Knox County, IN — Planting Guide
Knox County is in USDA Zone 6a. The average last spring frost is April 10 and the first fall frost is October 23, giving you a growing season of approximately 196 days.
At an elevation of 735 ft, Knox County receives approximately 38.9 in of rainfall annually. Summer highs average 91°F with winter lows around 22°F. The predominant soil type is Silt Loam.
Based on 30 years of NOAA climate station data, the last frost date here varies by 29 days year to year — ranging from March 26 in warm years to April 24 in cold years. The growing season is trending shorter by about 3.07 days per decade. Knox County scores 61/100 (Good) on the Microclimate Index.
🌡️ Zone
6a (-10°F to -5°F min)
❄️ Last Frost
April 10
🍂 First Frost
October 23
📅 Growing Season
196 days
⛰️ Elevation
735 ft
🌧️ Annual Rainfall
38.9 in
Monthly Watering Calendar
When you'll need to water your garden — based on average monthly rainfall vs. the ~1 inch/week most gardens need.
View detailed monthly data
| Month | Avg Rainfall | Rainy Days | Extra Water Needed | Watering Effort |
|---|---|---|---|---|
| Jan | 1.6 in | 8 days | — | None |
| Feb | 1.6 in | 6 days | — | None |
| Mar | 2.6 in | 8 days | 1.7 in | High |
| Apr | 3.8 in | 8 days | 0.5 in | Low |
| May | 4.4 in | 9 days | — | Low |
| Jun | 4.8 in | 10 days | — | Low |
| Jul | 4 in | 9 days | 0.3 in | Low |
| Aug | 4.2 in | 9 days | 0.1 in | Low |
| Sep | 3.5 in | 9 days | 0.8 in | Moderate |
| Oct | 2.7 in | 8 days | 1.6 in | High |
| Nov | 3.1 in | 8 days | — | None |
| Dec | 2.5 in | 6 days | — | None |
Annual total: 38.8 in. Gardens typically need ~1 inch of water per week during the growing season. Months marked "None" for extra water are outside the active growing season for your zone — most gardens are dormant and don't need irrigation during those months.
Knox County Soil Profile
Soil Type
Silt Loam
Soil pH
6-7.2
Drainage
Well Drained
Frost Risk Probability
Based on 30 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) | Apr 24 | Nov 6 | 196 days |
| Cautious | Apr 16 | Oct 29 | 196 days |
| Average year | Apr 10 | Oct 23 | 196 days |
| Optimistic | Apr 5 | Oct 19 | 197 days |
| Aggressive (risky) | Mar 26 | Oct 9 | 197 days |
Not very — frost dates can vary by ±29 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 3.1 days per decade). Use the "Conservative" dates and choose fast-maturing varieties.
Gardening Difficulty Score
Knox County offers good growing conditions. A little planning around frost dates goes a long way.
Local Gardening Help in Knox 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 Knox County's climate and soil.
County Extension Office
Knox County Purdue University Extension Extension Office
Phone: 765-494-8491
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 Knox County
Finding local nurseries & garden centers in Knox County
Why Buy Local
Local nurseries carry plants that are proven to grow in your area. Staff can give you advice specific to Knox 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 Knox County IN" or "garden center Knox 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 Knox County IN" or check your extension office and local parks department. Facebook groups like "Knox County Gardeners" or "Indiana 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
14.7 hours
Summer solstice daylight
Shortest Day
9.3 hours
Winter solstice daylight
Peak Sun Hours
9.3 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 | 9.6 hr | 3.8 hr | Short day |
| February | 10.5 hr | 4.7 hr | Short day |
| March | 11.7 hr | 5.4 hr | Short day |
| April | 13 hr | 6.5 hr | Neutral |
| May | 14.1 hr | 8 hr | Long day |
| June | 14.7 hr | 9 hr | Long day |
| July | 14.5 hr | 9.3 hr | Long day |
| August | 13.5 hr | 8 hr | Neutral |
| September | 12.2 hr | 6.9 hr | Neutral |
| October | 11 hr | 5.5 hr | Short day |
| November | 9.8 hr | 3.9 hr | Short day |
| December | 9.3 hr | 3.6 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 May through Oct.
