Obvious Signs Your Tomato Plants Aren't Getting Nearly Enough Sun

Your tomatoes may not be able to talk with words, but they can physically communicate with you when they are unhappy. A simple observation of your tomato plant's appearance will provide tell-tale signs if your plant requires more environmental support. Some symptoms you may notice when your tomato plant is struggling are elongated stems, a lack of flowers during the blooming period, slow ripening, or worse – no tomatoes at all. Though these issues are numerous, they can all be traced back to a root cause: a lack of sunlight.

Light exposure is paramount to all plants, as they need it for photosynthesis, and tomato plants are no exception to this rule. In fact, tomato plants are sun lovers and need a minimum of 6 hours of sun daily. Because sunlight is a foundational pillar of health for tomato plants, it makes sense that their growth will be less than ideal without enough exposure. The good news is you can prevent these symptoms from ever occurring by planting your tomatoes in the right location and using grow lights when needed.

It should be noted that the symptoms your tomato plant exhibits may differ slightly depending on how mature the plant is. A tomato starter plant lacking sunlight exposure will look different from a full-grown tomato plant dealing with the same obstacle. It's common for tomato seedlings to take on a leggy appearance when they don't receive enough sun. If this happens, you'll notice that the stem of your tomato transplant is elongated and thin rather than sturdy and thick. The tomato plant becomes leggy and fragile after trying to stretch as tall as it can to get closer to a light source. 

For mature tomato plants, a tell-tale sign of inadequate sun exposure is if your tomatoes have lots of foliage but lack flowers. When your tomatoes don't get enough sunlight, they won't have the energy they need to produce flowers but have enough reserves to make leaves. This is why you'll notice more leaves on your tomato plant instead of flowers once the blooming period begins. Similarly, a lack of flowers means a lack of fruit, so if your tomato plants aren't producing, inadequate sunshine may be the culprit. On the other hand, if your tomato plant produces tomatoes that are either slow to ripen or remain unripened, this can also be traced back to a lack of sun. 

When it comes to growing the best tomatoes, ensure you prevent many of these symptoms by planting them in the proper exposure in the first place. If you plan to grow your tomatoes from seed, place their starter trays near a window with lots of available sunlight. Providing seedlings with bright, overhead light, in particular, is essential to prevent the sprouts from elongating and becoming leggy as they grow in. If your window doesn't provide enough light for your tomato sprouts, you can supplement natural light exposure with an indoor grow light. While there are many types of grow lights to choose from, a single-bulb grow light would suffice in this situation.

For tomatoes grown outdoors, select a planting location that receives plenty of sun. Avoid crowding your tomatoes by planting them too closely to other plants that can overwhelm them with heavy shade. Growing tomatoes in a container can be helpful if you're unsure how much light a specific area in your garden receives. This way, you can simply move the tomatoes to a sunnier spot if you notice the plant isn't flowering or the fruit isn't ripening.