Cass County, IL — Planting Guide
Cass County is in USDA Zone 5b. The average last spring frost is April 15 and the first fall frost is October 16, giving you a growing season of approximately 184 days.
At an elevation of 703 ft, Cass County receives approximately 31.9 in of rainfall annually. Summer highs average 83°F with winter lows around 12°F. The predominant soil type is Silt Loam.
Based on 31 years of NOAA climate station data, the last frost date here varies by 30 days year to year — ranging from March 31 in warm years to April 30 in cold years. The growing season is trending shorter by about 1.46 days per decade. Cass County scores 64/100 (Good) on the Microclimate Index.
🌡️ Zone
5b (-15°F to -10°F min)
❄️ Last Frost
April 15
🍂 First Frost
October 16
📅 Growing Season
184 days
⛰️ Elevation
703 ft
🌧️ Annual Rainfall
31.9 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 | 1.4 in | 8 days | — | None |
| Feb | 1.4 in | 6 days | — | None |
| Mar | 2.3 in | 9 days | — | None |
| Apr | 2.8 in | 10 days | 1.5 in | Moderate |
| May | 3.6 in | 10 days | 0.7 in | Moderate |
| Jun | 3.7 in | 10 days | 0.6 in | Moderate |
| Jul | 3.3 in | 7 days | 1 in | Moderate |
| Aug | 3.8 in | 8 days | 0.5 in | Low |
| Sep | 3.3 in | 8 days | 1 in | Moderate |
| Oct | 2.6 in | 6 days | 1.7 in | High |
| Nov | 2 in | 8 days | — | None |
| Dec | 1.6 in | 7 days | — | None |
Annual total: 31.8 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.
Cass County Soil Profile
Soil Type
Silt Loam
Soil pH
6-7.2
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) | Apr 30 | Oct 29 | 182 days |
| Cautious | Apr 19 | Oct 25 | 189 days |
| Average year | Apr 15 | Oct 16 | 184 days |
| Optimistic | Apr 9 | Oct 10 | 184 days |
| Aggressive (risky) | Mar 31 | Oct 4 | 187 days |
Not very — frost dates can vary by ±30 days year-to-year. Use the "Conservative" row in the table below, and keep row covers handy for surprise late frosts.
Yes — growing seasons are getting shorter here (about 1.5 days per decade). Use the "Conservative" dates and choose fast-maturing varieties.
Gardening Difficulty Score
Cass County offers good growing conditions. A little planning around frost dates goes a long way.
Local Gardening Help in Cass 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 Cass County's climate and soil.
County Extension Office
Cass County University of Illinois Extension Extension Office
Phone: 217-333-7672
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 Cass County
Finding local nurseries & garden centers in Cass County
Why Buy Local
Local nurseries carry plants that are proven to grow in your area. Staff can give you advice specific to Cass 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 Cass County IL" or "garden center Cass 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 Cass County IL" or check your extension office and local parks department. Facebook groups like "Cass County Gardeners" or "Illinois 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
14.8 hours
Summer solstice daylight
Shortest Day
9.2 hours
Winter solstice daylight
Peak Sun Hours
9.4 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 | 9.5 hr | 3.8 hr | Short day |
| February | 10.5 hr | 4.7 hr | Short day |
| March | 11.7 hr | 5.5 hr | Short day |
| April | 13.1 hr | 6.5 hr | Neutral |
