Around the end of the growing season for your region with the colder nights coming in and perhaps a possibility of frost on the horizon, you need to start thinking about how to ripen tomatoes that are still green before you loose them completely.
One of the ways of ensuring that your tomatoes ripen is to continuously harvest your tomatoes as they become ready for picking, this releases energy to the tomatoes that are not quite ready and will encourage them to ripen.
Another general suggestion is that if you note that your night time temperatures are dropping below 70F then there is little to no chance of any new blossoms becoming fruit, so pinch these out and direct the energy they would otherwise have taken to your fruit that still needs to ripen.
Another handy way of turning tomatoes that are in a greenhouse is to hang a bunch of bananas in the greenhouse with the tomatoes, the ripening bananas will give out ethylene gas, which is the gas that causes fruit to ripen and bananas give it out in abundance, even after they have been picked. Why this works in a greenhouse is because its an enclosed environment which allows the gas to be effective.
Removing large fruit that is still green will give the smaller fruit more of a chance of getting the energy needed to ripen and if you select them correctly you may be able to place the removed tomatoes somewhere dark and dry to ripen them off, just check them every few days to make sure there is nothing going wrong or to see if they are ready to use.
If all else fails you can ripen tomatoes indoors but you have to get them off the vine before a heavy frost gets them, they can be protected up to a point by covering for light frosts but this is a little risky.
One method of ripening indoors is to take each tomato and wrap it in newspaper, place the wrapped tomatoes in a cardboard box up to 2 layers deep, any more and the tomatoes on the bottom layer will tend to get bruised and damaged as they ripen so stick to the 2 layer rule to be safe.
You can place a banana on the top to aid ripening if you want to, the tomatoes will produce their own ethylene gas as they ripen but a banana will add additional quantities of gas which is actually a ripening hormone. Place the box in a dark dry place, avoid high humidity as this will tend to cause rotting of the fruit and check periodically for progress. Make sure any fruit that is showing signs of a problem is removed and disposed of.
Temperature plays a part in the ripening process and the minimum temperature should be 55F for reasonable results, any lower and you will have tasteless, bland fruit. The ideal is between 65F to 70F for a speedy ripening period (2 to 3 weeks) and tasty fruit.
Things that prevent tomatoes ripening: –
- insufficient sun light
- extreme temperatures cold or hot
- if the tomato is large in size, just needs more time
- erratic watering schedule, tomatoes like consistently damp soil that is neither dried out or saturated, although you can back off on the watering a little as they start to ripen
- not picking off the ripe fruit
- allowing too many blossoms especially late in the season
- over fertilizing