What do you think of the following to rejuvenate a rather sterile substrate
(with thanks to Manfred Wirz, who came up with the idea of clay balls):
- take clean, dry clay and mix it with Dupla24 drops until it becomes
like playdough,
- roll 1/2" balls, punch a hole into them and add some hydroponic fertilizer
(NPK + micronutrients)
- close the hole again by rolling the balls once more and put them into
a microwave oven (on very low) for a minute or until dry and hard,
- then push the clay balls into the substrate near plants that need a little

To me, it seems the clay locks in the fertilizer both physically and chemically
and only plant roots can easily get at them.
The fact the the iron may be oxidized is fine because deep in the substrate
the Fe3+ will be reduced again anyhow.
Any comments?
re: Crypt roots growing up
I posted this question earlier but I didn't get a response :-(
My Crypt. wendtii's are growing hairroots _out_ of the substrate, straight up
into the water column.
Why would that be? The plants are very healthy otherwise.

TIA :)