Best Month to Compost
Jun
Microbial activity peaks when soil is warm.
Active Composting
8 months
Nearly year-round composting.
View detailed monthly data
| Month | Soil 4" Deep | Soil 8" Deep | Compost Activity | Time to Finish |
|---|---|---|---|---|
| Jan | 31°F | 40°F | ❄️ Dormant | ~36 weeks |
| Feb | 31°F | 37°F | ❄️ Dormant | ~36 weeks |
| Mar | 39°F | 42°F | ❄️ Dormant | ~36 weeks |
| Apr | 51°F | 50°F | ♻️ Active | ~14 weeks |
| May | 63°F | 59°F | ♻️ Active | ~14 weeks |
| Jun | 73°F | 70°F | 🔥 Peak | ~8 weeks |
| Jul | 80°F | 76°F | 🔥 Peak | ~8 weeks |
| Aug | 82°F | 79°F | 🔥 Peak | ~8 weeks |
| Sep | 75°F | 76°F | 🔥 Peak | ~8 weeks |
| Oct | 61°F | 66°F | ♻️ Active | ~14 weeks |
| Nov | 51°F | 56°F | ♻️ Active | ~14 weeks |
| Dec | 39°F | 44°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 Knox 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 6 common pests in your area
| Pest | Risk Level | Peak Months |
|---|---|---|
| Aphids | Moderate | Apr, May, Jun, Jul, Aug, Sep |
| Japanese beetles | Moderate | Jun, Jul, Aug |
| Squash vine borers | Moderate | Jun, Jul |
| Tomato hornworms | Moderate | Jun, Jul, Aug |
| Cucumber beetles | Low | May, Jun, Jul |
| Stink bugs | Low | 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 Knox County
Cover crops protect bare soil, fix nitrogen, suppress weeds, and improve soil structure — with county-specific planting dates.
Fall Cover Crops (7 options) — Plant after harvest to protect soil over winter
| Crop | Plant By | Terminate | N-Fixing | Soil Benefit |
|---|---|---|---|---|
| Austrian winter peas | Aug 18 | Mar 27 | ✓ Yes | Fixes nitrogen, good for heavy clay soils |
| Crimson clover | Aug 28 | Mar 27 | ✓ Yes | Fixes nitrogen, attracts pollinators in spring |
| Daikon radish | Sep 9 | Mar 20 | — | Deep taproot breaks compaction, excellent for clay soils |
| Hairy vetch | Jul 30 | Mar 20 | ✓ Yes | Excellent nitrogen fixer, good for depleted soils |
| Oats | Sep 17 | Mar 27 | — | Quick biomass, winterkills in cold zones — no spring tillage needed |
| Winter rye | Jul 31 | Mar 27 | — | Suppresses weeds, prevents erosion, breaks up compacted soil |
| Winter wheat | Jul 26 | Mar 27 | — | Erosion control, weed suppression, good biomass |
Spring Cover Crops (3 options) — Build soil before the main growing season
| Crop | Plant By | Terminate | N-Fixing | Soil Benefit |
|---|---|---|---|---|
| Buckwheat | Apr 22 | Aug 14 | — | Rapid growth, attracts pollinators, suppresses weeds |
| Sorghum-sudan grass | Apr 13 | Aug 28 | — | Massive biomass, breaks compaction, suppresses nematodes |
| White clover | Mar 15 | Aug 28 | ✓ 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 7 | Oct 9 | — | Deep roots break compaction, attract pollinators and beneficial insects |
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: 10 mph
Fall: 9 mph Winter: 11 mph
Prevailing wind: SW. Moderate wind — consider a temporary windbreak for young seedlings.
Windbreak Benefit
4.8/10
Moderately beneficial — a simple fence or trellis can protect delicate crops from wind stress.
Frost Pocket Risk
Low
Relatively flat terrain (170 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
19,337 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 1,500 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 38.8 inches of rain per year
- A 1,000 sq ft roof can collect roughly 19,337 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 Knox County
Soil Type
Silt Loam
Soil pH 6–7.2 · 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. (38.9 in. annual rainfall)
Season Tips
196-day frost-free season
Plenty of time for warm-season crops. Start heat-lovers indoors 6–8 weeks before last frost to maximise your harvest window.
