How to Ripen Green Tomatoes Indoors Before Frost Hits
Don’t lose your harvest to frost. Learn how to ripen green tomatoes indoors with simple, reliable methods that actually work.
Every fall, without fail, I find myself staring at tomato plants heavy with green fruit while the weather forecast teases frost. That’s always the gamble this time of year… do I haul them all inside now, or gamble on one more week of warmth?
I’ve tried it both ways over the years. Some seasons I’ve lost bushels to an early frost, and other times I’ve managed to turn those hard little orbs into beautifully red, juicy tomatoes, right inside the house. If you’re in the same spot, don’t worry. You don’t have to let your green tomatoes go to waste.
In this post, I’ll show you simple, reliable ways to ripen green tomatoes indoors, plus share a few tricks I’ve learned the hard way about what actually works (and what leads to a tray of mush).
Why Ripening Green Tomatoes Indoors Works
Tomatoes ripen thanks to ethylene gas. It’s basically the plant’s way of giving itself the signal to turn red. Outdoors, warmth and sunshine speed things up, but indoors we can mimic those conditions and let the tomatoes do what they were already programmed to do.
Just so you know, once a tomato reaches what’s called the “mature green” stage, it doesn’t need to stay on the vine to ripen. That means if frost is looming, you can pick those green fruits and still enjoy a red harvest later.
When to Harvest Green Tomatoes
Not every green tomato will ripen successfully indoors. If you’re unsure about timing, I’ve shared more in the best time to pick tomatoes and simple ways to preserve them. For green tomatoes, look for these signs before bringing them in:
- Size and shape: Tomatoes that have reached their full size are your best bet.
- Glossy skin: A shiny surface means the fruit is mature, even if it’s still green. I’ve learned that dull, matte ones usually won’t ripen indoors.
- Faint color break: A blush of yellow or pink at the blossom end is a good sign it’s ready to turn.
Those little marble-sized ones? Don’t bother waiting. They’re better off tossed into a jar of pickles because they rarely ripen.
Best Ways to Ripen Green Tomatoes
Here are the methods I’ve come back to year after year.
- In a Paper Bag with Fruit: Tuck a few green tomatoes into a paper bag with an apple or banana. Both release ethylene gas, which speeds up ripening. Fold the top and check daily.
- On a Tray or Cardboard Box: Spread tomatoes in a single layer in a shallow box or on a baking sheet. Keep them in a warm, dark place (like a pantry). Cover lightly with newspaper to hold in the gas.
- Hanging the Whole Plant: If frost hits but your plants are still loaded, pull up the whole plant (roots and all) and hang it upside down in a garage or basement. The fruit will continue to ripen gradually, and I feel like the flavor is just better this way.
- On a Sunny Windowsill (for Small Batches): This one works, but with caution. Direct sun can make tomatoes shrivel before they ripen. It’s best for a handful of fruit you’ll eat right away.
Troubleshooting: What to Do if They Rot Instead of Ripen
Sometimes you’ll check your tomatoes and find a soggy mess instead of a ripe harvest. Here’s why it happens and how to fix it:
- Too much moisture: If tomatoes are touching or covered too tightly, mold can set in. Give them airflow.
- Wrong stage of maturity: Immature green tomatoes simply break down instead of ripening. Harvest only those that are glossy and full-sized.
- Temperature swings: They do best at about 65–70°F. Colder, and they’ll just sit there, green. Hotter, and they’ll turn to mush before you know it.
Don’t wash your green tomatoes before storing. Wait until they’re red and ready to eat. Moisture on the skin invites rot.
Frequently Asked Questions About Ripening Tomatoes
Still wondering about the details? Here are a few common questions people ask:
Love this tip? Save it to Pinterest so you’ll know exactly what to do when frost threatens your tomato plants.
With a few simple tricks, those green fruits can still end up as jars of sauce, bowls of salsa, or thick slices on a sandwich. If salsa is your go-to, don’t miss my canning-friendly salsa recipe from fresh tomatoes, and if you’ll be making sauce or canning, here’s a trick for peeling tomatoes without boiling or ice baths.
Don’t let all that garden work go to waste now, at the very end. Pick those green tomatoes, ripen them indoors, and enjoy every last bite of the season. And while you’re wrapping up the garden, it’s also the perfect time to plant garlic for next year’s harvest.