Light Requirements For Tomatoes – How Much Sun Do Tomato Plants Need

by johnah on October 30, 2020

Light Requirements For Tomatoes – How Much Sun Do Tomato Plants Need?

Tomato plants require light in order to produce fruit. When it comes to tomato plants, they are very sensitive creatures and will not survive without some sort of supplemental lighting. One of the most common ways that people try to increase their tomatoes’ growth rate is with artificial lights such as fluorescent tubes or LED’s. These types of lights provide a lot of energy but at the cost of damaging your plant.

Another way to increase your tomato plants’ growth rate is by using natural growing methods such as those described here: Growing Tomatoes Indoors Without Lighting

The amount of light that tomato plants need depends on several factors including the type of soil, size, climate zone where you live and many other things. There are a few different types of light that can be used to grow tomatoes indoors.

Fluorescent Lights (Fixtures)

These are the best type of light for tomatoes because they provide a constant source of light. They work well if you have a sunny location or if you want to grow them in a greenhouse. Fluorescent bulbs last forever and are relatively inexpensive compared to incandescent bulbs which may only last two years before needing replacement.

High-Intensity Discharge Lamps (Metal Halide)

Metal halide lights are good for starting seedlings. They provide a lot of light but they can be unstable and may need regular replacement. These lights are more expensive than fluorescents.

Incandescent Lights

These lights are not suitable for growing plants and should only be used as a last resort. They can create a “hungry” environment for your plants so it’s best to just avoid using them altogether.

Always research your options before buying lights. There are many different types and factors to consider before deciding which are best for growing tomatoes.

How Much Water Do Tomatoes Need?

Watering your tomato plants properly is an important part of having a successful garden. Tomatoes need at least 1-inch of water per week. If you don’t provide enough water, they may grow slowly or not at all. If you over water your plants, this will cause the roots to rot and your plant will die.

Preparing Your Garden Soil

Tomatoes grow better in soil that has been amended with organic materials. This means that certain materials such as manure, wood chips, hay, or other similar products have been worked into the soil to add nutrients and complexity. You can also use single ingredient materials such as manure or wood chips but it will take more effort to make sure that your soil is balanced.

Make sure you read our page on types of garden soil to learn more.

Light Requirements For Tomatoes – How Much Sun Do Tomato Plants Need |

Watering Your Tomatoes

Tomatoes need a lot of water but they don’t like their feet soaking in water for long periods of time. It’s best to set the plants in holes that allow them to be elevated off the ground so that any water is draining out of the bottom of the plant container. Mulch can also be used around the plants so that moisture levels don’t get to low.

You should also avoid letting water sit in a saucer under your plant container because this makes it harder for the roots to get oxygen and can cause root rot. If you have a plant that is not getting enough oxygen, it will begin to grow vines that reach out for more air.

Use a spray nozzle on your hose so that the water doesn’t fall vertically on the plant. This creates a lot of pressure and can damage the leaves.

Make sure you water your plants in the morning so that they have all day to dry out a bit. If the plants are still wet at night, this can cause fungus and mold to grow.

Treat Your Plants For Pests And Disease

Just like all living things, tomatoes can get sick or be bothered by pests. One of the most common problems is wilt. This is easily identified by drooping leaves and a plant that seems to be struggling to stay alive.

There are several types of wilt that can affect tomato plants including:

Fusarium Wilt

This type of wilt attacks the roots of your tomato plant and should be treated right away. The soil around the base of the plant will turn brown and you will no longer be able to get water into the plant. You can try watering the plant from the bottom in the hopes of reviving it but if the damage is bad enough, the plant will not recover.

Verticillium Wilt

This type of wilt affects the plants vascular system and prevents nutrients from being delivered throughout the plant. The leaves at the top of the plant turn yellow and begin to wither and die. The stems and petioles will also turn a reddish color.

To fix this problem, remove all of the infected material and make sure to get down into the soil a few inches and remove everything that is discolored. In the future you can spray your plants with a solution of copper sulfate every five to seven days or plant resistant varieties.

Root Knot Nematodes

The root knot nematode is an microscopic worm that attacks the roots of tomato plants. This causes leaves to turn yellow and wither. The stem will also turn a reddish color.

You can treat this by getting rid of all of the infected material and planting resistant varieties.

Cucumber Mosaic Virus

This is a problem that is spread by thrips. It causes mottling on the leaves creating an uneven pattern of light and dark green areas. The leaves will begin to wither and die which in turn damages the fruit since it now doesn’t have enough energy to make the fruit properly.

If you see this, the best way to fix it is to wash off your plants with plain water to get rid of the virus.

Blossom End Rot

This is a problem in the soil and is caused by a lack of calcium as well as a bacterium. The ends of the tomatoes will begin to turn brown and become leathery. This problem can be prevented by planting in raised beds that contain lots of organic matter.

Add lime to the soil before you plant as well. You can also treat existing plants with liquid calcium.

Some other things to keep in mind is the pH of your soil. For healthy plants, the pH level should be around 6.5.