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 Knox County
108 vegetables that grow well in Zone 6a with planting dates for Knox County.
Show all 108 vegetables with planting dates
| Plant | Start Indoors | Direct Sow | Transplant | Harvest | Days to Maturity |
|---|---|---|---|---|---|
| Acorn Squash | Mar 6 | Apr 17 | Apr 24 | Jul 17 – Aug 21 | 80–100 |
| Amaranth | Feb 13 | Apr 17 | Apr 24 | Jul 24 – Sep 11 | 90–120 |
| Arugula | Mar 6 | Mar 27 | Apr 10 | May 15 – Jul 17 | 30–50 |
| Asparagus | — | — | Apr 24 | — | 730–1095 |
| Beets | — | Mar 27 | — | May 22 – Jun 19 | 50–70 |
| Belgian Endive | Mar 6 | Mar 27 | Apr 10 | Jul 31 – Sep 25 | 110–150 |
| Bitter Melon | Feb 13 | Apr 17 | Apr 24 | Jun 26 – Aug 7 | 60–90 |
| Black Beans | — | Apr 17 | — | Jul 17 – Sep 4 | 90–120 |
| Bok Choy | Mar 6 | Mar 27 | Apr 10 | May 22 – Jun 26 | 40–60 |
| Broccoli | Mar 6 | Mar 27 | Apr 10 | Jun 12 – Jul 24 | 60–90 |
| Broccoli Rabe | Mar 6 | Mar 27 | Apr 10 | May 22 – Jun 26 | 40–60 |
| Brussels Sprouts | Mar 6 | Mar 27 | Apr 10 | Jul 10 – Sep 4 | 90–130 |
| Butternut Squash | Mar 6 | Apr 17 | Apr 24 | Jul 24 – Aug 28 | 85–110 |
| Cabbage | Mar 6 | Mar 27 | Apr 10 | Jun 12 – Aug 7 | 60–100 |
| Calabash | Feb 13 | Apr 17 | Apr 24 | Jul 17 – Sep 11 | 80–120 |
| Carrots | — | Mar 27 | — | May 29 – Jul 3 | 60–80 |
| Cauliflower | Mar 6 | Mar 27 | Apr 10 | Jun 5 – Aug 7 | 55–100 |
| Celeriac | Mar 6 | Mar 27 | Apr 10 | Jul 24 – Aug 28 | 100–120 |
| Celery | Mar 6 | Mar 27 | Apr 10 | Jul 3 – Aug 28 | 80–120 |
| Celtuce | Mar 6 | Mar 27 | Apr 10 | Jun 12 – Jul 24 | 60–90 |
| Chard | Mar 6 | Mar 27 | Apr 10 | Jun 5 – Jul 24 | 50–60 |
| Chickpeas | Mar 6 | Mar 27 | Apr 10 | Jul 3 – Aug 14 | 80–110 |
| Chicory | Mar 6 | Mar 27 | Apr 10 | Jun 12 – Jul 24 | 60–85 |
| Chinese Cabbage | Mar 6 | Mar 27 | Apr 10 | Jun 5 – Jul 3 | 50–70 |
| Christmas Lima Beans | Feb 13 | Apr 17 | Apr 24 | Jul 17 – Aug 21 | 80–100 |
| Collard Greens | Mar 6 | Mar 27 | Apr 10 | Jun 5 – Aug 7 | 55–75 |
| Corn | — | Apr 17 | — | Jun 19 – Aug 14 | 60–100 |
| Cowpeas | — | Apr 17 | — | Jun 19 – Jul 31 | 60–90 |
| Cress | Mar 6 | Mar 27 | Apr 10 | Apr 24 – May 15 | 14–21 |
| Crookneck Squash | Mar 6 | Apr 17 | Apr 24 | Jun 12 – Jul 10 | 45–60 |
| Crosne | — | Mar 27 | — | Aug 28 – Oct 9 | 150–200 |
| Cucumber | Mar 6 | Apr 17 | Apr 24 | Jun 19 – Aug 14 | 50–70 |
| Daikon | — | Mar 27 | — | May 22 – Jun 19 | 50–70 |
