flood and drain medium question

ive got a 2x4 table plan on using 4 inch rockwool cubes...can the cubes just sit on the bottom of the tray or should there be something below them when the table is flooded?

thanks

Not the same question, but same concept with 6" rockwool cubes in a 4'x4' flood & drain and want to know which medium is better to cover the bottom of the table with and why? I am considering loose piece coir, hydrotron, silica rock. I'm leaning towards the loose piece coir due to its high aeration content and moisture retention capabilities, but the hydroton will give a great base for the root structure to take over.

Opinions? Plan on doing 4 white widow, 4 strawberry cough, 4 dutch dragon & 4 blueberry.

Hydroton works best IMO and really is best for ebb an flow because of how well it supports the roots and plants as a whole

Just as SmokeyMcPopkinZ said, Hydroton works best. I put my rockwool in containers that had a little Hydroton in there. I like this method since it's easier to pull out all the plants if you need to clean your tray.

I use 4" rockwool just straight on top of my trays. I have 2X4 and 4X4 and I have never ran into any problem. I used to run a layer of cocoa mat under my cubes but I would only suggest that if you have really big plants.

shaun1says said:

I use 4" rockwool just straight on top of my trays. I have 2X4 and 4X4 and I have never ran into any problem. I used to run a layer of cocoa mat under my cubes but I would only suggest that if you have really big plants.

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I wanted to try that but it seems like the roots have nowhere to go. How tall do you grow your plants?

hydroton is the future coco in net pots , in hydroton is my chosen method , but you'll need to mesh the drain/entry holes as its a bit messy at first