mixed medium grow beds

[Darnell Brawner]

I've seen some talk of clay balls vs gravel and was wondering why not both. 

Normal soil usually is composed of layers.

Example:

thin top layer of clay balls for easy planting

second layer of gravel for anchor support and affordability 

maybe a bottom layer of larger rocks?

Was just wondering. 

[Sylvia Bernstein]

Hi Danell,

The reason not to do this is that you dilute the main benefits of the expanded clay balls, which are that they are lightweight (about 1/2 the weight of gravel) and rounded, so they are easy on your hands and to work with in general.  Once you have multiple layers of media types in a grow bed, they will get mixed eventually, so the advantage of the expanded clay being easy to work with disappears.

[Darnell Brawner]

If the diameter of the gravel is smaller than the clay balls wouldn't the Brazil nut effect keep the balls at the top?

Lets say you wanted to grow some corn so when its small you can easily plant it in the clay layer then as the plant grows it sends roots down to the pebble layer for support.