Clay Pebbles

[chubby1891]

Ive already done a thread on the preparation of rockwool so now its the turn of clay pebbles

Although pretty much similar this is how I do mine

First off i take the full bag of pebbles and burst loads of holes in the bottom 6 inch of the bag while standing it in the bath. I then turn the shower on to the coldest setting(cos more water comes out) and rinse the bag through for about 5 minutes. This gets rid of most of the crap

I then as with the blocks soak them in ph 5.6 water for 24hrs preferably bubbled at around 20 degrees

Tip all the water away and replace with a mild nutrient solution with an ec and ph of which you intend starting your plants on. As long as they have around 12 hours soaking in this solution they will be fine

Your pebbles should then be nice and clean and ready to go into any system you wish, in fact even after soaking in just ph water your pebbles can be used, I just like to get a bit of nutrient into them

Hope this helps

Owd

A useful note thanks. Hadnt thought of using a low PH water for final flush, thanx

[sk2]

Helpful info, didn't realise they had to be washed before use, better wash them next time

[dokta-bud]

i always say wash the pebbles properly

and yes u should put pebbles in the bottom of any pot as it helps with drainage and aeration of the media also u could mix the pebbles into the coco aswell as drainage and aeration would b increased even more

hope this helps good luck

pebbles r cheap enuff just replace every grow but if u gotta reuse them wash them through with water then with liquid oxygen and then full strength cannazym is good

as 4 your ph changing u should leave your water stand for at least 24 - 48 hours b4 testing as this will allow chlorine and other nastys to dissolve and evaperate

hope this helps u out

[dokta-bud]

ARTIFICIAL EMOTION this 4 u as your picture looks SEXXXY as hell

yes put some pebbles in the bottom of your pots u could even mix a few into the coco aswell. this would only aid in drainage and aeration of the media

also anotha good tip for auto-pots would be to feed from the top until u got a good few roots popping out of the bottom.

i almost 4got just get rid of the root control disks as all they do is hinder the roots from forming but just make sure and keep checkin that the roots stay out of the blue smart valve

hope this helps gordgeous

let me no how its going

[Owderb]

and yes u should put pebbles in the bottom of any pot as it helps with drainage and aeration of the media also u could mix the pebbles into the coco aswell as drainage and aeration would b increased even more

Been there done that mate and you dont need to put pebbles in at all if you dont want

I now and have done for ages run with just coco, nothing else, and now its a lot less bother to get rid of too

Owd

Edited August 19, 2011 by Owderb

[Dangerous-Dave]

i left mine soak for 24 hrs with the water ph @5.5 checked it after 4 hrs and it had gone up to 6.3 so lowerd it again to 5.5 and then checked em this morning it went up to 6.5 this is also after flushing a pot out at a time with ph 6 havin 11ltr pots i flushed them with 5.1 ratio and still the ph is over 6.5 any ideas why? would it be better binning them and buying new?

[tradeup]

I've read a ton on these clay pebbles and I'm told that the Hydroton range tend to go a bit alkaline.

Which is the preferred clay pebbles, please? Thanks.

[Laphroaig]

I was taught by a friend using 12 litre pots of vermiculite in washing up bowls hand watered. That stuff was nasty and getting rid of it after each grow almost required your own private landfill. With clay pebbles all my waste from harvesting fits into one bin liner. Yes of course recycling the pebbles is more hassle than just dumping the contents of each pot into bin liner and throwing it in a skip, but in my book not having 20 bags of waste to dump after each grow substantially increases my security.

I have 2 sets of 10 litre inner pots for my IWS flood and drain system which I alternate. Here's how I prepare them. After harvest I leave them complete with the last few inches of "trunk" stacked in a corner till they start looking mouldy! I do this because if I try to break up the root ball straight after harvest it is packed so tightly you end up having to smash the pebbles to get them out of the medium, it's like a solid block. So after a couple of weeks sitting I empty one pot at a time into a round 50 litre tub I got from B&Q. Holding the trunk gently shake the root ball and the pebbles will fall off and if you've judged it right you will be left with the majority of the root system attached to the trunk and the pebbles in the tub. If you have left it too long you'll just be holding the trunk with a few big roots and the rest of the root system and pebbles in a big lump in the tub, no matter. Gently break the lumps up until you can mix the contents of the tub with your hand. Then with your hand mix the contents of the tub with a rotating circular action, I've found that using the flat of your hand horizontal and pushing down a little produces the best results right at the end. Not hard enough to crush the pebbles mind you.

