Perlite & Vermiculite

On Tuesday this week we talked a bit about perlite and vermiculite in seed starting mixes but I wasn't entirely sure what these materials were made of. So . . . 

Perlite, according to Wikipedia: "Perlite is an amorphous volcanic glass that has a relatively high water content, typically formed by the hydration of obsidian. It occurs naturally and has the unusual property of greatly expanding when heated sufficiently. It is an industrial mineral and a commercial product useful for its light weight after processing." http://en.wikipedia.org/wiki/Perlite

And Vermiculite: "Vermiculite is a hydrous, silicate mineral that is classified as a phyllosilicate and that expands greatly when heated. Exfoliation occurs when the mineral is heated sufficiently, and the effect is routinely produced in commercial furnaces. Vermiculite is formed by weathering or hydrothermal alteration of biotite or phlogopite.^[1]Large commercial vermiculite mines currently exist in Russia, South Africa, China, and Brazil." http://en.wikipedia.org/wiki/Vermiculite

Also on Tuesday we started some experiments with different seed-starting conditions so that you can get a visual sense of what a healthy (and unhealthy) transplant looks like. We used two different planting mediums Metro Mix 300 from Sun Gro horticulture and Seed Starter 101 from Morgan Composting.

Metro Mix ingredients: "Vermiculite, bark, Canadian Sphagnum peat moss, coarse perlite, bark ash, starter nutrient charge (with Gypsum) and slow release nitrogen and dolomitic limestone." (I think I told you that this was a nutrient-less mix, but as I look at the ingredients, I see that I was wrong in this. It does have that "starter" nutrient charge.) http://sungro.com/products_displayProduct.php?product_id=104&brand_id=17

Morgan's Seed Starter 101 "contains products like worm castings, meat and Bone Meal, Feather Meal, and paramagnetic rock." http://www.dairydoo.com/Morgan_Composting/For_Greenhouses.html

We planted four tomato plants in each of three 4-chambered plastic pots with two chambers filled with Seed Starter 101 and the other two with Metro Mix 300. We put one pot under a grow light, one in a sunny (well it will be if the sun ever comes out) window, and the other in a shady area of the porch. We'll water them and see what happens!