Question for Lucas .... ebb/flow water levels

[Mikey]

Just starting my first ebb/flow setup after running DWC for a couple of years and have a couple of questions I cant find answers for and found this quote by Lucas

"you ask good questions though, and raise an important factor, the interaction between irrigation depth and pot size in ebb flow

it deserves a thread of its own, how to manage plants grown in a conventional ebb flow table that is flooding to a 3" depth, and what that means to pot size, and total gallons of medium in the pots..."

I will be running a 4x4 table under 1200w high numbers with minimal spacing and veg time. Also using the Lucas formula in growrox as it has served me well. What would be a good depth table and pot size. I agree with Lucas that this would be an interesting thread and would answer some important questions for a lot of people.

[Lucas]

> What would be a good depth table and pot size.

commercial hydro tables are about 4" deep and can be flooded to about 3" give or take half an inch..

for high plant numbers.. the 6" square pot is a good size, imho

if going to ebb flow larger pots, such as 2 or 5 gallon, I dont recommend making deep ebb flow tables, because the deeper the water the heavier the weight of water, instead look at the Multiflow concept... electric floats connected to water pumps that fill and drain from a barrel to containers on the floor.. no table, but still ebb flow

http://www.hydroponics.net/items/details/multiflow.asp

Lucas

ps
one key concept to observe with ebb flow designs, is to not flood so deep that the top layer of rox gets wet, or the system will develop algae problems on the surface of the rox.. best to keep the top of the rox dry, preventing algae, and fungus gnats..

[lazi]

lucas, for 9 plants in a 4' x 4' space what is the ideal volume? (Multiflow) Also, does the shape make much difference? I already have some 15 litre kitchen bins, about 1 foot square and 18" high but I'll get something else if the plants would prefer it.

[Lucas]

the multiflow uses nested 2 gallon buckets.

the containers you have are twice as big, but would also work.

I recommend 2 gallon buckets, because you will have half as much medium to deal with, and 2 gallon buckets are shorter in height than the containers you are considering

[lazi]

Height isn't a problem and I don't mind buying extra hydroton, just want whatever the plants would prefer.

[Mikey]

> What would be a good depth table and pot size.

commercial hydro tables are about 4" deep and can be flooded to about 3" give or take half an inch..

for high plant numbers.. the 6" square pot is a good size, imho


ps
one key concept to observe with ebb flow designs, is to not flood so deep that the top layer of rox gets wet, or the system will develop algae problems on the surface of the rox.. best to keep the top of the rox dry, preventing algae, and fungus gnats..

Cheers Lucas

So you only flood about half way up the pot?

Would that not incourage roots to search beyond the pot?

Also what would be your reccommendation on veg time......roughly for a reasonable indica packed in nice and tight (64) ?... trying to push for 2LB

sorry about all the questions but its a big transition from the trusty old buckets?

Thanks again

Mikey

[Lucas]

I have replied in the Ask Lucas thread
https://www.cannabis-world.org/cw/showthread.php?p=49329#post49329