| Delicata Squash | Mar 6 | Apr 17 | Apr 24 | Jul 17 – Aug 21 | 80–100 |
| Edamame | — | Apr 17 | — | Jul 3 – Aug 14 | 75–100 |
| Eggplant | Jan 30 | Apr 17 | Apr 24 | Jul 3 – Sep 4 | 65–85 |
| Endive | Mar 6 | Mar 27 | Apr 10 | May 29 – Jul 3 | 45–65 |
| Escarole | Mar 6 | Mar 27 | Apr 10 | Jun 5 – Jul 3 | 50–70 |
| Fava Beans | Mar 6 | Mar 27 | Apr 10 | Jun 26 – Aug 7 | 75–100 |
| Fennel | Feb 13 | Apr 17 | Apr 24 | Jun 26 – Aug 7 | 60–90 |
| Garlic | — | — | — | — | 90–240 |
| Green Beans | — | Apr 17 | — | Jun 12 – Aug 7 | 50–65 |
| Horseradish | — | — | Apr 24 | Aug 28 – Nov 6 | 120–180 |
| Hot Peppers | Jan 30 | Apr 17 | Apr 24 | Jul 3 – Oct 9 | 70–120 |
| Hubbard Squash | Mar 6 | Apr 17 | Apr 24 | Aug 7 – Sep 11 | 100–120 |
| Kabocha | Mar 6 | Apr 17 | Apr 24 | Jul 24 – Aug 21 | 85–100 |
| Kai Lan | Mar 6 | Mar 27 | Apr 10 | May 29 – Jun 26 | 45–60 |
| Kale | Mar 6 | Mar 27 | Apr 10 | Jun 5 – Jul 31 | 50–70 |
| Kidney Beans | — | Apr 17 | — | Jul 17 – Aug 21 | 85–110 |
| Kohlrabi | Mar 6 | Mar 27 | Apr 10 | May 29 – Jul 3 | 45–65 |
| Komatsuna | Mar 6 | Mar 27 | Apr 10 | May 15 – Jun 19 | 35–50 |
| Leeks | Mar 6 | Mar 27 | Apr 10 | Jul 10 – Sep 25 | 90–150 |
| Lentils | Mar 6 | Mar 27 | Apr 10 | Jul 3 – Aug 14 | 80–110 |
| Lettuce | Mar 6 | Mar 27 | Apr 10 | May 15 – Jul 24 | 30–60 |
| Lima Beans | — | Apr 17 | — | Jun 19 – Jul 31 | 60–90 |
| Loofah | Feb 13 | Apr 17 | Apr 24 | Aug 7 – Oct 9 | 100–150 |
| Luffa | Feb 13 | Apr 17 | Apr 24 | Jul 24 – Oct 9 | 90–150 |
| Mache | Mar 6 | Mar 27 | Apr 10 | May 22 – Jun 26 | 40–60 |
| Melon | Mar 6 | Apr 17 | Apr 24 | Jul 3 – Aug 21 | 70–100 |
| Microgreens | Mar 6 | Mar 27 | Apr 10 | Apr 17 – May 15 | 7–21 |
| Mitsuba | Mar 6 | Mar 27 | Apr 3 | May 29 – Jul 24 | 50–70 |
| Mizuna | Mar 6 | Mar 27 | Apr 10 | May 15 – Jun 12 | 30–45 |
| Mustard Greens | Mar 6 | Mar 27 | Apr 10 | May 15 – Jul 17 | 30–50 |
| Napa Cabbage | Mar 6 | Mar 27 | Apr 10 | Jun 5 – Jul 10 | 55–75 |
| New Zealand Spinach | Feb 13 | Apr 17 | Apr 24 | Jun 19 – Jul 17 | 55–70 |
| Okra | Feb 13 | Apr 17 | Apr 24 | Jun 19 – Aug 14 | 50–65 |
| Onion | Mar 6 | Mar 27 | Apr 10 | Jul 10 – Aug 28 | 90–120 |
| Pac Choi | Mar 6 | Mar 27 | Apr 10 | May 22 – Jun 19 | 40–55 |
| Parsnip | — | Mar 27 | — | Jul 10 – Aug 21 | 100–130 |
| Patty Pan Squash | Mar 6 | Apr 17 | Apr 24 | Jun 12 – Jul 10 | 45–60 |
| Peas | Mar 6 | Mar 27 | Apr 10 | Jun 5 – Jul 31 | 55–70 |
| Peppers | Jan 30 | Apr 17 | Apr 24 | Jun 26 – Sep 4 | 60–90 |
