Use a breathable bag or box
If you’re hosting a thanksgiving dinner and need your tomatoes to ripen very quickly, grab a breathable plastic bag, or a paper bag, or a cardboard box – with tiny holes cut into it. Put the tomatoes in but only put a few, you don’t want to jam all of them in a single bag because they need some room for breathing. Tomatoes naturally release ethylene gas. When the gas is trapped in the container, it helps ripen the tomatoes faster.
If you want to further speed up the process, add a banana to the bag. Bananas release the most ethylene gas of any fruit, so putting them in the container will boost the ripening process. If you’re out of bananas, your second-best choice is an apple.
Place them on a sunny windowsill
The easiest way to ripen your tomatoes is to place them on a kitchen windowsill that receives ample sunlight. Position the tomatoes stem-side down so they don’t roll over or bruise on the hard surface. Let them bask in the sunlight for a few days, and they’ll be ripe and good to get onto your plate.
