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It’s no secret that gardening takes time, effort, and a ton of dedication. This is true whether you’re growing crops in the ground, in raised beds, or in containers on the back patio.
That’s why it can be disheartening to notice that your plants aren’t growing quite as you expected. Maybe your yellow squash is browner than anticipated, or your cucumbers are turning yellow on the bottom. Then, there are tomato plants, which tend to have a mind of their own.
Have you noticed that the leaves on your tomato plants are starting to get a little speckled? If white spots begin to appear, there are steps you can do to mitigate signs of disease and keep help your veggies thrive. Today, we’re sharing our white spots on tomato leaves advice to help you reverse the damage and get back on track.
What Are Tomatoes?
Tomatoes are one of the most popular crops for DIY gardeners, and for good reason. They’re relatively easy to grow, versatile to prepare and deliver a bountiful harvest without taking up a ton of space. If you’ve ever prepared the ultimate summer meal of a homegrown tomato, white bread, and a slather of mayo, you know that no grocery-bought variety can compare.
Native to Central and South America, tomatoes grow as a perennial plant in those countries. Technically, they’re the edible berries of the Solanum lycopersicum plant. For this reason, tomatoes are generally considered fruits, because they contain seeds and are formed from a flower.
Still, many nutritionists refer to them as vegetables, as they’re often utilized this way when cooking. In fact, in 1893, the U.S. Supreme Court officially ruled that tomatoes should be classified as vegetables due to their culinary applications.
While we can trace the history of tomatoes back to the early Aztecs, Europeans didn’t encounter them until the 16th century, when early explorers first set out to explore new lands. They didn’t become a dinner table staple until the 18th century, however, because there was a widespread belief that the plants were poisonous.
Cultivating Tomato Plants: Ideal Growing Conditions
Before we dive into how to care for tomato plants that are showing signs of distress, let’s briefly review what they need and how you can create an environment that encourages their growth.
At the minimum, your plants need well-drained soil and plenty of sunlight. If possible, check the soil to make sure it’s slightly acidic. Ideally, the acidity level should measure between 6.2 and 6.8. Not sure how to conduct your own soil pH test at home? This quick guide provides a simple breakdown that’s easy to follow.
To truly understand the nutrient makeup of your soil, consider hiring a landscaper to conduct a more thorough soil test. These results can reveal how much lime and fertilizer your garden needs. They can also detail the current level of nitrogen present. While this nutrient is required for sufficient plant growth, too much of it can leave you with lush, green foliage but very little flowering fruit.
If you don’t have access to such test data, most tomatoes do well with around 2.5 pounds of complete fertilizer (e.g. 10-10-10) per 100 square feet of soil. Rather than fertilizing the ground right when you plant the tomatoes, work it into the soil about two weeks before you’re ready to start planting.
White Spots on Tomato Leaves Advice to Know
You followed all of the directions. You made sure your soil was just right and you chose a garden plot with plenty of sunshine. You spaced the plants far enough apart, and you pruned them regularly. However, you walked out to the garden one morning to discover an unsightly problem. There are white spots on your tomato leaves that seemed to form overnight! What’s going on and what can you do about it?
First, take a deep breath. This issue is fixable as long as you know the right steps to take. It all starts with understanding how those white spots formed in the first place.
Why Do White Spots Form?
There are a few culprits that can cause little white spots to appear on the leaves of your tomato plants. Let’s take a look at some of the ones that could be at work, and how you can take care of the issue right away.
The most common reason for white spots is called powdery mildew. This can form when your tomato plants do not receive adequate amounts of any of the following:
- Air circulation
When these levels dip, it can cause different types of fungi to form. These fungi love living in areas that are dark and moist, with little to no airflow. As such, when your tomato plants are exposed to high amounts of summer humidity but don’t get enough sunlight or air circulation, the leaves can begin to suffer. In this case, “high humidity” refers to levels greater than 70%.
At the same time, too much of a good thing can have a negative effect. This especially applies to fertilizer. Over-fertilizing your plants can cause these levels to become off-balance as well, leading to fungal growth. For this reason, powdery mildew is more common in new plants, as inexperienced gardeners tend to oversaturate their gardens with fertilizer in earnest attempts to facilitate growth.