I've also used a bin liner held around the stem and detached the pebbles by gently hitting the root ball against a wall but with a tub you get to see what you are doing. Irrespective of how you do it it's always worth just spending a minute detaching the last of the pebbles stuck in the root and trunk you are left holding before throwing it away.

After mixing up the contents of the tub for a minute or two with your hand you'll see that the bits of root start clumping together in wads which can easily be picked out. You need to get the majority of these out, you don't need to be too anal about it but take a few minutes, picking them out then remixing the tubs contents and repeating the process until all the big clumps are gone. After that I give the pot they came from a good rinse round with tap water using a sponge to clean off any dirt and tip the contents of the tub back into the pot. Once I've done that for all my pots it's time to move on to next stage.

I'm in a very hard water area and after each grow my kit gets sprayed down / rinsed with a acidic solution around pH 2-3 to remove the salts that accumulate. Nitric acid is preferable but phosphoric is almost as good, vinegar and lemon juice are a no-no as is citric acid. I usually stack the pots in 4's or 5's any higher and the pebbles may get crushed at the bottom, each stack sits in a washing up bowl to which I add about 3-4 litres of acidified water from the top of the stack so it percolates down through the stack collecting in the washing-up bowl at the bottom, I'm aiming for about 1/2 full.

WARNING: Allow for additional drainage from the stacked pots above, after a couple of hours check the level in the bowl and top it up to about 3/4 full or whatever you feel you can safely handle. Because you really don't want to go slopping this stuff around!.

I rotate the stack every 24 hours so there is a new pot at the top and bottom of the stack, each time pouring the contents of the bowl they were standing in into the top of the stack of pots so that each pot spends 24 hours at the bottom soaking in the acidified water.

Once they are all done give each pot a good rinse through with tap water, ideally with a hosepipe so you can get some pressure going to agitate the pebbles in the pot. After this the pots should be left to drain on bricks or something that lifts the bottoms of the pots so air can get at them. Stack the pots using the rims instead of sitting the bottom of each pot on top of the substrate of the one beneath to maximise the air flow around them.

A week before you need them give them a rinse through with a concentrated hydrogen peroxide solution.

Note: To keep cost down get your H2O2 from a chemical supplier not a grow shop. eBay has people selling 5 litres of food grade 35% H202 for about £20, dilute it 50/50 with distilled water and you have 10 litres of 17.5% H202 for about £3 per litre as opposed to £10+ in the grow shops. (Avoid using tap water to dilute stock solution as the impurities will react with the H202 degrading its effectiveness over time.)

However in this instance tap water will do to dilute it. I usually use about a 3-4% solution following the same procedure as the acid bath except the stacks of pots are rotated every couple of hours. Because of the reactive nature of H202 it quickly degrades and will only be effective for a couple of days at most by which time it will have reverted back to plain old water. Rinsing through afterwards isn't required, however if you've ever got any H2O2 on your hands you'll know the effect it has on organic matter. Because I'm using an IWS system I usually give them a final few minutes under the hosepipe to rinse out any of the residual root matter that has been broken down by the action of the H202 before I put them into the outer pots of the IWS system.

In the system, which is dismantled and cleaned after each harvest, the pots and substrate are introduced to the nutrient mix which is cycled constantly for a day or so and adjusted until it is stable at the required pH and EC. When planting I remove the inner pot from the system. Remove the dry pebbles from the top of the pot, I usually fill the pots about an inch above the maximum flood level. Make a shallow depression in the damp pebbles. All my seedlings are grown aeroponically from clones so it's a simple matter of sticking the roots in the depression, trying to spread them out a bit in the process and then gently replacing the dry pebbles. A quick wetting down with nutrient solution from the top and I'm ready to rock'n'roll.

