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Rockwool
- Thread starter Sativan
- Start date
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bigganjabud
I used to be great at popping beans now not so much and tbh I ain't changed my
Rockwool is an interesting medium. It has great water retention and the same aeration. Roots love it, when used properly.
A lot of people have issues with it as clones or transplants because of the high levels of lye in fresh rockwool. It causes extreme rises in ph if not properly leached, and ph stabilized. Prepping before using is to run 5.0 water until the ph rises to 6, drain, resurate at 6 again until stabile. Drain the cubes to near dry by stacking 4-6 high. Capillary action will pull the moisture from the top cubes to the bottom. Take the soaked bottom cube and put it up top. Let it drain. Take all the bottom cubes and stack them in each other and wick them out until you only have 1 soaked cube. Transplant, and feed 6.0 400-600ppm of actual base fert.
Rockwool needs bigger rockwool or hydroton (expended clay pellets or other sterile substrate to help with plant retention and to help wick moisture away for more frequent feeedings. Don't use powdered innoculents, dextrose based carbs, beneficial funghi and the like, or most organic stuff in rockwool. Kelp extracts, b vits, humics/fulvics, diluted molasses etc are fine.
I like to drop ph a tenth a week from the first week of veg until my final flush. I usually start at 6.2 and end at 5.2 by my last weeks flush res. Cover the tops of cubes to keep light from entering the rhizosphere or the top of the cube. Light + Water = algae. Algae = fungus gnats. Fungus = pythium. So does overwatering.
I limit to 2 feeds max a day in the midst of bloom when my plants are hungriest and fed the hottest fert dose. 1 hour after lights on for the first few weeks, then 1 hour on after lights on and then another feeding 5-6 hours later in the middle of bloom. You want the media up top to get pretty well drained and not wet or doused, but moist and airy. Fuck. I wrote a lot!
A lot of people have issues with it as clones or transplants because of the high levels of lye in fresh rockwool. It causes extreme rises in ph if not properly leached, and ph stabilized. Prepping before using is to run 5.0 water until the ph rises to 6, drain, resurate at 6 again until stabile. Drain the cubes to near dry by stacking 4-6 high. Capillary action will pull the moisture from the top cubes to the bottom. Take the soaked bottom cube and put it up top. Let it drain. Take all the bottom cubes and stack them in each other and wick them out until you only have 1 soaked cube. Transplant, and feed 6.0 400-600ppm of actual base fert.
Rockwool needs bigger rockwool or hydroton (expended clay pellets or other sterile substrate to help with plant retention and to help wick moisture away for more frequent feeedings. Don't use powdered innoculents, dextrose based carbs, beneficial funghi and the like, or most organic stuff in rockwool. Kelp extracts, b vits, humics/fulvics, diluted molasses etc are fine.
I like to drop ph a tenth a week from the first week of veg until my final flush. I usually start at 6.2 and end at 5.2 by my last weeks flush res. Cover the tops of cubes to keep light from entering the rhizosphere or the top of the cube. Light + Water = algae. Algae = fungus gnats. Fungus = pythium. So does overwatering.
I limit to 2 feeds max a day in the midst of bloom when my plants are hungriest and fed the hottest fert dose. 1 hour after lights on for the first few weeks, then 1 hour on after lights on and then another feeding 5-6 hours later in the middle of bloom. You want the media up top to get pretty well drained and not wet or doused, but moist and airy. Fuck. I wrote a lot!
OldPhart
Member
I love RW and have had great success with it; funny thing is, I disobey virtually everything 2High suggested. LOL Guess that just goes to show how versatile it is. BTW, do what 2high said, that is down the line of 'standard' convention. I just do a good soaking in PH 5.0 nute solution for a couple minutes, then use them. I water up to 10x a day, my goal is to actually get the roots to grow in the tray that I cover with a layer of mini blocks (what I call my shallow water culture). I set the PH of the res. at 5.0, and let it drift up to around 6 over the period of 7-10 days, then either drop the PH back down to 5.0 by adding more nutes, or change the res. My system was not designed or thought out, I sort of developed it over time with assorted success and failures, but I like it and have had good luck. YMMV, but if you follow 2High's suggestions, you should have a good starting point, then you can start f'n with it.
Guess I just had too many issues to not do things the way I mention. I drop delta 4x4x4 or Hugo 6x6x6 in a container filled with rockwool mini cubes I call croutons.. top fed by 1/4" drip line with no drippers.
