variety in substrate

README.mdown

@@ -24,7 +24,7 @@ As a result of the above hubris we triple our efforts.
 - Make one extra of the above as a control for testing your sanitation.
 
 It is OK.
-Bird seed, agar powder, and sugar water are inexpensive.
+Bird seed, coconut husk, and sugar water are inexpensive.
 All other equipment can be reused.
 
 Saving a control will help you test for contamination introduced through your technique.
@@ -136,7 +136,7 @@ Skipping testing on [agar slants](#agar-slants) works well enough as long as you
 
 - [ ] aluminum foil
 
-imperial | metric
+Imperial | Metric
 -------- | ------
 16 oz | 450 ml
 
@@ -148,7 +148,7 @@ imperial | metric
 Mixing liquid culture is similar to [agar slants](#agar-slants) without needing to cool the test tubes in any particular position.
 A simple sugar like light corn syrup is dissolved in distilled water to provide mycelium calories for reproduction.
 
-ingredient | mason jar | ratio
+Ingredient | Mason Jar | Ratio
 ---------- | --------- | -----
 water | 300 ml | 100 ml
 simple sugar | 15 g | 5 g
@@ -192,7 +192,7 @@ Mixing 2:3 grams ratio of malt extract to agar powder is good for saving money b
 
 Scale the following recipe as needed to fill 1/3 of each test tube or 10 ml:
 
-ingredient | mason jar | ratio
+Ingredient | Mason Jar | Ratio
 ---------- | --------- | -----
 water | 300 ml | 100 ml
 agar | 9 g | 3 g
@@ -372,9 +372,9 @@ This guide does not address these special requirements.
 I leave it up to you to research your mycelium species.
 
 [Grain spawn](#grain-spawn) is a common source of nutrients and the most accessible source of grain spawn is wild bird seed.
-You should, however, provide mycelium a variety of grain spawn and [substrates](https://en.wikipedia.org/wiki/Substrate_(biology)) between generations of colonies so the strain does not lose it's ability to digest different sources of nutrition.
+You should, however, provide mycelium a variety of [grain spawn](#grain-spawn) and [substrates](#bulk-substrate) between generations of colonies so the strain does not lose it's ability to digest different sources of nutrition.
 
-These general instructions are the same for most grain spawn.
+These general instructions are the same for most [grain spawn](#grain-spawn).
 
 # Grain Spawn
 
@@ -396,7 +396,7 @@ Wild bird seed is dusty and full of bacteria and molds.
 Because the seeds are dry the bacteria has likely [endosporulated](https://en.wikipedia.org/wiki/Endospore), making it resistant to sanitization.
 Soaking and boiling the bird seed will clean it up a bit and encourage the endospores to reproduce, leaving them weaker to [autoclave](#autoclave).
 
-imperial | metric
+Imperial | Metric
 -------- | ------
 16 oz | 450 ml
 1 cup | 250 ml
@@ -473,8 +473,10 @@ However, exposing more surface area give the mushrooms more room to sprout.
 
 - [ ] take-out containers, black opaque, polypropylene
 
-Coconut husk (coir) holds moisture better than the mycelium cake we created in the [grain spawn](#grain-spawn) jar.
-We shall mix it with [grain spawn](#grain-spawn) for colonization as a [substrate](https://en.wikipedia.org/wiki/Substrate_(biology)).
+Earlier it was mentioned that mycelium want a variety of [grain spawn](#grain-spawn) and [substrates](https://en.wikipedia.org/wiki/Substrate_(biology)) between generations of colonies so the strain does not lose it's ability to digest different sources of nutrition.
+This guide uses coconut husk (coir) mixed with [grain spawn](#grain-spawn) for colonization as a substrate.
+You can also add coffee grounds, sawdust, straw, and rice husks for variety.
+Take caution to only change one thing at a time between generations or you risk overwhelming the mycelium.
 
 Many commercial gardening coir are treated with [endophyte](https://en.wikipedia.org/wiki/Endophyte) to protect plant roots.
 These endophytes do not protect our mushroom roots and will compete for resources like any other contamination.