As a gardener, it can be disheartening to prepare to harvest your long-awaited red, juicy tomatoes only to find a few yellow, strange-looking fruits. However, there are solutions to help you get colorful, bright-looking tomatoes again. The red color of the fruit is due to a pigment called lycopene. However, factors like high temperatures or too much direct sunlight can hinder the production of this pigment and lead to yellowish fruits.
Here are 5 ways to keep your tomatoes from turning yellow instead of red:
- Plant in a shady spot.
- Add a cover.
- Put out an umbrella.
- Use row cover hoops.
- Utilize shade cloth.
- Prune less.
Below, I’ll take you through each of these strategies for supporting your tomato garden. I’ll also provide a few product recommendations, tutorial videos, and considerations you’ll want to keep in mind for each of them. Lastly, I’ll talk about other common coloring issues that can occur while growing a tomato plant.
Why Your Tomatoes Might Be Turning Yellow
Red, juicy tomatoes are a staple of the backyard garden. Easy to grow and with a high yield, tomatoes of all varieties are one of the most sought-after crops among gardening enthusiasts. However, what happens if the color isn’t turning out how you were expecting it to?
Tomatoes usually turn yellow instead of red because they’ve been exposed to too much sun or overly high temperatures. This problem is widespread in locations where the climate is warmer. Yellow tomatoes may indicate a nutrient deficiency or a problem with the soil.
Tomatoes are red because of a pigment called lycopene. Sunshine can inhibit this pigment. Instead, the other carotenoids will come through more heavily, causing the tomato to become yellow.
Besides the yellow color, inhibiting lycopene may make the tomato less nutrient-dense. Lycopene is a highly beneficial nutrient for human consumption.
This video helps explain what this pigment does for humans when consumed:
It can be hard to tell what’s causing your particular crop to become yellow, so be observant and utilize some of your gardening tools.
A moisture meter will indicate the pH, moisture, and sunlight your garden is getting. Sticking one into the soil where your tomato crops are planted can show whether there are any fundamental issues with the ground inhibiting this pigment production.
Even infrequent observations can go a long way, though. Most commonly, too much sun is what’s making your tomatoes yellow.
If you’ve noticed your tomatoes are constantly getting pelted with sunlight, the below solutions will keep them from turning yellow and getting burnt:
1. Plant in a Shady Spot
Tomatoes need at least six hours of sunlight, but high temperatures will hinder lycopene production. You can plant your tomatoes in a shady spot where they won’t be exposed to too much sun but can still get their six hours.
Though this method requires some pre-planning if you sow directly into the dirt, it’s perfect for the container gardener. If you use a plant pot to grow your tomatoes, you can simply grab your container and move it elsewhere. If you’re a direct sower, this might be a strategy you utilize next season.
A product that might help optimize this approach is a moisture meter that can detect sunlight. Stick a moisture meter into the soil of your pre-planned spot and check the sunlight it gets at various intervals throughout the day.
If you’re looking for a simpler approach, you can get a product that detects the sunlight level such as a digital light meter.
This method is entirely free. Seeking out the perfect shady spot under a tree, near a fence, or in the shadows of your house helps you to utilize the resources already available to you and costs no money at all.
It’ll also help you practice your gardener’s intuition and help you get a better understanding of your plant’s needs and requirements.
This method requires some pre-planning and might not be feasible for every gardener.
If you sow your tomato seeds right into the ground and are looking at this article post-planting, there’s not much you can do about the spot your tomatoes are in. If you’re an urban gardener or garden on your apartment patio, there’s little you can do about shady conditions.
2. Add a Cover
If no natural cover is available for your tomatoes, you can make one yourself. It will require some DIY skills and a few materials, but the result will be worth it if your tomatoes have been yielding consistently yellow produce.
To do so, you’ll usually just need a plant cover of some sort and something to wrap it around. The plant covers also help keep pests like squirrels and rabbits away from your tomatoes.
This video shows how to build one with PVC:
This solution is perfect for apartment gardeners and urban farms. You can change the measurements or tweak the design until it works for your circumstances. For example, if you have a porch that gets tons of sun, you can create a shady area and move your plant once it gets enough sun.
If you don’t have the means or ability to build your own, you can also buy a crop cover at your garden center or online.
As mentioned, this method is excellent for patio farmers or urban farmers. Rooftop gardens often get sun all day long, so adding a shade cover may be necessary not just for tomatoes but for all their other plants as well. Container and garden box gardeners can even create a shade directly onto their current system.
This method may take some engineering and creativity on your end, which may be a disadvantage if DIY projects aren’t typically your thing. If you have sown seeds directly into the garden, there’s no way of assuring your seeds only get a certain amount of shade or sun.
3. Put Out an Umbrella
If you need a quick solution and don’t have time for DIY projects, an umbrella will do!
The root cause of yellow tomatoes is excess sun or too much heat, and some umbrellas are designed to combat this exact same issue. If you need something convenient and simple to cover your tomatoes with, just grab an umbrella.
This method is quick and cost-effective. You can utilize something you already have within your home to solve your problem instead of going to the store and having to splurge on a pricey solution. It’s an excellent short-term solution that can keep your produce safe while you work out a more permanent fix.
This method likely won’t work long-term. A gust of wind can take even the most perfectly weighed down umbrella out of your garden and expose your tomatoes to the sun.
A garden umbrella isn’t the most attractive look. Also, if you have a bigger tomato garden, you’ll still have to dip into your funds to purchase an alternative designed specifically for this purpose.
4. Use Row Cover Hoops
Row cover hoops aren’t necessary for gardens in the same way that a car radio isn’t necessary for a car. Your car will roll on and function without it, but the radio can make a huge difference!
