Experienced with hydroton, but rockwool has me stumped

[Hackk]

So for years now I've been growing with hydroton only. Well, this last cycle, I made the decision to try out RW blocks for my veg and flower cycles. I use trays for veg under T5's, then transfer to ebb n gro buckets for flower, and I use root riot plugs for cloning. (I use root riots over rw cubes because I tried using rw starters with this strain a long time ago, and they didnt root at all, and just acted weird. Thats why I chose to use riots, and also a reason why I chose to use hydroton over RW for veg and flower)...

Well hydroton as we all know is a hassle, a mess, and overall bitch to work with, so thats why I wanted to give RW blocks a try again. If the RW works out, I also plan to start running trays for flower as well.

Now here is my problem running rockwool (and also the problem of a friend running my strain as well, also giving RW a try after running DWC), they just look like crap! I am running the same nute mix I have for years, dropped from 4 feedings down to 2, then finally to 1 a day since the blocks hold more water, Ph went from 6.2-5, down to 5.7-9 and other than that, nothing else has changed. I am at almost 50 days of vegging to get to the same height and strength I would have gotten to in 25 days using hydroton. They are drinking barely anything, what would have been 1/2-1 gallon a day of rez water, is now a gallon a week. PH is barely fluctuating, same with PPMs. Its like the roots just HATE rockwool.

Am I/are we doing something wrong? I mean seriously, RW shouldnt be this disappointing, right? My friend and I are both experiencing the same problems, yet its the same strain I've had for years, and I know her like the back of my hand, and I've never seen her act this before. Can a strain hate rockwool? Can rockwool hate me?

P.S. just in case it gets down to microscopic details, we both are running Pargro brand rockwool compared to Grodan.

 

[Hackk]

nothing? Am I just so noob, I dont even deserve a response lol?

 

[BadRabbit]

So for years now I've been growing with hydroton only. Well, this last cycle, I made the decision to try out RW blocks for my veg and flower cycles. I use trays for veg under T5's, then transfer to ebb n gro buckets for flower, and I use root riot plugs for cloning. (I use root riots over rw cubes because I tried using rw starters with this strain a long time ago, and they didnt root at all, and just acted weird. Thats why I chose to use riots, and also a reason why I chose to use hydroton over RW for veg and flower)...

Well hydroton as we all know is a hassle, a mess, and overall bitch to work with, so thats why I wanted to give RW blocks a try again. If the RW works out, I also plan to start running trays for flower as well.

Now here is my problem running rockwool (and also the problem of a friend running my strain as well, also giving RW a try after running DWC), they just look like crap! I am running the same nute mix I have for years, dropped from 4 feedings down to 2, then finally to 1 a day since the blocks hold more water, Ph went from 6.2-5, down to 5.7-9 and other than that, nothing else has changed. I am at almost 50 days of vegging to get to the same height and strength I would have gotten to in 25 days using hydroton. They are drinking barely anything, what would have been 1/2-1 gallon a day of rez water, is now a gallon a week. PH is barely fluctuating, same with PPMs. Its like the roots just HATE rockwool.

Am I/are we doing something wrong? I mean seriously, RW shouldnt be this disappointing, right? My friend and I are both experiencing the same problems, yet its the same strain I've had for years, and I know her like the back of my hand, and I've never seen her act this before. Can a strain hate rockwool? Can rockwool hate me?

P.S. just in case it gets down to microscopic details, we both are running Pargro brand rockwool compared to Grodan.

Can't really sort out all of what's going on there, but I doubt RW has much of anything to do with it ... really, a million or so growers use it with great results, including me for over 8 years now. And in side by side comparisons, it has tended to perform better than pebbles.

Maybe your light needs changing, or some other issue .. virus? But yeh, weed will grow like gangbusters in RW ... there's something else going on.

You may want to try the small RW cubes, that's what I use ... they work just like the clay pebbles but retain moisture and nutrients better and you can just toss them out at the end.

 

[Hackk]

Thanks for responding rabbit...

