep 19 | 90–130 |
| Butternut Squash | Mar 21 | May 2 | May 9 | Aug 8 – Sep 12 | 85–110 |
| Cabbage | Mar 21 | Apr 11 | Apr 25 | Jun 27 – Aug 22 | 60–100 |
| Calabash | Feb 28 | May 2 | May 9 | Aug 1 – Sep 26 | 80–120 |
| Carrots | — | Apr 11 | — | Jun 13 – Jul 18 | 60–80 |
| Cauliflower | Mar 21 | Apr 11 | Apr 25 | Jun 20 – Aug 22 | 55–100 |
| Celeriac | Mar 21 | Apr 11 | Apr 25 | Aug 8 – Sep 12 | 100–120 |
| Celery | Mar 21 | Apr 11 | Apr 25 | Jul 18 – Sep 12 | 80–120 |
| Celtuce | Mar 21 | Apr 11 | Apr 25 | Jun 27 – Aug 8 | 60–90 |
| Chard | Mar 21 | Apr 11 | Apr 25 | Jun 20 – Aug 8 | 50–60 |
| Chickpeas | Mar 21 | Apr 11 | Apr 25 | Jul 18 – Aug 29 | 80–110 |
| Chicory | Mar 21 | Apr 11 | Apr 25 | Jun 27 – Aug 8 | 60–85 |
| Chinese Cabbage | Mar 21 | Apr 11 | Apr 25 | Jun 20 – Jul 18 | 50–70 |
| Christmas Lima Beans | Feb 28 | May 2 | May 9 | Aug 1 – Sep 5 | 80–100 |
| Collard Greens | Mar 21 | Apr 11 | Apr 25 | Jun 20 – Aug 22 | 55–75 |
| Corn | — | May 2 | — | Jul 4 – Aug 29 | 60–100 |
| Cowpeas | — | May 2 | — | Jul 4 – Aug 15 | 60–90 |
| Cress | Mar 21 | Apr 11 | Apr 25 | May 9 – May 30 | 14–21 |
| Crookneck Squash | Mar 21 | May 2 | May 9 | Jun 27 – Jul 25 | 45–60 |
| Crosne | — | Apr 11 | — | Sep 12 – Sep 26 | 150–200 |
| Cucumber | Mar 21 | May 2 | May 9 | Jul 4 – Aug 29 | 50–70 |
| Daikon | — | Apr 11 | — | Jun 6 – Jul 4 | 50–70 |
| Delicata Squash | Mar 21 | May 2 | May 9 | Aug 1 – Sep 5 | 80–100 |
| Edamame | — | May 2 | — | Jul 18 – Aug 29 | 75–100 |
| Eggplant | Feb 14 | May 2 | May 9 | Jul 18 – Sep 19 | 65–85 |
| Endive | Mar 21 | Apr 11 | Apr 25 | Jun 13 – Jul 18 | 45–65 |
| Escarole | Mar 21 | Apr 11 | Apr 25 | Jun 20 – Jul 18 | 50–70 |
| Fava Beans | Mar 21 | Apr 11 | Apr 25 | Jul 11 – Aug 22 | 75–100 |
| Fennel | Feb 28 | May 2 | May 9 | Jul 11 – Aug 22 | 60–90 |
| Garlic | — | — | — | — | 90–240 |
| Green Beans | — | May 2 | — | Jun 27 – Aug 22 | 50–65 |
| Horseradish | — | — | May 9 | Sep 12 – Oct 24 | 120–180 |
| Hot Peppers | Feb 14 | May 2 | May 9 | Jul 18 – Oct 24 | 70–120 |
| Hubbard Squash | Mar 21 | May 2 | May 9 | Aug 22 – Sep 26 | 100–120 |
| Kabocha | Mar 21 | May 2 | May 9 | Aug 8 – Sep 5 | 85–100 |
| Kai Lan | Mar 21 | Apr 11 | Apr 25 | Jun 13 – Jul 11 | 45–60 |
| Kale | Mar 21 | Apr 11 | Apr 25 | Jun 20 – Aug 15 | 50–70 |
| Kidney Beans | — | May 2 | — | Aug 1 – Sep 5 | 85–110 |
| Kohlrabi | Mar 21 | Apr 11 | Apr 25 | Jun 13 – Jul 18 | 45–65 |
| Komatsuna | Mar 21 | Apr 11 | Apr 25 | May 30 – Jul 4 | 35–50 |
| Leeks | Mar 21 | Apr 11 | Apr 25 | Jul 25 – Oct 10 | 90–150 |
