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Tomatoes - What Is Wrong With My Tomatoes?

Tomatoes - What Is Wrong With My Tomatoes?


August is here and the tomatoes are coming! Boy, are they ever! Ripening like mad every day… but along with the tomatoes, I’m also getting many tomato questions. People wondering what on earth has gone wrong, how to fix it, and how to prevent it in the future..

Here are the common issues that you may be noticing and how to deal with them. I have not added the wilts to this list as they tend to be early season issues, this post deals with common mid to late summer issues that you may be finding in your harvest right now.


Blossom End Rot - The most asked question about tomatoes throughout the growing season is about Blossom End Rot, when the end of the tomato turns black or brown and scabby looking.

This is actually not a tomato disease, but is a physiological issue brought on by a lack of calcium to the plant. This lack is not caused by an actual soil deficiency, but rather by some kind of stress to the plant… It may be from the weather conditions being too wet or too dry, too cool or too hot. It can also be caused by drought, low soil pH, or too much fertiliser.

The paste aka Roma style tomato is most apt to get BER. Others may also get it but the pastes are most susceptible.

How to fix BER? Despite the popular myth, you cannot fix the problem by adding eggshells or milk powder. However, you can fix the problem by changing the conditions accordingly.

Having a drought? Try to water regularly, not letting them run too dry or too wet.

Are you watering too much (most common reason)? Start deep watering twice a week instead.

Feeding them too much high nitrogen fertiliser? Stop fertilising or switch to a veggie fertiliser. Tomato fertilisers will have the right amount of nitrogen, and often also contain a bit of calcium, too. The best times to feed tomatoes is in the beginning for a few weeks after they have been transplanted and are starting to grow, and then again for a few weeks time when they are flowering and fruiting.

Often you will find that the weather improves, the plant adjusts, and the BER goes away on it’s own. If it persists throughout the growing season , check your pH to see if it is too low. Acidic soil can make it difficult for your plants to access the calcium in the soil. If you need to raise the pH, add lime in the fall so that it has time to make a difference for next year’s planting, it takes many months to change the soil ph.

Potted tomatoes are more prone to BER than garden grown tomatoes, as they cannot send roots down further underground to seek water and are solely dependent on you. Water every second or third day, depending on the size of the pot, less often in the beginning and then more often as the plant grows and the roots fill the pot. Feed potted plants weekly with a good liquid tomato food or liquid seaweed. Toss a bit of Epsom salts on top of the soil once a month.


Cat-Facing - If your tomatoes are lumpy or look like they have been fused together, that is nothing that you did wrong, is just poor pollination. At the time that it was getting pollinated, many weeks ago, the weather was either too hot, too cool, too wet, or too dry. This causes lumpy tomatoes. Not to worry, the ones that were pollinated later, will be normal.

Beefsteak tomatoes are the most prone to this cat-facing.


Cracking - Circular cracks on your tomatoes mean a big fluctuation of moisture happened in your garden. This often happens when conditions have been dry and warm and then suddenly Mother Nature provides you with a big, lovely rainfall. The tomatoes then grow so quickly that their skins cannot keep up with the swelling flesh and so they crack.

The cracks may go in circles around the top of the tomato or down the sides of the tomato as above.


Splitting - Is the same as the cracking above, also caused by a sudden good rainfall or a really heavy watering. These tomatoes that split right open are prone to problems like bugs, mould, or bacteria settling in, so I would not eat these guys. The ones with the skin cracks that sealed over are fine, but anything split open to the pulp inside is not safe to eat.


Green Shoulders - The tomato is ripe everywhere else but the top remains green and hard. Green shoulders are caused by extended periods of hot and dry weather or too much sun exposure. They will not soften up even if you leave them longer on the vine. Cut off the green shoulders and enjoy the rest of the yummy tomato.

Cure - Offer shade by placing other taller potted plants in front of them, or shade cloth, etc.. Also, when you are pruning your tomatoes, do not remove too much foliage as the leaves offer some shade and relief from the sun.


Mushy and stippled looking tomatoes - This is stink bug damage. Shield shaped stink bugs will go after just about any fruit, flower or veggie, and will make them go mouldy, or mushy, or twisted, always inedible. The bugs stipple the tomatoes as they suck out the juices, which turns the tomatoes all soft and they may even begin to rot on the vine. They are not edible, toss them in the compost bin.