Thats the thing that tripping me out. I KNOW that people have great success with RW, and thats why Im trying to use it again. I've been running the same strain for a long time now, and I know her very very well. She does great in hydroton, and the times I've tried using RW, it was a complete failure and the roots just hated it. I dont feel its a virus, and I honestly dont think Im making any mistakes (because my friend is getting the same results with his own method, which is different from mine). Im not a stupid grower, and I have everything pretty dialed in. Its just rockwool that kills me. For a neutral grow media, why have I always experienced so many problems?

I guess I need to rephrase my original question: For all of you that have used hydroton and switched to rockwool blocks, what techniques did you need to adapt? What changed, and did you first experience a stunting in all aspects of growth, and how did you overcome that?

 

[rocket high]

Ive also grown with rock-wool for years.
Did you condition the rock-wool to start off ... soak for 24 hrs in plain PH'd water .... its also a good idea to flush the rock-wool once a week with plain ph'd water as the salts build up quite easily and can cause serious problems ... the way to check is to get a syringe and draw water from the rock-wool but dont poke it to the rock-wool just gently press against it then put it in a jug and put your ec meter into it and see what the reading is ... in the past some of my readings have been off the scale that was before i knew to flush them every week ... if that comes back sound then i havent got the answer ... sorry .

Rock-wool is an amazing media once you get the hang of it . good luck.

 

[ilovenuggs]

I just switched over to the 4in cubes and am running a drain to waste system. I think that DTW is the way to go with rockwool.

They get one minute of feeding every 4 hours with GH nutes. I am generally running a (RO) mixture with an ec around .8 and a ph between 5.9 and 6.1 depending on how far along they are.

The 1.5 to 2ft plants are typically getting about 250ml of solution every 4 hours. Anything larger gets double. I have found no problems with salt buildup as it seems that the plants kick unwanted nutrients straight down the drain.

I would not bother with a recirculating system incorporating rockwool. This seems to create problems for most people.

So far everything is working awesome for me and I would encourage this type of setup to anyone. Good luck with your grow.

 

[Hackk]

Rocket, I did presoak, so I dont think thats the problem. I really want to make this a success so that I can move away from that annoying hydroton. But like I said, the plants are healthy, they just are growing at about 50% the rate of hydroton. The same goes for the amount of water drank, and ppm and ph fluctuations, it barely moves, it barely drinks, and it barely grows...

Is one watering a day too much or too little or just right? Im afraid I may not be getting any O2 to the roots...

 

[Hackk]

and everyone, I know this is a basic growing topic, and has been addressed a billion times. I have read them all, I know what Im doing, I just cant figure out the single variable thats causing me the problems... again, all I changed was from hydroton to rockwool, from a ph of ~6.3, down to ~5.7 for veg, and less feedings through the day. Everything else, nutes, lights, and environment has remained the same

 

[onetime64]

my 2 cents is its all about PH with the WOOL ...... one bad ph can be a nightmare

 

[Hackk]

onetime, I agree with you 100%! My first mistake that I'll admit to was originally keeping the ph at ~6.2 like it was with my hydroton. After I started seeing problems, I dropped it to 5.5 and slowly raised it from there until I saw the problems disappear. So now it sits between 5.7-5.9, but I still feel that regardless of the PH, my plants just DO NOT like RW...

 

[rocket high]

YOUR right onetime the ph is one to keep an eye on as it can fluctuate dramaticly like mines is doing right now .. it rises over night then i put it down and the same happens everyday this didnt happen with the last grow ... i think its because ive changed nutes and the buffering isnt as good with the stuff ive changed too.

 

[!!!]

bring the pH down to 5.2 and try to keep it there. You might just be overwatering, or overwatered in the past and the plants paid for it with a weak stunted root mass. Hydroton exposes roots to A LOT of oxygen, something you might have deprived your RW roots of if you overwatered even only a few times.

I say wait for the cube to be very light before watering again, to let roots go out to search for water. Do you have roots coming out the bottom of the cube?

How did you pre-soak? The little cubes require only 5-10 mins of soaking but the big ones require a lot more (as stated in replies above.)

Did you by any chance wring water out of the cubes or squeeze them to get excess water out? If you squeezed the bottom of the cubes too much to remove excess water (i.e., after a presoak) you may have messed up the composition of the cubes and their capillary action in uptaking nutes/water. algae growing on the cubes may also cause problems.

what are you feeding?

