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aconite · March 24, 2014

when someone asks about how to prepare a container mix, usually with the idea that there absolutely MUST be some compost or similar small particle component, i always advise to first make about half a liter of whatever they want to use and put it into a completely see through plastic cup, with holes in the bottom. then to let through a couple of liters of water and observe what happens.
this will nicely illustrate what Ed wrote above: "How many bb's does it take to make pudding drain??". The more water you let through (which simulates the waterings during the growing season), the more you will see your dusty particle component sink to the bottom and clog the container. it will also raise the perched water table in the cup, and with it create anaerobic conditions in the bottom. A particularly bad combination is compost and perlite, because perlite floats and moves to the top of the container very fast, but it happens that sometimes people only have access to perlite.
there is much more to this, but this simple experiment usually gets people thinking and tinkering with their mix until they see satisfactory water movement in their test cup.

there is one beautiful article that gives a very good understanding of how water behaves in container media, i always link it in posts like these, take a look it, it isn't long or hard to read:
http://oregonstate.edu/dept/nursery-...roperties.html

there is also a sort of easy solution if you can find this material, dr. Mark Dimmitt wrote an article about using coconut husk chunks (NOT coco peat, that stuff is awful) as a universal container media: http://www.tucsoncactus.org/html/gro...June_2013.html
sadly i can't find coco chunks anywhere near me and i've had no success finding a source online in the EU who can ship for even a relatively decent price (if any of you from the EU know of one please please let me know?), but you guys in the US should be able to get this.

March 24, 2014	#8
aconite Tomatovillian™ Join Date: Jan 2014 Location: Croatia Posts: 42	when someone asks about how to prepare a container mix, usually with the idea that there absolutely MUST be some compost or similar small particle component, i always advise to first make about half a liter of whatever they want to use and put it into a completely see through plastic cup, with holes in the bottom. then to let through a couple of liters of water and observe what happens. this will nicely illustrate what Ed wrote above: "How many bb's does it take to make pudding drain??". The more water you let through (which simulates the waterings during the growing season), the more you will see your dusty particle component sink to the bottom and clog the container. it will also raise the perched water table in the cup, and with it create anaerobic conditions in the bottom. A particularly bad combination is compost and perlite, because perlite floats and moves to the top of the container very fast, but it happens that sometimes people only have access to perlite. there is much more to this, but this simple experiment usually gets people thinking and tinkering with their mix until they see satisfactory water movement in their test cup. there is one beautiful article that gives a very good understanding of how water behaves in container media, i always link it in posts like these, take a look it, it isn't long or hard to read: http://oregonstate.edu/dept/nursery-...roperties.html there is also a sort of easy solution if you can find this material, dr. Mark Dimmitt wrote an article about using coconut husk chunks (NOT coco peat, that stuff is awful) as a universal container media: http://www.tucsoncactus.org/html/gro...June_2013.html sadly i can't find coco chunks anywhere near me and i've had no success finding a source online in the EU who can ship for even a relatively decent price (if any of you from the EU know of one please please let me know?), but you guys in the US should be able to get this.