It has become a recurring theme in my garden: I eagerly plant something new, full of hope and anticipation, only to be met with disappointment when things don’t go as planned.
Last summer, which is still very recent, I couldn’t wait to harvest my first batch of homegrown tomatoes. But, when I went to check on them, I was surprised but not shocked to see yellowing and strange spots on my fruit.
You might be wondering, “Why wasn’t I shocked?” Well, the truth is, I knew I had played a part in it…
In this article, I’ll walk you through five common causes of yellow spots on tomatoes, along with simple solutions to fix them. Along the way, I’ll also share how some of the yellowing on my own tomatoes was, in fact, my fault too.
Let’s dive into it!
4 – Early Blight (Fungal Disease)
If you notice yellow spots concentrated on the fruit near the lower part of the plant, there’s a good chance that early blight is the culprit.
This fungal disease mainly affects the leaves but, if left unchecked, it can spread and damage the developing fruit as well.
You might notice dark circular spots, almost like rings appear out of nowhere, eventually spreading upwards. Like any other fungi, it thrives in damp, humid conditions and weakens the plant slowly over time.
Solution: Your first priority should always be to cut off affected leaves and dispose of them somewhere far from your garden. Then, apply fungicides, improve air circulation by pruning, and try to keep everything as dry as possible.
3 – Sun Damage
When tomatoes are exposed to direct sunlight for too long, particularly after a cloudy spell, they can begin to develop yellow, almost leathery spots. This can also happen if the temperature is too high or constantly fluctuating, leaving the plant confused and vulnerable.
Solution: Provide shade to your tomatoes during peak sunlight hours using row covers or installing shade cloths on poles in the garden. You can also plant taller growing crops around your tomato patch (e.g., corn, sunflowers, etc.) to relieve them from harsh sun exposure.
2 – Watering Issues
If you have a tendency to overwater or underwater your tomatoes, the soil can remain soggy for too long, leading to root rot. Because of this, your tomato plants will struggle to absorb nutrients and resources from the ground properly, causing yellow spots and overall weakness.
Solution: Ensure your soil is well draining so excess water doesn’t puddle around the plants. For watering, a good rule of thumb is to water whenever the top inch of the soil feels dry to the touch. Avoid getting the leaves wet as moisture on the leaves tends to attract pests and fungal infections.
1 – Lack Of Important Nutrients
Insufficient nutrient supply can also become a reason for yellowing fruit. Newer growth and foliage production is impacted when there’s not enough nitrogen, potassium, or magnesium present to support normal, healthy development.
Solution: Address the nutrient deficiencies directly using a balanced or specialized fertilizer. Consider certain nutrient supplements like Epsom salt for magnesium or homemade remedies like coffee grounds for nitrogen.
Once you address the root cause head-on, everything else will fall into place by itself.
Final Words
By now, I hope you’ve gotten a better idea of what might be causing those yellow spots on your tomatoes and how to address them.
After repeated experiments in my garden and all the knowledge I’ve absorbed through research, I’ve learned that sometimes, it’s a mix of factors that could lead your tomatoes down this path but the grower and his care habits always play a role.
Start giving your damaged tomato plants some specialized care, and soon you’ll be rewarded with a bountiful, healthy harvest of the juiciest, freshest tomatoes in no time!
