What's the best medium to use in a flood and drain system?

I just got my mylar tent, flood and drain table and nutes today. I am so excited, I am nearly ready to start my first proper grow. I have some White Widow seeds coming, there is no decent weed in this town so clones are out the question, I have to grow a kronic mother from seed first. I am starting with some 30w CFL's (2020 lumens) but am buying a 400w HPS for flowering. I am ready to buy the medium for the table but am still shopping for suggestions. The most obvious is plant in rockwool cubes then fill rest of pot with expanded clay, but I am worried the plants wont effectively root around the big expanded clay balls, is there a better medium to use in my flood and drain?

I may sound a little daft or may be miss reading but are you using soil or hydro?? GW

Why would you want flood a plant with 4" of water when you can just pump a little water on top.

IMO flood and drain is silly unless you are in a situation where you can't hook up drip tube to each plant. Why do you want to pump 20 gallons into a flood table when you could just as easily pump 3 gallons onto the top of your plants.

If you use hydroton you will have to water 4 times a day and if your timer fucks up your plants will be dead fast. If you use coco you can water once or twice a day and if you miss a day your plants won't be totally dead.

All you need to convert ebb and flood to top feed is $12 worth of drip stuff. You don't need emitters, straight tube works fine.

Awww .. my setup sucks, not what i was hoping to hear but got a few ideas i want to test out with this system so i will perservre , but if all fails i can see how it could be easily converted to a drip feed setup, the tray wont be a waste of $$$ (phew).

flood and drain is much easier than drip system. you need to flood just with one outlet to water evenly all plants unlike the multiple drip system. it is much better in aeration of the the roots since when the water drains it sucks fresh air to the rootzone. the best medium for this would be small sized expanded clay balls. they retain water for long time in case of pump failure and they are really foolproof. use the small rockwool cubes like 2" so that your roots meet the air ASAP. if you fill the whole table with rocks, you will not need to make it very deep 3-4" depth of rocks. also you will not need to cover the table to prevent algae growth. after going through different hydroponic systems, flood and drain is my favorite choice. It is by far better than drip system also in results. I can bet everything I got that if you put 2 clone plants side by side under same light same genetics and size, drip feed one plant and flood and drain the second from the same res, the flood and drain will yield more. I only choose DWC over it when it is freezing cold because it is easier to heat rootzone in a DWC res than it is to keep the growrocks warm, and DWC is also very good in yields but is more maintenance all in all...

I run ebb and flow as it`s very easy, plus you can put quiet a bit of plants on the table and move them around very easy. I use rock wool to start my plants, then place the rock wool in/on top of the expanded clay pellets. Last but not least, I put all this in netpots, that way, like I said before, I can move my plants any where I like. During 18/6 I flood 3-4 times, I can miss 2 feedings before my plants show a little droop. During 12/12 I flood about 6 times, I can miss up to 3 feedings before I see droop. I wouldn't use just rock wool, prone to algae growth. I also had root rot problems with rock wool.
My two cents, decreasing in value everyday.

Thanks zem and YeahT0ast (love that song) this is exactly the advice i was looking for, pretty much what I thought, but without a second and third opinion I'm not doing anything! Cold never seems to be much of a problem where I live, so i dodge a bullet there. Have you ever heard of a system doing hourly floods, i read about one that had massive yeilds, would you only do this during flowering? Are there risks associated with this method?

I use 6" rockwool blocks and NO hydroton. Just the blocks sitting on the tray. hydroton adds more to cost and need to be cleaned every cycle.
Please , check out my sigs and see how easy Flood and Drain can be. Drip systems can be nice but they do clog up.

I'm with Kervork, at least in theory- you don't need to 'flood', but drip is not the answer either...

I have been developing My DIY 21st Century F & D system that anyone can copy

Air Pots + Lava Rock + low mist heads + analog timer. Now, you will likely use a small starter cube and a small net pot to get your seedling/clone root system going (Pic #2). At this stage I insert plant into a small net pot then into a small AP, then into the F & D system.

Transferring is non-shocking as you simply put the intact net pot into the small Air Pot, and fill in with Lava Rock. Later insert the small AP into a ~ 1G AP.

This method allows for easy moving of individual plants

I run the heads ~ 15-30 seconds and pause 20- 40- 60- 120 minutes+ (depending on size of roots/plant and age). Each feed cycle delivers ~ 4ozs to each AP. The low mist head spray covers the entire surface and trickles down through the LR. What the root system doesn't drink quickly drains. As it drains, the porous LR catches small amounts which feeds in between and keeps some moisture around the roots.

Growth is explosive. See my completed thread below + I am finishing a thread over on IC

Here are some crude photos, as I am still working out a few details

inluvwitbud said:

Thanks zem and YeahT0ast (love that song) this is exactly the advice i was looking for, pretty much what I thought, but without a second and third opinion I'm not doing anything! Cold never seems to be much of a problem where I live, so i dodge a bullet there. Have you ever heard of a system doing hourly floods, i read about one that had massive yeilds, would you only do this during flowering? Are there risks associated with this method?

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you can do hourly floods but I don't think it will be any better than doing 6 -10 floods per day, thats just my opinion. the only risk I see is if the flood/drain hole is not big enough or gets clogged water might stay flooded in the tray for most of the time. cleaning growrocks is no more a tough job for me. I harvest and remove the rootball and most roots. then I rinse the tray and res then fill with water and 35% H2O2 then flood the tray to run it through the system then I shut the pump and close the drainhole and keep it for hours then I drain and rinse and I'm ready to grow.

That reminds me of a joke. Two guys walk into a bar, the first one says I'll have some H2O, the second guy says I'll have some H2O too! The second guy dies.

I just find hydroton easy as it not only floods and drains well, providing good aeration, but holds just enough water to help in an emergency. I've had a 24 hr pump failure with no damage to the plants.
However, any inert material can be used. I've heard of marbles, gravel and even lego being used.
Prefer root-riot cubes to rockwool though.
Got to like the netpot idea though. This is something I have been thinking of. Just a correx sheet cut to fit with holes for the netpots. More room for roots and less washing of hydroton.
Forget drip irrigation. I use it outside and, whilst it works, drippers do block regularly.

cues said:

Got to like the netpot idea though. This is something I have been thinking of. Just a correx sheet cut to fit with holes for the netpots. More room for roots and less washing of hydroton.

Click to expand...

This system with the correx sheet over the table and the net pots, what may be the risks factors involved with this method - would you need more frequent floods if the roots were exposed to nothing but air for so long. I think I will buy a second pump so I can swap them out if there is a failure, this seems to be the number one concern with the flood and drain system that I can see, second to cleaning the medium by the looks of it, which is what makes this idea of your cues so tempting.

Im having major probs with high Ph using rockwool, any suggestions?