Exactly, the paper i pasted from describes the same phenom you have been describing for over 10 years. I have always raged that the big greenhouse media suppliers claim that 30% perlite into a peat is a high porosity mix. And so many growers prefer short squatty containers [helpful for blow over prevention but nothing else] Container Geometry is almost as important as the mix. i remember in 1984 I took a 400 level greenhouse management course at University of Delaware. The prof soaked a rectangular sponge and held it by the edges parrallel to the sink flatwise and let water drain, then he rotated the sponge on the shorter vertical axis and more water drained, when that free drainage ended he then rotated the sponge vertically in it tallest plane and more water drained. When I read your suggestion about using a draping shoelace as draining wick to lower the PWT the distance of the wick, I shouted YES at the elegant simple brilliance. In 1977 I grew a marijuana plant in a milk crate full of gravel, the stalk was over 2 inches in diameter [no different than growing in glass.] BTW, in your gritty mix what are the ratios and actual particle size for each component? I would think to use slightly larger particle sizes than i think you were using and i would probably consider using zeolite or a calcined DE or calcined clay. BTW, Ep minerals makes several absorbents both DE and Clay, Calcined or regular as various spill absorbers available in any auto parts store. 5o pounds for about 10 dollars. Don''t know the particle sizes but likely need to be screened to eliminate the fines. The clays are generally calcium bentonite and not sodium bentonite so less sodium and less swelling. I beileve Arcillite and Tuface are calcium bentonites. I was just thinking that decomoposed granite and even bark add no water holding capacity but with DE and Proper sized ceramics you could add more waterholding capacity but still maintain the airspace. The airspace in the ep mineral clay was pretty low when I measured it last, but I did not screen it. Somewhere I have a spreadsheet with AFP, WHC, TP, TPv, etc for over a dozen components and mixes. I have run quite a few in both 16 oz and taller 32 oz cups, [1 liter exactly when filled to rim overflow which makes that size intuitively easy for all the math. I think i found your posts about 3 years ago and then lost them. Am I correct in thinking you have some water release curve data around somewhere. Someone posted some WRC showing that Axis DE or perhaps the Axis clay media held huge amounts of water but easily released over 75% to the plant. TI can not find that post. I was actually searching for Vertical hydraulic conductivity, Capillary Rise and Capillary rate and wicking when your links showed up. The axis DE is like $90 a bag for 50 pounds so i think I could more cheaply reproduce from other products but have to screen. where I live in idaho, there is a Celatom DE plant less than 60 miles away, 2 zeolite mines, a sodium bentonite mine, WHC and Airspace mid 20s in the 2 larger particle sizess. Also the best white pumice [Hess] source mine a few hours away. I had hoped better water holding capacity. I plan on rerunning all the mixes again in a few months now that i have more standardized my process using multiple cup sizes, some of them tamped or shaken to settle, some top watered, some bottom water, measure distance of subsidence if any. I also have a vegetronix tensionometer now and will take additional measures at various depths to measure the exact tension and also verify depth of pWT which i can usually see through the transparent cups if I use a marking dye and saturate from below. Anyway I will share those spreadsheets in the near future If i were to guess, you have some sort of plant and soil science background or some civil engineering background and a love for plants. At any rate, your explanations and examples are some of the best I have ever come across, and your shoelace suggestion is brilliant, truly. i read so much WRONG advice or the wrong analysis for reason why something works or does not work. it is refreshing to come across accurate information Garret Goyette

Hi, folks, can't imagine what you are going thru, with the impending hurricane and all the upheaval that goes with 'preparation' for it's arrival, or just the internal and physical displacement that is evacuation. World weather patterns sure are a mess now. Yesterday the news told us it was a category 5, today they say downgraded to cat.3. To me, it's still a hurricane. We hope and pray that it will weaken, and not cause the devastation the last one did. Jo, yes the sand I'm talking about is beach sand, it's called 'Sydney sand.' Don't know if this makes sense, but I use it because it's 'accurate'And is strong. It is the standard sand used by tilers for cement beds, or screeds, and for grouting. Some call it plasterer's sand. As I said, never had a problem with it until I used the 'washed' version. The washed version may be from a source with such high salt content, that it HAS to be washed, but still ends up with salt residue that affects the work. Believe it or not, this sand is more sharp, than smooth. I haven't encountered any problems with oxide in it, ( mineral colourants), but I do have to control accurately, the amount of plasticiser in the mix, or it will cause what looks like a cold joint in the finished piece. As for testing the amount of salts in the material, I was told to use a salt meter they use in hydroponic food and flower production. The method is similar to Tango's sand and water in a jar, only you test the water with the meter, and it will tell you if you have excessive salts in the material. Tango, I don't know what they mean by French Cement, I'm having a hard time just getting the price out of them. I think they have a new product, and are testing the water as far as information and pricing go. Looks like they will send me a couple of 40kg bags to trial soon, though.Can't wait to try it. As for pics, I borrowed a digital and got some shots of the exhibition, and some other stuff , and it's getting put onto disc, and then I will try to post it here . May be of interest to someone out there. Slate