How do the plants "look like they don't like RW"? yellowing leaves? burns? spotting? wilting? it matters..

why the switch to RW anyway? hydroton is cheaper and re-usable. If you like hydroton maybe give rockshale a try.. it's fantastic and doesn't roll around all over your house like hydroton.

 

[Hackk]

bring the pH down to 5.2 and try to keep it there. You might just be overwatering, or overwatered in the past and the plants paid for it with a weak stunted root mass. Hydroton exposes roots to A LOT of oxygen, something you might have deprived your RW roots of if you overwatered even only a few times.

I say wait for the cube to be very light before watering again, to let roots go out to search for water. Do you have roots coming out the bottom of the cube?

How did you pre-soak? The little cubes require only 5-10 mins of soaking but the big ones require a lot more (as stated in replies above.)

Did you by any chance wring water out of the cubes or squeeze them to get excess water out? If you squeezed the bottom of the cubes too much to remove excess water (i.e., after a presoak) you may have messed up the composition of the cubes and their capillary action in uptaking nutes/water. algae growing on the cubes may also cause problems.

what are you feeding?

How do the plants "look like they don't like RW"? yellowing leaves? burns? spotting? wilting? it matters..

why the switch to RW anyway? hydroton is cheaper and re-usable. If you like hydroton maybe give rockshale a try.. it's fantastic and doesn't roll around all over your house like hydroton.

Wow !!!, a lot of great advice there. Let me address each of your questions. But first, after reading your post I finally decided to lift up the blocks after a month and half to see if there are roots, and there are NONE... so here goes

You are probably correct about over watering in the beginning and stunting them early on. I went from 4 feedings a day with hydroton down to 2 with rochwool figuring that would be good, but it wasnt. I then dropped it to once a day thinking that would work better, but after lifting it up just now, it is very heavy, and there are NO roots showing, which obviously shows I have a problem. So I'll give it a few days to dry... how many feedings and how often would you recommend?

I presoaked for a little over 24 hours in 5.3-5.5 water in a clean bathtub. I didnt squeeze the cubes, I simply "flicked or bounced" them to remove excess water, so I dont believe that is the problem. I do have a bit of algae growth that took place before I had a chance to put covers over the blocks, now the little bit that remains is purely on the upper rim of the block where some light creeps in under the covers...

I am feeding with a hybrid of basic lucas, fulmag, silica, and roots excelerator. with ppms ranging between 700-1000 on a .7 conversion

I say they dont look healthy for a few reasons. Yellowing, dying lower to mid foliage, slow growth, and slight spotting. Most of the problems were when I had the PH too high, since I lowered it, the leaves have come back to life, the plant looks decent, but is still extremely stunted. When I would be getting around 1-2 inches of growth a day with hydroton, Im getting MAYBE a centimeter now with RW.

and finally, I wanted to use RW for a few reasons actually... First, I recently had some shoulder injuries, and the hydroton is heavy, and a trouble to work with. I also wanted to try to run tables vs pots, and I know that RW is a sure bet if youre running tables. And I dont have the method or space for cleaning hydroton, so its dumped every cycle, and thats just a huge waste, and its actually cheaper for me to buy RW at my local shop for some reason. The Pargro brand is almost half the price of grodan, so that probably why I saved money.

After all of this is coming together, and what you pointed out, Im really leaning towards the fact that its over watering. I have unplugged my timer, and Im gonna give it a few days and see what happens. But the fact that NO roots are popping out in almost two months, that is not a good thing...

and one last thing, you say to drop it to 5.2 and keep it there... Obviously Im not expert on the use of RW, but that ph seems extremely low. If I did a proper presoak, I cant imagine needing to drop it that low, am I correct?

 

[Work2much]

I think you guys nailed it: overwatering. You should have had roots busting out the bottom of those cubes after one week but it takes a dryer medium for that to happen but when it does you can then work your way up in feedings.

IMO overall results are better in hydroton, even considering the need to wash between cycles. A couple hours of extra work for a medium that gets more air to the roots, can drink more water and be fed more eveyday is worth it.

