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View Full Version : can i use clay gravel as growing medium?



cage
03-25-2011, 07:53 AM
hello all!

trying to build my first small aquaponics system at home. but i am having a hard time finding expanded clay here in Mauritius. does the gravel size for growing medium matter? the one i bought seems pretty small compared to the one i saw from the websites!
http://img69.imageshack.us/i/img2133d.jpg/
would these be ok as a growing medium?

jcx
03-25-2011, 12:10 PM
1/4 inch gravel is best from my experiences. Clay pellets are for grow kiddies. I use a layer of 1/4 gravel at the top and lower 2 inches and fill the middle with hydromite. Really I don't think the hydromite is worth the money. I have a cucumber kicking ass in rocks I stole from the landscaping in fount of an office. If you use rocks that are too small the path ways for water will get clogged up with fish crap and your worms will have a harder time moving around.


If you use rocks from outside be sure to cook them before you use them. Just google "How to cook rocks" I'm sure you will find some useful information. :twisted:

cedarswamp
03-25-2011, 01:35 PM
Your picture looks alot like flourite gravel. I have about 50 lbs of the stuff left from my planted aquaria days, but from my understanding it's a little small for aquaponics, although I'm going to try experimenting with it for my radishes rather than using perlite where the algae on top drives me nuts. It does have a high CEC.

cage
03-26-2011, 01:19 AM
i been thru some plant stores and i saw something called "ceramic granile" and "expanded perlite" which the store told me was good for hydroponics. i am new here so i am afraid it might be harmful to the fish so my question is can i use those as my growing medium? if those are still no good then i think i will go for the heavy river gravel :D

keith_r
03-26-2011, 07:57 AM
perlite will end up getting all through your system, don't use that!
not sure about the ceramic granule stuff.. but ceramic should be stable
river gravel works well, just stay away from limestone - you can test media by putting it in vinegar, if it bubbles you don't want to use it

urbanfarmer
03-26-2011, 08:49 AM
You can use anything that won't wash away. Heck, if done right you could use pure sand. Pea gravel of about 3/4" size if often recommended, but many prefer larger, smaller, or a good mixture of the range of sizes. I have had success with every grow medium I have ever used. The plants don't seem to care much.