15 Common Problems With Garden Grown Tomato Plants

Growing tomatoes is one of the truest joys of summer. In the United States, tomatoes are one of the most common crops for the home gardener and it’s not hard to see why! Home grown tomatoes can be used in a variety of different ways, and provide the taste you’ll never get from a grocery store.

While incredibly popular to grow, tomatoes are also one of the more ‘fussy’ vegetables around. Many, if not most, gardeners will encounter problems with their tomatoes in any given season. Some issues are relatively benign or cosmetic, while others present a real risk to the health of the plant and your potential yield.

Let’s take a look at the most common issues you are likely to come across this season. We’ll look at problems with the plant, the fruit itself, and common tomato diseases to watch out for. Once you’ve identified the issue you’re dealing with, we’ll show you how to correct it and hopefully prevent it from happening again.

Broken Branches

Seeing broken stems or branches on your tomato plant can be devastating. This has happened to me on more than one occasion after strong storms ripped through our area. What you’ll see is a branch or set of branches snapped off at a certain point.

I once had an entire tomato plant (planted in a container that weighed close to 50lbs) get knocked over because the trellised plant acted like a sail in heavy wind. Thankfully, that plant was ok, but it was a little nerve wracking!

Unfortunately, there isn’t anything you can do for branches that have already broken off. But you can take steps to ensure the rest of the plant (and future tomatoes) are safe.

Causes

Broken branches can be caused by a few things but all stem from a lack of proper support. If a tomato is trellised properly – either in a heavy-duty cage or trellis system – it should be able to withstand heavy wind and the weight of heavy fruit. If you’re using a flimsy tomato cage (or one that is too small for your plant), you’re at increased risk of losing branches.

How to Fix & Prevent

If you’re fairly new to growing tomatoes, check out our article on trellising tomatoes. You’ll learn the correct way of supporting your plants no matter how big they grow. This will ensure that the plant is supported in such a way that it can withstand environmental factors and the weight of heavily fruited branches.

Blossom Drop

Blossom drop is a common issue that causes frustration for many gardeners. We are always so excited to see the first flowers on our tomato plants. But what happens if those flowers simply drop off the plant rather than producing fruit?

While this can seem to happen at random, there is always a reason for blossom drop and a way to fix the problem from repeating.

Causes

Temperature fluctuations, poor pollination, inconsistent watering, excessive humidity, excessive nitrogen, pests, and disease can all impact blossom drop. The common factor here is stress. When your tomato plant experiences too much stress while flowering, it will drop flowers to save energy and recover.

How to Fix & Prevent

Learning the proper way to plant, grow, and care for your tomatoes will go a long way in preventing this problem from ever happening. While we can’t control the weather, we can certainly ensure we provide our tomatoes with consistent watering, proper fertilization, and daily pest/disease management.

Yellowing Leaves

When a plant’s vibrant green leaves begin to yellow, it is often an early warning indicator of a larger problem. The good news is that most causes of yellowing leaves are easily fixed and preventable. When leaves start turning yellow, they will often fade to black or shades of brown which will indicate the problem has advanced more seriously.

Causes

Yellowing tomato plant leaves can be caused by quite a few problems including under- or overwatering, transplant shock, soil compaction, nutrient deficiency, pests, or disease. For most of these issues, you can fix the problem once you’ve identified it and help support your plant correctly throughout the remainder of the growing season.

How to Fix & Prevent

Fixing or preventing yellowing leaves will depend on the root cause. Unfortunately there are many different causes that will cause your tomato leaves to yellow. The good news is that most of them are preventable.

Leaf Curl

Leaf curl or leaf roll is another common tomato problem you are likely to encounter. This condition worries many new gardners, but take heart in the knowledge that there is usually no cause for alarm.

Causes

Most causes of tomato leaf curl are stress related. Over- or underwatering, environmental stress, excessive pruning, transplant shock, excessive pest exposure, and nutrient imbalance can all cause this stress reaction in your tomatoes.

While these are all relatively easy to fix and prevent, there are some causes that are more damaging to your plant. Diseases like the curly top virus and tomato yellow leaf curl can both be deadly to your tomato plant.

And exposure to certain herbicides either through drift or direct application can also be quite damaging. Due to the vast difference in severity, it’s important to be sure of the cause of your tomato curl before taking action to fix the problem.

How to Fix & Prevent

Just like with yellowing leaves, the fix or prevention tip will depend on the root cause. There are also multiple reasons for leaf curl, and both treatment and prevention will depend on the root cause.

Blossom End Rot

Blossom end rot is a condition that causes the fruit of tomato plants to turn brown and rot from the bottom. This happens when the plant is unable to bring up enough calcium through the roots, causing the plant to become deficient in that micronutrient. It’s really upsetting when you see this happening in your tomato plants because the affected tomatoes are a total loss.

