Worm Farming pH Meter for Red Wiggler Composting Bins Quickly check the pH in your worm bin so you can know if your worms are in danger! Easy-to-read gauge alerts you to acidic conditions with just a glance so that you know when you need to react to keep your worms safe. Eliminate the guesswork involved in maintaining your worm bin and experience the peace of mind knowing that you will always know if a problem arises. Nine inch probe reaches deep into the worm bedding to get the most accurate reading possible. Perfect for use with the Worm Factory, the Vermihut, and any other worm composing kit. No batteries required.