Quote:
Originally Posted by Oonagh  I'm new to NPTs (learning, getting ready to set one up) and I was wondering, can anyone explain why the gravel around a potted plant would go severely anaerobic? I'm not planning on trying it, I just want to get a better understanding of what happens in different situations in the substrate. Thanks! |
Easy Explanation. If you have a light scattering of gravel (1/4" deep), oxygenated water will flow over it keeping it aerobic. Nitrifying and other anaerobic bacteria will colonize the gravel. All good!
If you have a gravel substrate that is 2-3" deep, then oxygenated water doesn't penetrate that very well. Also, somewhere in that 3" are deep pockets that accumulate organic matter that make it really anaerobic and toxic.
When I see gravel substrates of more than 1", I just cringe. If you want that deep a substrate, then make sure that you vacuum it frequently.