Changes

===Organic component alternatives===

===Organic component alternatives===

Even low-phosphorus composts are known to export phosphorus over many years. The use of compost is not recommended in nutrient-sensitive watersheds where phosphorus pollution is a concern, or an [[Additives| additive]] to enhance nutrient retention of the media should also be included (see below). There are a number of alternative sources of soil organic matter which have undergone field studies which have benefits and potential concerns:

Even low-phosphorus composts are known to export phosphorus over many years. The use of compost is not recommended in nutrient-sensitive watersheds where phosphorus pollution is a concern, or an [[Additives| additive]] to enhance nutrient retention of the media should also be included in the blend, or a layer be included above the stone reservoir, or a reactive media vault be included in the treatment train downstream of the bioretention (see Additive below for available options). There are a number of alternative sources of soil organic matter which have undergone field studies which have benefits and potential concerns:

{|class="wikitable"

{|class="wikitable"

|-

|-

!Peat moss

!Peat moss

|Doesn't leach phosphorus||Must be extracted from natural wetlands

|Doesn't leach phosphorus||Must be unsustainably extracted from natural wetlands

|-

|-

!Shredded paper (e.g., Pittmoss)

!Shredded paper (e.g., Pittmoss)