For a naturally curious gardener, it isn’t abnormal to ask left-field questions like, ’Can tomatoes grow in indirect sunlight?’ After all, the conventional wisdom is that, as summer crops that abhor cold, tomatoes need a fair amount of sunlight daily to thrive and produce a robust harvest. That is absolutely correct.
But how far can one go against the grain when conditions make it difficult to get the requisite quota of sunlight daily for growing tomatoes? For many folks, the first instinct is to drop the idea of planting tomatoes. Others, though, would consider this a challenge and try to figure out if this is something they can get away with.
In this article, we would shed more light on what is possible (or not) when it comes to growing tomatoes in the shade or indirect sunlight.
Can Tomatoes Grow in Indirect Sunlight?
Each time a question like this comes up, chances are the grower is smack in the middle of any of the following scenarios:
- Growing tomatoes indoors in pots
- Growing tomatoes outdoors in pots on the patio, balcony, or porch
- Windowsills tomatoes that don’t get enough sunlight
- Cultivating them in a heavily-shaded garden
In all the situations above, the common theme is the absence of adequate sunlight for optimal tomato growth. This could be due to where the plants are located. It could also be the result of obstacles like trees or buildings blocking sunlight from reaching the plants.
In all cases, the tomatoes get more shade than sunlight.
That said, a definition of ‘indirect sunlight’ as opposed to ‘direct sunlight’ in the context of growing tomatoes seems like the best place to start.
What is Direct sunlight?
Direct sunlight simply means long, unobstructed, and uninterrupted exposure to sunlight.
For potted tomatoes grown indoors, the plants can get this kind of exposure when they are placed in close to South- or Southwest-facing windows. Outdoors, plants located in a Southward facing direction would also be exposed to direct sunlight as long as there are no interruptions.
For tomato plants, the length of exposure should be at least 6 – 8 hours daily.
When it comes to growing tomatoes though, not all direct sunlight is good. For instance, direct exposure to sunlight in the afternoon might be too much especially if you live in a hot location.
While this exposure in the afternoon won’t kill the plants, the pollen (not existing fruits though) on the flowers might be destroyed. So the best solution is to give the plants some shade. Scalding of stems and leaves sunburn are also issues that might occur when plants are exposed to too much mid-day sunlight in hot locations.
Morning sunlight though, no matter the location, is always good for tomato plants
What is Indirect sunlight?
When it comes to growing tomatoes or other plants, indirect sunlight is not so straightforward to define especially indoors.
A basic but functional definition would be sunlight that passes through a medium before reaching the plant. The medium, in this case, could either be tree leaves, reflecting surfaces, window shades, etc.
So while the plants are not directly touched by sunlight, the vicinity could be very bright. And in many cases, the brightly lit area might be enough for the tomatoes plant to flourish.
While South-facing plants get lots of direct sunlight, East-facing windows or areas receive indirect sunlight in the daytime and most times all year.
On the other hand, windows or locations that face westwards are exposed to indirect sunlight early in the morning and afternoon.
As for North-facing windows or areas, the indirect sunlight is way too low to support plant growth. This is one of the situations you might need tomato species adapted to growing in low-light situations.
Can Tomatoes Grow in Indirect Sunlight or Shady Areas?
The basic sunlight requirement for optimal tomato growth is a non-compromisable factor. It is practically impossible to delink healthy tomato plants and sunshine.
That said, the answer is not definitive. Before going any deeper, it bears reiterating that you can only get the best tomatoes when the plants are exposed to at least 6 hours of sunlight.
But the 6 – 8 hours of sunlight exposure doesn’t have to be uninterrupted for optimal growth. The exposure can be split into intervals of a few hours. The daily total number of hours, though, should be in that ballpark.
This essentially means that you can grow tomatoes in indirect sunlight if they are exposed to some direct sunlight.
In the absence of any direct sunlight, growth is still possible but don’t expect the plants to do well. This is especially critical in areas with short tomato growing seasons because the absence of adequate sunlight means the fruits would be ready for harvest late in the season. The window for harvest is going to be short with little time margin to get plenty of fruits.
If you are dealing with the problem of too much indirect light, shade, or too little sunlight when growing tomatoes, the following measures can be implemented to redress the situation:
- You could change the location and choose a sunnier spot next planting season
- If your tomato plants are in pots, simply relocate them to a spot that gets more sunlight
- Trim or prune branches of nearby trees blocking the sun
- If you have to cultivate the plants near the house, always choose the south side of the house
- For indoor plants, move the plants to windows or windowsills on the southward facing side of the house.
- If the indoor location has no windows, the basement, for example, artificial light can be deployed as a good substitute for sunlight.
Growing Tomatoes in Indirect Light: How to Optimize Growth
While it is difficult to grow tomatoes in indirect light, their ability to adapt to less than ideal growing conditions can be utilized. Though yield wouldn’t be comparatively high when growing in the shade, some varieties actually produce quality tomato fruits when grown completely in indirect light.
One way to address this shortfall is to cultivate more plants. Also, providing support via the use of trellises and pruning to promote air circulation and faster growth of the main stem are known to improve growth and fruits quality.
Better air circulation is crucial because incidences of disease infections are higher when tomatoes are cultivated in the shade. With improved air circulation, the drops of water on the leaves and stems dry faster making plants less susceptible to diseases.
With direct sunlight out of the equation, it is important to optimize other tomato growth requirements to encourage growth. In that regard, ensure your soil is very fertile and rich with all the necessary nutrients. You’d have to carry out a soil test to get an idea of the type of fertilizer and soil nutrients needed.
You also have to make sure you water regularly and observe all proper drainage practices if the plants are cultivated in pots. And to make sure the dependence on luck or good fortune for a good harvest is cut down, opt for tomato varieties that have shorter maturity dates.
What about the ripening of the fruits? Don’t tomatoes fruits need sunlight for the fruit to ripen?
This is where you catch a break from this less than ideal situation of cultivating tomatoes with zero sunlight. Tomatoes fruits don’t need sunlight to ripen.
Studies show that the fruits actually ripen a lot faster in the shade or in the absence of sunlight. Ethylene gas and heat are the two factors required to produce ripe tomatoes.
Basically, your job is to get the plants to maturity and the flowering stage. At this point, the lack of sunlight ceases to become a decisive factor.
Indirect light/Shade-tolerant Tomato Species
We mentioned earlier that one way to ensure a decent harvest when planting tomatoes in the shade is to cultivate shade-tolerant tomato varieties. Fortunately, there are several such varieties and you can get the seedlings from reputable horticulture stores.
In the cherry tomato family, your choices include Red Juliet Hybrid, Red Principe Borghese, Vernissage Yellow, Isis Candy Cherry, Black Cherry, Evans Purple Bear, and Golden Sweet.
If you prefer classic round tomatoes, there are several varieties that grow well in indirect sunlight. These include Red Carmello, Golden Sunray, Belize Pink Heart, Red Marglobe, Early Wonder, Arkansas Traveler, and Violet Jasper.
There are also various tomato varieties in the Beefsteak Type and Plum & Paste tomato groups.