Ebb and flow flood tables with rockwool watering

[BBQdDude]

Looking on watering advise. I use ebb and flow with tables. I use 4X4 rockwool as medium. I use 1K light. I normally do 10 plants per table. I use a coco mat on the table "floor" to keep roots in the dark. I use covers/squares on top of the rockwool also.

Right now i water ONLY during lighted hours. I flood the tables four times a day at 15 minutes. Is that too many times? I don't see drooping on the leaves but this is one thing I never really looked into and took for granted.

 

[BadRabbit]

Looking on watering advise. I use ebb and flow with tables. I use 4X4 rockwool as medium. I use 1K light. I normally do 10 plants per table. I use a coco mat on the table "floor" to keep roots in the dark. I use covers/squares on top of the rockwool also.

Right now i water ONLY during lighted hours. I flood the tables four times a day at 15 minutes. Is that too many times? I don't see drooping on the leaves but this is one thing I never really looked into and took for granted.

There's almost no such thing as too much when you're using RW, it drains and stabilizes very quickly ... don't know about the coco though, been using ebb and flow tables for about 15 years and never tried that approach.

BTW, I buy the loose rockwool bags and put it in plastic mesh pots, works great, gives the flexibility of moving your plants around like a dirt grow. Costs tons less than the preformed cubes in the long run.

I've heard the "only flood at night" before, but I really don't take it seriously ... I find 4 to 5 floods, evenly spaced throughout the 24 hr period works just great.

good luck

 

[FlowerFarmer]

BBQdDude,

So your flooding every 3 hours if you are flooding 4 times a day during a 12 hour lights on period?


In hydroton, which holds nowhere near the amount of water RW most are flooding 15 min every 4 hours. This is the standard schedule for flooding hydroton.

RW is typically best suited for top feed (Grodan states this as well), but many get away with flooding it w/o nute accumulation issues (so long as you are not allowing things to get too dry)

I'd personally taper it back a bit to see if you see better results, but if you've got a well established root system it likely matters very little. I' would caution with that schedule from the get go however on fresh clones/transplants.. too wet can lead to slow grow, root rot, and damping off.

Maybe flood once per day when the plants are younger, and bump to twice (maybe 3) per day once roots have been well established.

I wouldn't flood at night.



Just my 2c

 

[RoostaPhish]

Yes the lower the watering amounts the better. It is really all about how quickly they are using the water. I grow 7' trees in my ebb and flow trays, and they only need 1 watering a day while young and 2 watering's a day when full size. However it is a little different of a setup from what you have, I fill the tray with growcubes and place my 4" blocks on top of them sunk down a little. This holds more moisture and allows for greater distance between feedings. Plants are huge however and their root mass completely fills the tray. Both over and under watering can have negative effects.

 

[resinryder]

4" cubeswill dry out faster than the 6x6 ones. Be careful with 15 minutes on at a time. My first grow with rw I flooded for 15 minutes and ended up with root rot. I'd imagine with the coco mat at the bottom it will hold a bit more moisture too.
What I have always done to figure my flood times is this, and you can take this with a grain of salt, try it, or ignore it, your choice.
Turn the pump on. Time how long it takes to either get 1/2 way to 3/4ths way up the block or to the opening on the over flow drain pipe which ever comes first. Then give it another minute. That is how I find what my flood times should be. Times vary depending on the sizeof the pump. Hasn't failed me whether in rw or smart pots filled with coco since the above mentioned root rot 15 years ago.
The number of times a day depends on how quickly the rw drys out. In the 4" cubes you may need to give a flood during lights off especially when they get bigger and require more water.
Flush with a clearx type product every 30 days. RW will load up with salts from the nutes and block the air transfer in the cube which will cause you problems.

 

[BadRabbit]

BBQdDude,

I wouldn't flood at night.


Just my 2c

FF - why not?

 

[FlowerFarmer]

I'm sure someone with a bit more knowledge can expand on this using better words.


