another newbie to rockwool in need of confidence

hey all! I am looking to go from an all hydroton ebb n flow setup to all rockwool. I had originally planned to just pull the harvested plant stump out of each pot leavin the pebbles for use in the next run... sadly this was blown to bits upon my first harvest. the pebbles are hardly visible through the webbing of roots and recycling all the hydroton just isnt gunna be worth the effort and time. Since the stuff is so heavy and non compressible, disposing of it each run is not a job i want.

so this leads me to rockwool. i want to root clones in rockwool and then pop them into the hugo blocks. these blocks will be compressed and disposed of after each run. The hangup is that I am honestly intimidated to be switching to a never before used media after mastering the hydroton. I have been combing through guides and success stories with rockwool grows via ebb and flow. there were a few but not as many as I was hoping to find.

the setup consists of two 4x4 flood tables per room sharing one 90 gallon rez

My main concerns are as follows

1. nutrient salt buildup
2. oversaturation of the root zone early on even with a brief once daily flood
3.ph fluctuation
4 algae on the blocks and it ending up in my rez

i use the flora nova series with silica, hygrozyme, dutch master zone and have been changing the rez every 2 weeks. is this still a solid lineup when using rockwool?

will i be crazy to change the rez only biweekly when using rockwool?

do i definitely need to flush the system between nute changes?

should i only flood once daily and how far up the tray?


and finally, to lighten the mood a bit, am i overthinking this and just need to get elbow deep into a run or two to feel more at ease?

I appreciate any and all help.

I use hydroton, bought and paid for now reusable forever. I'd hate to have to go buy new media for every run, but I guess if you'd rather buy the blocks then doing a soak and rinse then it's your choice.

I've never ran the blocks but I remember hearing you only flood once a day (only a couple inches high). You can get covers (or make your own out of panda film) to go over the blocks and prevent algae. Good luck.

dude, i suggest that if you want to switch from hydroton, keep the rocks and don't throw them because you will be sorry that you did once you need to go rebuy new hydroton. i am running the same hydroton batch for 10 years now, this is THE best hydroponic medium IMO. all your concerns about rockwool are in place and add to it that you cannot get the same root aeration in RW as in hydroton. cleaning this is not that hard, just remove the entire rootball shake it let the rocks fall off, the ones that remain deep inside can be kept aside for later with the rootball, I don't even empty the entire grow tray, just clean most roots, then flood with high concentration 35% H2O2 food grade, i leave it overnight or more, let it disintegrate the roots, then flush with water i allow the H2O2 to drain through my system and descale everything inside, then grow on. you don't have to be anal about it, you will never be able to remove every bit of roothair and it doesnt present any problems. I remember trying many ways to clean roots including bleach and water, putting in the oven and what else, the best easiest is using H2O2 35% which is magic stuff IMO, during the grow I would add it at 1ml/L or 1/2 that every 2-3 weeks and it keeps my res clean free from slime or larvae even without recirculating my ferts, that is I tried to flood and drain with no overflow returning water and aerating it, and the water remained clean indefinitely. hope this helps...

I'll bite.

1- Yep, nute salt builds up. Are you keeping moms in rockwool?
2- Saturate the roots. I flood 3 times with lights on
3- Remember, you want a PH sweep. Figure out how much time you want to spend chasing it.
4- plastic covers on top of your RW.

tallen said:

I use hydroton, bought and paid for now reusable forever. I'd hate to have to go buy new media for every run, but I guess if you'd rather buy the blocks then doing a soak and rinse then it's your choice.

I've never ran the blocks but I remember hearing you only flood once a day (only a couple inches high). You can get covers (or make your own out of panda film) to go over the blocks and prevent algae. Good luck.

