Troubleshooting Tomato Problems

, written by Benedict Vanheems gb flag

Harvested tomatoes

Growing tomatoes successfully depends on avoiding some common pitfalls that can trip you up along the way. Knowing what to expect and what to do about it will greatly improve your chances of a truly terrific crop of tomatoes. Read on to discover how to troubleshoot some of the most common tomato problems...

Common Tomato Pests

Aphids and whitefly

Aphids and whiteflies are regular visitors from early summer. They often congregate in large numbers, sucking sap from your plants and leaving their sticky excrement, known as ‘honeydew’, on the foliage. Some types also transmit plant diseases.

Small infestations can simply be blasted off with a jet of water. Or try spraying plants with a solution of soapy water, taking care to reach the undersides. To minimize potential problems attract pest predators such as ladybugs and hoverflies by planting flowers close by – marigolds are a good choice. You can even buy these predators to introduce into enclosed environments such as a greenhouse.

Spider mite

Warm, dry conditions are perfect for spider mite, which like aphids and whitefly can quickly weaken plants. Look out for their faint webbing. Peer closer and you may be able to see the tiny, usually red, mites.

Spider mites love drought-stressed plants, so don’t let your tomatoes dry out. If spider mites do attack, spray the foliage with a fine mist of water, ensuring you reach all parts of the plant. Then cover the plant with a row cover for a few days to create the shady, humid conditions that will repel the mites.

Tomato hornworm parasitized by braconid wasp larvae

Tomato hornworm

Many parts of North America are prone to tomato hornworm, a caterpillar that chews holes into tomatoes. Check plants regularly for signs of damage and remove and destroy any caterpillars you find. Cocoons like those shown in the photo above are great news – they belong to braconid wasps, which feed on hornworms to bring them under control.

Tomato Diseases

Late blight

Late blight strikes during spells of warm, wet weather. Foliage and then the fruits become covered in brown blotches; eventually the plant simply wilts and collapses. Late blight also affects potatoes, which are related to tomatoes.

Blight is rare on indoor tomatoes, so grow plants under cover if it’s been a problem in the past. Avoid splashing the foliage when watering, and remove and destroy infected plants as soon as you spot the first signs of blight. You could also grow varieties described as ‘blight resistant’.


Blossom end rot

Blossom end rot is a disease caused by dry soil conditions and a shortage of calcium. Fruits form sunken black patches at the blossom end of the fruit.

Ensure your tomatoes have enough water at all times, and feed them regularly with a liquid tomato fertilizer. This is the best way to guarantee your plants are getting all of the minerals and nutrients they need for healthy growth. Pay particular attention to plants in confined spaces, such as pots or growing bags.

Watering and Feeding

Split fruits

Irregular watering often leads to split fruits, when a sudden rush of water causes the fruits to swell quicker than the skins surrounding them. Instead of leaving soil to completely dry out between each watering, aim for consistent soil moisture. Water regularly and mulch tomatoes with plenty of organic matter to keep roots cool and moist.


Mineral deficiency

Mineral deficiencies usually show up in the leaves first. Magnesium deficiency is the most common form and often arises as a result of high potassium levels. To correct the deficiency, spray a solution of Epsom salts directly onto the foliage then switch to a tomato feed that contains a higher proportion of magnesium.

Wilted plants

Plants can wilt when the soil is either too wet or too dry. Too wet and the roots literally drown, while very dry soil won’t supply plants with all the moisture they need.

Pay close attention to watering. Containers of tomatoes should have good-sized drainage holes at the base so that excess water can drain out. Raise containers up onto pot feet if water doesn’t drain away easily. In all cases, water generously when it’s dry, or set up an irrigation system if you can’t be there to water. Later on in the season mature plants with lots of foliage may need watering twice a day.


Poor Fruit Set

Poor fruit set, when flowers fail to produce fruits, is a very common problem. A lack of bees, excess heat, poor nutrition, and very dry or humid air are all possible causes.

