According to Science Daily, peat mosses can hold up to 25 times their dry weight in water; more than natural sponges have the capability of doing.
Depending on the peat source, most peat mosses have a pH in the range of 3.5 to 6 on average. For certain plants, having a growing medium with a slightly acidic pH is a big advantage.
Once it is harvested and dried, peat moss weighs approximately 150-170 kg per cubic meter; in comparison, a cubic metert of top soil weighs about 800 kg
After peat is dried down to create peat moss the resulting product is very “springy” and resists compaction, allowing for plenty of open pore space within the material.
Even though peat moss retains water incredibly well it also has the ability to drain freely. Excess water quickly moves through the material to drain out.
Since it formed in unaltered, low oxygen conditions peat moss doesn’t contain bacteria, fungus, weed seeds, or harmful chemicals.
Peat moss doesn’t naturally have much mineral content since it forms in nutrient-poor areas. Due to its structure though it has a high cation exchange capacity, or more simply, it has many negatively charged sites that can hold onto positively charged molecules such as nutrients and water.
Unlike some other growing media, peat moss is easy and clean to work with. It doesn’t leave behind the dust and mess that compost can, and doesn’t blow around like perlite.