| Pole Beans | Feb 13 | Apr 17 | Apr 24 | Jun 19 – Aug 14 | 55–70 |
| Potatoes | Feb 13 | Apr 17 | Apr 24 | Jul 3 – Sep 11 | 70–120 |
| Pumpkin | Mar 6 | Apr 17 | Apr 24 | Jul 24 – Sep 11 | 85–120 |
| Purslane | Mar 6 | Mar 27 | Apr 10 | May 22 – Jun 26 | 40–60 |
| Radicchio | Mar 6 | Mar 27 | Apr 10 | Jun 12 – Jul 17 | 60–80 |
| Radish | — | Mar 27 | — | Apr 24 – May 15 | 22–35 |
| Rhubarb | — | — | May 1 | — | 365–730 |
| Romanesco | Mar 6 | Mar 27 | Apr 10 | Jun 26 – Aug 7 | 75–100 |
| Rutabaga | — | Mar 27 | — | Jun 19 – Jul 24 | 80–100 |
| Salsify | — | Mar 27 | — | Jul 10 – Aug 21 | 100–130 |
| Savoy Cabbage | Mar 6 | Mar 27 | Apr 10 | Jun 19 – Aug 14 | 70–110 |
| Scallions | Mar 6 | Mar 27 | Apr 10 | Jun 5 – Jul 3 | 50–70 |
| Scarlet Runner Beans | Feb 13 | Apr 17 | Apr 24 | Jun 26 – Jul 31 | 60–80 |
| Shallot | Mar 6 | Mar 27 | Apr 10 | Jul 10 – Aug 28 | 90–120 |
| Shiso | Feb 20 | Apr 17 | Apr 24 | Jun 19 – Aug 14 | 50–70 |
| Snap Peas | Feb 13 | Apr 17 | Apr 24 | Jun 19 – Aug 14 | 55–70 |
| Snow Peas | Mar 6 | Mar 27 | Apr 10 | Jun 5 – Jul 31 | 50–65 |
| Soybeans | — | Apr 17 | — | Jul 10 – Sep 4 | 80–120 |
| Spaghetti Squash | Mar 6 | Apr 17 | Apr 24 | Jul 24 – Aug 21 | 85–100 |
| Spinach | Mar 6 | Mar 27 | Apr 10 | May 15 – Jul 17 | 35–50 |
| Squash (Summer) | Mar 6 | Apr 17 | Apr 24 | Jun 12 – Aug 14 | 45–65 |
| Squash (Winter) | Mar 6 | Apr 17 | Apr 24 | Jul 17 – Sep 11 | 80–120 |
| Sunchoke | — | — | Apr 24 | Aug 14 – Oct 9 | 110–150 |
| Sunflower | Feb 13 | Apr 17 | Apr 24 | Jul 3 – Aug 21 | 70–100 |
| Sweet Corn | — | Apr 17 | — | Jun 19 – Jul 31 | 60–90 |
| Sweet Potatoes | Feb 13 | Apr 17 | Apr 24 | Jul 24 – Sep 11 | 90–120 |
| Tatsoi | Mar 6 | Mar 27 | Apr 10 | May 15 – Jun 19 | 35–50 |
| Tomatillo | Feb 13 | Apr 17 | Apr 24 | Jun 26 – Sep 4 | 60–85 |
| Tomatoes | Feb 13 | Apr 17 | Apr 24 | Jun 26 – Sep 4 | 60–85 |
| Turnip | — | Mar 27 | — | May 8 – Jun 12 | 40–60 |
| Watercress | Mar 6 | Mar 27 | Apr 10 | May 22 – Jun 26 | 40–60 |
| Watermelon | Mar 6 | Apr 17 | Apr 24 | Jul 3 – Aug 21 | 70–100 |
| Wax Beans | — | Apr 17 | — | Jun 12 – Aug 7 | 50–65 |
| Winter Melon | Feb 13 | Apr 17 | Apr 24 | Jul 24 – Sep 11 | 90–120 |
| Yard Long Beans | Feb 13 | Apr 17 | Apr 24 | Jun 19 – Jul 31 | 55–80 |
| Zucchini | Mar 6 | Apr 17 | Apr 24 | Jun 12 – Aug 7 | 45–60 |
🍓 Fruits to Grow in Knox County
27 fruits that grow well in Zone 6a with planting dates for Knox County.