The good news? While these spots might be surprising and even a little disheartening, they will not kill your plant. However, you may notice that your yield count will begin to dwindle and your tomatoes may even take on a slightly different flavor.
Tomato plants do need lots of sunlight to grow, but that isn’t all that they need. When the leaves on your plants are exposed to high amounts of sunlight for prolonged periods of time, a condition called sun scalding can occur. Put simply, the leaves simply burn in certain places, which causes white marks.
Did you grow your tomato plants indoors from seeds or saplings before transplanting them into an outdoor garden? If so, the shock of the bright, direct sunlight could cause the plants to fall victim to sun scalding. When this occurs, the leaves will first turn white as a signal that something’s going wrong.
Over time, they will begin to wilt and eventually fall to the ground. This can stunt the growth of your tomato plants and lower your yield. If the leaves are sun scalded before any fruit grows, the plant might be compromised for the season. On the other hand, if you already had ripe tomatoes before the issue started, those crops might be salvageable. Keep in mind, though, that you may notice blisters or soft spots in certain areas.
Light blight can be a devastating disease to your tomato crops, affecting the stems, leaves, and fruits of the plants. This is the disease that was responsible for the great Irish potato famine in the 19th century.
What’s behind all the destruction? A fungus-like pathogen called Phytophthora infestans. When this pathogen develops on a host plant, it grows and spreads rapidly. This condition first appeared in the United States in the 1840s and is most common in gardening areas that are cool and damp.
The first signs of late blight that you might notice are damp, irregularly shaped lesions on the leaves of your tomato plants. Usually, the younger and smaller leaves are those first affected. You may also notice white or brown spots, as well as a cottony white growth on the undersides of the leaves.
While it might be tempting to simply prune off these affected leaves, resist the urge to use them as compost for your garden. These leaves will still contain blight, and mixing them into the rest of your soil can cause the infection to spread to other plants.
How to Treat White Spots on Tomato Plants
Once you’re able to identify what caused the white spots you see, your next step is to take action. Here are a few ways you can redeem and restore your tomato crop and enjoy the rest of the summer’s bounty. While the effects cannot usually be reversed in full, early treatments are most effective.
Pruning the Plants
You already know that it’s smart to prune your tomato plants on a regular basis. This simple act encourages growth, prevents overcrowding, and keeps pests at bay. Yet, did you also know that you can use it to treat any white spots that occur?
Pruning is especially helpful if powdery mildew is to blame. As long as you catch the issue early, you can prune off the infected leaves to prevent the fungal infection from spreading to other parts of the plant, or to others planted nearby.
Why is it so helpful? Pruning puts more space between your tomato plants. This act alone increases air circulation in your garden, which can mitigate the effects of the disease. Be sure to dispose of any leaves that you prune and sanitize your tools (including your gardening gloves) when you’re done. Otherwise, the infection could linger and spread the next time that you use them.
While pruning, take care to only remove the infected leaves. Taking off too many could inflict too much damage onto your plants, leaving them vulnerable and exposed.
Applying Milk Spray
It might sound simple, but milk spray can be very effective in the fight against fungal-related white spots like powdery mildew. To make it, simply blend three parts of water with two parts of milk. Add it to a spray bottle and apply it to your leaves on a weekly basis until the spots disappear.
While researchers aren’t exactly sure what makes milk spray such a powerful opponent, studies suggest that when the proteins in the milk interact with sunlight, they create a short-term antiseptic effect. If there are fungi present on the leaves, the spray essentially burns them to death. For that reason, it’s important to apply milk spray in the direct sunlight to achieve the full effect.
Applying Neem Oil
Some gardeners swear by neem oil as a gentle, eco-friendly way to keep white spots at bay. This is a naturally occurring pesticide found in the seeds of a neem tree. Indigenous to the Indian subcontinent, neem is an evergreen tree that also grows in other areas of the tropics.
