Lawn dethatching should not be done regularly. In fact, you should only take out your electric dethatcher when the grass in your lawn stops growing or when it starts to get brown and patchy. This happens because thatch build-up prevents any water or nutrients from going into the soil, eventually halting growth of the grass. Even if you try to water or add fertilizer over this build-up, the grass won’t respond well. This is why using a dethatcher is your best option. With a dethatcher, you can easily remove this part of the grass so that it starts growing again.