GSM is the metric measurement of the weight of a fabric, it is a critical parameter for any textile product. The weight may affect density, thickness and many physical properties of the fabric, such as strength. The higher the GSM, the thicker the pot. 247Garden currently offers a range of fabric pots ranging from 40GSM seedling pots to 400GSM pots designed for longer lasting outdoor grows such as these below. Feel free to give us a call 877-929-9720 if you have any question or concern. Thank you for your business and we look forward to growing with you.