 

[Indonesia]

definately over-watering- rockwool should be treated much like soil, only watered when the rockwool is light from being dry. a plant wont grow roots and shoots very fast if the roots aren't getting oxygen. like soil, the ratio of root volume to cube volume will affect the irrigation frequency.
If you use a big cube for a little plant, it could take days, maybe even a week, for the roots to drink the solution in the big cube. better to use a smaller cube until bunch of roots pop out, then transfer small cube filled with healthy roots to a perfectly hydrated cube(not soaked-use throwing motion to drain water from a cube). then wait till the big cube feels light before watering again. Indo uses 2 inch cubes for seeds and clones, and would transfer to 4-6inch cube when roots have filled the 2inch cube.

peace

 

[Hackk]

Thanks, but we're talking about RW blocks, not starters...

So let me ask the final question, what the hell do YOU guys do for watering the 5x5 blocks? I mean, that stuff stay wet forever! Do I water once a week, twice a week, twice a month, what do you guys do?

 

[gmanwho]

learning the watering cycle with rockwool can be rough. they hold alot of water. an if they dont dry out some your temps in the rockwool will be to cold for roots .especially depending on your room temps. this could be why you are experiencing slow growth.

Bwell

 

[Indonesia]

for watering a 5x5 block- for maximum growth rate, only water when the rockwool is not soaked(like a pot of soil, you dont water if the soil is already soaked), the frequency is determined by size of plant and how fast the plant is growing. for a smaller plant with a small root mass in a big block, top water each individual block,or use drippers attached to a pump. water until there is a little runoff, then wait until the rockwool is lighter until you do it again. once you have a big plant for the 5x5 cube, you can water several times a day, flood and drain style. indo suggests you wait to flood until the plants can drink up all the water in the cube at least once in a day.Indo has seen really big plants in 4x4 blocks that could handle being flooded once every 2 hours(with a really low flood level, had to topwater to flush every once in a while).that means that the plant could use up the water in the cube every 2 hours!

peace

 

[Scrogerman]

Try NFT, works perfectly with RW Blocks, very simple to run. In NFT the Blocks stay WET 24/7, constant solution movement/flow keeps solution & roots oxygenated(constant 2mm Film of nute solution), heater in Res keeps solution at the right Temp which is paramount. I dont like seeing 4" or 5" RW cubes used in E&F, often see problems for some reason, i think the small 1/2" cubes like 'cellmax' etc are the way to go with E&F in pots if you have to use RW.
If RW can freely drain it will hold the perfect water to air ratio, one reason why its been so popular in large commercial farms for years. as far as i know RW Blocks are designed to be run in NFT, Fibre orientation(within the Block) could be an issue with trying E&F with the Big Cubes/Blocks, not sure on that one!
Like has been pointed out, RW needs to be leached to remove unwanted salt build-up/accumilation, fortnightly is as far as id let it go before a clean/leach-out. stays perfect!(one of the few Con's to using RW)
I luv RW, its easy as piss to use, but i think which Nutes you use, or Brands of are very important, have you tried using a different brand! more likely the brand of blocks your using as apposed to your plants not liking RW, i very much doubt that indeed!
Ive never heard of the brand of RW your using either, never had a problem with Grodan.
Try a simple NFT 205 tank or whatever size you want 424 etc & Run Ionic Nutes or something simple, never had a problem with it. hang in there & dont give up, once you get it worked out RW can be rewarding.

(pictured)
simple NFT 424 (aka TurboTank in the US) running 8 x 5" RW cubes(ScrOG), circulating 24/7, the cubes never dry out & are always heavy, also, running Ionic(Veg) & VitaLinkMax(Bloom) Nutes. barely any maintainance, was a success as usual! PH 5.5 - 6.0 start to finish.



Photo's of your Rig n stuff may help. Did you manage to get to grips with RW after? NFT
PM me if you want Hack!
Good Luck with it!

 

[NoTdanNeeDe]

when the roots grow out of the rock wool block do you have to water when the roots start to dry or when the block gets dry? or will they both dry at the same rate?