Should your tomatoes be red by now, but they are stuck on green? In this podcast, Joe Lamp’l demystifies the reasons why tomatoes take their sweet time to ripen.
BHG020-Why Won’t my Tomatoes Ripen?!?
This is about the time each year (mid to late summer) that I start getting the same question from a lot of frustrated gardeners; why won’t my tomatoes ripen? They’re big and green on the vine, but they just sit there! Why won’t they turn red?”
Well, first of all, take comfort in knowing that nothing’s wrong. Here’s the dirt on what’s happening; under ‘normal’ conditions, from the point of fertilization, it takes about 50 days until a tomato fruit reaches full maturity. But if you stop to think about it, tomato plants have a lot going on– all at the same time. While they’re producing and ripening fruit, the plants are still putting on new growth, developing more extensive root systems and making components for color and flavor.
Fortunately, tomato plants are equipped to handle this multi-tasking quite well. When conditions are ideal, such as a favorable climate, plenty of spring showers and moderate summer temperatures, plants thrive and the harvest comes quickly. However, those “ideal conditions” are a lot harder to come by these days. Typical spring weather quickly evolves into an overly hot, dry summer. So now, the plants are faced with demands that require some redirection in how their energy is distributed.
The key resource needed to produce the food energy responsible for healthy plants and ripe tomatoes starts with sufficient leaf surface. When plants become laden with fruit, additional foliage surface area is needed to keep up with these increased demands. But now the plant is called upon to spread its energy in a multi-tasking balancing act that becomes even more demanding as the season wears on. So even though tomato fruit reaches full size in about 25 days, it doesn’t completely ripen until sufficient compounds are present to give it the color, taste and texture we love. And with over 400 of these compounds building together into a crescendo of perfection, that won’t happen until conditions are again in balance.
Air temperatures above 85 degrees are one of the most common reasons tomatoes don’t ripen as fast as you might expect. When temperatures rise above this level, tomatoes stop making carotene and lycopene pigments, two of the most important and recognized components in the symphony.
And below ground, temperature is just as important. The roots require soil temperatures below 80 degrees for optimal growth. So as temperatures rise below the soil surface, shallow rooted plants respond by developing a deeper, more robust root system, further diverting the energy needed for ripening fruit.
So if you’ve run out of patience and you just can’t handle Mother Nature’s timetable, there is something you can do to speed up the process. If the plant is laden with fruit, take some off. I know this might be hard to do, but with fewer tomatoes, there’s less demand on the plant and with less demand, there’s more energy that can be concentrated on ripening the remaining ones, when Mother Nature gives the signal to resume.
And here’s one idea you might be tempted to try–adding extra fertilizer seems like a logical thing to do, to give those tomatoes a little extra boost. But don’t do it. The environmental changes that result in this ripening slowdown are nature’s way of dealing with and resolving the challenge. It’s not a nutritional deficiency. In fact, adding fertilizer now could exacerbate the problem by forcing the plants into a growth mode at an inappropriate time.
Tomato plants really are adaptable and they’ll adjust to environmental changes in due time. All that’s required of you is patience, consistent irrigation and a good layer of mulch to help moderate soil temperatures. Just consider it delayed gratification and I promise, you will be rewarded for your patience!
But here’s something you can do that doesn’t require any patience; check out all of our other Burpee Home Gardens Podcasts. There are 26, just like this one, and they’re all designed to help you be a more successful gardener. From planting to harvest, we’re there every step of the way. You can download all the episodes for free in iTunes, or listen online at burpeehomegardens.com where you can also get great gardening ideas and inspiration any time! You can subscribe to the series for free in iTunes, or listen online at Burpeehomegardens.com, where you can also find great ideas and inspiration any time.
Now go get dirty!
About Joe Lamp'l
Joe Lamp'l is the Host and Executive Producer of the award winning PBS television series Growing A Greener World. Off camera, Joe dedicates his time to promoting sustainability through his popular books, blog, podcast series, and nationally syndicated newspaper columns. Follow Joe on Twitter
I am a long time successful NY & CT tomato home gardening individual. However, relocating to SW Florida, I find that my tomatoes turn red but are hard as baseballs and very thick skinned. My plants were sown as seedlings in a brand name container unit with a cherry and a slicer tomato in each of 2 containers. What gives?