Most gardeners I know didn’t invest in row cover hoops until a little later in their gardening journey, not because it’s challenging to install them, but because it can be a considerable commitment budget-wise. Once you install them, though, you’ll instantly feel the relief they provide!
In the context of this article, row cover hoops are excellent for tomatoes. Whether they’re sown into the ground, and you need a row cover to take on and off, or you’ve got a tomato plant container you can pull in and out, you’ll be able to provide your plant with some much-needed shade.
It doesn’t take too much effort to move around your tomato plants if you get the right hoops. You can also use cover hoops in the winter, so you’ll get double use out of the product if you have to build it or buy it. More importantly, this solution is bound to last you for years to come, making the investment worthwhile.
This method won’t work well if you have a large tomato crop. It’ll work best if you have a few small container plants or a small section you can cover.
It’s pretty time-consuming because you’ll need to pull your plants in and out or keep moving the cover hoop around. You’ll also have to make a sizable withdrawal from your gardening budget.
5. Utilize Shade Cloth
Shade cloths are one of the most widely used methods for protecting tomatoes from the sun. The shade will not only keep out UV but can significantly reduce the temperature of your garden as well. Fortunately, this method doesn’t require a lot of handiness or cash.
You can get shade cloths at your local gardening store or order them online. To use, you’ll set up a tent-like structure for your tomatoes that allows the shade to come off and on easily. Be sure to get one that allows water to penetrate for rainfall or irrigation systems.
This video shows the way that one gardener utilizes cover crop for their large tomato garden:
Like the cover method above, this approach is highly flexible. However, the main difference is the size and convenience of the systems. Adding a cover usually means finding something that provides complete shade over a small area.
You can use any number of materials to cover these types of gardens. However, a shade cloth does the same thing but can tent over a larger area.
This method is perfect if you have a large tomato garden. Most of the previous methods work best for small container plants or just a few sown plants, but the shade cover allows for more flexibility in what can fit underneath. Given its functionality, this approach is relatively affordable.
The method can be time-consuming because you’ll have to remove and add the shade cover daily to ensure your tomatoes are getting enough sun. Depending on how much shade cloth you need, the structure you’ll need to build, and how many tomato plants you have, the set-up process can require a lot of time and effort.
6. Prune Less
Cover leaves help protect your tomatoes from the sun. If you’ve been pruning tomato leaves pretty often, this may be the reason why your tomatoes have been turning yellow instead of red.
Luckily, the solution is simple: just prune less! Or, if you need to, you can focus on leaves that aren’t doing much to protect the plant from the sun. As I’ve already mentioned, a little shade is necessary, so trim your tomato plant accordingly.
Pruning your leaves less is free! Not to mention it might actually save you some time. This method is doable by anybody who has tomato plants and doesn’t require any additional materials, tools, or extensive technical knowledge. Overall, it’s one of the simplest short-term solutions.
If pruning isn’t your presenting problem, this method will make little to no difference. This method works best only if you are suspicious you’ve been over-pruning. Pruning can also help make your plant lighter, and by stopping the process altogether you might start weighing it down.
Why Aren’t My Tomatoes Turning Red?
Tomatoes are one of the most vibrantly colored fruits, so seeing that they haven’t turned red might indicate that there’s a bigger problem at hand. Sometimes a tomato not turning red is perfectly normal, while others, it may indicate something is wrong with your soil.
Your tomatoes may not be turning red because of a potassium deficiency, too much sunlight, because they aren’t ripe yet, or because the variety you have planted doesn’t turn red.
The color that your tomato plants currently are can indicate what the problem is and should guide your next steps.
Your Tomatoes Aren’t Ripe
Tomatoes are green before they’re ripened. If you notice green tomatoes on your tomato plant, this isn’t a bad sign! It just means your plants are growing and will soon be ripe enough to eat.
Just be patient and wait for the color to change. As long as they’re firm and seem to be the right texture, they’re just growing at their own pace.
However, if something is amiss with the texture or they start to fade up in the sun, there might be a deficiency in your soil that’s stunting their growth.
There May Be a Potassium Deficiency
If your tomatoes are just an odd color, something else may be going on. Proteins inside of your tomato are what create the red pigment. If a protein is lacking or hindered by sunlight or heat, the tomato won’t turn red.
Therefore, if you’ve noticed an orange or yellow tomato, or your tomatoes just won’t turn red and have been staying green for a while, sometimes, a nutrient deficiency may be to blame.
If you know your soil has tons of nutrients and potassium, it may be your pH that’s off. Soil pH indicates how acidic or alkaline a plant’s soil is. Plants tend to like a balanced soil of about 6.8, which is below neutral on the scale.
If you think this might be your problem, it might be a good idea to check in on your soil health in general. You can get a moisture meter or a pH test to see if your soil lacks any nutrients or has shifted on the pH scale.
Check What Variety You Have Planted
You may also consider what type of tomatoes you have planted. Some tomato varieties are supposed to be golden, orange, or even yellow.
This gardener planted 54 tomato varieties in one year and described their differences:
Tomatoes are an easy plant to grow, and they usually produce a pretty high yield quickly. This makes them the ideal plant for beginning gardeners.
However, many newbies and professional gardeners may sometimes run into discoloration issues. Yellow tomatoes signify that temperatures are too high, or your tomatoes are getting way too much sun. Discoloration can also point to potassium deficiency or sunburn.
A green tomato indicates that your tomatoes aren’t ready to be harvested yet. If this is the case, be patient, and your tomatoes will eventually ripen.