Show all 27 fruits with planting dates
| Plant | Start Indoors | Direct Sow | Transplant | Harvest | Days to Maturity |
|---|---|---|---|---|---|
| Alpine Strawberries | — | — | May 1 | Jul 31 – Nov 13 | 90–180 |
| Aronia | — | — | May 1 | — | 730–1095 |
| Blackberries | — | — | May 1 | — | 365–730 |
| Blueberries | — | — | May 1 | — | 730–1095 |
| Boysenberries | — | — | May 1 | — | 365–730 |
| Cantaloupe | — | — | May 1 | Jul 10 – Aug 14 | 70–90 |
| Che Fruit | — | — | May 1 | — | 1095–1825 |
| Cranberries | — | — | May 1 | — | 730–1095 |
| Currants | — | — | May 1 | — | 730–1095 |
| Elderberries | — | — | May 1 | — | 730–1095 |
| Goji Berries | — | — | May 1 | — | 730–1095 |
| Gooseberries | — | — | May 1 | — | 730–1095 |
| Grapes | — | — | May 1 | — | 730–1095 |
| Ground Cherry | — | — | May 1 | Jul 10 – Sep 4 | 65–80 |
| Hardy Kiwi | — | — | May 1 | — | 1095–1825 |
| Haskaps | — | — | May 1 | — | 730–1095 |
| Honeydew | — | — | May 1 | Jul 24 – Sep 4 | 80–110 |
| Jostaberry | — | — | May 1 | — | 730–1095 |
| Lingonberries | — | — | May 1 | — | 730–1095 |
| Medlar | — | — | May 1 | — | 1095–1825 |
| Mulberries | — | — | May 1 | — | 730–1825 |
| Pawpaw | — | — | May 1 | — | 1095–2555 |
| Persimmon | — | — | May 1 | — | 1095–2555 |
| Quince | — | — | May 1 | — | 1095–1825 |
| Raspberries | — | — | May 1 | — | 365–730 |
| Serviceberries | — | — | May 1 | — | 730–1095 |
| Strawberries | — | — | May 1 | Jul 31 – Nov 13 | 90–365 |
🌿 Herbs to Grow in Knox County
38 herbs that grow well in Zone 6a with planting dates for Knox County.
Show all 38 herbs with planting dates
| Plant | Start Indoors | Direct Sow | Transplant | Harvest | Days to Maturity |
|---|---|---|---|---|---|
| Angelica | Mar 6 | Mar 27 | Apr 3 | — | 365–730 |
| Anise | Mar 6 | Mar 27 | Apr 3 | Jul 3 – Sep 18 | 90–120 |
| Basil | Feb 20 | Apr 17 | Apr 24 | Jun 19 – Aug 21 | 50–75 |
| Bee Balm | — | — | Apr 17 | Jul 17 – Oct 2 | 90–120 |
| Borage | Mar 6 | Mar 27 | Apr 3 | May 29 – Jul 17 | 50–60 |
| Caraway | Mar 6 | Mar 27 | Apr 3 | — | 365–450 |
| Catnip | — | — | Apr 17 | Jun 19 – Aug 21 | 60–80 |
| Chamomile | Mar 6 | Mar 27 | Apr 3 | Jun 5 – Aug 14 | 60–90 |
| Chervil | Mar 6 | Mar 27 | Apr 3 | May 15 – Jul 17 | 40–60 |
| Chives | — | — | Apr 17 | Jun 19 – Aug 28 | 60–90 |
| Cilantro | Mar 6 | Mar 27 | Apr 3 | May 15 – Jul 17 | 40–60 |
| Comfrey | — | — | Apr 17 | Jun 19 – Aug 28 | 60–90 |
| Cumin | Mar 6 | Mar 27 | Apr 3 | Jul 17 – Sep 18 | 100–120 |
| Dill | Mar 6 | Mar 27 | Apr 3 | May 15 – Jul 17 | 40–60 |
| Echinacea | — | — | Apr 17 | Aug 21 – Oct 30 | 120–180 |
| Epazote | Feb 20 | Apr 17 | Apr 24 | Jun 12 – Aug 7 | 45–60 |
| Fennel (herb) | Mar 6 | Mar 27 | Apr 3 | Jun 5 – Aug 14 | 60–90 |
| Feverfew | — | — | Apr 17 | Jul 17 – Oct 2 | 90–120 |
| Garlic Chives | — | — | Apr 17 | Jun 19 – Aug 28 | 60–90 |
| Horehound | — | — | Apr 17 | Jul 3 – Aug 28 | 75–90 |