Bob, I’m not sure which varieties you are growing but you may want to check out some heirloom selections of tomatoes. The expert is Craig Lehoullier and we featured him on an episode of GGW. https://www.growingagreenerworld.com/episode-803-epic-tomatoes/
here is a link to his website. http://www.craiglehoullier.com/ I know he will be able to help you grow epic tomatoes. Happy gardening!
This is my first year planting tomatoes…I tried a method I seen online….planted 4 slices of tomatoes on top of a pot of potting soil, then covered slices with more potting soil (Miracle Gro) and have kept them watered…They grew into many, many sprouts…I then picked the best sprouts and put two sprouts per pot, into more larger pots because instead of starting a ground garden, since I was just experimenting…and they have taken off…I have four large pots, vines propped up and lightly tied because they are heavy, tomatoes are growing, some at a good size but also many tiny ones….But the grown ones are still green…They have been fertilized a couple of times… I read some of your responses on here and in some you say they need sun to ripen, but others it sounds like you’re saying they don’t…mine do get sunlight second half of the day…Is that enough because I read elsewhere to much sun can make them crack from moisture and it will attract the critters to them…Well since I said my tomato plants are in large pots, and not a ground garden do they require more sun to get them to start to ripen and once they do can I pick those, bring inside and put in paper bags or set on the window sill to finish the ripening?
Hi Debra. If you’re able to get your tomatoes to a point where they start showing color, such as half pink, half green, you can safely pick them and allow them to ripen inside. You don’t need to leave them on the vine or keep them in the sun to ripen. This is known as the breaker stage. If you want to learn more about this, I did a blog post exactly on this very topic. And it doesn’t matter if you’re growing in the ground or in containers. the ripening process works the same way. Here’s the link: https://joegardener.com/when-is-the-best-time-to-pick-a-tomato/
I have grown Tiger Tomatoes for the 1st time and they are still green, should I persevere and keep them outside still or cut all of them from the plants? I live in the North East of England
I would leave them on the plant until they start to show color. That’s the “breaker stage” at which point it’s safe to remove them and they will ripen inside safely and taste just as good as a vine-ripened one. You could leave it on the vine until it ripens there but no reason to do so once it starts to change color. Leaving it on the vine exposes it to additional risk from critters or cracking due to excess moisture, etc.
This is my first year growing tomatoes. My plants are huge, some stand taller than me, and im 5ft 9. I know you have said that the plants need below 80 degrees which we are now getting. However my concern is that we are now getting low 50’s. Can this hurt the tomatoes before they ripen? I am worried that we will get to frost levels before my tomatoes turn red.
Frost will kill your plants but not temps in the 50’s. However, it will stall fruit ripening. Keep an eye on the weather and pick all remaining fruit before frost / freezing temps arrive. Fruit that is showing color will continue to ripen off the vine all by itself. Fruit not showing any color can ripen in time. Simply put it in a paper bag, close it up and set it aside. Check on it periodically and you should see that they slowly ripen.
Oh, no! I saw you mention that tomatoes don’t turn red if air temperatures are above 85 degrees! I live in southern Arizona where 100 degrees or above is very normal for summertime. The tomato plants are very healthy and producing a lot of tomatoes. They simply aren’t changing colors. Can I keep them going into fall time for that optimal 85 weather to make my harvest? Or is it too late and I might as well toss them and start over in fall time?
wait it out and see what happens. No harm in that. Experimenting and discovery are the keys to being a better, smarter gardener Estefania.
So we are having a freeze starting. I dug up my 4’plant s of several large green tomatoes and put them in my greenhouse with a light. I am hoping they will turn red. i think I should put more soil in the 5 gallon container. they are so big, I don’t want to lose them. Any ideas?
You can add more soil to your tomato plants without hurting them. The key is to make sure all the roots are covered and they are getting plenty of water. Digging up plants in fruit at this late date will be a challenge but I think you did the right thing. Otherwise, you risked losing them completely. Also, worst case, you can pick those large green tomatoes and place them in a closed paper bag to ripen on their own, or cook up some fried green tomatoes. Good luck.