But,
Very little water is used at night. A plant's stomata closes at night as there is no need for co2 since there is no photosynthesis going on during this dark period. Since the stomata are closed, there is no (or at least very little) water evaporation from the plant's leaves.

The plant does perform cellular respiration at night as it undergoes light-independent reactions so perhaps a little bit of water is used, but not enough to warrant night time flood cycles which can spike your humidity extremely high in your room and can lead to powdery mildew & botrytis/rot if you're not careful.

I don't think it is necessarily bad to water at night, just not needed. Unless of course if you are in small enough RW blocks that they are drying out before lights on/your next water schedule.

 

[meltybubble]

I'm sure someone with a bit more knowledge can expand on this using better words.


But,
Very little water is used at night. A plant's stomata closes at night as there is no need for co2 since there is no photosynthesis going on during this dark period. Since the stomata are closed, there is no (or at least very little) water evaporation from the plant's leaves.

The plant does perform cellular respiration at night as it undergoes light-independent reactions so perhaps a little bit of water is used, but not enough to warrant night time flood cycles which can spike your humidity extremely high in your room and can lead to powdery mildew & botrytis/rot if your not careful.

I don't think it is necessarily bad to water at night, just not needed. Unless of course if you are in small enough RW blocks that they are drying out before lights on/your next water schedule.

I think you use great words!
Great advice.


peace.

 

[sdd420]

I've left mine on for all day no problems what so ever . The draining process is adding oxygen as it drops into reservoir and my plants haven't mindedit . I flood every hour 10 minutes peace sdd

 

[BadRabbit]

I'm sure someone with a bit more knowledge can expand on this using better words.


But,
Very little water is used at night. A plant's stomata closes at night as there is no need for co2 since there is no photosynthesis going on during this dark period. Since the stomata are closed, there is no (or at least very little) water evaporation from the plant's leaves.

The plant does perform cellular respiration at night as it undergoes light-independent reactions so perhaps a little bit of water is used, but not enough to warrant night time flood cycles which can spike your humidity extremely high in your room and can lead to powdery mildew & botrytis/rot if you're not careful.

I don't think it is necessarily bad to water at night, just not needed. Unless of course if you are in small enough RW blocks that they are drying out before lights on/your next water schedule.

Thank you FF; very interesting. I think you hit my take there ... I'm not watering the plants as much I'm keeping the media at proper wetness. With the way I use RW, (not small cubes, loose RW in mesh pots) shouldn't be an issue as it holds moisture very well. With hydroton or small RW blocks as you mentioned, I wouldn't want to go 12 hours without a flood cycle.

I would think the impact on humidity to be minimal, unless one is having a problem with such in the room.

However, it's all up to the grower and their results.

best,
rabbit

 

[meltybubble]

With hydroton or small RW blocks as you mentioned, I wouldn't want to go 12 hours without a flood cycle.


Hi there,
I have found not feeding during the "dark period" not only increases growth but is heathy for them.
They go into shutdown mode if you like no water no intake of food, no light no issue.
All the hydroponic books I have read say the same. Hydroponics are really simple once the fundamentals are understood.
I dont use much hydroton, just enough to stop light hitting the roots and have never had issues.
It can be detremental to feed in the "dark period" considering best growth rate is achieved by only feeding when "lights on".
To avoid confusion to the op, I use trays and plant onto spreader matting. Enough hydroton to stop light and corex covers over the cubes to pervent mold,fungus.


Regards,

 

[BadRabbit]

With hydroton or small RW blocks as you mentioned, I wouldn't want to go 12 hours without a flood cycle.


Hi there,
I have found not feeding during the "dark period" not only increases growth but is heathy for them.
They go into shutdown mode if you like no water no intake of food, no light no issue.
All the hydroponic books I have read say the same. Hydroponics are really simple once the fundamentals are understood.
I dont use much hydroton, just enough to stop light hitting the roots and have never had issues.
It can be detremental to feed in the "dark period" considering best growth rate is achieved by only feeding when "lights on".
To avoid confusion to the op, I use trays and plant onto spreader matting. Enough hydroton to sotp light and corex covers over the cubes to pervent mold,fungus.


