Help with kelp (mycology)

[Lemon69]

I understand that kelp can be used as a mushroom substrate ingredient. I have it in whole form - some of it is sitting in water to prepare a broth for ramen. In what proportion is kelp used and in what form is it used? I understand that some organic materials must be steeped in water before being used in a substrate - for example, coffee.

Sorry this post is in a more extraction related forum.

 

[downwardsfromzero]

You're not getting this mixed up with agar, are you?

 

[Lemon69]

You're not getting this mixed up with agar, are you?

Although I remember kelp having some relationship with agar, people specifically talk of using it as a supplement in substrates. I'll just start with supplemental amounts similar to that of coffee and in two forms, one form that has undergone a water extraction and one that hasn't.