Maybe you have uncovered an old secret about ripening tomatoes that didn’t get passed down with the fried green tomato recipe. Pick some and the rest will ripen more quickly! Who knew? Thanks Joe.
i bought the big boys and yes they are big and green, I cleaned out as much as I could I have some leafs with tomatoes on them and flowers I cut down. I brought them into the house and put them in a vase will they grow in water and it’s cool in here.
Thank you
I have a beautiful plum tomato plant with several red tomatoes on it but they are hard as can be. Will they get riper and softer before they stay on there too long?
Hi Debbie. I’m sorry I’m just now seeing this so many weeks after your question. So by now, you know the answer. Did that get softer or did they rot on the vine? I’m thinking (and hoping the softened up in time for you to enjoy them before they passed their prime). Tomatoes generally have an internal clock that is very much tied to environmental conditions. There’s not much we can do to speed it up or slow it down. They ripen when they’re ready. So tell us what happened? Thanks.
thanks for this post. I too have never had luck with tomatoes. But this year I chanced it once again and bought my plants at a local nursery located and specializing in plants (and tomatoes) athigh altitude (7000). It has been raining like crazy and all my veggie and herbs are growing like crazy.
I have two (cherry tomatos and yellow grape tomatoes) and tomatillos all growing in one large patio container. Except for a few days, the weather has not been above 85. Tomatillos are growing like gangbusters and I’m harvesting them everyday. The tomatoes are green seemingly for at least a month. I will continue to hope and be patient.
Hi, I am a second year gardener and I have a variety of tomatoes. I have noticed that between this year and last year my tomatoes are actually ripening. Even though i have a moderate aphid infection. I believe the differences this year are;
1 Rock dust ( This adds various elements that may have been taken out when putting in a previous lawn, plus it is a boost in nutrients not just the basic NPK)
2 I found a high phosphorus bat guano and purchased this and put it in at the end of last season and beginning of this season. This will help with flower production
3 I use compost tea when a dry spell hits. This beneficial bacteria will help break down the rock dust to be usable by the plants. and to help the growth of roots i put my banana peels in the compost tea.
4 I trimmed off lower leaves to help production of flowers. ( I like having side shoots pop out. Lots of people trim them. What i found is if you have a side shoot right below a flower cluster; the side shoot will most likely will impede the development of that flower cluster so trim those ones.)
This may have helped, or may not have, but this year I have tomatoes ripening. Last year I only had one ripen on vine, nearing September.
Anyways good luck gardening and have fun, take care of your plants and they will take care of you. 🙂
I have at present 110 tomatoes , of various sizes , all on one hanging plant. Two of them are ripening red. Will all the others grow well too , or are there too many on one plant?
In time Rob, yes. But that’s a lot of work for one plant. Are these cherry tomatoes? That would explain the high number. Temperature and sunlight will have the most to do with when you tomatoes ripen. But the heavy load of so many tomatoes drawing resources to do so may slow that down. Some people remove some of the excess tomatoes to divert energy to the remaining ones to speed up the ripening process. This is especially true towards the end of the season.
I am growing tomatoes on a hanging quick grow system like you see on tv and in 2 large bins that are arated. I have big full plants and some green tomatoes for months now. they wont grow to full or turn red. most have black spots,so I added miracle grow and this Epsom salt calcium mix I saw to get rid of the black spots. I just cant get any to redden and grow to maturity. very frustrated.same thing last year with out the black spots. what am I doing wrong? please help. I live in western Kentucky.
Hi Eric. Getting tomatoes to ripen is mainly a product of having enough light, and temperatures that are warm enough but not too warm, as my posts discusses. In short, I would do all I can to maximize the amount of sunlight your plants are getting. While you can’t control temperatures, tomatoes will only fully ripen on the vine within a certain range.
Also, adding too much fertilizer, especially if heavily nitrogen based, will produce lots of rich green foliage but few ripe tomatoes as the energy is going into foliage production vs. fruiting. Best to use a fertilizer that has a higher middle number in the ratio mix.