| May | 14.2 hr | 8.2 hr | Long day |
| June | 14.8 hr | 9.4 hr | Long day |
| July | 14.6 hr | 9.1 hr | Long day |
| August | 13.6 hr | 8.6 hr | Neutral |
| September | 12.2 hr | 6.9 hr | Neutral |
| October | 10.9 hr | 5.6 hr | Short day |
| November | 9.7 hr | 3.7 hr | Short day |
| December | 9.2 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 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 | 23°F | 32°F | ❄️ Dormant | ~36 weeks |
| Feb | 23°F | 29°F | ❄️ Dormant | ~36 weeks |
| Mar | 32°F | 36°F | ❄️ Dormant | ~36 weeks |
| Apr | 44°F | 45°F | 🐢 Slow | ~24 weeks |
| May | 58°F | 55°F | ♻️ Active | ~14 weeks |
| Jun | 68°F | 65°F | 🔥 Peak | ~8 weeks |
| Jul | 76°F | 70°F | 🔥 Peak | ~8 weeks |
| Aug | 80°F | 73°F | 🔥 Peak | ~8 weeks |
| Sep | 72°F | 70°F | 🔥 Peak | ~8 weeks |
| Oct | 57°F | 59°F | ♻️ Active | ~14 weeks |
| Nov | 41°F | 49°F | 🐢 Slow | ~24 weeks |
| Dec | 29°F | 38°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 Cass 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 | Low | 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 Cass 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 16 | Aug 21 | — | Rapid growth, attracts pollinators, suppresses weeds |
| Sorghum-sudan grass | Apr 19 | Aug 14 | — | Massive biomass, breaks compaction, suppresses nematodes |
| White clover | Mar 16 | Aug 21 | ✓ 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 | Apr 30 | Oct 2 | — | 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 11 | Mar 25 | ✓ Yes | Fixes nitrogen, good for heavy clay soils |
| Daikon radish | Aug 20 | Mar 25 | — | Deep taproot breaks compaction, excellent for clay soils |
| Hairy vetch | Aug 6 | Mar 25 | ✓ Yes | Excellent nitrogen fixer, good for depleted soils |
| Oats | Sep 19 | Apr 1 | — | Quick biomass, winterkills in cold zones — no spring tillage needed |
| Winter rye | Jul 25 | Mar 25 | — | Suppresses weeds, prevents erosion, breaks up compacted soil |
| Winter wheat | Jul 11 | Mar 25 | — | Erosion control, weed suppression, good biomass |
Wind & Microclimate
Wind dries soil, stresses plants, and affects frost patterns. Understanding your exposure helps with garden placement.
Seasonal Wind Speed
Spring: 12 mph Summer: 9 mph
Fall: 10 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 (241 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
15,849 gal
Per 1,000 sq ft of roof area (at 80% collection efficiency)
Recommended Setup
6 rain barrels (55 gal each)
For a typical 500 sq ft garden. Serious collectors: consider a 1,750 gal tank.
Legal Status
Unrestricted
Rainwater harvesting is fully legal in your state with no restrictions.
Best Collection Months
May, Jun, Jul, Aug
Highest rainfall months — your barrels will fill up quickly during these months.
Months to Draw From Storage
Jan, Feb, Dec
Dry months when you'll rely on stored water — size your storage for this gap.
Rainwater collection tips for your area
- Your county receives approximately 31.8 inches of rain per year
- A 1,000 sq ft roof can collect roughly 15,849 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 Cass County
Soil Type
Silt Loam
Soil pH 6–7.2 · Excessively 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
184-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 Cass County
106 vegetables that grow well in Zone 5b with planting dates for Cass County.