Cure - Spray stink bugs with Safer’s insecticidal soap. Pick them and drown in a bucket of soapy water. Plant lemon balm, thyme, parsley, sweet alyssum, daisies, and zinnias to entice parasitic wasps and tachinid flies to your food garden. They are your best defense against these nasty pests. Other beneficial insects will also help to control the numbers, so plant a good variety of both herbs and annual flowers in amongst your vegetables. Do a really good garden clean up in fall so that the stink bugs are not left to overwinter in your potager. Safer’s is said to have a stink bug trap that will lure them away from your garden.


Curled foliage - Leaves will curl in on themselves in an effort to save water, lose less moisture in times of hot weather. This will happen if the soil is too dry when the hot weather comes, or if you have drying high winds or dusty winds along with high temperatures. The curling means that there is not enough moisture in the roots to bring water to all the leaves, so they curl upwards to prevent further water loss from happening. This can also happen if the tomato is growing in too small of a pot and going too hot and dry.

Sadly, once the leaves have curled in on themselves, they will not right themselves, will stay like that all summer. Not very instagrammable ; ) Any new foliage will usually be fine, flat and fresh looking , but the old leaves will remain curled. Leaf curl, however, is not anything to worry about, except maybe serves as a summer long reminder to water deeply and regularly.

Picture from Grow Veg.

Picture from Grow Veg.

Leaves turning yellow - Generally caused by a nutritional deficiency or poor soil, unless you also have wilt, brown spots or lesions.

Cure - Feed your plants with a good organic tomato food, an all purpose fertiliser, or liquid seaweed. Use water soluble or liquid feeds for the fastest results. If using liquid seaweed, use as a spray on foliar feed (spray it right on the leaves).

Feed potted tomato plants weekly throughout the summer with a water soluble fertiliser as mentioned above. Also, toss a tablespoon or two of Epsom salts on top of the soil once a month for a shot of magnesium. Potted plants will quickly use up the nutrients in the pot, even if you added manure at planting time, and so will need to be fed regularly to thrive.

Side dress around the tomatoes with compost or manure both in pots and in the garden.

Prevention - Feed your soil annually to feed your plants. Add compost or manure to garden beds each fall as you do garden clean up. This will add nitrogen and nutrients to the soil and feed the teeming soil life that keeps your veggies growing healthily in summer. If needed, also add organic granular fertiliser to the bed, similar to Gaia Green 4-4-4.


Blossom drop, sterile flowers, tomatoes that just won’t ripen - Temps are too high for the plants to thrive. Tomatoes prefer to be in the mid 20’s Celsius (60’s-70’s Fahrenheit) to grow, flower and fruit well. When temperatures are too high, flowers may shrivel and fall off the vines, or may become sterile and not form into fruits. You may also notice in times of hot and dry weather that your tomatoes are taking a very long time to ripen.

Cure - if outside, is very hard to change the temps to make a difference unless you are able to offer them some kind of shade. However, what you can do is make sure that your tomatoes are watered regularly and deeply, well fed with a good tomato food or all purpose fertiliser, and well pollinated. Attract bees, birds, and beneficial insects to your garden with lots of flowers and a water source that you freshen daily.

In the greenhouse - hose down the floor a few times a day to help bring down the temperature, provide good ventilation with open doors and vents, run a fan in the greenhouse to move the air around, and install shade cloth to provide shade, or plant tall plants in front of the greenhouse.


Sunscald/sunburn - A white spot on your tomato. This is most common in greenhouses, if the tomato is really close to the side of the wall or touching it. It can also happen in the garden if too many leaves have been pruned off of the vine, offering no the tomatoes no protection from the sun. Sunscald changes the flavour of the tomato, making it inedible. Toss into the compost bin.

Prevention - keep fruits further back from the greenhouse walls, especially if they are glass. Do not over-prune your vines, leave on the foliage to provide protection from the heat of the sun.

Picture from the Carolina Farm Stewardship Association

Picture from the Carolina Farm Stewardship Association

And of course, the worst of them all… Late Blight

Late blight is always a concern here in the PNW once the fall rains begin, or as the humidity rises. It is a fungal spore that is spread by wind and rain, and it flourishes in warm, humid conditions. Late blight will wipe out your entire tomato patch in a matter of just days.

Cure - There is no cure. If you saved seeds from the tomato plant and it later comes down with blight, do not keep those seeds as they may be carrying the blight and bring it back to your garden next year.