Regards,

I've been using ebb and flow tables, 3 to 4 at a time, for 15 years ... I speak from experience and seeing the results, not reading books written by other people. I remain skeptical on the importance or value of the no dark watering idea, and my plants are big and healthy too. Perhaps the plants are taking up less moisture, but a 5 minute flood is not going to damage or limit the growth of the plants, I just don't buy it. I would certainly disagree with the idea that it's a basic of hydro growth. Conversely, I would argue that, especially if you are using hydroton, a 12 hour no flood period may leave your media too dry and THAT could indeed negatively affect your plants.

That said, it's important to keep an open mind and I will probably try it just to see if I notice any differences.

I also reject the idea that a small amount of algae growth on the top of a RW cube or pot causes even the slightest problem at all. While there's nothing wrong with covering something with pebbles, I find it's best in the long run to not have any of those little fuckers anywhere near my tables ... they spill, clog lines, don't hold water well and always seem to end up on the floor and digging into a foot at some point. Just my take on them, others may love them.

best,
rabbit

 

[roasthawg]

I have killed plants by overwatering in 4x4's... not in 6x6's though.

 

[BadRabbit]

I have killed plants by overwatering in 4x4's... not in 6x6's though.

hi roasthawg ... do you mean a 4x4 cube of RW? (I don't use cubes so the lingo is obscure to me). May I ask how you overwatered them? Why does your larger cube work better?

best,
rabbit

 

[roasthawg]

hi roasthawg ... do you mean a 4x4 cube of RW? (I don't use cubes so the lingo is obscure to me). May I ask how you overwatered them? Why does your larger cube work better?

best,
rabbit

Yeah, 4"x4" rw cubes. They got overwatered I believe from a combo of water levels going up too high on the flood cycle and the flood cycle lasting too long. Plenty of people have grown in the 4x4's no problem but I had a hell of a time with them. The larger cubes seem to hold more air, especially up top. That's my theory at least... never had any problems once I switched to hugos.

 

[meltybubble]

I've been using ebb and flow tables, 3 to 4 at a time, for 15 years ... I speak from experience and seeing the results, not reading books written by other people. I remain skeptical on the importance or value of the no dark watering idea, and my plants are big and healthy too. Perhaps the plants are taking up less moisture, but a 5 minute flood is not going to damage or limit the growth of the plants, I just don't buy it. I would certainly disagree with the idea that it's a basic of hydro growth. Conversely, I would argue that, especially if you are using hydroton, a 12 hour no flood period may leave your media too dry and THAT could indeed negatively affect your plants.

That said, it's important to keep an open mind and I will probably try it just to see if I notice any differences.

I also reject the idea that a small amount of algae growth on the top of a RW cube or pot causes even the slightest problem at all. While there's nothing wrong with covering something with pebbles, I find it's best in the long run to not have any of those little fuckers anywhere near my tables ... they spill, clog lines, don't hold water well and always seem to end up on the floor and digging into a foot at some point. Just my take on them, others may love them.

Twice you said about the 15 years here.
I also speak from expierence with years not much behind.
Have you any data or references to back this, apart from a five minute flood?
I look forward to your results. Maybe the experts are wrong.
Regards

 

[sdd420]

I have killed plants by overwatering in 4x4's... not in 6x6's though.

Not in an ebb and flow no way dude your running buckets or something else. I've left my pump on 12 hours no problem. It really is flexible and depends on plant size too but get real

 

[sdd420]

My reservoir is under my ebb and flow so as it drains and drops like a waterfall it super oxygenates the solution. My plants love it

 

[sdd420]

Relax smoke some it's all gooood peace sdd

 

[sturgeongeneral]

I run a set up very similar and you definately can over water thise rockwool cubes. I run 4x4 cubes in a 3x3 tray under a 1k and water 1 time per day for a few minutes till it starts to drain off then let it go a minite longer... You can check your cubes for weight. If they feel heavy theres plenty in them.