Make sure pollinating insects such as bees can reach plants growing in greenhouses and tunnels. Improve pollination by simply twanging or tapping on supports to dislodge the pollen, or gently twiddle the flowers between your fingers.

Provide as much ventilation as possible in hot weather. If your climate’s also very dry, raise the humidity around plants with regular watering. And make sure to feed your plants regularly with either an off-the-shelf tomato feed or a homemade high-potassium liquid fertilizer such as comfrey tea.

Don’t be put off by all these potential problems. So long as you know what you’re looking at and react quickly, your tomatoes are likely to recover. Please drop us a comment below to let us know about any other tomato problems you’ve encountered and how you got around them.

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Show Comments


"My toms - growing in a repurposed recycling box with runner beans now in full fruit - have brown lesions on the leaves which start within the leaf and have a dark line round the edge of the dead bit like the dark line you get at the edge of a stain on cloth. From looking online the differential diagnosis is K deficiency or Septoria though neither have pics exactly like mine. The runner beans leaves are a bit pale but only a few are browned. With 4 runners and 2 toms in a 40 litre box (50x35x25H cms) I am sure they are overcrowded. I have been feeding with Doff Container and Basket Feed but noticing it had no Magnesium I gave it a spray of Andrews Liver Salts yesterday and today got some Westland Tomato food. Have I got Septoria? Underside of leaves just light brown lesions; no sign of life. The fruit are just setting and look fine What to do?"
SteveP on Wednesday 16 August 2017
"Hi Steve. That's a really tricky one to answer without seeing the pictures. It could be septoria, or full-blown tomato blight. If your tomatoes are still alive then it won't be the latter! Overcrowding is probably a big reason behind the problem anyhow. All plants need enough light and airflow to keep them healthy, growing strongly and better able to shrug off disease. It's probably too late now - though certainly feeding with a liquid tomato feed will have a lot of benefit if it's related to nutrient deficiency. Next year I'd recommend giving plants the full space they need, even if it means growing fewer plants. The overall outcome and yield will be higher if plants can grow unfettered."
Ben Vanheems on Friday 25 August 2017
"Thanks Ben. Can I send pics to this site? Can't see how to. The local (as in other side of a narrow road) church had a plant sale and I overbought. Then OH used most of the containers I planned to use for other stuff so I finished up making do. I have just bought 10x 60 litre flexitubs (Homebase £3.50) so will be fine next year. All has grown splendidly. The runner beans are up to 8ft and the toms spreading out from the pot and up to 4ft plus. Could hardly have more beans on the plants and the toms setting well - had the first ripe one yesterday but most just setting. I water a lot - huge demands on only 40 litres of soil - and had used a general liquid feed (Doff Container + basket)until I learned about Mg deficiency in toms. Which the brown could be. So i sprayed them with Andrews Liver Salts (to hand) until I got tom feed. I now have two - Westland and Levington Tomorite. Any preference? I may have stopped the browning - time will tell. Thanks for your help."
SteveP on Friday 25 August 2017
"PS I just read about beans putting Nitrogen into the soil (which I knew intellectually but had not thought of in this case). Will that disturb the N P K balance, and does it matter? "
SteveP on Friday 25 August 2017
"Hi Steve. It sounds like you've now got everything under control, and more root space next year will certainly make life easier for your plants (and you!). I have no preference on the tomato feeds you've mentioned - they're both good brands and if they're marketed specifically for tomatoes you'll be fine. The tomatoes won't be affected by the nitrogen put into the soil by the beans. The beans will be using most of this nitrogen - it would really only be properly released into the soil when the beans die back - and even then there wouldn't be enough to disturb the NPK balance overly."
Ben Vanheems on Tuesday 29 August 2017
"Hi, I've had a really good crop of tomatoes thus far. But, now most of the fruit at the ends of the longest stems (and it's a huge plant) have not completely developed before they just seem to collapse. Like a balloon that the air has gone out of. any ideas? We live in the high desert area (3600 ft) of So.California, so very hot and dry...watering once a day on a drip line for about 45 minutes. Thanks, Karen"
