grow bed depth

[JGudde]

I am wanting to upgrade my system with more
growbeds. My greenhouse is small and I am wondering
if I go with 16" deep growbeds instead of 12" would
be a way to improve my growbed to fish tank ratio.
Has anyone tried this or knows if this will help.
Thanks

[badflash]

Deeper won't make much difference unless you are having trouble with plants falling over. Increasing the surface area gives you more plants, and that improves the uptake of minerals and nitrates, etc.

[Murray]

Deeper could give a longer service life because solids can be processed, although it is possible that too deep can mean that solids in the bottom of a deep bed could become anarobic causing poor performance of the system. It has been shown over a long period of time that 1' deep grow beds are very good and one foot deep is possibly the optimum depth for gravel/media based systems.
That is not to say shallow beds, say 6" deep will not work, of course they will...but, the need to clean the media may come around earlier than expected.
Domestic media based aquaponics systems are very forgiving in their operation...which is great for the home operator. There is a reasonable range of operational latitude, so the home operator can choose to operate their system in a manner that best suits their budget and available hardware.

[JGudde]

My thought was a deeper grow bed would supply more surface area
for the bacteria to grow. I am not sure which the more important
the area for bacteria or the number of plants. I just know they talk about a ratio of 1 to 2 ratio fish tank to growbed.

[badflash]

It takes a very small amount of growbed to provide the proper amound of bacteria. Plants are needed for the nitrate and phosphate removal. An alternative to suface area are vine crops. Heavy feeders and they expand up.

[JGudde]

Thanks the amount of bacteria was my concern but it
sounds like plant numbers are more important.