Click to expand...

do you grow in pots of it or a full tray with loose pebbles? the soak and rinse sounds easy enough, i just cant get the damn pebbles out of the very tightly bond root maze. that is my one huge hangup :/

zem said:

dude, i suggest that if you want to switch from hydroton, keep the rocks and don't throw them because you will be sorry that you did once you need to go rebuy new hydroton. i am running the same hydroton batch for 10 years now, this is THE best hydroponic medium IMO. all your concerns about rockwool are in place and add to it that you cannot get the same root aeration in RW as in hydroton. cleaning this is not that hard, just remove the entire rootball shake it let the rocks fall off, the ones that remain deep inside can be kept aside for later with the rootball, I don't even empty the entire grow tray, just clean most roots, then flood with high concentration 35% H2O2 food grade, i leave it overnight or more, let it disintegrate the roots, then flush with water i allow the H2O2 to drain through my system and descale everything inside, then grow on. you don't have to be anal about it, you will never be able to remove every bit of roothair and it doesnt present any problems. I remember trying many ways to clean roots including bleach and water, putting in the oven and what else, the best easiest is using H2O2 35% which is magic stuff IMO, during the grow I would add it at 1ml/L or 1/2 that every 2-3 weeks and it keeps my res clean free from slime or larvae even without recirculating my ferts, that is I tried to flood and drain with no overflow returning water and aerating it, and the water remained clean indefinitely. hope this helps...

Click to expand...

thanks for the responses.

Idk how you are seperating the roots from the hydroton so easily.... the only way i can shake the two apart is if the plant was not given enough time to establish a good root system. the ones that are cling to every pebble tightly and the hydroton is hardly visible through the root mass.

zem, so you just fill the trays with hydroton and the individual plants are vegged in the same room? I should have explained better, i have one veg room and two flower rooms. once the plants are of size, they get moved to a flower room and are immediately flipped. if i had the tray filled with the hydroton, the plants would have very little time to dig their roots into the new real estate.

what amount do you mix for the high concentration H2O2?

i really like your idea of the full tray of loose hydroton, just gotta figure out how i can veg my plants in another room so the monthly harvests are not delayed. any ideas?

hydrohomer said:

I'll bite.

1- Yep, nute salt builds up. Are you keeping moms in rockwool?
2- Saturate the roots. I flood 3 times with lights on
3- Remember, you want a PH sweep. Figure out how much time you want to spend chasing it.
4- plastic covers on top of your RW.

Click to expand...

i could keep mothers in whatever media I want. Guessing the rockwool isnt best for long term growth so probably keep them in a separate flood table potted in hydroton or soil.

not sure what you mean by ph sweep? as of right now i dont chase the ph. just initial nute mix and it stays between 6 and 7 no prob. is ph chasing more common when using rockwool?

flooding three times a day with rockwool seems a bit high, even with hydroton 3 times tends to be plenty in my experiences. do you flood less at first and more as the root systems start cranking and sucking up much more water?

Yeah I grow in 6" pots. I pull everything out by the plant base and bang the rootball a few times on the side of the plastic tub I'm going to use to soak the hydroton in. Once they stop coming out easy I take the rootball in my hands and just twist and rub and pull and get it all separated, it's really not that hard if your not afraid to really get in there and get it done. (and really this is all the work you have to do!)

Once I've got all the hydroton and rootballs separated I just fill the tub with water and a shot of bleach (sometimes some hygrozyme) and stir it up with my hand and get any big chunks out and put a lid on it till I'm ready to use it. Easy as that. If it's sitting for long periods I'll open it on occasion and throw another shot of bleach in it. I just make sure I rinse it real well to get the bleach off it when I'm ready to use it.

I've tried several ways and this one is by far the easiest for me, and as Zem said, you don't have to worry about gettin every little piece of root out, just get the majority (the bigger stuff) and you'll be fine.

Myles I go first in small rockwool cubes then into 1 liter pots with hydroton till flowering then I put in flowering tray by a normal transplanting. filling the entire tray offers some advantages like more root volume and no need for tray cover or pots.

tallen said:

Yeah I grow in 6" pots. I pull everything out by the plant base and bang the rootball a few times on the side of the plastic tub I'm going to use to soak the hydroton in. Once they stop coming out easy I take the rootball in my hands and just twist and rub and pull and get it all separated, it's really not that hard if your not afraid to really get in there and get it done. (and really this is all the work you have to do!)

Once I've got all the hydroton and rootballs separated I just fill the tub with water and a shot of bleach (sometimes some hygrozyme) and stir it up with my hand and get any big chunks out and put a lid on it till I'm ready to use it. Easy as that. If it's sitting for long periods I'll open it on occasion and throw another shot of bleach in it. I just make sure I rinse it real well to get the bleach off it when I'm ready to use it.

I've tried several ways and this one is by far the easiest for me, and as Zem said, you don't have to worry about gettin every little piece of root out, just get the majority (the bigger stuff) and you'll be fine.