| Hyssop | — | — | Apr 17 | Jun 26 – Aug 28 | 70–90 |
| Lavender | — | — | Apr 17 | Jul 17 – Oct 30 | 90–200 |
| Lemon Balm | — | — | Apr 17 | Jun 19 – Aug 7 | 60–70 |
| Lemon Thyme | — | — | Apr 17 | Jun 26 – Aug 28 | 70–90 |
| Lovage | — | — | Apr 17 | Jun 26 – Aug 28 | 70–90 |
| Marjoram | — | — | Apr 17 | Jun 19 – Aug 28 | 60–90 |
| Mint | — | — | Apr 17 | Jun 19 – Aug 28 | 60–90 |
| Oregano | — | — | Apr 17 | Jun 19 – Aug 28 | 60–90 |
| Parsley | Mar 6 | Mar 27 | Apr 3 | Jun 5 – Aug 7 | 60–80 |
| Rue | — | — | Apr 17 | Jun 26 – Aug 28 | 70–90 |
| Sage | — | — | Apr 17 | Jul 3 – Aug 28 | 75–90 |
| Savory | — | — | Apr 17 | Jun 12 – Aug 7 | 50–70 |
| Sorrel | Mar 6 | Mar 27 | Apr 3 | May 15 – Jul 17 | 40–60 |
| Tarragon | — | — | Apr 17 | Jun 19 – Aug 28 | 60–90 |
| Thai Basil | Feb 20 | Apr 17 | Apr 24 | Jun 19 – Aug 21 | 50–75 |
| Thyme | — | — | Apr 17 | Jun 26 – Aug 28 | 70–90 |
| Valerian | — | — | Apr 17 | Aug 21 – Oct 30 | 120–180 |
| Yarrow | — | — | Apr 17 | Jul 17 – Oct 2 | 90–120 |
Monthly Planting Guide for Knox County
Gardening Guides & Resources
Helpful guides from The Ultimate Homestead to improve your garden in Knox County.
Frequently Asked Questions
What planting zone is Knox County, IN?
Knox County is in USDA Hardiness Zone 6a. 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 Knox County, IN?
Based on 30 years of NOAA weather station data, the median last spring frost in Knox County falls around April 10. In 8 out of 10 years, last frost lands between March 26 and April 24 — a 29-day window of variability. Use April 24 as your conservative safe-to-plant date for frost-sensitive crops.
When is the first fall frost in Knox County, IN?
The median first fall frost in Knox County arrives around October 23. In cold years it can arrive as early as October 9; in mild years as late as November 6. Harvest or protect frost-sensitive crops — tomatoes, peppers, basil, squash — before this date.
How long is the growing season in Knox County?
Knox County has a frost-free growing season of approximately 196 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 3.07 days per decade.
What is the soil like in Knox County for gardening?
Knox County has predominantly Silt Loam soil with a pH range of 6–7.2 and Well Drained drainage. Most vegetables and herbs grow well with standard composting and seasonal soil amendment.
What is grown commercially in Knox County?
Knox County has commercial agriculture that includes Corn, Soybeans, Hay, Wheat, Oats. These crops reflect the local climate and soil conditions — what succeeds commercially often translates well to home gardens in the same area.
Is Knox County a good location for home gardening?
Knox County scores 61/100 (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 Knox County gardeners in Zone 6a 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.