Show all 106 vegetables with planting dates
| Plant | Start Indoors | Direct Sow | Transplant | Harvest | Days to Maturity |
|---|---|---|---|---|---|
| Acorn Squash | Mar 11 | Apr 22 | Apr 29 | Jul 22 – Aug 26 | 80–100 |
| Amaranth | Feb 18 | Apr 22 | Apr 29 | Jul 29 – Sep 16 | 90–120 |
| Arugula | Mar 11 | Apr 1 | Apr 15 | May 20 – Jul 22 | 30–50 |
| Asparagus | — | — | Apr 29 | — | 730–1095 |
| Beets | — | Apr 1 | — | May 27 – Jun 24 | 50–70 |
| Belgian Endive | Mar 11 | Apr 1 | Apr 15 | Aug 5 – Sep 30 | 110–150 |
| Bitter Melon | Feb 18 | Apr 22 | Apr 29 | Jul 1 – Aug 12 | 60–90 |
| Black Beans | — | Apr 22 | — | Jul 22 – Sep 9 | 90–120 |
| Bok Choy | Mar 11 | Apr 1 | Apr 15 | May 27 – Jul 1 | 40–60 |
| Broccoli | Mar 11 | Apr 1 | Apr 15 | Jun 17 – Jul 29 | 60–90 |
| Broccoli Rabe | Mar 11 | Apr 1 | Apr 15 | May 27 – Jul 1 | 40–60 |
| Brussels Sprouts | Mar 11 | Apr 1 | Apr 15 | Jul 15 – Sep 9 | 90–130 |
| Butternut Squash | Mar 11 | Apr 22 | Apr 29 | Jul 29 – Sep 2 | 85–110 |
| Cabbage | Mar 11 | Apr 1 | Apr 15 | Jun 17 – Aug 12 | 60–100 |
| Calabash | Feb 18 | Apr 22 | Apr 29 | Jul 22 – Sep 16 | 80–120 |
| Carrots | — | Apr 1 | — | Jun 3 – Jul 8 | 60–80 |
| Cauliflower | Mar 11 | Apr 1 | Apr 15 | Jun 10 – Aug 12 | 55–100 |
| Celeriac | Mar 11 | Apr 1 | Apr 15 | Jul 29 – Sep 2 | 100–120 |
| Celery | Mar 11 | Apr 1 | Apr 15 | Jul 8 – Sep 2 | 80–120 |
| Celtuce | Mar 11 | Apr 1 | Apr 15 | Jun 17 – Jul 29 | 60–90 |
| Chard | Mar 11 | Apr 1 | Apr 15 | Jun 10 – Jul 29 | 50–60 |
| Chickpeas | Mar 11 | Apr 1 | Apr 15 | Jul 8 – Aug 19 | 80–110 |
| Chicory | Mar 11 | Apr 1 | Apr 15 | Jun 17 – Jul 29 | 60–85 |
| Chinese Cabbage | Mar 11 | Apr 1 | Apr 15 | Jun 10 – Jul 8 | 50–70 |
| Christmas Lima Beans | Feb 18 | Apr 22 | Apr 29 | Jul 22 – Aug 26 | 80–100 |
| Collard Greens | Mar 11 | Apr 1 | Apr 15 | Jun 10 – Aug 12 | 55–75 |
| Corn | — | Apr 22 | — | Jun 24 – Aug 19 | 60–100 |
| Cowpeas | — | Apr 22 | — | Jun 24 – Aug 5 | 60–90 |
| Cress | Mar 11 | Apr 1 | Apr 15 | Apr 29 – May 20 | 14–21 |
| Crookneck Squash | Mar 11 | Apr 22 | Apr 29 | Jun 17 – Jul 15 | 45–60 |
| Crosne | — | Apr 1 | — | Sep 2 – Sep 16 | 150–200 |
| Cucumber | Mar 11 | Apr 22 | Apr 29 | Jun 24 – Aug 19 | 50–70 |
| Daikon | — | Apr 1 | — | May 27 – Jun 24 | 50–70 |
| Delicata Squash | Mar 11 | Apr 22 | Apr 29 | Jul 22 – Aug 26 | 80–100 |