I think transplanting them in to a drained and minimizing my feeds keep the rhizo running wild in search for moisture. Also the drier, the less prone to necrotic or "water soaked" mushy or lazy roots. A good swing upwards in PH is a great indication through the week as long as it's brought back down to optimal levels.
Mudraya
Active member
Grodan website states that you only need to soak in pH 5.5 water for a half hour then flush with 5.8-6.2 nutes before use. It's pretty simple. That's what I do. I recirculate and feedback is clear that pH does not rise so it is effective. I also currently water 5x per day in flower open drip style and they are loving it. Start with 2 or 3 until they have roots well established, then go to 5, usually at start of 12/12. More water, more oxygen, more stable pH and ppm, less effected by heat.
Mudraya
Active member
10x a day.... that's awesome lol. Is your media volume a bit undersized to allow for that, greenhouse cucumber/tomato style?
Watering 5 to 10 times a day is more work than I can handle, I crapped out at 4. Now I am down to 2 and the garden still grows. Watering by hand is time consuming.
Fresh transplants get watered 6 or more time a day until roots are established then it goes down to twice. I measure runoff volume versus input volume to see what the plant holds.
The mature water cycle has gone back and forth over the years and whatever I currently use is considered the best. I am guessing that means the differences are there but small enough to ignore.
Once a day in the morning versus once a day at night was given a shot for most of a year, growth was not as good as twice a day.
Rockwool croutons are my media. Soaked in 5 pH for much less than an hour then rinsed with half strength used nutes, I don't want to waste good nutes, pH remains stable.
The first few years of growing it was a quick rinse with tap water and go. At times the transplanted seedlings would be slow to start, but none actually died. Watering 6 times a day put the pH in its place fairly quickly.
OldPhart
Member
I'll grow 30" plants with 6-8 tops on each plant, out of a 4 inch cube... So yeah, you could say that it is undersized, but the roots will make about a 1 inch slab in the bottom of the tray. Basically the roots are their own media, with a layer of mini-cubes to keep the top dark/wet. During lights on, all standing water will be out of the root layer within an hour, that is why the crazy frequent watering; on a timer of course. This was a method that I found by accident, and now I encourage the plants to grow this way. Biggest issue is keeping the drain clear of roots, about once a week I have to cut the roots back from/out of the drain.
I personally see no need for anything bigger than a 6x6 or a 4x4 on top a 6x6 for capillary action to “suck” or wick the top cube dry for more frequent feedings. Old school demanded 20-30% runoff, a dry out period and huge rhizo, but today rootbounding and air pruning with a wet media without runnoff (to keep the residual salts from binding or stacking salts) is the new wave... just food for thought.
Back to your question: I would start with 1 watering at 30-40 oz a day until plants are sucking it up pretty quickly, then double that with a second feeding 6 hours later throughout. if their drying up faster than than that, add a 3rd interval.. and a fourth.. Keep your EC low and try not to run off too much. If you see a drop in PH, Flush..
5lrootsexcel
New member
30-40 oz in 1 feed is way too much if your goal is to feed multiple times a day. I would spread that feed out into a multiple feeds and add more feedings as needed.
I've been messing with feeding time and amount lately and each feed is just barely enough to get a bit of runoff. I feed 12+ times per day
toohighmf is right. 8 in cubes are big but if that's your style, roll with it. I thought I would need 8 in cubes when I switched over to rw but I haven't even had to use cocomats. Let's say you water half a gallon per day, that means you need a 850 gal nute tank. That's a lot of water to be mixing. I would definitely get a dosatron setup.
EvergreenState
Active member
I follow Grodan's advice from the videos on their site and I've never had any problems. It's very simple and straightforward. I believe they say on their site that you not suppose to squeeze or try to excessively drain the water out after you ph correct them. It really is very easy to do it right; just follow their advice. They know how to use their product.
Mudraya
Active member
Exactly. We tend to over complicate it in the pursuit of perfection. However, I take issue with them recommending lemon to ph the first soak lol.
I’m surprised nobody has posted the link yet so here is the Grodan website https://grodan101.com. It has easy directions to follow.
Also if you follow @grodan101 on Instagram check out their feed, they have a chart to help determine the amount of each feed. About 100ml each watering is the goal if I remember correctly so once you dial your pump to get those volumes to each plant you then would adjust the number of times per day to get little to no runoff.
Also if you follow @grodan101 on Instagram check out their feed, they have a chart to help determine the amount of each feed. About 100ml each watering is the goal if I remember correctly so once you dial your pump to get those volumes to each plant you then would adjust the number of times per day to get little to no runoff.