Causes

Calcium deficiency is primarily caused by one of three things: uneven watering, calcium deficiency in the soil, or the pH is too low (tomatoes prefer a slightly acidic environment around 6.5). Any one or a combination of these can cause this issue.

How to Fix & Prevent

To fix problems with blossom end rot, you really need to know what’s causing it. Start by focusing on consistent watering habits and find that goldilocks amount of “not too much and not too little”. Pick off the affected fruit and see if the problem rectifies itself. If not, go ahead and test your soil for calcium deficiencies or a pH imbalance.

Cracking Fruit

Cracking fruit is probably an incredibly common issue we see with tomatoes. What happens is that ripe fruit can split – sometimes at the top and sometimes down the side. Some heirloom varieties are especially prone to this since the skins are naturally thinner.

Oftentimes, insects and birds will use this opportunity to dive in and eat the fruit. If you see fruit beginning to crack, harvest it immediately.

Causes

Rain is usually the culprit here. As the plant takes up water rapidly after a heavy rainfall, the fruit can swell, causing some to crack.

How to Fix & Prevent

One of the best ways of preventing cracked fruit is to harvest your tomatoes before they’re fully ripe. Once tomatoes start to blush, they will continue to ripen off the vine and be just as delicious and sweet. If you want to keep the fruit on the vine for as long as possible, be sure to harvest tomatoes that are close to ripe before any major rainfall.

Consistent watering habits will also help prevent cracked fruit. The plant won’t draw up as much water after a rain if it has been well watered all season.

Sunscald

You’ll know you’re dealing with sunscald when your ripe tomatoes are present with large yellow or white patches that form on the side of the fruit that faces the sun. Think of this as your tomatoes getting a bad sunburn!

Causes

Sunscald is a result of the tomato fruit having too much contact with direct sun. This usually is a result of over pruning your tomato plant, which removes foliage that would normally shade the fruit.

How to Fix & Prevent

Properly pruning your tomato plant will go a long way toward preventing this problem. You always want to leave enough foliage and branches so fruit is adequately shaded from too much direct sun.

Catfacing

Catfacing is a physiological problem that makes tomato fruits look deformed. This problem is more commonly found in large-fruited varieties. Fruit appears heavily misshapen and parts may ‘scab over’ creating an ugly brown rough patch on the deformed part of the fruit.

The good news is that the deformity is purely ornamental and the fruit will taste the same. If the look bothers you, just cut that portion off and compost.

Causes

Catfacing occurs when plants are pollinated during cool evenings when temperatures are below 55 degrees. If flowers begin pollinating before the blooms drop off (due to cold temperatures), they can stick to the developing tomato.

This is what creates the lumps and deformities typical of the problem. It can also happen when a plant is exposed to man made commercial pesticides.

How to Fix & Prevent

The best way to prevent catfacing is to wait and plant your tomatoes until nighttime temperatures are consistently above 60 degrees. If you live in a cooler climate where temperatures are more variable in the summer, try adding a layer of black plastic to your garden.

Spreading this along the soil line can help soil retain heat even on cooler nights. This is commonly done with early spring plantings as well.

Zippering

Tomato zippering is not often talked about, but it’s quite common. The good news is that on the long list of tomato problems, this one is purely cosmetic and won’t impact the overall health of the plant or taste of the fruit.

The name says it all here… Zipper-like lesions will appear on the skin of the fruit – often right in the center. The issue usually only affects a few tomatoes rather than an entire set.

Causes

Problems with zippering start when the fruit is first developing, which makes this a difficult issue to spot until you see the lesions on fully formed fruit.

During periods of high humidity (and sometimes during abrupt shifts to cooler weather), the anther – the end part of the stamen – becomes stuck to the side of the developing fruit. As the fruit grows, this extends into the long scar that looks just like a zipper.

How to Fix & Prevent

Unfortunately, little is known about why this occurs to some tomatoes and not to others. Maintaining good airflow around your tomatoes can help quite a bit with concerns around humidity. And if you have low areas in your garden where cooler air settles, you may want to avoid planting your tomatoes there.

Poor Fruit Set

There is nothing more frustrating than seeing a plant with a lot of flowers and very little fruit. Well, perhaps if the fruit you are seeing is smaller than you would expect and not very flavorful.

Causes

Poor fruit set is most often caused by excessive nitrogen in the soil. Nitrogen is just one of 3 macronutrients your tomatoes need to thrive. Here’s a little cheat sheet of what is found in tomato fertilizers:

• Nitrogen. Promotes foliage growth. Too much will lead to very bushy plants with little to no fruit.
• Phosphorus. Crucial for the growth and development of roots as well as fruit.
• Potassium. Helps the plant grow rapidly and produce flowers and fruit.

As you can see, too much nitrogen in the later stages of the plant’s development will cause it to focus all its energy on foliage production rather than flowers and fruit.

Another potential cause is that your plants are too close together. Tomatoes are self-pollinating and need wind to move pollen between flowers. If your tomato spacing prevents adequate airflow, this could be your problem.