Click to expand...

so unlike zam, you just grow em in pots in an otherwise empty tray? this is how i have done my first few runs.

zem said:

Myles I go first in small rockwool cubes then into 1 liter pots with hydroton till flowering then I put in flowering tray by a normal transplanting. filling the entire tray offers some advantages like more root volume and no need for tray cover or pots.

Click to expand...

so planting em in the tray of hydroton at start of flowering works well without them getting time to sink roots first? Thats real great news. I've been using 5.5 inch square pots for all my plants.

Do you have any pics of your transfering process? Im gunna go take a look at all the material you have posted

and what was the dose for the h2o2 soak?b i have a bottle of the 35% already in my pile of gear

Myles117 said:

so unlike zam, you just grow em in pots in an otherwise empty tray? this is how i have done my first few runs.

Click to expand...

yes, 6" pots from start to finish. I have panda film stretched over the flower trays though so the roots can spread and stay healthy. I just cut holes in it for the pots and give it a quick wipe down at the end of a run and reuse it for the next run. By the end of flower there is a mass of roots across the whole bottom of the tray.

would you mind snapping a picture of the tray with the covering? sounds like a great idea, just not sure how id do it when moving 16 plants from a veg room to the flower room when they are a bit chubby and ready to go.

cheerd

I'm not comfortable posting pics but I can explain it to you. Stretch to panda across the tray and hold it in place using squeeze clamps or whatever works. Figure out how you want your spacing and take an empty pot and a sharpie and trace around the bottom of the empty pot (the hole will be slightly smaller than where it will rest on the pot but that is good). Then just cut out the holes with a razor knife or a pair of scissors. Then when it's time to transfer just drop the pots with the plants in the holes and pull up on the panda a little and it will be nice and snug-the pots will then hold the panda in place (still use the squeeze clamps to hold the edges though).

Doing it this way I no longer have to worry about algae or debris falling in the tray as no light ever hits the water and the panda film catches any falling debris. Also, it reflects any light that gets through right back up to the plants

Edit- I just wanted to give credit to who I learned this trick from since I did not come up with it myself. A member named Panhead had a thread a while back that explained it. I just copied it and it works awesome.

Myles117 said:

so unlike zam, you just grow em in pots in an otherwise empty tray? this is how i have done my first few runs.



so planting em in the tray of hydroton at start of flowering works well without them getting time to sink roots first? Thats real great news. I've been using 5.5 inch square pots for all my plants.

Do you have any pics of your transfering process? Im gunna go take a look at all the material you have posted

and what was the dose for the h2o2 soak?b i have a bottle of the 35% already in my pile of gear

Click to expand...

I would usually give the plants 3-4 days of 24/24 light just after transplanting to allow for more root growth in the new tray. one could however, just use 1-2 liter netpots. filling the entire tray with hydroton allows me to skip having a lid and pots and also gives more root volume.
make sure that your H2O2 is food grade and not with stabilizers or anything. I use H2O2 in the range of 0.5-1 ml/L in the feeding and go much much higher in concentration like 4-5x when I am cleaning hydroton between grows

tallen said:

I'm not comfortable posting pics but I can explain it to you. Stretch to panda across the tray and hold it in place using squeeze clamps or whatever works. Figure out how you want your spacing and take an empty pot and a sharpie and trace around the bottom of the empty pot (the hole will be slightly smaller than where it will rest on the pot but that is good). Then just cut out the holes with a razor knife or a pair of scissors. Then when it's time to transfer just drop the pots with the plants in the holes and pull up on the panda a little and it will be nice and snug-the pots will then hold the panda in place (still use the squeeze clamps to hold the edges though).

Doing it this way I no longer have to worry about algae or debris falling in the tray as no light ever hits the water and the panda film catches any falling debris. Also, it reflects any light that gets through right back up to the plants

Edit- I just wanted to give credit to who I learned this trick from since I did not come up with it myself. A member named Panhead had a thread a while back that explained it. I just copied it and it works awesome.

