Rockwool to hydrorocks, drip system question

I have seeds germinating in rockwoolcubes.

They will be transplanted to a hydrorock box. Im using a dripper system for watering them.
My question is should I insert my drip lines to the cubes and make the watering cycle so the cubes get almost dry and then again hydrate them, or should I enter the driplines to the hydro rocks and continously pump water?

the rock wool cubes are 2,5x2,5 and the hydrorock box will be 55liter tray. I tried searching all over the web but couldnt find a similar system using dripfeed.

The danger is when the rockwool stays damp for too long. I've had much better results when putting the drippers down in the pebbles where it won't keep the rockwool damp. I quit using rockwool and use aerocloners, then transplant directly to clay pebbles. When you go this route, the dripper goes where it will keep the stem dry. That's it.

Douglas.Curtis said:

The danger is when the rockwool stays damp for too long. I've had much better results when putting the drippers down in the pebbles where it won't keep the rockwool damp. I quit using rockwool and use aerocloners, then transplant directly to clay pebbles. When you go this route, the dripper goes where it will keep the stem dry. That's it.

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So when the roots are long enough can i let the rockwool dry and just feed through the pebbless?

Just drip into the pepples, so the RW cube don't get a direct hit.

I grow in clay pepples, and root in RW cubes.

Palindrome said:

Just drip into the pepples, so the RW cube don't get a direct hit.

I grow in clay pepples, and root in RW cubes.

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This works, yes. Once the roots are long enough you can simply keep the pebbles below the cube wet during feedings.

i used to try a combo of rocks with a rockwool cube.
if you water to keep the rocks at the perfect rate, the rockwool is too wet.
if you water for the rockwool, the rocks are too dry.
so in the end i eliminated using rockwool, just transplant straight into rocks.
why bother doing something that just wont quite work ideally?
You can get it to work ok though.

jack hairy said:

i used to try a combo of rocks with a rockwool cube.
if you water to keep the rocks at the perfect rate, the rockwool is too wet.
if you water for the rockwool, the rocks are too dry.
so in the end i eliminated using rockwool, just transplant straight into rocks.
why bother doing something that just wont quite work ideally?
You can get it to work ok though.

Click to expand...

Last time I did hydro was on a bubbler system like 10 years ago And the setup worked fine. But yeah Ill root em up good And go For the pebbles.

Thank you all for very helpful replies. Peace And love

I too use aero/bubble cloners and go straight to pebbles or DWC. Rockwool is itchy and needs proper drainage. I'm sure you'll do fine this time around as well.

Welcome to ICMag!!

Been reading up and seems like I should just transplant into bigger rockwool cubes, because the setup will be too complicated on the irrigation part.

If I go for the 6inch cubes, should they just sit on the tray or can i put 40liters of pebbles under them for more root space?

I would run the dripper according to the needs of the rockwool so the pebbles would be dry propably most of the time. (I'm guessing)

I got 10 plants with 1200w SPNA if that makes any difference.

Rockwool cubes in hydroton/clay pepples/grow rocks is super simple to irrigate.

Just transplanted, so got a bunch of pic's that might give you some inspiration to how simlpe it can be done.


Rooted clones being transplanted, it's fast and easy.^^


Placed on a flat drain table, with a felt mat to hep even drainage.


home made drip rings, pump set to a timer makes sure they are kept fed and wet.

IMO it dosn't get much more simple, and hard to impossible to overwater. My last flowering, I ran the pumps 24/7 to see how it would handle "NFT"

yeah, 1 inch cubes pose no real problem when transplanting into rocks,
but try putting a 4" cube in a 5 gallon bucket of rocks and then you will see the incompatability.

Hydronewbie said:

Been reading up and seems like I should just transplant into bigger rockwool cubes, because the setup will be too complicated on the irrigation part.

If I go for the 6inch cubes, should they just sit on the tray or can i put 40liters of pebbles under them for more root space?

I would run the dripper according to the needs of the rockwool so the pebbles would be dry propably most of the time. (I'm guessing)

I got 10 plants with 1200w SPNA if that makes any difference.

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I have set my hugos on top of four inches of hydroton, in 3 gallon maxipots. The hydroton wicks the water out of the hugo. If I were you I'd consider using dripperless lines; open-ended so the liquid all just flows out over a couple minutes or so. You calculate out how long to have your pump run to get anywhere from 16 to 32 oz or more per site per 3 minutes on time. Continuous dripping is of no benefit; the block needs drier times in between feedings.

Hit the top of the block; you want to make sure it soaks. It will drain with the rocks underneath it wicking away the extra.

The most important factors when using the 6 inch hugo blocks are making sure to flush them well at 5.5 ph first, and to make sure they drain properly after each watering. After the first ten days when roots are established the plant itself will drain the hugo really well twice a day or so.

If you just set a hugo block on a tray and water it, it will not drain off properly. Being too saturated will impede root growth. Do a quick search here for 'hugo' and read up on the particulars. Seriously. You don't want to just wing it with the hugo blocks.

It is absolutely crucial to not overwater in the first ten days or so after transplanting into the block. To avoid this, do a thorough flush (seriously, like 2 gallons through the top of the block at least) to lower the ph, and then lift up the block and turn it so it is corner-pointing-down. It will drain much faster this way. You can use an empty 5 inch pot as a support for doing this.

