Answer: If the browning is around the margins of the leaves it can indicate under watering or fertilizer burn. If there are splotches or spots of tan on the leaves, it might be sunscald. If the spots or areas are brown, it could be a fungal disease. I would pick off the affected leaves and wait for healthy new growth. This will get rid of any disease that might be present. Sunburn is purely a cosmetic problem: fertilizer burn can be avoided by feeding with a half strength dilution of a water soluable fertilizer (such as Miracle Gro). As for watering, containerized plants can dry out much faster than the same plants in the ground so it is important to check frequently. When the soil is dry to the touch, it's time to water. Hope this information helps you determine just what the problem might be. Best wishes with your nasturtiums.
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