Pumice is the Best soil conditioner. It has  excellent water and air holding properties

. Advantages of using pumice in potting media and garden soils include:

• It has vital nutrients in the microscopic surface pores, which helps regulate fertilizer feedings
• It helps to Increases water retention in light and sandy soils.
• It helps to reduce crusting, cracking, flooding and shrink-swelling.
• It helps to reduce water requirements and holds moisture in the soil.
• It is inorganic in nature and can be recycled and reuse because it cannot be decomposed or compact over time.
•  It is pH neutral.
• It does not attract nematodes, host fungi, insects.