Karen Luzzi on Tuesday 11 September 2018
"Hi Karen I am no expert at my elevation of 360ft on the England/Wales border (Chirk) let alone in your conditions but try VASTLY more water. Tomatoes need a lot. eg we had about half an inch last night but I have just had to water mine (in containers) because the compost is almost dry. Remember tomatoes are almost all water and if you have a huge plant it all needs to get there through the central roots; plus water for photosynthesis. Do your leaves look happy? Just about to eat a mix of home grown toms! Best wishes Steve"
SteveP on Tuesday 11 September 2018
" Hi Karen. To echo Steve’s points above, it could be that the tomato plants have simply outgrown their capacity to supply enough nutrition and water to the developing fruits. This would especially be the case if the roots are limited by growing in a container, for example. So while you may be supplying enough moisture and nutrition, it could simply be that the roots find it physically impossible to take it all up in enough time and quantity to service all parts of the plant. "
Ben Vanheems on Wednesday 12 September 2018
"Hi, our tomatoes in different plots and different types have yellow marks as they are ripening. Some are round raised spots, What is the cause?"
Susan Arlove on Saturday 2 February 2019
"Hi Susan. The tomatoes could potentially have either 'greenback', where uneven ripening occurs, or blossom end rot. You'll know if you have blossom end rot because the end furthest from the stalk will be sunken, brown and starting to rot. If they aren't, then it could be greenback - a disorder that affects older heritage/heirloom varieties more than modern cultivars. There isn't much you can do about greenback, but making sure plants are properly fed will help to reduce the symptoms of this disorder."
Ben Vanheems on Monday 4 February 2019
"Hi. I have a 3 week old transplanted tomato plant. Several stems have developed leaves with small 2mm brown spots. They are in middle of plant, and top of plant otherwise looks fine. Nothing on underside of leaf. Could this be very early tomato blight? Is there a way to upload a photo to show you? Can't figure out how to do that "
Mark on Saturday 25 May 2019
"Hi Mark. This could be blight, or it could be leaf spot. The best way to get a full identification is to check out our disease identification guides. To do this, click on the Pests tab right at the top of this web page. Once there, click on 'Plant diseases' and search diseases by tomato. There are some great photos there which should help to confirm exactly what you've got - and there's some good advice too. "
Ben Vanheems on Thursday 30 May 2019
"Hello! My tomato seedlings are about 2.5 months old and were started in a germination kit. About a month ago, I transplanted them, but unfortunately most of my plants have a strange problem: there is a narrowed/contracted, woody area on the stem about 2cm above the soil line. They also had a few leaves just drop off in the week or two after transplantation. Are my seedlings going to survive? This issue seems to share characteristics of damping off, though the plants are a bit older. Advice greatly appreciated."
Knar on Friday 8 May 2020
"Hi Knar. That seems a bit of a mystery to me. Are any of the leaves wilted - which could be a sign of a fusarium or verticillium wilt? Check out our Pests tab above and click on Plant Diseases, then search Tomato Diseases Identification. Otherwise leaves dropping could simply be due to the shock of transplanting and/or less than ideal conditions, which may cause a temporary setback while the plants find their feet and settle in."
Ben Vanheems on Monday 11 May 2020
"I started tomatoes from seed and they were doing really well separated them put them into a larger pot. They've been growing for probably a month now and it seems like they're good and healthy but they're just not getting any bigger. Is it possible that the soil is too hard for the roots to grow in? I'm thinking that I need to transplant them into the ground and make sure that the soil is porous enough for their roots to grow. Your help would be greatly appreciated"
Shirley Ann Pullen on Tuesday 16 June 2020
"It could be that they need more space at the root level, yes. Check to see if the roots are crammed in or not. Alternatively it may be that they aren't getting enough moisture. They also prefer warmth and good light levels - all could be factors. If you intend to plant them into the ground then I would do so as soon as possible, to give them more room and a more stable root environment. You will probably find they suddenly start growing quickly!"
Ben Vanheems on Tuesday 16 June 2020
