Have you noticed your tomato plant leaves turning white and drying out? Don’t worry – you’re not alone! This post will explain what might be causing the issue, what you can do to save your plants, and how to avoid this problem in the future.
This was my first year growing tomato seedlings instead of buying them, and let me tell you, it was an adventure! I started by planting tomato seeds in January and moved them to the greenhouse in early April. The weather was pretty unpredictable – some days the temperature went over 20°C, while others dropped below 10°C.
My tomato seedlings grew nicely inside a heated hallway with plenty of natural light from the windows. Everything was going well until I transplanted them into the greenhouse. The first two days, they looked great, but soon after, I noticed that the leaves of some plants started turning white, and the edges began drying out.
At first, I thought the plants were lacking magnesium, but the leaves were more white than yellow, so it didn’t seem to be a magnesium deficiency. After some online research, I found out that what I was dealing with was sunscald. I didn’t realize that moving my plants directly from the indoor light to the greenhouse could cause this.
Although my seedlings had plenty of light indoors, they weren’t exposed to direct sunlight. Fortunately, after transplanting, there were several cloudy days, which helped protect the plants from intense sun exposure and probably saved them from drying out completely.
Common Reasons Why Tomato Leaves Turn White
If your tomato plant leaves are turning white, it’s often due to one of the following causes:
- Sunscald (Exposure to intense sunlight)
- Overwatering
- Too much fertilizer
- Nutrient deficiencies (calcium, nitrogen, phosphorus, etc.)
- Fungal diseases
I also faced a fungal disease called early blight last year, but the symptoms were different from what I experienced this time.
What is Sunscald?
Sunscald isn’t actually a plant disease – it’s more like a sunburn for plants. It happens when plants, especially seedlings, are suddenly exposed to intense sunlight after being in a low-light environment. The plant becomes sensitive to UV rays, and the leaves start to turn white or get scorched.
Sunscald can affect not just tomatoes but also peppers, cucumbers, corn, eggplants, pumpkins, and even fruit trees. Unfortunately, since sunscald isn’t a disease, there’s no real “treatment” for it. The best solution is prevention.
If your tomato plants are affected, there’s not much you can do to save the damaged leaves, as they will eventually die off. However, if the stem and growing tips are still green, the plant can recover.
If the plant is large enough, you can speed up the recovery by removing the affected leaves since they won’t regenerate.
How to Prevent Sunscald in Seedlings
My mistake was not giving my tomato seedlings enough time to adjust to direct sunlight before moving them into the greenhouse. If your seedlings have been growing indoors or in a shaded spot, you need to gradually expose them to direct sunlight to avoid sunscald.
Here’s what you can do to help your seedlings adapt:
- Take your plants outside for a few hours each day before transplanting them. Start with 1-2 hours of sun exposure on the first day.
- Gradually increase the exposure over a period of 7 days, allowing your plants to acclimate to the sun.
- Once your seedlings can handle a full day of sunlight, they’ll be ready to go into your greenhouse or garden.
By gradually exposing your plants to sunlight, you’ll help them grow stronger and better able to withstand the direct sun without the risk of sunscald.
FAQs
Q: Can I save my tomato plant if it’s affected by sunscald?
👉 Yes, the plant can recover if the growing tips and stem are still healthy. Remove the damaged leaves and ensure proper care moving forward.
Q: How can I tell if my plant is overwatered?
👉 Overwatered plants will have yellowing or white leaves, soft or mushy roots, and a waterlogged appearance. Make sure your pots have proper drainage to avoid waterlogging.
Q: Is there a way to fix nutrient deficiencies in my tomato plants?
👉 Yes, conduct a soil test to determine what nutrients are lacking, and use a balanced fertilizer or amend the soil with compost to restore necessary nutrients.
Q: What should I do if I notice a fungal infection like early blight?
👉 Remove affected leaves, apply a fungicide, and practice crop rotation to prevent future infections.