How to Fix & Prevent

If you believe nutrients are the problem, shift immediately to a fertilizer that is heavy in phosphorus and potassium. For future plantings, know that a balanced (10-10-10) slow-release fertilizer is a great choice to add upon planting.

Once your plant sets its first flower, begin to add a fertilizer closer to a 5-10-10 every two to three weeks. This will help the plant produce more flowers and direct its energy into turning those flowers into fruit.

If you think the issue is spacing, you’ll need to help out your plant with pollination. Giving it a gentle shake a few times a day will help move pollen around.

Early Blight

Although somewhat problematic to deal with, blight is luckily easy to identify. Pale yellow spots will appear on the lowest leaves of your plant, turning into a necrotic dark brown patch with yellow at the edges. It looks a bit like a bull’s eye.  Leaves will eventually turn 100% yellow and fall off. Sometimes, the spots will occur on the stems and cause leaves to quickly fall off. This disease moves up the plant from the soil.

Causes

Early blight is caused by a fungus in the soil called Alternaria solani. If you expect this disease is your problem, plan to completely replace the contaminated soil before your next planting.

How to Fix & Prevent

Some tomato varieties are resistant to diseases like early blight. If you have been plagued by this disease in the past, think about choosing those varieties for future plantings.

For your current plant, completely remove diseased leaves and stems. Do NOT compost them or you will spread the disease to all your other plants. You can treat the plant with an organic fungicide.

Powdery Mildew

Powdery mildew looks just like it sounds – a whitish dust that settles on the leaves of a plant. It almost looks like a bunch of pollen dusted there or your child sprinkled flour on the plant. As the disease progresses, however, that dusting will turn into larger white blotches, fuzzy stems, and dead leaves.

Causes

The disease can be caused by a few different fungi in the soil including Podospaera xanthii, Erysiphe cichoracearum, and Sphaerotheca fuliginea. Regardless of the particular strain of fungi, the symptoms are similar and typically take hold during mid- to late summer. This disease loves temperature fluctuations between hot and dry to moist and humid.

How to Fix & Prevent

Fixing this problem is pretty simple. Remove the affected leaves and throw them away (do not compost). You can also wipe diluted neem oil over nearby leaf surfaces to slow the spread and prevent additional infection.

Prevention is always the best bet moving forward. Powdery mildew has a hard time taking hold in plants that have good air circulation. So, proper pruning and spacing of your tomato plants will go a long way in ensuring their protection from this disease.

But the best preventative method is to water your tomato plants from the base and not the leaves. Powdery mildew spreads from the soil when water splashes it up to the undersides of leaves. Soaker hoses or a drip system are great options for watering that will prevent this problem.

Septoria Leaf Spot

Septoria leaf spot is another fungal disease that looks a bit like blight in the early days. Brown spots will appear on the lower leaves and will eventually spread to the stems. As it gets worse, the disease causes spots to grow into large brown areas on the leaves. When left unchecked, leaves will turn completely yellow, then brown, then fall off and die.

Causes

Caused by the fungus Septoria lycopersici, it is most common in areas that have extended wet periods or generally humid weather.

How to Fix & Prevent

Like early blight, septoria leaf spot can be managed if discovered early. Remove the affected leaves and stems and throw them away (do not compost). Apply a fungicide designed to treat the disease. Follow all directions on the bottle until the problem is resolved.

Fusarium Wilt

Another common soil based disease, Fusarium wilt infects the tomato plant’s roots, preventing the transportation of water and essential nutrients to the rest of the plant. The disease is very problematic, but rarely kills the host. In addition to the yellowing leaves, you will notice a failure to thrive, poor growth, general wiltyness, and poor (if any) fruit production.

Causes

Fusarium wilt is caused by a fungus called Fusarium oxysporum, which can be found in affected soil.

How to Fix & Prevent

Because many gardeners can’t easily identify fusarium wilt, they continue trying to revive the plant with water and fertilizer with no success. Unfortunately there is no cure for this disease.

If you encounter fusarium wilt, there is nothing you can do to save the plant. Cut your losses and remove the plant immediately. There is no cure, and the disease can spread to other plants in your garden if left unchecked. Be careful not to let your affected plants touch others in your garden as you remove them. Do not compost.

Verticillium Wilt

Verticillium wilt is most commonly seen in cooler Northeast gardens. Like early blight and Septoria leaf spot, yellow patches start to show up on the lower leaves and progress to brown spots, and curled dead leaves.

Causes

Verticillium wilt is caused by a soil-borne fungus called Verticillium albo-atrum. Depending on your geographical climate, you may or may not see this come up in your garden.

How to Fix & Prevent

Like fusarium wilt, there is no saving a plant affected by verticillium wilt. Remove the plant immediately, taking care to not let it touch other plants in your garden. Do not compost. Keeping your garden free of debris can help limit many bacterial diseases.