"I am growing purple cherokee tomatoes for the first time and they are just now setting fruit. However, all the tiny green tomatoes have split or cracked open and I can see the seeds inside of them forming. They are in containers but I have been watering very regularly and consistently. Any ideas why this is happening?"
Renee Lou on Thursday 18 June 2020
"Hi Renee. It does sound like a classic case of fruits splitting because of a sudden influx of water after being quite dry. It can be quite hard to maintain consistent moisture levels in containers, particularly if they are on the smaller side, so this could be the problem. "
Ben Vanheems on Monday 22 June 2020
"I have 2 large heirlooms and several other indeterminant types. the determinate cherries i put in planters and are doing very well. The plants look strong healthy large and robust probaby 7 foot high, blooming, but no fruit! I have tried everything, self polination, pest control, fertilizers, regular watering, and i feel like the only thing left is they are too close to one another? each plant is atleast a foot away from one another, but they are in a small bed planter about 2.5 foot wide. I am scared to transplant them and risk them dying, when they look so good just have no fruit. I would be happy to send photos. I am at a loss "
april on Thursday 23 July 2020
"^ OH and i live in charleston sc, have grown tomatoes before albeit not in this exact location without problems. the temps here are high, but plenty of humidity "
april on Thursday 23 July 2020
"Hi April. I have to say I'm at a loss too, sorry. It could be that they are a bit close to each other, but then if they are flowering and a good size already, I can't see why they wouldn't take the next step and set fruit. It could be particularly high temperatures, but if it's not any hotter than usual and you are growing heat-tolerant varieties then I'm not sure why that that would be the case either. Are you feeding and watering your plants enough? That is of course important too to help them set."
Ben Vanheems on Thursday 23 July 2020
"This year none of my plants have had any tomatoes. The leaves and stems are all green and look healthy but only my cherry tomato in a container had fruit but none of the in-ground plants did. Noticed flowers back in June but so far nothing. Never have had this problem before - what could be wrong?"
Victor on Wednesday 12 August 2020
"Hi Victor. It could be any number of problems. I would check out our article 'Top 3 Reasons Why Your Tomatoes Are Not Setting Fruit' - you can search for it in the search box at the top of the page. Sadly this just sometimes happens - and is deeply frustrating when it does, I sympathise."
Ben Vanheems on Thursday 13 August 2020
"My grown-from-seed cherry tomatoes are loaded with fruit, but often when ripening, the tomatoes end up hollowed out by something. Cleaned right out, leaving just a shell. Seems to be an overnight visitor, possibly. Any ideas? - "
Irene Maxwell on Wednesday 16 September 2020
"Hi Irene. Hollow tomatoes are a sign of either incomplete pollination or something happening early on the development of the tomato. Temperature and rain/watering variations or an imbalance of nutrients can all play a part. Hollow tomatoes tend to be more common at the start of the season than later on."
Ben Vanheems on Thursday 17 September 2020
"I have a problem with the tomato blossoms falling off but first I get a yellowish colored circle around the stem about 3/4 of a inch behind the blossom . I wonder if it's a bug or blight there seams to be spiders around tiny ones "
John R Nardecchia on Tuesday 23 March 2021
"That sounds unusual - the yellowish colored circle. If you are seeing lots of tiny spiders though, it sounds like the issue might be spider mites. You can search pests by crop by heading to the Pests tab at the top of this page. You may find some of the images there helpful in narrowing down the pest at work."
Ben Vanheems on Wednesday 24 March 2021
"My tomato plants are producing very few trusses of flowers, I have successfully grown tomatoes for about 10 yrs but never had this problem. Any thoughts or solutions?"
Rosemary Anderson on Monday 5 July 2021
"Hi Rosemary. If the plants are looking healthy then it may simply be that there's too much nitrogen in the soil/potting mix. Make sure you are applying a tomato feed at regular intervals, according to the packet instructions. It could also be down to the weather - cooler starts to summer don't see plants moving along quite as quickly as they should. Here in the UK the summer seems very cool indeed, and my plants are a few weeks behind where they should be. "
Ben Vanheems on Monday 5 July 2021

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