Click to expand...

i understand your choice, no worries.

i now know just what you mean and it sounds like a great concept. even if i end up doing the tray full of loose hydroton, the sheet over it would eliminate much of the gunky buildup and if just going with pots, the exposed roots wont look like a worm stranded on the sidewalk in august

do you swap our your nutes weekly/biweekly? and do you use a sterilizing product or active cultures to keep problem free conditions?

zem said:

I would usually give the plants 3-4 days of 24/24 light just after transplanting to allow for more root growth in the new tray. one could however, just use 1-2 liter netpots. filling the entire tray with hydroton allows me to skip having a lid and pots and also gives more root volume.
make sure that your H2O2 is food grade and not with stabilizers or anything. I use H2O2 in the range of 0.5-1 ml/L in the feeding and go much much higher in concentration like 4-5x when I am cleaning hydroton between grows

Click to expand...

yeah i got this gallon just for adding to my rez previous to switching to dutch master zone. its food grade.

btw have you ever gotten any of it on ur skin without paying attention? dopey me, turned my skin white and burned quite a bit. wont make that mistake again lol

so 5 ml/l is plenty? since you do this in the same tray, do you just run your pump constantly so it is always flooding and draining via the overflow?

finally, with a tray full of hydroton, how often do you flood your tray during flower? I was doing 3-4 floods a day during lights on when growing in pots. curious if the full tray retains moisture saving me a flood or two a day.

cheers to both of ya, doing a good job bolstering my wavering confidence in hydroton in a large garden.

Myles117 said:

i understand your choice, no worries.

i now know just what you mean and it sounds like a great concept. even if i end up doing the tray full of loose hydroton, the sheet over it would eliminate much of the gunky buildup and if just going with pots, the exposed roots wont look like a worm stranded on the sidewalk in august

do you swap our your nutes weekly/biweekly? and do you use a sterilizing product or active cultures to keep problem free conditions?

Click to expand...

I change the rez every 2 weeks. In between I go by ppm's as to whether to top off with straight water or nutes. I run beneficial bacteria instead of a sterile res, but it works either way, that's just my preference. I flood every 2 hours lights on and once halfway through lights out just to make sure the roots don't dry out. I've got new timers on the way and am going to experiment with flooding every hour.

Myles117 said:

i understand your choice, no worries.

i now know just what you mean and it sounds like a great concept. even if i end up doing the tray full of loose hydroton, the sheet over it would eliminate much of the gunky buildup and if just going with pots, the exposed roots wont look like a worm stranded on the sidewalk in august

do you swap our your nutes weekly/biweekly? and do you use a sterilizing product or active cultures to keep problem free conditions?



yeah i got this gallon just for adding to my rez previous to switching to dutch master zone. its food grade.

btw have you ever gotten any of it on ur skin without paying attention? dopey me, turned my skin white and burned quite a bit. wont make that mistake again lol

so 5 ml/l is plenty? since you do this in the same tray, do you just run your pump constantly so it is always flooding and draining via the overflow?

finally, with a tray full of hydroton, how often do you flood your tray during flower? I was doing 3-4 floods a day during lights on when growing in pots. curious if the full tray retains moisture saving me a flood or two a day.

cheers to both of ya, doing a good job bolstering my wavering confidence in hydroton in a large garden.

Click to expand...

not 5ml/L, 0.5ml/L or 1/2ml/L. yes i got some on my skin it's nasty, actually i had a stupid worker once who thought its water and used it to wash off paint from his hands, i saw him jumping up and down like crazy from itching LMAO
I used to do few floods, fact is you can flood very few times maybe even once if you only want them to survive, but I have seen better results using more floods. why would you want to "save" yourself a flooding? is it not done by a timer? the cost of flooding is very minimal. I flood every 2 hours when lights on and do a flood in mid of dark period then a flood just before lights on, total 8x/24hr

but you had said 4-5 times that dose to zap the crap between runs. That is what i was referring to with the 5 ml/l

and i guess just to save the pumps to last a bit longer over their lives. maybe thats overthinking things? lol

im always paranoid about pump failures, so much so that i was pondering having two pumps per tray just in case one fails. i only check in every other day.

lucky your coworker was washing off paint and didnt take a swig youch

so i think imma do a side by side test my next run. one 4 x4 tray with hugo blocks and a drip feed and the other 4 x 4 with all rockwool not sure if imma go with just pots or full tray but if i fall on my face with the blocks ill let ya both know how right you were kiss-ass lmao. cant say how thankful i am to have received the words of wisdom. imma soil grower at heart trying to change my stripes