Was looking for answer as to why my big green tomatoes are not turning red. found just what I needed. Was ready to start watering with jugs of miracle grow plant food. Glad I read this . Thanks
** Hi, and thanks for all your great (info) I live in S – Florida, ( temp) problems, summer time heat, but my question is, I have some tomato plants that have been producing fruit for (5) years, is this normal, they shut down late summer, come back, (FEB-MARCH) love – it , but I did not know tomato plants could do this ?? thank you . Joe
omigoodness, thank you for this post! I will quit bugging my cherry tomato plants about when their green fruit will turn red – they’re big and beautiful and green, and have been so for really only about 10 days…they’ve got ages to go! And I’m in Australia, hence the weird time frame!
Hi. I live in Idaho at elevation about 6,000 feet. I have a hard time with tomatoes in general, don’t know why. Cant really plant them until last of May first of June because of frost. This year, I made it a point to buy some bigger plants that already had blooms and some had little tomatoes on so that they would grow and ripen. I also bought some regular starts. The bigger plants stagnated and the smaller plants caught up to them. I did get lots of tomatoes this yar which is encouraging, however it is now the middle of October and they are still really green. We got a hard frost the middle of September and several nights since. Still trying to baby them along but with no success. They are just not ripening. What’s the deal? Also, how much should I be watering since it is freezing at night?
Hi Rene. Tomatoes that are slow to ripen is almost always an environmental condition. In your case, the cool temps are wreaking havoc with the plants ability to complete the processes that lead to ripening before the cold weather sets in. At this point, I think you will have to pick those green tomatoes before frost turns you plants to mush. Once picked, place them in a paper bag and with a little luck, they’ll turn red in time.
As for watering, you could do that during the day once temperatures rise. Any moisture remaining in the soil at night will not be a concern if it freezes.
I started my Endless Summer seeds indoors back in March 2014. I planted them in the ground in mid-May and am STILL waiting on them to ripen. I have six plants that have slightly pink tomatoes and another six plants that are still green. The seed packet states 78 days to maturity, but we’re way over that and it will frost soon here in Nebraska. All my other crops did very well and we had no problem with drought or insects. I plant tomatoes every year and this is the first time I’ve ever had a problem with the fruit not ripening. If we use the pink tomatoes will we still get good flavor?
Hi, same issue here in GA. My Big and Better Boys are about 6.5 feet tall now. Not overly laden with green tomatoes but no red ones. I did have one mostly red one but cut it and the seed areas were all dark green. I was wondering if it could be partially because there is so much foliage that not much sun actually gets to the tomatoes. Do the fruits themselves depend on sun to ripen? My weather conditions are as you described, very hot in the 90s with frequent but short t-storms.
Hi Laura. The fruits don’t need sun to help them ripen. In fact, sun can scald them rather than help. But temperature does have the most to do with why your tomatoes don’t fully ripen as quickly as you think they should.
If summer temps are quite high– would it help if I found a way to partially shade the tomatoes ?
Good question Corri. As I think about this, it’s kind of a catch-22. The high heat certainly will cause the ripening process to be put on hold, yet the shade will also slow down the process that is necessary to ripen fruit even if the temperatures fall back to productive ranges. I think it depends on how much you can reduce the temperature and how much the shade is cutting down on the sunlight needed. And with such variability of temperatures, I doubt any two days or seasons would be the same. This is one of those questions that is worth some hands on experimentation. I’d like to try this to find out and you should do if you can. It’s a very interesting question. I’ve never tried but plan on it. Let me know if you find any online information on this. Sometimes there is good university research for things like this.
Well, we’ve been patient… It’s October 24th, and we’ve frost protected the vines twice so far. The 46 transplants went in on May 20, and we’ve eaten exactly two red tomatos, though there are hundreds of large green ones hanging on the vines. Still think our patience will pay off? Every other year, we’d have a hundred tomatos ready to can by now, and be tired of eating them fresh. It’s been 6 weeks since the temperature was over 80. By now we’re having nights in the 30s. The vines still look good, but the fruit just won’t turn.