| Edamame | — | Apr 22 | — | Jul 8 – Aug 19 | 75–100 |
| Eggplant | Feb 4 | Apr 22 | Apr 29 | Jul 8 – Sep 9 | 65–85 |
| Endive | Mar 11 | Apr 1 | Apr 15 | Jun 3 – Jul 8 | 45–65 |
| Escarole | Mar 11 | Apr 1 | Apr 15 | Jun 10 – Jul 8 | 50–70 |
| Fava Beans | Mar 11 | Apr 1 | Apr 15 | Jul 1 – Aug 12 | 75–100 |
| Fennel | Feb 18 | Apr 22 | Apr 29 | Jul 1 – Aug 12 | 60–90 |
| Garlic | — | — | — | — | 90–240 |
| Green Beans | — | Apr 22 | — | Jun 17 – Aug 12 | 50–65 |
| Horseradish | — | — | Apr 29 | Sep 2 – Oct 14 | 120–180 |
| Hot Peppers | Feb 4 | Apr 22 | Apr 29 | Jul 8 – Oct 14 | 70–120 |
| Hubbard Squash | Mar 11 | Apr 22 | Apr 29 | Aug 12 – Sep 16 | 100–120 |
| Kabocha | Mar 11 | Apr 22 | Apr 29 | Jul 29 – Aug 26 | 85–100 |
| Kai Lan | Mar 11 | Apr 1 | Apr 15 | Jun 3 – Jul 1 | 45–60 |
| Kale | Mar 11 | Apr 1 | Apr 15 | Jun 10 – Aug 5 | 50–70 |
| Kidney Beans | — | Apr 22 | — | Jul 22 – Aug 26 | 85–110 |
| Kohlrabi | Mar 11 | Apr 1 | Apr 15 | Jun 3 – Jul 8 | 45–65 |
| Komatsuna | Mar 11 | Apr 1 | Apr 15 | May 20 – Jun 24 | 35–50 |
| Leeks | Mar 11 | Apr 1 | Apr 15 | Jul 15 – Sep 30 | 90–150 |
| Lentils | Mar 11 | Apr 1 | Apr 15 | Jul 8 – Aug 19 | 80–110 |
| Lettuce | Mar 11 | Apr 1 | Apr 15 | May 20 – Jul 29 | 30–60 |
| Lima Beans | — | Apr 22 | — | Jun 24 – Aug 5 | 60–90 |
| Mache | Mar 11 | Apr 1 | Apr 15 | May 27 – Jul 1 | 40–60 |
| Melon | Mar 11 | Apr 22 | Apr 29 | Jul 8 – Aug 26 | 70–100 |
| Microgreens | Mar 11 | Apr 1 | Apr 15 | Apr 22 – May 20 | 7–21 |
| Mitsuba | Mar 11 | Apr 1 | Apr 8 | Jun 3 – Jul 29 | 50–70 |
| Mizuna | Mar 11 | Apr 1 | Apr 15 | May 20 – Jun 17 | 30–45 |
| Mustard Greens | Mar 11 | Apr 1 | Apr 15 | May 20 – Jul 22 | 30–50 |
| Napa Cabbage | Mar 11 | Apr 1 | Apr 15 | Jun 10 – Jul 15 | 55–75 |
| New Zealand Spinach | Feb 18 | Apr 22 | Apr 29 | Jun 24 – Jul 22 | 55–70 |
| Okra | Feb 18 | Apr 22 | Apr 29 | Jun 24 – Aug 19 | 50–65 |
| Onion | Mar 11 | Apr 1 | Apr 15 | Jul 15 – Sep 2 | 90–120 |
| Pac Choi | Mar 11 | Apr 1 | Apr 15 | May 27 – Jun 24 | 40–55 |
| Parsnip | — | Apr 1 | — | Jul 15 – Aug 26 | 100–130 |
| Patty Pan Squash | Mar 11 | Apr 22 | Apr 29 | Jun 17 – Jul 15 | 45–60 |
| Peas | Mar 11 | Apr 1 | Apr 15 | Jun 10 – Aug 5 | 55–70 |
| Peppers | Feb 4 | Apr 22 | Apr 29 | Jul 1 – Sep 9 | 60–90 |
| Pole Beans | Feb 18 | Apr 22 | Apr 29 | Jun 24 – Aug 19 | 55–70 |
