So i recently read about some people that use crushed red bricks or crushed red brick tiles as akadama substitute, both being fires clays. Has anyone used red bricks that can give some feedback if it works or if it is a good idea? Thanks!
As a rule of thumb, fired clays are not direct replacements for akadama.
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I read that some brick that arrives at the crushing plant still has concrete attached to it, which contains lime amongst other ingredients. Horticulturally, lime is used to raise the ph of soil. So if you have higher ph loving species fine, but a neutral ph has been recommended for coniferous material in bonsai craft [ nb incidentally a slightly higher ph allows for more nutrient uptake, but in bonsai craft, the idea is to regulate throughout the year the times appropriate to feed and withhold nutrient application ]
Many roofing tiles nowadays are made of a concrete composite with an external water-deflecting coating to make them visually indistinguishable to terracotta roofing tiles, and these end up in the crusher plant too
Even some of the ingredients in the brick clay mixture itself could present a higher ph - so it’s an inconsistent/ unstable sample measure
That said, as an ingredient, it’s usually cheaper, usuallly locally available, and represents enviro friendly repurposing recycling (including the comparative energy costs offset of less fossil fuels to run the crusher than what’s involved in mining and mine transport distances)
Crushed red brick & terracotta could potentially replace volcanic rock or zeolite in a soil mix (if your batch measured neutral ph if intended for the generic soil mix) for airation purposes