Keep reading below, and you’ll learn to read your tomato plant like a book, picking up on its subtle clues… Macronutrient Deficienciesĭifferent plants have different needs, so the best fertilizer for tomatoes varies by the variety you’re growing. Often, it’s not a nitrogen top-up it needs, but rather a trace amount of molybdenum, a micronutrient that helps plants convert nitrates in the soil into nitrogen that can be used. Just because its leaves are yellowing doesn’t mean it needs a nitrogen fix. The yellowing is the nitrogen deficiency, and the leaf curling downwards is the lack of water uptake.īefore you reach for the fertilizer, know that the tomato plant is tricky with fertilizers. The lack of nutrient uptake – particularly nitrogen – causes yellowing leaves.Ī nutrient deficiency with overwatered tomato plants results in downward leaf curl with yellowing leaves. The plant struggles to take up water and nutrients when the rot worsens.

You’ll only see leaves wilting with a downward curl around the edges. The noticeable signs of root rot above the soil are leaves drooping and curling downward.Ĭatch it early enough. Traditional wisdom tells you that the plant can’t be thirsty, but the reality is that if the soil is waterlogged, the roots can start to rot, and when that happens, the plant will defensively try to prevent the rot from spreading. The confusing part of this type of curling is that it tends to happen after a heavy watering, such as after deep watering the soil or when there’s been a heavy downpour. Take this as a sign of the plant telling you it can’t get a drink. Leaf Curling Downĭownward leaf curl is a problem to address ASAP. Tomatoes like the soil to be moist but not wet.

That being said, check the soil moisture level because too high a heat will cause the soil to dry faster. When temperatures are high, it’s just the plants’ way to use better the moisture it has access to. It doesn’t mean, though, that the plant needs more hydration. When transpiration is happening faster than respiration is, leaf curl reduces the surface area, helping the plant store water until it can convert it to energy.

When it’s too hot for the tomato plant (in the high 90 degrees Fahrenheit), the upward leaf curl is a survival technique because it reduces the surface area, lessening the water lost to transpiration. Transpiration is the water movement inside the plant, after which excess water escapes through the stomates on the underside of the tomato leaves.Respiration is when the plant transforms the carbon dioxide it absorbs into oxygen during photosynthesis.You’re witnessing a battle of respiration versus transpiration, which is just a part of how plants grow. You see the plant protecting itself from drought, even if it has enough water in the soil. Mature leaves are bigger, and those are the ones to curl because of their size. New growth will be smaller so they won’t need to curl to conserve energy. When it’s caused by dry, hot weather, it’s the mature leaves that curl. To confirm that this is what’s happening, look at new growth. You’re more likely to notice upward leaf curls when it’s too hot and humid for the plant. This happens particularly during summer and spring as the temperatures rise. This is the most common version of tomato leaf curl you’ll encounter. Tomato Leaves Curling Symptoms and the Reasons for Tomato Leaves Curling Leaf curling up Leaf discoloration and the direction of curling (upward curl or downward curling) help identify the cause.

Symptoms and the Reasons for Tomato Leaves CurlingĬommon causes of tomato leaf curling are micronutrient deficiencies (molybdenum and boron), Curly Top Virus, Tomato Mosaic Virus (ToMV), or insects such as broad mites and the tomato pinworm.

Cucumber seedlings leaves curling down