| Lentils | Mar 21 | Apr 11 | Apr 25 | Jul 18 – Aug 29 | 80–110 |
| Lettuce | Mar 21 | Apr 11 | Apr 25 | May 30 – Aug 8 | 30–60 |
| Lima Beans | — | May 2 | — | Jul 4 – Aug 15 | 60–90 |
| Mache | Mar 21 | Apr 11 | Apr 25 | Jun 6 – Jul 11 | 40–60 |
| Melon | Mar 21 | May 2 | May 9 | Jul 18 – Sep 5 | 70–100 |
| Microgreens | Mar 21 | Apr 11 | Apr 25 | May 2 – May 30 | 7–21 |
| Mitsuba | Mar 21 | Apr 11 | Apr 18 | Jun 13 – Aug 8 | 50–70 |
| Mizuna | Mar 21 | Apr 11 | Apr 25 | May 30 – Jun 27 | 30–45 |
| Mustard Greens | Mar 21 | Apr 11 | Apr 25 | May 30 – Aug 1 | 30–50 |
| Napa Cabbage | Mar 21 | Apr 11 | Apr 25 | Jun 20 – Jul 25 | 55–75 |
| New Zealand Spinach | Feb 28 | May 2 | May 9 | Jul 4 – Aug 1 | 55–70 |
| Okra | Feb 28 | May 2 | May 9 | Jul 4 – Aug 29 | 50–65 |
| Onion | Mar 21 | Apr 11 | Apr 25 | Jul 25 – Sep 12 | 90–120 |
| Pac Choi | Mar 21 | Apr 11 | Apr 25 | Jun 6 – Jul 4 | 40–55 |
| Parsnip | — | Apr 11 | — | Jul 25 – Sep 5 | 100–130 |
| Patty Pan Squash | Mar 21 | May 2 | May 9 | Jun 27 – Jul 25 | 45–60 |
| Peas | Mar 21 | Apr 11 | Apr 25 | Jun 20 – Aug 15 | 55–70 |
| Peppers | Feb 14 | May 2 | May 9 | Jul 11 – Sep 19 | 60–90 |
| Pole Beans | Feb 28 | May 2 | May 9 | Jul 4 – Aug 29 | 55–70 |
| Potatoes | Feb 28 | May 2 | May 9 | Jul 18 – Sep 26 | 70–120 |
| Pumpkin | Mar 21 | May 2 | May 9 | Aug 8 – Sep 26 | 85–120 |
| Purslane | Mar 21 | Apr 11 | Apr 25 | Jun 6 – Jul 11 | 40–60 |
| Radicchio | Mar 21 | Apr 11 | Apr 25 | Jun 27 – Aug 1 | 60–80 |
| Radish | — | Apr 11 | — | May 9 – May 30 | 22–35 |
| Rhubarb | — | — | May 16 | — | 365–730 |
| Romanesco | Mar 21 | Apr 11 | Apr 25 | Jul 11 – Aug 22 | 75–100 |
| Rutabaga | — | Apr 11 | — | Jul 4 – Aug 8 | 80–100 |
| Salsify | — | Apr 11 | — | Jul 25 – Sep 5 | 100–130 |
| Savoy Cabbage | Mar 21 | Apr 11 | Apr 25 | Jul 4 – Aug 29 | 70–110 |
| Scallions | Mar 21 | Apr 11 | Apr 25 | Jun 20 – Jul 18 | 50–70 |
| Scarlet Runner Beans | Feb 28 | May 2 | May 9 | Jul 11 – Aug 15 | 60–80 |
| Shallot | Mar 21 | Apr 11 | Apr 25 | Jul 25 – Sep 12 | 90–120 |
| Shiso | Mar 7 | May 2 | May 9 | Jul 4 – Aug 29 | 50–70 |
| Snap Peas | Feb 28 | May 2 | May 9 | Jul 4 – Aug 29 | 55–70 |
| Snow Peas | Mar 21 | Apr 11 | Apr 25 | Jun 20 – Aug 15 | 50–65 |
| Soybeans | — | May 2 | — | Jul 25 – Sep 19 | 80–120 |
| Spaghetti Squash | Mar 21 | May 2 | May 9 | Aug 8 – Sep 5 | 85–100 |
| Spinach | Mar 21 | Apr 11 | Apr 25 | May 30 – Aug 1 | 35–50 |
| Squash (Summer) | Mar 21 | May 2 | May 9 | Jun 27 – Aug 29 | 45–65 |
| Squash (Winter) | Mar 21 | May 2 | May 9 | Aug 1 – Sep 26 | 80–120 |
