Tomato plants are large, fast-growing plants. Like most veggies, they need lots of light to perform at their best. So, in this article I’ll share how much light tomato plants need, and how to find the perfect planting spot.
Quick answer: Tomato plants grow best in full sun, meaning at least 6 hours of unobstructed sunlight, every day. Tomatoes will still grow in less light, but may produce lower yields on smaller plants.
Tomato Plants Naturally Search For Light
If you have ever grown a tomato without a tomato cage or trellis, then you know how they like to sprawl. This creeping, ground-crawling growth habit is a tomato plant’s natural instinct in search of more light and space to grow.
Since we like to grow tomatoes vertically, we give our plants a cage or tie them to a string to keep them off the ground. However, the plants still need as much light as they can get.
Since the plant is not allowed to sprawl as it would do in nature, it is important to both prune and space them properly. This allows for improved airflow and light coverage across the plant’s upper foliage.
Keep tomato plants spaced by at least 24″ to allow each individual plant to get plenty of sunlight from above. With less lateral growth, the plant needs all the light it can get from straight above.
How Much Sun Do Tomatoes Need?
To reiterate, tomato plants need at least 6 hours of direct sunlight per day for optimal growth. However, more sunlight is better, with plants performing best under full sun, all day long.
Can you grow tomatoes in the shade?
While I don’t recommend it, tomato plants will technically grow in shady locations. However, the plants will be smaller and much less productive than those grown in direct sun.
If this were a “yes or no” question, I would answer “no.” If you have a shady spot to grow plants, choose something other than a tomato to grow (like leafy greens or root veggies).
If your location gets just a few hours of sunlight, it may be worth trying to grow a small, determinate type tomato plant in a container. However, if you want a big harvest, prepare for disappointment!
Do tomatoes like morning or afternoon sun?
Now this is a good topic – do tomato plants prefer morning sun or afternoon/evening sun? The answer will depend on how hot it gets in your region in mid summer.
Here in New England, our summers can be brutally hot, easily reaching 100°F. The hottest part of the day is mid-afternoon, usually around 3:00PM. At this time, the direct sunlight and heat can actually stress tomato plants.
So, in our region, tomatoes perform better with lots of morning and mid-day sun, but can sometimes benefit from shade in the afternoon.
Afternoon shade isn’t a requirement, but can in some cases help reduce heat stress. Most tomato varieties will naturally handle the sunlight, especially when mulched and kept watered through the heat.
Can tomatoes get too much sun?
We grow many of our tomatoes in a wide-open field where the sun shines all morning, day, and evening. In mid-summer, this equates to about 13 hours of sunlight, every day!
And the tomatoes love it.
We have found that tomatoes grown in all-day sun are more productive and delicious than those with less light. The increased light exposure gives the plants more energy to produce larger plants, more fruits, and more flavor compounds in the tomatoes.
While tomatoes don’t need all-day sun, the simple rule you should follow is this: the more sun, the better!
Choosing The Right Location For Tomatoes
With the information above, how can you pick the perfect spot for your tomato plants? Well, since more light is better, you need to find the sunniest spot available to you.
The ideal location for growing tomato plants is a South-facing site without any obstructions to the light. Avoid areas with tall trees or buildings that may cast shadows during the day.
Perhaps just as important is to avoid shading other plants in your garden with your tomatoes. Tomato plants are tall (many varieties easily grow over 8 feet when trellised), so I recommend planting them on the North side of your garden.
In other words, plant shorter plants on the South-side of your tomatoes to prevent them from being in shade. This ensures all your plants are able to get the sun they need.
Tips to get more light on your tomatoes
If your only growing location is not very sunny, I have some tips for increasing sun exposure for your tomatoes. Your situation may require some clever thinking to give your tomatoes the light they need!
- Use a hanging basket. Hanging a tomato plant can help increase light exposure on the foliage. Locate the best spot to position a hanging hook, install it, and hang your pot out in the sun. This is a great solution for anyone growing on a covered balcony or porch. Hanging tomatoes may sprawl, but this is okay and actually makes harvesting easier!
- Train plants into a sunnier spot. A similar option to a hanging basket is to train your tomato towards a sunnier spot. So if your plant is in a shady spot like a balcony, you can tie the main stem to a string or trellis, leading it towards the sunlight. Once the plant is out in the sun, it will grow faster and generate more energy to produce tomatoes.
- Rent a community garden plot. If your space simply doesn’t get any direct sunlight, then your best bet may be to find a different location entirely. Community garden plots are a popular (and usually cheap) option for those who don’t have their own land to garden. Even if you live in a city, check your local area to see what is available!
- Grow indoors. Another option is to grow tomatoes indoors using grow lights. I rarely grow tomatoes completely indoors, but it is possible. Use a strong grow light, giving the plants 12-16 hours of light daily. Or, try using an Aerogarden along with their tomato seed kit.
Nothing beats a well-positioned, outdoor garden for growing healthy, big, bountiful tomato plants. But I believe everyone should have the joy of growing their own tomatoes, in whatever space they have.
By the way, the same principles of lighting apply to most garden vegetables, including peppers, onions, basil and other herbs, eggplants, potatoes, and more. Full-sun gives these crops the best chance at growing successfully (though temperature is a whole different topic).
I hope this article helps you determine where to plant your tomatoes. How much light you give your tomato plants will directly impact the growth rate, size, and yield from your plants. Happy growing! 🍅