This is a general sign of hot and dry summer days, many potted plants show this behavior. Here in the Netherlands we just recently had a very hot and dry period for more than a week (heat wave), and I have some potted plants too with brown edges.
This is caused by the combination of drought and heat. Even if you water the plants daily, it is still not enough for the plant to take it up. Some plants are more prone to this than others. You can try to prevent it next year by putting it in the shade when dry and hot weather is coming. Your plants will survive, maybe remove the affected leaves when enough healthy new leaves are present.