New to rockwool

P

phantom grower

Member
Tolerance Break said:
Also, buy 4in cubes in bulk, it's worth it. I buy them in cases of 144 for less than $2 per cube after shipping.
Click to expand...
U mentioned my blocks are too saturated and I shouldnt be feeding for 3 days, of course that's not exact and would be different if I had the plastic still on. Wouldn't that be 3 days without the roots getting oxygen?
 
Tolerance Break

Tolerance Break

Well-Known Member
phantom grower said:
U mentioned my blocks are too saturated and I shouldnt be feeding for 3 days, of course that's not exact and would be different if I had the plastic still on. Wouldn't that be 3 days without the roots getting oxygen?
Click to expand...
Rockwool has some unique characteristics that I would suggest reading about, but ill do my best to explain...

All grow medium is emulating dirt. Some medium (coco) doesn't hold any water, which means the roots get tons of oxygen but you need to flood more. Rockwool on the other hand is unique in how it maintains its ratio and allows more time between floods.

There are so many methods of using rockwool, its easy to apply one person's method to your set up and have poor results.

For instance, I have 4 inch cubes in a flood tray. I water my plants manually (flip a switch) until flip. I flip my plants as soon as I see roots come out of the bottom. For the first week and some change, I have my timer set to feed once every 3 days, for 5 minutes during lights on. This is just enough time for the water level to hit about 1/3 up the cube for a moment and then it drains. The cubes suck up plenty of water (the water has dissolved oxygen from the physics of being pumped into the tray) and the drain action helps add more air, but keep in mind, as the plant drinks, the block breathes, and the roots sticking out the bottom are getting plenty of air as well. As the plant (and roots) grow, they drink faster. I'm starting week 4 and they've been drinking once a day for almost 2 weeks. Soon they will get another feed before lights off to prevent severe dryback, because when the cubes dry too quickly, the plant cant eat all of the nutrients which causes them to accumulate as salts in the medium. This process happens naturally with or without over drying, but over drying makes it orders of magnitude worse by combining PH and Nutrient lockout at the same time, this is why rockwool should be flushed once every one to two weeks.
 
Tolerance Break

Tolerance Break

Well-Known Member
Note, none of this is perfect. My plants don't hit a measured % of dryback before I water again. I'll lift cubes and look at my plants to gage my next adjustment. It doesn't have to be perfect, and chasing perfection by making constant adjustments ends up leaving the plants unhappy. They like a certain level of consistency in their day to day schedule. I try to make one or two big adjustments a week, like increasing light % or flood times, and micro manage my PH by raising it a little bit every couple days until I get from 5.5 to somewhere shy of 6.5 by the time I need to change the res. Sometimes it will go from 5.5 to 5.7 to 6 to 6.3, sometimes I'll start around 5.7 leave it for three days, go to 6.2, and end up changing my res on day 7 without another manual bump. The plants don't seem to mind, they stay perky, and that's all that matters.
 
P

phantom grower

Member
Tolerance Break said:
Note, none of this is perfect. My plants don't hit a measured % of dryback before I water again. I'll lift cubes and look at my plants to gage my next adjustment. It doesn't have to be perfect, and chasing perfection by making constant adjustments ends up leaving the plants unhappy. They like a certain level of consistency in their day to day schedule. I try to make one or two big adjustments a week, like increasing light % or flood times, and micro manage my PH by raising it a little bit every couple days until I get from 5.5 to somewhere shy of 6.5 by the time I need to change the res. Sometimes it will go from 5.5 to 5.7 to 6 to 6.3, sometimes I'll start around 5.7 leave it for three days, go to 6.2, and end up changing my res on day 7 without another manual bump. The plants don't seem to mind, they stay perky, and that's all that matters.
Click to expand...
Thank u for taking the time to help! I'm definitely doing too much and not leaving enough time to see if wat I'm doing is making a difference
 
S

Swarog

Member
I only grow rockwool but I'm still learning and in my opinion this is the most annoying stage for plants in rockwool its really easy to over water them and on the flip side they can dry out super quick. Once you they get a bit bigger though it becomes super easy. I have pretty much the same take as Tolerance Break I think you are over watering and should be careful with nutrient levels when they are still so small.
 
P

phantom grower

Member
Tolerance Break said:
Note, none of this is perfect. My plants don't hit a measured % of dryback before I water again. I'll lift cubes and look at my plants to gage my next adjustment. It doesn't have to be perfect, and chasing perfection by making constant adjustments ends up leaving the plants unhappy. They like a certain level of consistency in their day to day schedule. I try to make one or two big adjustments a week, like increasing light % or flood times, and micro manage my PH by raising it a little bit every couple days until I get from 5.5 to somewhere shy of 6.5 by the time I need to change the res. Sometimes it will go from 5.5 to 5.7 to 6 to 6.3, sometimes I'll start around 5.7 leave it for three days, go to 6.2, and end up changing my res on day 7 without another manual bump. The plants don't seem to mind, they stay perky, and that's all that matters.
Click to expand...
Okay so in my situation my cubes will dry out quicker because I don't have them wrapped anymore. This will lead to ppm spikes and salt buildup. I'm planning on letting them dry a little longer than I was previously and this will also come w a buildup, I guess my question would be, are there negatives to watering till runoff everytime I water, which would be every couple days?
 
pegboy

pegboy

Well-Known Member
Theres more going on there than overwatering. I hardly give them any nutes at that age. Back it way off. And as far as overwatering its pretty hard not to at that age. I'm no expert but I pretty much expect my seedlings wil be slightly overwatered until they grow into the cubes. It never concerned me much and its never developed into a long term problem. For me its almost expected.
 
J. Rocket

J. Rocket

Well-Known Member
Bucsfan80 said:
Why use rockwool at all? You have rooters why not just put in hydroton and flood and drain?
Click to expand...
rockwool is super simple...no muss, no fuss, no chasing PH and ppm, and no 30 gallon (or so) res to deal with dumping.
fresh nutes every feeding.
runoff recycles to my outdoor garden.
simplify and enjoy more:peace:

drain to waste rockwool*
 
Last edited:
You must log in or register to reply here.
Top