Flood and Drain

I am gonna give hydro a go.... Flood and drain table 1.2m x.1.2m SOG (36 plants)

My question is how deep does the flood cycle need to be. The reason I ask is the table I am looking at is 12cm deep and therefore I can only flood the table to a depth of 11cm. The square pots I am using are 19cm x 19cm x 25cm high so effectively only half the pot will be submerged. Will capillary action and humity within the hydroton at the top of the pot be enough for the top roots?

Thanx in advance.

Not a flood and drain person myself but I would think yes, as long as flooding continues long enough for capillary action to happen....just my opinion.

should be okay in coco. or rockwool. hydroton doesnt have very good capillary action.

can you get shorter pots? or a deeper tray?

That tray will work but I'd suggest using straight rockwool. You can start them in the plugs and then just place those into the larger 4x4 or 6x6 cubes.
It's a pretty versatile medium. Just make sure to presoak and flush regularly to avoid salt build-up!

Thanx for the advise folks but I am going with Hydroton to maximise root oxygen uptake. Rockwool retains to much water to get the full potential of flood and drain.

I say good choice on the rock for medium. IMO flooding halfway on a pot that size should be sufficient. Make sure when you put your clone in to keep it as high in the pot as possible to prevent any stem rot. what medium are you using to clone? The rapid rooters work terrific.

joe macclennan said:

I say good choice on the rock for medium. IMO flooding halfway on a pot that size should be sufficient. Make sure when you put your clone in to keep it as high in the pot as possible to prevent any stem rot. what medium are you using to clone? The rapid rooters work terrific.

Click to expand...

I am using an aerocloner, no medium, just net pots and plugs. Clones are now rooting and should be ready to transplant in 4-5 days.

Another question. I now have it all set up and running, pots, hydroton, air stone etc etc and all seems fine. my Set up is in the loft and it is no mean feet getting 80-100+ litres of water up there, I am seeing some sludge/dust that has been washed off the new hydroton. Now I know the hydroton is inert and therefore so will the sludge but will this be a breeding ground for nasties or will I be good to clean her out at the end of the grow? Caution says clean her out, but do i need too? Can I just flush her through with H202 before I nute the tank and put clones in?

Thanx in advance.

Re: Surface roots. You don't want roots at the surface of hydroton. It's not completely light-proof. Never flood Hydroton to the top for this reason and because it floats.
Re: Sludge. You HAVE to rinse hydroton both before use and between grows. I do mine in the bath with a colander and it takes me a good hour every time. The problem with the sludge is that it blocks your pumps and plays havoc with pH. All adding h202 will do is make sure your sludge is sterile. It won't get rid of it.

Use the small black plugs and clay pellets. Fill them half way to start so the water gets to the plug. Later as they grow you will need more weight so you can add and fill the pots at that point. The rockwool would also work but they are gnat magnets, that many plants and you might wind up with a real issue.

cues said:

Re: Surface roots. You don't want roots at the surface of hydroton. It's not completely light-proof. Never flood Hydroton to the top for this reason and because it floats.
Re: Sludge. You HAVE to rinse hydroton both before use and between grows. I do mine in the bath with a colander and it takes me a good hour every time. The problem with the sludge is that it blocks your pumps and plays havoc with pH. All adding h202 will do is make sure your sludge is sterile. It won't get rid of it.

Click to expand...

Cheers big ears, I kinda knew that but was hoping to I didn't need to clean the whole system out.

Ok, another Q.

I will stretch my clones b4 transplanting to the table, this should give me a couple of inches of hydroton to sink the roots but they wont quite be hitting the flood level. If I would normally be flooding 4-5 times a day for 20 mins, how often would I be needing to top feed the clones to keep em happy and for how long?.

I'd be soaking them with a pint glass full each every 2 hours of lights on. Next time try and get your clones big enough to go straight in. I grow mine on in pots in coco (summer, windowsill, winter, cupboard with a couple of 23w cfls) then wash it off before going into hydro.

cues said:

I'd be soaking them with a pint glass full each every 2 hours of lights on. Next time try and get your clones big enough to go straight in. I grow mine on in pots in coco (summer, windowsill, winter, cupboard with a couple of 23w cfls) then wash it off before going into hydro.

Click to expand...

Cheers matey. The clones aren't quite ready yet, will throw some nutes in the cloner when fully rooting and stretch em a few inches. I have a family (many kids) so strive for maximum efficiency with minimum graft so every 2 hours is a bit of a bummer especially as gonna veg in hydro for 1 week , oh well, no pain no gain.

Thanx for the help bud, appreciated. Will prob call on you again pretty soon. +rep

cues said:

Re: Surface roots. You don't want roots at the surface of hydroton. It's not completely light-proof. Never flood Hydroton to the top for this reason and because it floats.
Re: Sludge. You HAVE to rinse hydroton both before use and between grows. I do mine in the bath with a colander and it takes me a good hour every time. The problem with the sludge is that it blocks your pumps and plays havoc with pH. All adding h202 will do is make sure your sludge is sterile. It won't get rid of it.

Click to expand...

yup, he is totally correct. Sorry I should have mentioned that new rock needs to be rinsed. The best way I have found to clean rock (new or used) is in a washing machine. Find an old machine that you never want to use again and it will hold up to three five gallon buckets of rock at a time with dirty rock I add around a cup and a half of bleach and let it run through its cycle. I like to cycle it two or three times at least to get rid of all salts and root material built up on the hydroton. you can tell it is clean when the drain water starts running clean. I replaced the standard black hose for the washer drain with some clear vinyl tubing. I have used my washer for years and it still works great. If you remove the lid you can spray the rock as it spins out to accelerate the cleaning process. you will have to bypass the safety switch on the lid tho.