Backyard Aquaponics
A place to discuss aquaponics

I picked up a couple of lengths of hydroponics channel in roadside chuckout yesterday and have been thinking for a while that I would like to use some channel in my home system when I build it to grow lettuce along my fenceline. I got even more excited about this possibility when I saw Sleepe's homemade automatic float dump chamber thingy today and i saw how I could set it up without needing additional pumps(don't know the real name of it), anyway that is another story.

I was looking at rockwool as a medium to use in tubes within the channel with a view to tossing it after each lettuce is grown. Now this expense would add up and I do like to recycle so here is the question/idea. Can anyone see any reason why I could not use fiberglass insulation batt offcuts stuffed into tubes as a grow media for lettuce instead of rockwool or why it would not work? I am happy to trial it so the whether it works question is not so important but I do need to find out if new batts are treated with any type of insecticide or anything that would stop me doing it?

Would tend to think that they're most likely treated with fire retardant chemicals... I'd be very hesitant...

Why not just use el-cheapo lettuce net pots, filled with either 25:75 perlite:vermiculite... or clay balls...

Clay balls can be recycled... and with a bit of care... so can the lettuce pots...

I do he pick me out clay ball crap, its a bugger, but they cost me a few quid to start with at the same time ,

Good point about the fire retardant, anyone know for sure - maybe I should ring a manufacturer. I though the glass batts were used because it was naturally fire retardant.

I've used yogurt cups with holes punched in them as my "net pots" and I can use gravel or perlite as the media in them which is reusable too. and to save the step of having to top water them or start the seeds separately to plant into the "net pots" I install a bit of rayon mop string as a wick in each one. It draws up enough moisture to start the seed and guide the roots down to the water without me having to add an extra step into the process. Has worked well for me in both hydroponic and Aquaponic situations for lettuce.




I'm pretty keen on not spending too much money on things that can only be used once. The mop I have been taking strings from cost between $3 and $4 and it only takes 1/2 of a string for each cup, I've hardly made a dent in that mop head in well over a year though I don't grow too much with this method currently as I've got big grow beds. The yogurt cups are re-usable if one is careful with them but they were gonna be thrown out anyway as they are not even recyclable here so I figure my added use for them is only a good thing. The gravel of course is re-usable. Perlite has drawbacks around AP so I try to minimize my use of it so it doesn't wind up floating around the system.

Definitely make sure any water sent to such troughs is filtered since solids gunk up the troughs and roots something nasty and provide too good a place for negative bacteria to breed.

And a green yogurt cup at that!

As for the insulation or other materials...when in doubt, don't risk it.

Nice Trick!

Used to use rockwool when I did hydro, bags and nft. Always used it for cuttings. After a soak in acid it is ph neutral.
Never have liked pearlite or vermiculite too messy (pearlite floats and vermiculite turns to sludge). Hydroton dosn't have the water holding ability of rockwool but if your flow is gauranteed its reusable. The rockwool bags could be used a few times. I suppose theoretically if you could heat the rockwool to burn off the organics it could be reused, but at the time it was cheap
Not sure about insulation, was warned against it years ago but that might have just been someone trying to sell me something.

Found this

"Residential fibreglass batt insulation contains about 5% resin binder that is capable of out gassing formaldehyde fumes into the air. The pink coloured insulation manufactured by Owens-Corning Fiberglas Corporation contains, in addition, about 1% dye that has its own out gassing characteristics. The resin used in insulation is usually a phenol-formaldehyde product, but Manville Corporation uses a urea-extended phenol-formaldehyde resin, which outgases at a faster rate. Of the major insulation manufacturers, the batt insulation produced by Certainteed Corporation, with 4% phenolformaldehyde resin and no dye, is probably the least potent from an out gassing standpoint, however, it can still bother people sensitive to formaldehyde."

Ok found an alternative PET fibres, used as pillow stuffing mainly called Dacron, seems to have the advantages of rockwool.
All you have to do is convince your wife the pillows need changing

Thanks for the research Sleepe, pillows sound like a good alternative, otherwise you can get dacron wadding from Spotlight for next to nothing for the amount you would need.

I've started seeds on moistened cotton balls before. Actually works quite well for lettuce. Then again, lettuce seeds will start on paper towel or mop strings or just about anything with a little bit of moisture.

If you want fiberous material, try quilter's poly batting from a craft store or a local mega-mart. The green-ish label is the only one to get if you go to a walmart. Check the materials/ingredients on any other stores though. Word of caution from experience, don't allow air to get trapped in it and dry it out when it is underwater.