After applying a pesticide, even an organic one, it’s always best to wash thoroughly with hot soapy water. That’s enough in most cases.
However, if the product is labeled poisonous (symbolized by a skull and crossbones) or corrosive (symbolized by a hand soaking in acid), it’s better to wash in cold water instead. Cold water closes your pores and reduces absorption. Showering with hot water, on the other hand, can open your pores and could allow more absorption.
Finally, wash the clothes you wore for the pesticide application separately from other clothes… and in hot water. In this case, hot water will remove more of the pesticide than cold water. If the product bears the poison symbol (skull and crossbones), keep the clothes for use during other pesticide applications only.