There are many videos on yutube to find about setting up a dirted tank, with and without peat, with compost or without mixed with kitty litter etc...
One practice all of them did is kinda drystart the cycle with only moist soil for several weeks.. I guess this is done, not to get those massive amonia and nitrite spikes in the water collum and so you do not need to do so many water changes to cycle it.
But i with Darrel on this one, loam is one of the best options.. it doesn't degrade so fast if it ever does ?? And it has good exchange capacities msot aquatic plant like it a lot. You could look in the pond section of the lfs for Water lily substate, this contains loam and everything else that rots and stinks..
No pun intented.
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Personaly i'm not up to the challange, i'm not into organic substrates in aquariums.. I can agree with the fact that for slow burners with a lot of rooted plants it is a very good practice. Depending on what you planning to plant, still you can slow burn as good on substrates like Akadama, Fuji sand and other lava pumis related gravels and add root and water collum fertilization. Most low tech suitable plants are also not the plants that need lots of everything.
Hence the nurseries grow them lush and green on rockwool. Emersed where they have loads of Co2. Submersed low tech and then give 'm a highly fertilized organic soil?? Doesn't realy make sence to me.. But that's probably just me..