Grodan claims that there is no reason to flush the blocks anymore due to a new manufacturing process. Bullshit. Flush well and check the runoff ph. It will initially be in the 7.5 ph range and slowly come down. They also say to just soak the block at 5.5 ph for a half hour. Again, bullshit. Flush it, don't soak it. Amount of liquid run through the block isn't an issue because you drain it off at the end anyway before transplanting. Use ph adjusted water initially, but finish the flush with ph adjusted nutrients so the block has them available for the plant.

Once you transplant and set the hugo on top of the hydroton it will drain really well as long as the pot isn't sitting in a pool of liquid. It definitely needs to drain away. For DTW like I am doing I shoot for about 10% to 15% runoff.

Read that hugo thread. Those guys know all of the details.

A quick update: the runoff ph has finally settled at around 6, which is perfect. I feed at 5.7 so the entire block is within in the right ph range now. Took a while of watering at 5.4 to bring it down. Plants are going ape shit, roots are coming out the block sides and bottom. Nice!

I agree with Palindrome.

My drippers are 2" distant to RW cube. Watering allday.







approx 12 days after repot in clay pebbles:

There are huge huge Grodan blocks (55x37x17cm). Regular delta (plus?) RW can hold too much water - this stuff is worse. About 2yrs ago I restarted growing and purchased 4 of this blocks ($180 aud total). Normally, two are leaned together and nutrient is dripped in, the nutrient has to be drip drip dripped in SLOWLY or intermittent 1,2,3 cup waterings BECAUSE this block holds 20 LITRES OF WATER eaeaseaeaeasillllllly. Small plant big pot horror. 4 grows later i got a 3cm slice and incorporated it as a layer within Expanded Clay balls - established plants' roots only just made it through - the water supplied is bubbling with air too.

I've just had success cutting this very heavy Grodan rockwool into 3x3cm cubes putting into pots with lots of air gaps and handwatering 100 food with no runoff ! Well, they got a bit overfed so I watered with pH2O and 20ml from the 50ml total runoff. pH was over 7 so I watered with pH2O tinee runoff - any substantial runoff will super soak that RW fool ! something Grodan never addresses when they say 10%+ runoff. Anyway, cubes and hand watering, was easy...... and the RW was reused from my failed earlier crop with the stuff 2 years ago. Chow for now. If you want photos I can provide

Sitting RW block on top of Balls in a plastic pot works but they can't be bumped or you need to secure them to start with. I just started hand watering this setup with the pots in plastic bags - it works for the start. When it comes time to watering, continous for me, I find the RW still gets too wet but not to any effect. IF YOU SUBMERGE the RW into the BALLS it will be supersoaked all the time - the suggestion above of just watering the balls beneath is a good one. Thanks.

This is all RW. Different from the above photos RW on Balls. See the rot in the middle - that happened earlier - surprised the plant produced. The right side worked (cbd hash plant cbd crew x 2)

Dr Watt said:

Sitting RW block on top of Balls in a plastic pot works but they can't be bumped or you need to secure them to start with. I just started hand watering this setup with the pots in plastic bags - it works for the start. When it comes time to watering, continous for me, I find the RW still gets too wet but not to any effect. IF YOU SUBMERGE the RW into the BALLS it will be supersoaked all the time - the suggestion above of just watering the balls beneath is a good one. Thanks.

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Grodan strongly discourages constant feed with rockwool. The rockwool and roots need to become semi-dry regularly for the roots to expand properly. Have you read grodan's info from their site? Read the one about water first. They really cover all aspects of how to use rockwool to your biggest advantage. Rockwool is definitely not something you should just wing it with. Not that you are; just sayin'.

I'm at about two weeks after the transplant now and my hugo blocks are draining just fine over hydroton. It wicks the excess right out of there. I put extra grodan about an inch up the sides of the blocks and everything's pretty damned stable for now. The roots are bright white and already coming out the sides and bottom. I will be getting a screen in there this week to further steady the plants.

I went from hand watering 16 oz every 3 days or so at transplant to the current daily 24 ounces; they are sucking it up now and growing like a mofo and I'm flipping them in a couple days. PH has finally stabilized. I expect to be watering 32 oz twice a day by week 3 of flower. DTW for me.

I use an enzymatic cleanser called Z7 to keep the root rot away. I haven't had root rot for years since I started using it. Cheap and 100 percent effective.

I knew not constantly wetting Grodan was the key. I did go to the Grodan site 'bout 6mths ago but I smoke so much weed I miss a lot - all I figured was that their claim of 10% runoff had hairs on it for small plants - I just grew ok with NO RUNOFF ka ching (edit:with larger plants) !!

If you do a very slow drip (hard to do in practice) then continous feed is okay - check the grodan site ! (sorry pal)

I had great success with Sm Cubes on 7.5x7.5 then a Hugo with intermittent watering (3) for 15 crops in 2005. I thought I could grow - i couldn't.

The only technique frostqueen excellent excellent advice hasn't mentioned, and a technique that worked first for me in 1991 and then at various times subsequently, is to :

"flush" the RW Grodan and THEN draw out the exess water with a pippette to perfection levels

Do this every 3 days for tiny plants and you just can't miss BIG EDIT > OR 3 TIMES A DAY COS YOU CAN'T LOSE

ps 16fluidoz=1/2 litre (5x100ml), a Cup is 250ml; fluid ounce = liquor shot (30ml). So 30ml, 250ml, 500ml, 1000ml. 1ml you can do too !!!!!

Duplicate post of above. I really do smoke too much