Answer: Rain will leach nutrients from the soil and this can cause a plant to turn red. You might try a foliar feed with a water soluble fertilizer. Container plants in general will grow better on a regular fertilization program, be it with fertilizer or with compost tea or some other form of supplementation. The caterpillar could be eating the basil; simply relocate the caterpillar and see if that does the trick.
Q&A Library Searching Tips