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Can You Grow Tomatoes In 24 Hours Of Light

When you begin planting your tomato seeds indoors during the early spring, you will want to make sure they receive enough sunlight to begin growing. Many gardeners even introduce a grow light during this time. While tomato plants are sun-loving, preferring 6-9 hours of sunlight a day, can you give your tomato plants too much light? Can you grow tomatoes in 24 hours of light?

Yes, tomatoes can grow in 24 hours of light, but that does not mean they should. Tomatoes, just like other plants, need a day-night cycle to grow optimally. While some studies have been done where scientists grew tomatoes in 24 hours of light, it is not ideal for the home gardener to mimic.

Read on to learn more about how much light tomato plants need, ways to mimic sunlight, and why plants need time without light. 

Do Tomato Plants Need Time With No Light?

It is no secret that tomatoes love sunlight. Every gardener knows that tomato plants thrive with full-day sun. It seems intuitive that your tomato seedlings would love 24 hours of a grow light, but that is not always the case. It has been noted that tomato plants exposed to 24 hours of light produce fewer tomatoes than the plants who got some time with no light!

As everything in nature exists in cycles, day and night cycles are essential for plants. If you grow a tomato seedling under a grow light that is never turned off, your tomato plant can become stressed, as it has no rest stages. Tomatoes tend to do great in an 18-12 hour cycle, which means 18 hours of light followed by 12 hours of dark. But why are dark cycles so important for tomato plants? 

What Do Tomato Plants Do At Night

Just as humans need a rest cycle, tomato plants do, too! During the sunlight hours, your tomato plants are busy turning the sun’s light into energy in photosynthesis. Photosynthesis creates all the energy stored within the plant to continue to grow, produce leaves and fruit, repair itself when it is damaged, and store energy for days when there is not as much sunlight.

Your tomato plant will essentially ”catch its breath during the night cycle.” This means your plant is not actively performing photosynthesis and can take the time to allow all the energy it created to the areas that need it the most! Think of the cycles of no light like sleep for the plant.

Sleep is important to rest and repair in humans, allowing our bodies to take the time to heal and rejuvenate to prepare for the next light cycle. The same goes for your tomato plants! 

How Much Light Do My Tomato Plants Need

As mentioned earlier, tomato plants love the sun, needing at least 6 hours of direct sunlight to survive. Pay attention to your tomato plant placement when deciding where to grow your tomato plants. Your tomato plants will be much happier in an area with 7-9 hours of sunlight daily.

But what happens if you do not have a sunny area to grow tomatoes? Should you not grow tomatoes? Luckily, there are a few options for those who want to grow tomatoes but do not have an ideal sunny spot for them! 

Grow Tomatoes In A Greenhouse

If you are growing tomato plants in pots, another great option is to grow your tomato plants in a greenhouse! When growing tomatoes in a greenhouse, you can control the temperature, keeping the plants nice and warm regardless of the weather outside.

This option is great for those who want to grow tomatoes but may not have the ideal sunlight. Greenhouses keep the environment constant, making it ideal for tomato plants. By growing in a greenhouse, you can also control other aspects, including the amount of water your tomato plants receive and a level of protection from pests and bugs.

Since the greenhouse provides a physical barrier between your plants and the outside world, the only water your plants will receive will be from you. This helps prevent overwatering if the weather has been particularly rainy. Overwatering can lead to root rot and other issues in tomato plants. Puddling water can create a breeding ground for insects that could harm your tomato plants. 

Grow-houses and Plastic Covers

If you do not have enough room for a proper greenhouse, you can try a grow-house! Much smaller, easily movable, and customizable grow-houses are a great option for those who want the same benefits of a greenhouse with much less hassle.

A grow-house is usually 5-7 shelves with a plastic cover over it, using the same materials as a proper greenhouse. You can easily break down your grow-house for storage at the end of each season, making it a convenient option for those growing tomatoes in pots. But what if you have already planted your tomato plants in the ground? Is it too late?

Nope! While it may seem like a hopeless situation when you notice your tomato plant is not receiving enough sunlight, luckily, you can correct this problem! While a greenhouse or grow-house will not help you much with an in-ground tomato plant, you can find small plastic plant covers online or at your local garden center.

These plastic plant covers will create a mini greenhouse effect for your tomato plants! These covers come in multiple sizes, so you can be sure you will find one that will fit your tomato plants.

Grow Lights For Tomato Plants

Another option some gardeners choose to use is a grow light. These lights will mimic the sun’s and help your plant perform photosynthesis. Some gardeners like to use grow light during the early stages of planting to help the seeds germinate quicker.

While these lights are a great option, it is not recommended to leave them on. A seedling exposed to too much light may grow too large too quickly and not be able to survive the transfer to your outdoor garden. As mentioned earlier, tomato plants do great with 18 hours of light (including grow light time) and 12 hours of rest. 

Final Thoughts 

While tomato plants will grow wonderfully in an outdoor setting with 6-9 hours of sunlight alone, some gardeners wonder if their tomato plants need more light. While it has been shown that tomato plants will grow in 24 hours of light, it is not advised.

Typical tomato plants will happily grow and produce in the standard 6-9 hours of direct sunlight. If you cannot guarantee that your plant will receive the necessary amount of sunlight, you can try a greenhouse, grow-house, plastic cover, or grow lights.

Plants need a rest cycle, so be sure that your plants are getting some ”downtime” during a night cycle. This allows your plants to rejuvenate and prepare for the next day. Growing tomato plants is easy and fun and does not require any special tools unless you wish to include them. Proper soil, adequate water, and good direct sunlight are all your tomato plants need to thrive! 

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