You can have it tested through your local cooperative extension office or a local gardening center such as TSC. If the level is too high or too low, you can adjust it by adding powdered limestone or apple tree ground up bark.

You should also make sure there is good air flow throughout the plants. If your planting location is low and flat, consider raising it up by adding a wooden frame. You can also add more soil to make the area taller.

Just make sure to slope it slightly so that water runs downhill and doesn’t pool around the base of the plants.

To help your tomato plants grow strong and healthy, start off by improving your soil. You can do this by turning over the soil 8 to 10 inches deep and mixing in organic material such as rotted cow manure, compost or aged leaf mold. Add a balanced fertilizer that is low in nitrogen and high in phosphorous and potash.

Make sure that you water your plants well and that the ground doesn’t dry out. If your plants begin to get sickly, you can spray them with copper sulfate mixed with water. Make sure to get the mixture on the leaves and the stems as well as the ground around them.

When picking out your plants, be sure to choose disease resistant seeds and transplants. Pest resistance is also helpful since you won’t have to apply as many pesticides. There are also organic solutions you can use such as neem oil and pyrethrin.

Here is a helpful video from the University of Arkansas that will tell you how to pick out disease resistant plants.

This next video is from a local nursery that is located in Southern Illinois. It will provide you with more information on how to plant, care for, and pick the right kind of plants for your garden.

Light Requirements For Tomatoes – How Much Sun Do Tomato Plants Need from our website

Problems with Fruit Set

This next video will tell you what you can do if your tomatoes have a hard time setting fruit. The cause could be from plants that are not mature enough or could be due to an excess of fertilizer. Check the base of your plants to see if the stem is swollen.

If the stem above the soil is not swollen or the plant has small leaves, then it isn’t mature enough to produce fruit. In this case, you should pick off any flowers that have set and wait another month before trying to re-pollinate.

If the stem is swollen and the plant has large leaves, then your plant is mature enough to produce fruit. If your plants are getting a lot of rain or excess moisture, this could cause them to set too much fruit. In this case, you should pick off all of the fruit that has already set and remove any flowers as well.

Also, you will have to fertilize less and water the plants less.

If your plants haven’t set any fruit after 6 weeks, then the problem may lie with the pollen. In this case, you should do a “jungle drop”. This basically means that you pull off all of the flowers on one plant and leave all of the flowers on the other plant.

This will give the remaining flowers more energy to produce fruit.

This last video will tell you how to do a jungle drop.

Harvest, Storage & Canning

Once your plants begin to set fruit, they will ripen at different times. You can pick the ripe ones as soon as they are dark and soft. Some varieties will turn lighter in color when they are really ripe.

To ripen the rest of the fruit, you can place them in a single layer into a paper bag. Check the bag every day and take out any that are ripe. This will make it easier for you to pick as many as you can while they are ready.

There is much debate about whether it’s better to pick and eat your tomatoes when they are still slightly firm or wait until they are really soft. Just like with humans, it seems that tomatoes taste best when they are fully ripe.

The best way to store your tomatoes is to keep them on the vine until you are ready to use them. If this isn’t possible, you should keep your tomatoes on a cool counter or in the refrigerator. Don’t wash or soak your tomatoes prior to storing them.

This next video shows how you can preserve your tomatoes at their freshest state by canning them.

This next video shows you how to pickle your tomatoes.

This next video shows you how to make tomato sauce from fresh tomatoes.

This next video shows you how to dry your tomatoes.

Here is another video on how to store your tomatoes.

Common Problems & their Solutions

This next video will tell you what you can do if your plants get too much or too little water. It will also provide the best way to water your plants.

This next video will tell you what you can do if your plants are diseased or having trouble with bugs.

This next video will tell you what you can do if your fruit has growth cracks, is splitting or has soft or hollow spots.

This next video will provide various solutions to common problems that can occur with your plants.

Light Requirements For Tomatoes – How Much Sun Do Tomato Plants Need - Picture


Tomatoes are a very versatile food. Here are just a few recipes to give you ideas on how to use them in your meals. Remember that you can always add or take away ingredients to make the recipes your own.

This next video will show you how to make fried green tomatoes.

This next video will show you how to make gazpacho, a cold tomato soup from Spain.

This next video will show you how to make garden fresh salsa, which can be served with tortilla chips or as a condiment for other foods.

This next video will show you how to make your own ketchup from scratch.

Now that you have learned about growing your own food, go out there and give it a try! Just remember to keep records of your progress. Happy Gardening!

Sources & references used in this article:

Plant growth under controlled conditions. V. The relation between age, light, variety and thermoperiodicity of tomatoes by FW Went – American Journal of Botany, 1945 – JSTOR

Plant growth under controlled conditions. II. Thermoperiodicity in growth and fruiting of the tomato by FW Went – American Journal of Botany, 1944 – JSTOR

Effect of light on the formation of a pigment in the tomato fruit cuticle by AA Piringer, PH Heinze – Plant Physiology, 1954 –

Mulch surface color affects yield of fresh-market tomatoes by DR Decoteau, MJ Kasperbauer, PG Hunt – 1989 –



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