| Potatoes | Feb 18 | Apr 22 | Apr 29 | Jul 8 – Sep 16 | 70–120 |
| Pumpkin | Mar 11 | Apr 22 | Apr 29 | Jul 29 – Sep 16 | 85–120 |
| Purslane | Mar 11 | Apr 1 | Apr 15 | May 27 – Jul 1 | 40–60 |
| Radicchio | Mar 11 | Apr 1 | Apr 15 | Jun 17 – Jul 22 | 60–80 |
| Radish | — | Apr 1 | — | Apr 29 – May 20 | 22–35 |
| Rhubarb | — | — | May 6 | — | 365–730 |
| Romanesco | Mar 11 | Apr 1 | Apr 15 | Jul 1 – Aug 12 | 75–100 |
| Rutabaga | — | Apr 1 | — | Jun 24 – Jul 29 | 80–100 |
| Salsify | — | Apr 1 | — | Jul 15 – Aug 26 | 100–130 |
| Savoy Cabbage | Mar 11 | Apr 1 | Apr 15 | Jun 24 – Aug 19 | 70–110 |
| Scallions | Mar 11 | Apr 1 | Apr 15 | Jun 10 – Jul 8 | 50–70 |
| Scarlet Runner Beans | Feb 18 | Apr 22 | Apr 29 | Jul 1 – Aug 5 | 60–80 |
| Shallot | Mar 11 | Apr 1 | Apr 15 | Jul 15 – Sep 2 | 90–120 |
| Shiso | Feb 25 | Apr 22 | Apr 29 | Jun 24 – Aug 19 | 50–70 |
| Snap Peas | Feb 18 | Apr 22 | Apr 29 | Jun 24 – Aug 19 | 55–70 |
| Snow Peas | Mar 11 | Apr 1 | Apr 15 | Jun 10 – Aug 5 | 50–65 |
| Soybeans | — | Apr 22 | — | Jul 15 – Sep 9 | 80–120 |
| Spaghetti Squash | Mar 11 | Apr 22 | Apr 29 | Jul 29 – Aug 26 | 85–100 |
| Spinach | Mar 11 | Apr 1 | Apr 15 | May 20 – Jul 22 | 35–50 |
| Squash (Summer) | Mar 11 | Apr 22 | Apr 29 | Jun 17 – Aug 19 | 45–65 |
| Squash (Winter) | Mar 11 | Apr 22 | Apr 29 | Jul 22 – Sep 16 | 80–120 |
| Sunchoke | — | — | Apr 29 | Aug 19 – Oct 14 | 110–150 |
| Sunflower | Feb 18 | Apr 22 | Apr 29 | Jul 8 – Aug 26 | 70–100 |
| Sweet Corn | — | Apr 22 | — | Jun 24 – Aug 5 | 60–90 |
| Sweet Potatoes | Feb 18 | Apr 22 | Apr 29 | Jul 29 – Sep 16 | 90–120 |
| Tatsoi | Mar 11 | Apr 1 | Apr 15 | May 20 – Jun 24 | 35–50 |
| Tomatillo | Feb 18 | Apr 22 | Apr 29 | Jul 1 – Sep 9 | 60–85 |
| Tomatoes | Feb 18 | Apr 22 | Apr 29 | Jul 1 – Sep 9 | 60–85 |
| Turnip | — | Apr 1 | — | May 13 – Jun 17 | 40–60 |
| Watercress | Mar 11 | Apr 1 | Apr 15 | May 27 – Jul 1 | 40–60 |
| Watermelon | Mar 11 | Apr 22 | Apr 29 | Jul 8 – Aug 26 | 70–100 |
| Wax Beans | — | Apr 22 | — | Jun 17 – Aug 12 | 50–65 |
| Winter Melon | Feb 18 | Apr 22 | Apr 29 | Jul 29 – Sep 16 | 90–120 |
| Yard Long Beans | Feb 18 | Apr 22 | Apr 29 | Jun 24 – Aug 5 | 55–80 |
| Zucchini | Mar 11 | Apr 22 | Apr 29 | Jun 17 – Aug 12 | 45–60 |
🍓 Fruits to Grow in Cass County
27 fruits that grow well in Zone 5b with planting dates for Cass County.
