Awesome Vlad. 'Reminds me of what little I know about Growing Power, but raft style.
@ Jon: I don't think wicking alone will be moist enough to dissolve controlled release type frets, esp close to the surface. The coir should hold it in place as long as the water level is not high enough to float them off. Personally I like Vlad's approach a bit better. At least there should be less chance of reactions.
A one inch air layer is most important in any wicking bed system. A balance of both air and water are necessary for good root growth. Too much water and a lack of air are good conditions for root-rot. Too much air and too little water produce air pruned roots with woody tips which can also lead to termination. Remember, capillary action only travels about 300mm or one foot vertically from the water surface, so as your reservoir empties, tap roots need to travel so much further to reach water. It is good to keep the reservoir topped up in spring, until tap-roots mature enough to reach the lowest point in the reservoir. An appropriate material should be used to give even water distribution. I originally use geotextile or landscape fabric ( a non woven synthetic) but am trying to develop a natural woven wick that makes the system truly organic. The best combination so far is verticle cornstalks with diagonal weaves of barley and wheat. * Trade secret: Wrap the bottom part of wick with plastic.
Because I have access to rolls of geotextile, I have different sized ("Smart pots" type) bags made to experiment with. I use 80% perlite and 20% compost, with fish water and wick bed overflow water to grow all sorts of crops especially root crops like potato. Bag culture works great! The nice thing with perlite is that once you have done it a few times, you can pretty much judge how much water to "load up" before it naturally flushes. I find I get much better performance with deep watering every few days than light sprinkles every day or to load it daily.
@ Vlad: I have several people interested in working with me on an aeroponics system but to date, none have manned up and actually start. I would be honored to work with you on this if you are serious about it. This project has been on my back burners for over a decade. I think it's time to bring it to light.
Sorry, Jon I forgot to answer you question as to nutes...on the PL-Lighting discussion page the peppers in the hydroton only net pots get a (relatively) classic blend of mineral salts and TE's along with some 'organic' N inputs...The ones pictured in the coir/perlite/vermiculite/zeolite/castings deal get a half-baked 'organic' recipe that I came up with while experimenting with a third very small, very disposable system (two basil plants, one pepper and the ever present salad).
On the N side of things...I noticed that when I started adding some nitrite (hummonia based) to my otherwise pure nitrate blend (brewed worm castings seem to be all nitrates) my pH in the reservoir seemed to be freaky stable for long periods of time...I also used this method to grow out those salads and spinach pictured in that same PL-L discussion. Not a single water change, not a single pH adjustment (actually that's not entirely true since every time I top up with my nutes I am in actuality automatically adjusting pH as a secondary effect). P also comes from my hummonia and the castings/tea. Wood ashes also seem to be 2%-8% P (dry weight) and between 5%-14% K (dry weight). Calcium carbonate (or rather its aqueous bicarbonate form) I have -o- plenty in my water. When I do my one and only initial pH adjustment at the beginning, I treat my water with a 16-18% HCL solution which will give off CO2, but more importantly the plant usable form of calcium (Ca2+). So I don't add finely ground eggshells anymore. Mg is also in the water, but Epsom salts could be used. Sulfer is an easy one...TE's from Kelpak (MaxiCrop). I thought about using 10-20 grams of rusty nail filings for every 50 litres of nute solution, but opted out as I have a perfectly good box of EDDHA Fe...
That's pretty much it...just sorta wingin' it touchy feely intuitive. Which at the moment suits me. The hydroton only trough is a slightly more clinical affair...(but not by much)
NO3 and NO4 in a 1:2 ratio
In a blend all depending on how I'm feeling that day, and what I think would be a wise combo for a number of reasons at any given stage of plant development...
I start off with very low EC value (not counting what's already in my tap water) and slowly build up as my plants age/grow. Chili's, unlike Bell peppers don't need a whole lot, so this makes things a bit easier with them. With the dual root zone deal, I really cant take meaningful EC values, so it's sort of a mojo/voodoo thing. Working great so far. I did everything I could while they were seedlings/sprouts (...the usual stuff...24 hour fans to make them do the hula-workout, 24 hour light no 'sleepy time', no coffee breaks)... to keep them, super stocky, short, nice tight inter-nodal growth, stalks are like shrubs already. PL-L worked great... I'm not saying that it's because of the dual root zone set up, but there is a definite visual difference in those plants. Sorry I'm rambling now...
Jon Parr said:
Fascinating, Vlad. I saw mention of dual root zone in another post of yours, but didn't have time to ask what you meant. I'd love to pick your brain on your homemade nutes. Salt based or organic blend? I have been considering using CRF's, as in controlled release fertilizer. They are granular pellets designed to be mixed into compost or top-dressed on soil. Each time you water, some ferts dissolve into surrounding soil, like licking a lollipop. I've considered adding some pellets to the media, but I'm chicken. I don't have any fish that I don't mind losing. But this dual root zone thing may be the trick. You could add some CRF's to the coco blend you use, and place the bottom of the net-pot right at the water line of a flood and drain media bed. Each time water touches the coco, capillary attraction would keep it wet, and I doubt any coco water would leach downward. Top roots would feed in coco and bloom nutes, bottom roots would feed in AP water and nitrates. Hmmmm. Plus, the watering would be part of the AP automation, meaning you can go on vacation without worrying about top feeding. The CRF's are very cheap, last 3 months, and you could always add a sprinkle to select plants that need something without treating your whole system. I just bought some CRF's with extra iron and micros. I like it. Could probably even grow potatoes and such this way.
I'm not sure what you have in mind but I'd be happy to share/work with you. You seem to do things in really big ways, and well, the things I do are pretty laughable in scale.
My 'serious' project is to finish getting the 2131 sq.foot greenhouse outfitted with the AP hybrid system. But again, if I can help you out somehow I would be honored to.
BTW...how do I go about getting those seeds to you exactly? You can message me instructions. We are ridiculously snowed in at the moment and the post is in town. (getting cabin fever already)...
I could only wish for snow. To me, snow is free water come spring. Right now, my soil is about ready to split........
As for the seeds. NO rush. We still have a few weeks. I'll e-mail you my address.
I'll try to post a lil something on aeroponics through my blog but basically the practice so far has been to push water at high pressure and low velocity through a spray head. Higher tech models might have some sort of disrupter. The most sophisticated of which use ultrasonic. These are used in labs today to grow truly medical quality plants, with potato being a crop of choice. The problem with this system is that it requires a lot of energy to push water and that process usually generates a lot of heat at the wrong place as well as the high cost of repair/ replacement and maintenance (salting up).
The Israelis developed a spinning atomizer as well as the Chinese with their little fog makers, but these had to be maintained constantly. Any micro electrical leakage and corrosion and salt buildup became a constant problem/ battle. Remember, this was back in the days of hydroponics and reactive agents. Concoctions that were unstable at best. We don't have that problem (so far) in aquaponics so...aeroponic systems of any type are more feasible using aquaponics nutes.
My proposed system which was originally actuated by....anyway. Remember the movie the God Father. Remember when the old man dies? What killed him? That's right! A low tech mist! Pushing air is a lot more efficient than pushing water. In other words a venturi. Now float that on the surface and we have a verticle mist. These particles should be small enough, (sufficient) to grow but not exactly ideal. A mist of five microns is thought to be ideal. This can be achieved by bouncing it off tefflon coated and insulated sonic disrupters, to be whisked off by air current into grow chambers, where root-hairs take in their organic bounty.