How much water? Drip system vs flood and drain

[whoalon]

How often/much water do I need?

I have a drip system set up and I was told to have the timers set to water 3 times per day for 1 minute each time.

I have a flood and drain system that I was told to flood 5 times per day for 4 minutes each time.

I am seeing some slight yellowing of leaves on the flood and drain, is this from too much water?

I have also noticed that the plants closest to the pump on my drip line are yellowed slightly, while the ones on the end of the line (far from the pump) are perfect. Are the ones closest to the pump getting to much pressure compared to the end of the table? How can I remedy this?

 

[fallen]

if it was too much water they'd probably be drooping, if it's from not enough water, they'd be extending up trying to transpire as much as possible,

it sounds like either a nute deficiency or lockout or something like that, but i could be wrong.


give us more info though, that's not enough

 

[Akornpatch]

Tell us more.

PH?
PPM?
Res temp?
Type of nutes used?
Type of lights?
How long is the F&D?

 

[whoalon]

2nd week Veg

PH:
5.8

PPM:
900

Res temp:
70 degrees

Type of nutes used:
Protect
GH Micro
GH bloom
PB pro grow
Diamond Nectar
Hygrozym

Type of lights:
1,000w HPS

How long is the F&D:
pump on 4 minutes, takes about 15 minutes to drain.


I measured the amount of water coming out of each drip line. The ones farthest from the pump (where the plants look good) are getting around 300ml of water. The ones closest to the pump are getting 500ml of water.

 

[Herban Legend]

Drip times are different because of the size of the drip system and the medium you choose to use. You also try to setup so drippers deliver the same amount of water. Do this by making all the drip lines the same length coming from the same source.
Ebb systems need at least a full saturation of ten minutes or more. People with trays normally flood for 15 minutes. People with large trays or multi-bucket systems flood for 30 minutes(because they take longer to flood). Most people set up for 3 floods a day.

 

[Akornpatch]

Can you put a restricting valve on the closer ones? Maybe they're getting too much of a good thing.

 

[whoalon]

I put a "T" in the middle of my drip line and ran the pump from there, the water is evenly distributed now.

I am not sure what to do with the F&D. I have talked to a few growers, and got a different answer from everyone. 5 times a day, 3 times a day, once a day, and once very twenty hours.

I have rockwool cubes(and slabs) on the drip system, and coco grow 8" pots on the F&D. Does one require more water than the other?

 

[Herban Legend]

Rock wool retains more water and is fed less often.
Cocoa is not a medium I have tried so I have to leave that one alone. I try only give info with things I have experience in, not stuff I read and never done it myself.
I can tell you this, when it comes to ebbs, its rather easy to find your numbers.
Once fully flooded it should flood for 10 minutes for full saturation. The time it takes to flood depends on your system.
Then you watch your leaves on a daily basis. When they are up you need to increase the feeding. When they are down you need to decrease. Perfection is straight out with maybe a slight droop at the ends. Feedings depend on the evaporation and absortion rate so humidity is a factor, the plant is a factor,ph is a factor, medium water retention is a factor and so on. So if you are looking for a magic number you have to watch the leaves, if you want the most common standard for cannabis growing its 3 times a day. When lights turn on, half way thru the light cycle, and then a hour to .5 hour before lights out.
For DWC and drip feeders that use air stones as a source of water movement the info above does not apply.