| Sunchoke | — | — | May 9 | Aug 29 – Oct 24 | 110–150 |
| Sunflower | Feb 28 | May 2 | May 9 | Jul 18 – Sep 5 | 70–100 |
| Sweet Corn | — | May 2 | — | Jul 4 – Aug 15 | 60–90 |
| Sweet Potatoes | Feb 28 | May 2 | May 9 | Aug 8 – Sep 26 | 90–120 |
| Tatsoi | Mar 21 | Apr 11 | Apr 25 | May 30 – Jul 4 | 35–50 |
| Tomatillo | Feb 28 | May 2 | May 9 | Jul 11 – Sep 19 | 60–85 |
| Tomatoes | Feb 28 | May 2 | May 9 | Jul 11 – Sep 19 | 60–85 |
| Turnip | — | Apr 11 | — | May 23 – Jun 27 | 40–60 |
| Watercress | Mar 21 | Apr 11 | Apr 25 | Jun 6 – Jul 11 | 40–60 |
| Watermelon | Mar 21 | May 2 | May 9 | Jul 18 – Sep 5 | 70–100 |
| Wax Beans | — | May 2 | — | Jun 27 – Aug 22 | 50–65 |
| Winter Melon | Feb 28 | May 2 | May 9 | Aug 8 – Sep 26 | 90–120 |
| Yard Long Beans | Feb 28 | May 2 | May 9 | Jul 4 – Aug 15 | 55–80 |
| Zucchini | Mar 21 | May 2 | May 9 | Jun 27 – Aug 22 | 45–60 |
🍓 Fruits to Grow in Union County
27 fruits that grow well in Zone 5b with planting dates for Union County.
Show all 27 fruits with planting dates
| Plant | Start Indoors | Direct Sow | Transplant | Harvest | Days to Maturity |
|---|---|---|---|---|---|
| Alpine Strawberries | — | — | May 16 | Aug 15 – Oct 31 | 90–180 |
| Aronia | — | — | May 16 | — | 730–1095 |
| Blackberries | — | — | May 16 | — | 365–730 |
| Blueberries | — | — | May 16 | — | 730–1095 |
| Boysenberries | — | — | May 16 | — | 365–730 |
| Cantaloupe | — | — | May 16 | Jul 25 – Aug 29 | 70–90 |
| Che Fruit | — | — | May 16 | — | 1095–1825 |
| Cranberries | — | — | May 16 | — | 730–1095 |
| Currants | — | — | May 16 | — | 730–1095 |
| Elderberries | — | — | May 16 | — | 730–1095 |
| Goji Berries | — | — | May 16 | — | 730–1095 |
| Gooseberries | — | — | May 16 | — | 730–1095 |
| Grapes | — | — | May 16 | — | 730–1095 |
| Ground Cherry | — | — | May 16 | Jul 25 – Sep 19 | 65–80 |
| Hardy Kiwi | — | — | May 16 | — | 1095–1825 |
| Haskaps | — | — | May 16 | — | 730–1095 |
| Honeydew | — | — | May 16 | Aug 8 – Sep 19 | 80–110 |
| Jostaberry | — | — | May 16 | — | 730–1095 |
| Lingonberries | — | — | May 16 | — | 730–1095 |
| Medlar | — | — | May 16 | — | 1095–1825 |
| Mulberries | — | — | May 16 | — | 730–1825 |
| Pawpaw | — | — | May 16 | — | 1095–2555 |
| Persimmon | — | — | May 16 | — | 1095–2555 |
| Quince | — | — | May 16 | — | 1095–1825 |
| Raspberries | — | — | May 16 | — | 365–730 |
| Serviceberries | — | — | May 16 | — | 730–1095 |
| Strawberries | — | — | May 16 | Aug 15 – Oct 31 | 90–365 |
🌿 Herbs to Grow in Union County
37 herbs that grow well in Zone 5b with planting dates for Union County.
