posted by Celest .
the advantage of gravel is :
the disadvantage of gravel:
the advantage of sand
the disadvantage of sand
Here's a website that discusses using sand and gravel in hydroponics.
However, I'm sure it will be easier for you to find these answers in your science book.
our teacher took our books
weight is a strong disadvantage to both
sand disadvantage is it stays wet
advantage of gravel: air gets to root hairs.
For my orchids, I have found expanded clay particles are superb. I add 1/2 expanded clay, 1/2 shredded rubber tires.