Show all 27 fruits with planting dates
| Plant | Start Indoors | Direct Sow | Transplant | Harvest | Days to Maturity |
|---|---|---|---|---|---|
| Alpine Strawberries | — | — | May 6 | Aug 5 – Oct 21 | 90–180 |
| Aronia | — | — | May 6 | — | 730–1095 |
| Blackberries | — | — | May 6 | — | 365–730 |
| Blueberries | — | — | May 6 | — | 730–1095 |
| Boysenberries | — | — | May 6 | — | 365–730 |
| Cantaloupe | — | — | May 6 | Jul 15 – Aug 19 | 70–90 |
| Che Fruit | — | — | May 6 | — | 1095–1825 |
| Cranberries | — | — | May 6 | — | 730–1095 |
| Currants | — | — | May 6 | — | 730–1095 |
| Elderberries | — | — | May 6 | — | 730–1095 |
| Goji Berries | — | — | May 6 | — | 730–1095 |
| Gooseberries | — | — | May 6 | — | 730–1095 |
| Grapes | — | — | May 6 | — | 730–1095 |
| Ground Cherry | — | — | May 6 | Jul 15 – Sep 9 | 65–80 |
| Hardy Kiwi | — | — | May 6 | — | 1095–1825 |
| Haskaps | — | — | May 6 | — | 730–1095 |
| Honeydew | — | — | May 6 | Jul 29 – Sep 9 | 80–110 |
| Jostaberry | — | — | May 6 | — | 730–1095 |
| Lingonberries | — | — | May 6 | — | 730–1095 |
| Medlar | — | — | May 6 | — | 1095–1825 |
| Mulberries | — | — | May 6 | — | 730–1825 |
| Pawpaw | — | — | May 6 | — | 1095–2555 |
| Persimmon | — | — | May 6 | — | 1095–2555 |
| Quince | — | — | May 6 | — | 1095–1825 |
| Raspberries | — | — | May 6 | — | 365–730 |
| Serviceberries | — | — | May 6 | — | 730–1095 |
| Strawberries | — | — | May 6 | Aug 5 – Oct 21 | 90–365 |
🌿 Herbs to Grow in Cass County
37 herbs that grow well in Zone 5b with planting dates for Cass County.
Show all 37 herbs with planting dates
| Plant | Start Indoors | Direct Sow | Transplant | Harvest | Days to Maturity |
|---|---|---|---|---|---|
| Angelica | Mar 11 | Apr 1 | Apr 8 | — | 365–730 |
| Anise | Mar 11 | Apr 1 | Apr 8 | Jul 8 – Sep 23 | 90–120 |
| Basil | Feb 25 | Apr 22 | Apr 29 | Jun 24 – Aug 26 | 50–75 |
| Bee Balm | — | — | Apr 22 | Jul 22 – Oct 7 | 90–120 |
| Borage | Mar 11 | Apr 1 | Apr 8 | Jun 3 – Jul 22 | 50–60 |
| Caraway | Mar 11 | Apr 1 | Apr 8 | — | 365–450 |
| Catnip | — | — | Apr 22 | Jun 24 – Aug 26 | 60–80 |
| Chamomile | Mar 11 | Apr 1 | Apr 8 | Jun 10 – Aug 19 | 60–90 |
| Chervil | Mar 11 | Apr 1 | Apr 8 | May 20 – Jul 22 | 40–60 |
| Chives | — | — | Apr 22 | Jun 24 – Sep 2 | 60–90 |
| Cilantro | Mar 11 | Apr 1 | Apr 8 | May 20 – Jul 22 | 40–60 |
| Comfrey | — | — | Apr 22 | Jun 24 – Sep 2 | 60–90 |
| Cumin | Mar 11 | Apr 1 | Apr 8 | Jul 22 – Sep 23 | 100–120 |
| Dill | Mar 11 | Apr 1 | Apr 8 | May 20 – Jul 22 | 40–60 |
| Echinacea | — | — | Apr 22 | Aug 26 – Oct 7 | 120–180 |
| Epazote | Feb 25 | Apr 22 | Apr 29 | Jun 17 – Aug 12 | 45–60 |
| Fennel (herb) | Mar 11 | Apr 1 | Apr 8 | Jun 10 – Aug 19 | 60–90 |
| Feverfew | — | — | Apr 22 | Jul 22 – Oct 7 | 90–120 |
| Garlic Chives | — | — | Apr 22 | Jun 24 – Sep 2 | 60–90 |