Prevention - Plant tomatoes 18 to 24 inches apart for good air flow between the plants, this is one of the very best ways to prevent any fungal issues from beginning and then spreading through your tomatoes. Water early in the day, never in the evening. Do not wet the foliage, always water at ground level with weeping hoses or a drip system.


Tomatoes in mid to late summer in general - You may notice that some of your tomatoes are lush and green, growing huge and wonderful. You may also notice some tomatoes looking like the one above… a bit of brown leaves, drying blossoms, tired looking plant. Both are completely normal for this time of year and the tired looking leaves are nothing to worry about.

If you have brown lesions forming on the stems, speckled leaves or tomatoes, something more dangerous looking, then you need to be on the look out for blight or viral issues. However, if your plant looks just looks a bit peaked, this is not unusual for this time of year.

For any tomato plants that are still making lots of fruits, generally these will be indeterminates, make sure to water well and feed weekly. Remove any foliage that is touching the ground or very brown/yellow. Remove any fruits that are not right, have any of the issues mentioned above. They still have about 4 weeks to go, if all goes well, before the fall weather strikes (usually in mid-September).

For determinate plants that are pretty much done for the season, keep watering them well until the fruits are harvested and then remove the plants from the garden. Once they are done, they are done. Read more about indeterminates and determinates below. Remove any foliage that you think does not look right, just in case it is fungal, to keep it from spreading to your other tomatoes. You can feed it weekly if you feel that it still has a way to go before it is finished, do not starve it for it’s last few weeks or you may not have much to harvest.

Martino’s Roma - A determinate (aka Bush) type tomato.

Martino’s Roma - A determinate (aka Bush) type tomato.

Indeterminate versus Determinate Tomatoes - On a last note.. a little bit of clarification about bush tomatoes and vining ones..

If your tomato has now stopped flowering and making more fruits, it is likely a determinate (aka bush) type.

Determinates grow anywhere from 2 to 4 feet tall. They do not need any pruning but do require a cage to keep them upright as they get heavy with tomatoes. They begin flowering and fruiting early in the season, put on lots of tomatoes at one time, and they also all ripen around the same time. You will have a few early ones here and there, but the majority will all ripen within two weeks of each other. This makes determinate tomatoes ideal for canning or saucing.

Most of the paste and plum tomatoes that are used for making tomato sauces, diced tomatoes, spaghetti sauce, etc.. are all determinate varieties. Tomatoes like Early Annie and Sasha’s Altai are also determinates. They are generally the first to fruit, will put on a good amount of tomatoes, and then finish flowering and fruiting in mid to late summer. There is nothing you can do to entice it into flowering more when it is done for the year.

Indeterminate tomatoes are known as vining tomatoes. They grow tall, anywhere from 6 to 12 feet during the summer, and will keep on growing from spring till fall. They also make flowers and set fruit from spring until the fall frost kills them off. This is why often times, people will top (snap the tops off) their indeterminate tomatoes in mid to late August. This stops the vine from growing and fruiting, instead puts it’s energy into ripening the fruits on it already. They tend to start fruiting a bit later in the spring than the determinates do, but will keep on going indefinitely.

Indeterminate tomatoes are often staked, grown up strings, or grown in large, sturdy cages. Suckers should be removed so that they put on more fruits and less vines, but they will still become very large plants and so need good supports.

Both types of tomatoes are fantastic and it really depends on what you want to do with them. I have many customers ask me for just determinates in the spring because the plants are easier to grow and care for, and they will fruit sooner rather than later. As our summers are not very long and we need to worry about late blight when the rains come, having tomatoes that finish off in early September is sound idea.

If you do a lot of canning, sticking with mostly determinate paste tomatoes is a great idea.

If, however, you want tomatoes ripening throughout the season for fresh eating, and would like them throughout the season (and into the fall, as well), then grow a few indeterminate tomatoes, too. Especially if you have a greenhouse. If you only have room for a few tomatoes in the greenhouse, grow the indeterminates in there so that they fruit till November, and grow the bush types in the garden.

Now, these new tree type tomatoes from the ‘dwarf tomato project’ may be a game changer when it comes to all of this, but that is a conversation for another day.

Black Cherry - An indeterminate (aka Vining) tomato.

Black Cherry - An indeterminate (aka Vining) tomato.

Happy growing and harvesting!

Small Batch Plum Jam

Small Batch Plum Jam

August In The Vegetable Garden - Harvesting, Blossom End Rot, fall & Winter Planting

August In The Vegetable Garden - Harvesting, Blossom End Rot, fall & Winter Planting