I have my doubts that you’ll have any red tomatoes before you lose your vines to frost at this point. It’s hard to pinpoint why things are different this year, but that’s where you can be a Sherlock Holmes and think about why this year is different. Was it a particularly cool summer / fall? Tomatoes are genetically programmed to ripen under the right conditions (not too hot or cold). Besides the varieties that actually ripen as green, I have a feeling it was temperature mostly.
Seems like luck of the draw. I gave a friend leftover plants, that I had no room to plant. Mine are producing wildly, while his have not yielded a single tomato. They came from the same six plant pack. I feed mine miracle for tomato food as instructed. And I have my best garden in years. I got bit by mislabeled plants too. My husky red cherries turned out to be Roma plums. Home depot strikes again,,!! Lol.
Thanks for the info. We live in San Diego and were getting worried because our Best Boy plants are loaded with green tomatoes , but none are turning red. One of our plants decided that it was a Cherry tomato even though Home Depot sold it as a Best Boy and it’s making lots of red Cherry Tomatoes. So I guess “patience is the key.” Summer is only a week away.
Mis-labeling is more common than most people realize Ken but glad you did. Also, patience will turn any green tomato if given time before the first frost of fall. Good luck and thanks.
Thanks for the info. One more question – I live in northern Iowa. Is there a specific brand of tomato that is best for BLT’s? How about canning? Do you have any advice on soil preparation and fertilzing? Any ingenious raised bed ideas?
Not living in northern Iowa, I don’t know what varieties grow best there. But I’m sure there are a few that are perfect for BLT’s and anything else. Have you tried calling your local county extension office? They should have Master Gardeners on duty that should have an expert in vegetable gardening and would know the best tomato varieties. Or find an Independent Garden Center or Nursery in your area (not a box store!). The local nursery will have avid gardening employees or owner that knows, or knows someone that is an expert in local flavors. Seek locally and you will find your answer.
As for soil prep and fertilization, I have one word: COMPOST. Amend your native soil with lots of organic matter, namely compost. It improves your soil in so many ways and contains important nutrients your plants need to get growing and thrive along the way. Your raised beds can simply be mounded soil to about 6 inches high in the middle and a foot wide at least, or use wood or stones or cement blocks to create a physical barrier and fill with the best soil you can find. I believe you have exceptional soil in N. Iowa! Make your beds at least 6 inches deep. More is better. I like beds that are 4 feet wide. Length is simply a matter of personal choice, budget and space. Good luck.
How interesting! I’d been feeding my tomatoes madly, having planted them rather late and now realise that I’ve probably been “killing them with kindness” ! So all the Miracle Grow has actually stopped them from ripening?! I’m not left with a load of very large, hard green tomatoes!!!
I’ve tried putting them on a windowsill and in a bag with bananas but nothing happens!
I am going to enter six of them into my local honey show this weekend anyway. They may be inedible but there’s nothing in the rules to say tomatoes have to be red!
Thanks for the information. My tomatoes are big and green! They are a salvage job, someone (wifey) thought she would put a bunch of seeds all in one pot! So when they all started growing, I
Separated them into 2 big pots, leaving about 6 in each. Neither of us grew them before, but I knew there was too many together. Long story short,, they are supported by sticks all around the pot,,loops!!! It looks funny, but they are growing great, but green. I know having them in pots don’t help none!!! ^ – ^
great information but my tomatoes are still green hope they ripen before frost thanks
Sad to say you will not feel right doing it but you have to top all the leaders off your tomato plants trim severly all the bottom branches and sucker all remaining branches with blossoms on them only leaving enough foliage to feed the remaining tomatos then you hav a great chance off most of them ripening before frost hits that way all the energy can go into ripening the remaining big green tomatos also cut back on your watering some but only in the initial stage when you prune them severly give them a booster shot of one 235mg of aspirn disolved in a gallon of water with two tablespoons of molasses and 1 tablespoon of epsom salt and 1 tablespoon of fish emolsion if you have it all in 1 gallon of water per plant then let it be and hopefully you will be alright just leave enough leaves on the plant to produce photosythisis