Backyard Aquaponics
A place to discuss aquaponics

I've read
Expanded Clay Balls - $$$ but easy to work with and light
Gravel - cheap but heavy and harder to work with.

Since normal soil has layers why not have a layered grow bed where you have a layer of clay balls that is easy to transplant into when the plants are small then a layer under that of gravel so as the plant grows they can better anchor themselves.

It was just an idea.

Quite a few people have done that, it's a good idea. I was thinking of doing it but just decided to stick with the scoria as it was cheaper.

I have crushed stone as my base to 200mm deep with 100mm clay balls on top. Works great.

cool it made since to me but I've never really seen an article about it.

Tried it. It all ends up mixing together after a couple of years; especially as you rip out old plants and tugging the root balls out disturbs the entire media column. Use the cheaper media for the mean time -- save your pennies and then "upgrade" when you can afford to do the whole lot.

The only way I'd do layers is in REALLY deep GB where the entire root zone is clay balls (with a decent margin) with cheap media below that; or in shallower GBs to plant only very shallow rooted plants i.e. mainly small herbs and lettuce.

I did about half half hydroton and gravel and it has worked pretty well, after a couple of years there is still a nice layer of the clay on top.

I have mixed river gravel and Canna clay balls in about a 3:1 ratio, deliberately all mixed in initially, and it works just fine, definitely no problems planting seedlings. It really is not all that hard on the hands, and if you have a large rooted plant to put in, just use a small gardening shovel.

Then there is my golden rule that i keep trying to get into everyones head, if you leave some bed depth with no gravel - 2inch or so, then you can flood the bed to the almost overflowing point and then any rock becomes alot lighter and moves a lot easier... meaning that even scoria can be moved around and planted into almost as easily and nicely on the hands as a standard, non flooded expanded clay.

obviously you only flood the bed completely when planting/harvesting - works excellently for harvesting too, root balls come out easier without breaking, although not needed this also helps with clay balls.

Wow Bryshelle, you have big balls!

I thought they were called cojones?

After that thread hijack from me i have to make amends by commenting on the theme.

I also have a mixed bed with hydroton and scoria at about 50/50 mixture.

It combines some of the benefits of heavier media - stability - with the easier to work with clay balls.

I've often thought about this when pottering around the patch.
3 of my beds have different mixes,1/2 cracked pea gravel 1/2 clay, 1/2 18mm pea gravel 1/2 clay, and full clay.
Yes the gravel mixes as bunson says, more so in the cracked gravel. I do flood the beds on occasion and some of the clay does rise to the top. Once any of the beds are flooded it is easy to plant and remove root balls. I no longer remove the root balls, I lift the plants a bit and cut the below the bottom of the stem at the top of the root ball and am amazed at how the roots disappear so quickly without a trace but I digress... I have no experience with a straight gravel bed yet, it is in the next expansion plan.
Point I'm working towards is that as the clay is documented to have more surface area for our bacteria friends than the gravels technically it would be best utilised below the water level in our biofilter and the only reason we have it at the top is for ease of planting.
Thoughts?