Pressing its fruit and seeds creates neem oil, which you can use if you’re wary of applying a manufactured pesticide to your garden. Not only does neem oil keep your plant leaves green and healthy, but it can also keep other bugs and pests away, including:
If you want to use neem oil on your tomato plants, fill a spray bottle with the liquid. Spray the leaves in the morning and evening for optimal results. This way, other beneficial insects, such as honeybees, can safely travel around the plants during the day.
Using Baking Soda Sprays
You can also make a quick baking soda spray and apply it to the affected leaves. To do so, mix the following together:
- One teaspoon of baking soda (sodium bicarbonate)
- One drop of liquid dish soap
- Two gallons of water
Coat the plants with the solution, including their stems and all leaf surfaces.
Answer: Early preventative action is the best way to keep your tomato plants healthy all season long. Thankfully, there are a few steps you can take early on to help them look their best. These include:
Keep at least 18 to 24 inches of space between each plant for optimal circulation
Choose a garden spot that gets six to eight hours of direct sunlight every day
Plant mildew-resistant varieties of tomato plants (e.g. Granadero tomatoes)
If you want variety in your garden, try planting one disease-resistant tomato variety between two low-resistance ones. This way, if one plant becomes infected, the disease won’t be able to travel across the entire row.
Answer: Worried that your tomato plants are lagging due to overwatering? This isn’t usually the case. Instead, this condition is marked by other characteristics, such as:
Cracked tomato skins
Blistered tomato skins
Bumps on the lower plant leaves
If you continue overwatering, you could drown the roots of your plants and cause them to die. If you notice any of these issues, cut back on your watering times until the condition improves.
Answer: Answer: Inexperienced gardeners may see tiny white spots on their tomato leaves and think it’s a disease. If you look a little closer, you might notice that those dots are moving!
If this is the case, it’s likely aphids. These are tiny, sap-feeding insects that tend to invade tomato plants over others. While they can be many colors, some appear translucent, which can make them look white in the sun. Large populations of aphids can cause the leaves on your plants to curl. They can also lead to leaf yellowing and deterioration and could cause younger plants to die.
As long as you catch them early, you can usually spray aphids with water or simply brush them away with your hand. The natural pesticides described above can be useful if populations are more significant.
Answer: White spots on tomato leaves are one thing, but what happens when white spots appear on the tomatoes themselves? If you notice white spots or white lines on the fruit, invasive pests are usually to blame. Stink bugs and leaf-footed bugs are two insects that love to feast in your garden!
To feed, these bugs insert their mouthparts into the tomato. This can cause the crop to develop green, yellow, or white spots on its skin and inner flesh. Usually, you can cut out these spots and salvage the rest! Those cloudy spots should be isolated and are easy to remove.
Answer: Unfortunately, this isn’t an issue you can ignore. If the case is mild, there’s a slight chance that it might resolve itself on its own. However, it’s best to intervene as quickly as possible. A small infection of powdery mildew can quickly manifest into a bigger one, which can ultimately ruin an entire crop of tomatoes.
Of course, you want to be smart with your time and efforts. This is a condition that usually affects plants later in the season. If you’ve already harvested a good number of tomatoes and you’re satisfied with your crop, it might be more effective to focus your attention on preventing powdery mildew from occurring next year. Collect all of the diseased leaves, and cut the affected stems back.
This way, the fungus is effectively removed from your garden and will not remain in the soil over winter. Dispose of all the landscape waste in a paper bag and do not mix it with the rest of your compost.
Enjoy a Healthy, Thriving Tomato Crop
At-home gardening can be a rewarding, enriching activity. There’s nothing like preparing a meal from the foods that you grew from the ground up.
If your plants become damaged or diseased at any point in the season, take heart. There are proactive measures you can take to mitigate the affliction and help them return to their original glory. Our best white spots on tomato leaves advice? Choose a well-ventilated garden spot that has the right amounts of shade, sunlight, and air. Then, check your plants regularly for any signs of distress, and remove the affected areas immediately.
Your garden can still be successful and thriving, even amid setbacks like fungal infections and blight. For more advice on how to make this the best one yet, feel free to check out our other helpful guides!