There are many reasons why you might want to pick tomatoes when they’re still green. Perhaps the local squirrel population have also discovered your tantalizing tomato crop and has begun to go after your still-ripening tomatoes. Maybe your tomatoes are too heavy and seriously weighing down the vine. Maybe you are afraid of disease, rot or insects getting a hold of your green tomatoes before they have a chance to ripen.
Consider picking and ripening your green tomatoes indoors to give them a fighting chance.
If you’re seeing a bit of red on those green tomatoes, picking them individually and bringing them inside may be the best chance for ripening tomatoes. Like many fruits, tomatoes continue to ripen once they’ve been picked.
Ethylene is a gas produced by fruits, including tomatoes, that promotes ripening. Many commercial tomatoes are actually picked while still green for shipping and ripened at their destination by introducing them to an ethylene-rich environment. Although it sounds a little nefarious, the practice is common. Tomatoes ripened after picking tend to be a little less flavorful than their vine-ripened counterparts, but for home growers, it’s a great way to rescue imperiled tomatoes and can be done naturally and with little effort.
Tomatoes that have been given a head start on the vine have the best chance of ripening once picked. Give green tomatoes a little squeeze. If they give a little, the ripening process is already underway. Better still, tomatoes already showing signs of reddening are good candidates for post-pick ripening. Skip fruit that is marred or showing signs of decay. No amount of indoor ripening will improve them.
Left on the countertop, tomatoes will produce ethylene on their own and ripen eventually. Depending on the variety and how ripe they were when picked, the process can take several weeks. With a little help, though, ripe, red tomatoes are right around the corner.
Tomatoes aren’t the only fruit cranking out ethylene. Storing green tomatoes with other ethylene producers can speed up the ripening process considerably. Apples are a good choice, but bananas are ethylene producing powerhouses.
Select a banana that is yellow, but still shows some green at the ends. Barely green bananas are in their ethylene producing prime and the gas they release can reduce the time it takes to ripen picked tomatoes by days or even weeks.
Wash tomatoes and allow to dry completely before storing. For just a few tomatoes, place them in a paper bag with a banana and store at room temperature out of direct sunlight. Avoid high humidity, which can lead to decay or fruit fly issues. Larger quantities can be placed in a cardboard box instead of a bag. Leave a little space between tomatoes to improve circulation and speed up the ripening process. If dealing with an especially large harvest of green tomatoes, wrap each tomato in paper or place a few sheets of newspaper between layers to limit contact.
Sources:
https://www.hgtv.com/outdoors/flowers-and-plants/vegetables/how-to-ripen-green-tomatoes