Show all 37 herbs with planting dates
| Plant | Start Indoors | Direct Sow | Transplant | Harvest | Days to Maturity |
|---|---|---|---|---|---|
| Angelica | Mar 21 | Apr 11 | Apr 18 | — | 365–730 |
| Anise | Mar 21 | Apr 11 | Apr 18 | Jul 18 – Oct 3 | 90–120 |
| Basil | Mar 7 | May 2 | May 9 | Jul 4 – Sep 5 | 50–75 |
| Bee Balm | — | — | May 2 | Aug 1 – Oct 17 | 90–120 |
| Borage | Mar 21 | Apr 11 | Apr 18 | Jun 13 – Aug 1 | 50–60 |
| Caraway | Mar 21 | Apr 11 | Apr 18 | — | 365–450 |
| Catnip | — | — | May 2 | Jul 4 – Sep 5 | 60–80 |
| Chamomile | Mar 21 | Apr 11 | Apr 18 | Jun 20 – Aug 29 | 60–90 |
| Chervil | Mar 21 | Apr 11 | Apr 18 | May 30 – Aug 1 | 40–60 |
| Chives | — | — | May 2 | Jul 4 – Sep 12 | 60–90 |
| Cilantro | Mar 21 | Apr 11 | Apr 18 | May 30 – Aug 1 | 40–60 |
| Comfrey | — | — | May 2 | Jul 4 – Sep 12 | 60–90 |
| Cumin | Mar 21 | Apr 11 | Apr 18 | Aug 1 – Oct 3 | 100–120 |
| Dill | Mar 21 | Apr 11 | Apr 18 | May 30 – Aug 1 | 40–60 |
| Echinacea | — | — | May 2 | Sep 5 – Oct 17 | 120–180 |
| Epazote | Mar 7 | May 2 | May 9 | Jun 27 – Aug 22 | 45–60 |
| Fennel (herb) | Mar 21 | Apr 11 | Apr 18 | Jun 20 – Aug 29 | 60–90 |
| Feverfew | — | — | May 2 | Aug 1 – Oct 17 | 90–120 |
| Garlic Chives | — | — | May 2 | Jul 4 – Sep 12 | 60–90 |
| Horehound | — | — | May 2 | Jul 18 – Sep 12 | 75–90 |
| Hyssop | — | — | May 2 | Jul 11 – Sep 12 | 70–90 |
| Lavender | — | — | May 2 | Aug 1 – Oct 17 | 90–200 |
| Lemon Balm | — | — | May 2 | Jul 4 – Aug 22 | 60–70 |
| Lemon Thyme | — | — | May 2 | Jul 11 – Sep 12 | 70–90 |
| Lovage | — | — | May 2 | Jul 11 – Sep 12 | 70–90 |
| Mint | — | — | May 2 | Jul 4 – Sep 12 | 60–90 |
| Oregano | — | — | May 2 | Jul 4 – Sep 12 | 60–90 |
| Parsley | Mar 21 | Apr 11 | Apr 18 | Jun 20 – Aug 22 | 60–80 |
| Rue | — | — | May 2 | Jul 11 – Sep 12 | 70–90 |
| Sage | — | — | May 2 | Jul 18 – Sep 12 | 75–90 |
| Savory | — | — | May 2 | Jun 27 – Aug 22 | 50–70 |
| Sorrel | Mar 21 | Apr 11 | Apr 18 | May 30 – Aug 1 | 40–60 |
| Tarragon | — | — | May 2 | Jul 4 – Sep 12 | 60–90 |
| Thai Basil | Mar 7 | May 2 | May 9 | Jul 4 – Sep 5 | 50–75 |
| Thyme | — | — | May 2 | Jul 11 – Sep 12 | 70–90 |
| Valerian | — | — | May 2 | Sep 5 – Oct 17 | 120–180 |
| Yarrow | — | — | May 2 | Aug 1 – Oct 17 | 90–120 |
Monthly Planting Guide for Union County
Gardening Guides & Resources
Helpful guides from The Ultimate Homestead to improve your garden in Union County.
Frequently Asked Questions
What planting zone is Union County, OH?
Union County is in USDA Hardiness Zone 5b. This zone classification determines which perennial plants survive winter and sets the baseline for frost timing across the county.
When is the last frost in Union County, OH?
Based on 31 years of NOAA weather station data, the median last spring frost in Union County falls around April 25. In 8 out of 10 years, last frost lands between April 10 and May 11 — a 31-day window of variability. Use May 11 as your conservative safe-to-plant date for frost-sensitive crops.
When is the first fall frost in Union County, OH?
The median first fall frost in Union County arrives around October 19. In cold years it can arrive as early as October 7; in mild years as late as October 31. Harvest or protect frost-sensitive crops — tomatoes, peppers, basil, squash — before this date.
How long is the growing season in Union County?
Union County has a frost-free growing season of approximately 177 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 0.76 days per decade.
What is the soil like in Union County for gardening?
Union County has predominantly Silt Loam soil with a pH range of 5.8–7.2 and Moderately Well Drained drainage. Most vegetables and herbs grow well with standard composting and seasonal soil amendment.
What is grown commercially in Union County?
Union 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 Union County a good location for home gardening?
Union County scores 68/100 (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 Union County gardeners in Zone 5b organize planting dates, track what's growing, and never miss a planting window.
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