Tomatoes don’t always ripen on their own in the cooler late-season weather of Illinois and Indiana, but there are easy ways to help them along.
I’ve had great success using a few simple tricks to turn those stubborn green tomatoes into juicy reds. From bringing them indoors to using everyday household items, the process is easier than you might think.
With just a little effort, you can enjoy ripe, homegrown tomatoes before the season ends.
1. Paper Bag Method
Place green tomatoes in a paper bag with a ripe banana or apple. These fruits release ethylene gas, which speeds up ripening naturally. Many Illinois gardeners swear by this technique when September brings cooler nights.
Check the bag daily to catch tomatoes at perfect ripeness and prevent overripening. In Indiana’s humid climate, leave the top slightly open to prevent moisture buildup and mold.
2. Root Pruning
Gently push a garden spade into the soil around your tomato plants to cut some roots. This stress signals the plant to finish ripening its fruit quickly. Indiana gardeners find this especially effective in late August.
The technique works because the plant shifts energy from growth to fruit ripening. Many Illinois vegetable farmers use this method when forecasts predict an early frost.
3. Reduce Watering
Cut back on watering when tomatoes reach full size but remain green. The mild water stress encourages ripening as plants focus energy on fruit instead of new growth. Many Indiana community gardens use this strategy.
Don’t let plants completely dry out though! In Illinois’ sometimes scorching late summers, monitor soil moisture carefully. Just reduce frequency while maintaining enough water to prevent wilting.
4. Greenhouse Effect
Cover tomato plants with clear plastic to create a mini-greenhouse. This traps heat and speeds ripening, perfect for Indiana’s sometimes cool September days. Make sure to secure the plastic so it doesn’t touch the plants.
Remove covers during extreme heat to prevent cooking your tomatoes! Illinois gardeners often use this method in early fall when temperatures fluctuate between warm days and chilly nights.
5. Remove New Flowers
Pinch off any new flowers that appear late in the season. Your Indiana tomato plants will redirect energy to ripening existing fruit instead of producing new ones that won’t mature before frost.
This technique is especially important in northern Illinois where growing seasons end earlier. Start removing flowers about 30 days before your region’s average first frost date.
6. Indoor Ripening
Harvest mature green tomatoes before frost and bring them indoors. Place them stem-side down on a windowsill or counter away from direct sunlight. Many Indiana families have traditions of gathering tomatoes before the first predicted frost.
Check daily for ripening progress and remove any that show signs of rot. Illinois gardeners often extend their harvest by several weeks using this simple method.
7. Temperature Management
Keep ripening tomatoes at 65-75°F for best results. Too hot or cold slows the process. In Illinois’ variable fall weather, moving plants to protected areas can help maintain ideal temperatures.
Consider using row covers at night when temperatures drop. Indiana gardeners sometimes use Christmas lights under covers to add gentle warmth when early September brings unexpectedly cool evenings.
8. Trim Leaves
Remove some leaves around tomatoes to increase sun exposure. The additional sunlight helps green tomatoes ripen faster in Indiana’s sometimes cloudy late summer days. Don’t remove too many leaves at once to avoid sunscald.
Focus on trimming leaves that shade the fruit. Illinois gardeners find this especially helpful when plants have become overgrown and dense by August’s end.
9. Uproot Entire Plants
When frost threatens, pull up whole tomato plants with fruit attached and hang them upside down in a garage or basement. The tomatoes will continue to ripen slowly on the vine. This old-timer trick is still used in rural Indiana.
Check plants regularly and harvest tomatoes as they ripen. Many Illinois families extend their harvest by weeks using this method during early autumn cold snaps.
10. Calcium Boost
Water plants with a calcium solution made from crushed eggshells soaked in water. The calcium helps strengthen cell walls and promotes even ripening. Indiana gardeners save eggshells all season for this purpose.
Apply this natural boost every two weeks during the ripening period. Many Illinois organic gardeners prefer this method over commercial products for late-season tomato care.
11. Companion Planting
Plant marigolds and basil near tomatoes early in the season. These companions improve growing conditions and can lead to earlier ripening. Many Indiana community gardens use this technique to great success.
The aromatic oils from these plants also help repel pests. Illinois gardeners notice that tomatoes grown with companions often ripen more uniformly than isolated plants.
12. Potassium Feeding
Apply a potassium-rich fertilizer when tomatoes are forming. Potassium helps trigger the ripening process. Banana peels buried near plants provide a natural source that many Indiana organic gardeners prefer.
Avoid high-nitrogen fertilizers late in the season. Illinois garden experts recommend switching to potassium-focused feeding by mid-July to encourage timely ripening before fall arrives.
13. Early Variety Selection
Plan ahead by choosing early-ripening varieties suited to the Midwest. ‘Early Girl’ and ‘Fourth of July’ varieties perform exceptionally well in Indiana’s growing conditions and often ripen before common problems arise.
Save seeds from your fastest-ripening plants. Many Illinois family gardens maintain their own early tomato strains adapted to local conditions through generations of careful selection.