| Horehound | — | — | Apr 22 | Jul 8 – Sep 2 | 75–90 |
| Hyssop | — | — | Apr 22 | Jul 1 – Sep 2 | 70–90 |
| Lavender | — | — | Apr 22 | Jul 22 – Oct 7 | 90–200 |
| Lemon Balm | — | — | Apr 22 | Jun 24 – Aug 12 | 60–70 |
| Lemon Thyme | — | — | Apr 22 | Jul 1 – Sep 2 | 70–90 |
| Lovage | — | — | Apr 22 | Jul 1 – Sep 2 | 70–90 |
| Mint | — | — | Apr 22 | Jun 24 – Sep 2 | 60–90 |
| Oregano | — | — | Apr 22 | Jun 24 – Sep 2 | 60–90 |
| Parsley | Mar 11 | Apr 1 | Apr 8 | Jun 10 – Aug 12 | 60–80 |
| Rue | — | — | Apr 22 | Jul 1 – Sep 2 | 70–90 |
| Sage | — | — | Apr 22 | Jul 8 – Sep 2 | 75–90 |
| Savory | — | — | Apr 22 | Jun 17 – Aug 12 | 50–70 |
| Sorrel | Mar 11 | Apr 1 | Apr 8 | May 20 – Jul 22 | 40–60 |
| Tarragon | — | — | Apr 22 | Jun 24 – Sep 2 | 60–90 |
| Thai Basil | Feb 25 | Apr 22 | Apr 29 | Jun 24 – Aug 26 | 50–75 |
| Thyme | — | — | Apr 22 | Jul 1 – Sep 2 | 70–90 |
| Valerian | — | — | Apr 22 | Aug 26 – Oct 7 | 120–180 |
| Yarrow | — | — | Apr 22 | Jul 22 – Oct 7 | 90–120 |
Monthly Planting Guide for Cass County
Gardening Guides & Resources
Helpful guides from The Ultimate Homestead to improve your garden in Cass County.
Frequently Asked Questions
What planting zone is Cass County, IL?
Cass 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 Cass County, IL?
Based on 31 years of NOAA weather station data, the median last spring frost in Cass County falls around April 15. In 8 out of 10 years, last frost lands between March 31 and April 30 — a 30-day window of variability. Use April 30 as your conservative safe-to-plant date for frost-sensitive crops.
When is the first fall frost in Cass County, IL?
The median first fall frost in Cass County arrives around October 16. In cold years it can arrive as early as October 4; in mild years as late as October 29. Harvest or protect frost-sensitive crops — tomatoes, peppers, basil, squash — before this date.
How long is the growing season in Cass County?
Cass County has a frost-free growing season of approximately 184 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 1.46 days per decade.
What is the soil like in Cass County for gardening?
Cass County has predominantly Silt Loam soil with a pH range of 6–7.2 and Excessively Drained drainage. Most vegetables and herbs grow well with standard composting and seasonal soil amendment.
What is grown commercially in Cass County?
Cass County has commercial agriculture that includes Corn, Soybeans, Hay. These crops reflect the local climate and soil conditions — what succeeds commercially often translates well to home gardens in the same area.
Is Cass County a good location for home gardening?
Cass County scores 64/100 (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 Cass County gardeners in Zone 5b 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.