Takes a week of 18 hour days for the roots to hit the bottom of the pot at which point I flick to 12/12. Two weeks later as part of stripping I take a knife to the bottom of the inner pots and remove the thick mat of roots that have grown through, it doesn't hurt them much and as you're hacking away on the surface anyway you may as well, it actually promotes further root production but most importantly ensures the plants feeding during the height of flowering isn't restricted by blocking the feed pipe with roots.

Gonna stop now because this was supposed to be about pebbles.

Peace

[Guest Green six]

Bit of a noob question, but does contact with dry Hydroton not damage / dry out roots? And if so, how do DWC rigs combat this?

Edited January 19, 2012 by Green six

[Antipodean]

These pebbles being made from clay I got to thinking that taking them back

to a temp around 1000 deg C might be a good way to clean them -

Found a friendly potter and have been doing this for a couple years now -

Seems to be working ok breaking down the salts, nutes etc -

Would appreciate comments on this method - any one else doing it?

[hydro2]

Clay pebbles will always raise the ph until they stabilise, soaking them in a ph of 5.5 does help this process but as Owd said they have to be washed thoroughly, just giving them a quick rinse is no good as they still hold dust & this is what causes the ph to rise. Soaking the pebbles also helps them swell & retain water. I have heard a lot of people ask how the plants manage to grow "when the pebbles are dry". If you crack open a pebble it has a double layer & the layer inside is what retains the moisture, so if you are growing in dwc or recirc, the plants roots uptaking the feed is what keeps the pebbles inside moist & of course acts as the stability for the plant.

I find Plantit pebbles to be of good quailty & I would have to agree again with the layer of pebbles at the bottom to be not necessary if using coco as it will drain off to much, I just mix some pebbs through mine.

Sorry for hijacking your thread Owd.

H2

[Wiggles41]

I turn getting rid of used pebbles into a game and recreate The Great Escape by hiding them down me trousers and dropping them when no 'Nazi camp guards' are looking

[Laphroaig]

Wow, talk about an epiphany. If you stack the pots after a grow so the air can get to them and they actually dry out completely it's awesome, mine have been standing for about 3 months and when I came to tip the pebbles out into my big tub to sort the old roots out they were just this fluffy mass that disintegrated, hardly picked anything out at all. I just gave the pebbles a good mix round with my hand in the tub and the roots turned to powder, threw everything back into the pot, grabbed the garden hose and rinsed it through from the top for a few minutes, sorted. Will still need to give em a good wash with H2O2 before I use em but it took me 5 mins as opposed to 20-30mins when they're wet and I have to pick the wads of root out. No more pickin' bits of root out for me in future!

Peace

[great dane]

Please help ,ive had this problem for months ,ive bought my pebbles from 3 different shops ,at different times , i have washed all, even boild them ,put them in a plastic bin and jet washed them ,put them in my bath (24hr)to soak,pissed the wife off a load, YET THE C.F STILL SEEMS TO RISE ,after 5 days 18hr on, showing on my meter up to 8-10 witch then seems to burn my girl s roots,ive been told all storys about different pebbles ,thats why i bought from different supplyers .does anyone else have this problem .

[Laphroaig]

I haven't, there again I've only ever shopped at Greens, you may pay a few quid more but stuff like this doesn't happen. The whole idea of hydroponic substrates is that they are chemically inert.

Because you get the same issue with different batches I'll hazard a guess it isn't that. My guess is it's just transpiration. The plants take up water and nutrients at different rates, modern nutrients are designed to try to match the needs of the plants but it is impossible to get the balance just right all the time, for every strain, throughout the course of its development. Hence the different bloom & flower mixes, but even then it's far from an exact science. So there's always going to be an imbalance between the amount of nutrients needed and the volume of water the plant uses both for nutrient transport and maintaining its internal environment. Every week or two, depending on the size of your tank and number of pots, you need to drain all the nutrient solution from the system and refill with fresh to restore a balanced range of nutrients. But in between you still need to add plain water to the nutrient tank to replace what the plants are using otherwise the nutrient solution will become concentrated and the plants will be unable to get the nutrients they need. I'm guessing that you're filling the tank, watching the level fall and not topping up with fresh water to maintain a set level. Hence the increased electrical conductivity and unhappy plants.

Peace

Edited October 7, 2012 by Laphroaig