I think that the "empty big box store" part of idea is terrible for a number of reasons. One would be infrastructure problems in old or even newer dissimilar buildings. A fast-food restuarant or even a large retail store doesn't buy and raze the lot next door to put up a newer building just because they need more space - there are functional flaws in the older building design even though it was purpose built for that business at one time. It would be prohibitively expensive to repurpose these buildings (or it would have been done $$$.) Another reason would be zoning laws and concerns. For example - if I owned a furniture retail store next to a large grocery store that shut down I doubt that I would be much more upset over a livestock auction moving in next door than over a lettuce factory because I would want the traffic from a compatible business or barring that traffic at all. It would have been great if the article was about q business succeding because of their beliefs against long odds because local consumers wanted their product (this can be done). What I read the article as was that a government supported group in Vancouver *CANADA* (because IMO the writer wants to confuse Vancouver BC with Vancouver WA) has a "system" that they think has potential and then all of a sudden the article shifted with no transition to the *US* where it appears that not a leaf of lettuce has been grown. The phrases "might yield", "should finish" and "plans to grow" should send "investors" running, Well meaning people and government at different levels can do a lot of damage to progress by favoring one idea (or person) over another. Many should step aside and let things take their course. There seems to have been quite a bit of *REAL* success in CSA (Community Supported Agriculture) and farmer's markets recently.

Sounds like you have a great start. A few things I thought of when i read your plan- You do not have to change the nutrients every 2 weeks. Although frequent nutrient changes will not harm the plants they are wasteful and nutrients are not cheap. Over time you'll get a feel for when the nutrients need changing becasue the plants will let you know when something is out of ballance. Depending on many factors including what you are growing, stage of growth, how many things you are growing, size of resivior, original concentration of nutrients, etc. you may only need nutrient changes once a month. I respect that some people choose to do frequent, scheduled nutrient changes but it is not required to have a successful grow. As you get more comfortable with hydro growing you'll learn to 'read' your plants and they will tell you when something is off. Â Check the pH often. From what you wrote, it sounds like you are already aware that pH is an important part of hydroponic growing. pH controls what nutrients the roots will be able to absorb. If your solution goes to acidic or basic the nutrients will be 'locked out' and the plant will suffer. Â It is okay to turn the drippers off at night. This idea scares some people and they will say things like 'the roots will dry out', 'you miss 8 hours of feeding time', 'the drip emitters will clog' and I'm sure many other things. The truth of the matter is- Generally plants do not "eat" or "drink" at night so you are not missing any feeding time. If you are using a suitable growing medium, it will hold enough moisture to keep the roots moist for a few hours in the dark. And finally, stalagmites (sp?) are formed in caves from a constant dripping of water depositing trace ammounts of nutrients that buildup over time. Nutrient deposits can build up and clog emitters regardless of pump timing. Drip emitters designed to conserve water in terrestrial gardens, where excess water seeps into the ground and is wasted, are not the best or most reliable for use with hydroponics. I use 'rings' made from a 6" piece of airline tubing wrapped around a T connector, with pin holes melted around the inside. The flow rate is much higher than a commercialy available 1 or 2GPH dripper you might use in your dirt garden, but becasue the water is recycled, nothing is wasted and they are much less prone to clogging with debris or nutrient salt buildup. ÂWhat growing medium are you planning to use in the cups, and what size cups will be used? I ask becasue you did not list any provisions for supporting the plants and unless you are using a dense medium and/or large growing cups, you will need some form of external support for the plants as they grow. Â Use of compact fluorescent lights. I'm not knowledgable enough about it to make much of a recomendation other than you should talk to the people in the 'Growing Under Lights' forum here at GW. Fluro's are great for seed starting but may be lacking for 'growing on'. ÂContinuous producing plants I took from what you wrote that you plan to use a single large plastic tote with the plants suspended in cups flushed into the lid. Saddly, there is almost no chance that a system of this size will continuously produce all of the veggies you described. If you built multiple systems (one for each type of plant) you could get close, but as described you'll only have space for 1-2 of each plant and 2 pepper plants (assuming we are talking about bell pepers) will not produce a continuous yeild, nor will 2 squash vines. I'm not trying to be a pessimist; I just want you to have realistic expectations before you invest all the time and money into building something. I think what you are trying to do sounds great and although it may not eliminate the need for storebought veggies entirely, you can supliment your diet with food you grew free of pesticides and other harmful chemicals. ÂAirating the solution If you plan to run this system in a part of your house that you regularly spend time in, you will quickly discover that walmart air pumps are LOUD. Because getting oxygen to the roots is critical for cellular respiration, you do want to airate the liquid but it can be done without an annoying air pump. The drip rings i described above in the section about turning the drippers off at night can perform the same function as an air pump (proably better) and are very quiet. They produce small jets as water is forced through the holes. When the jets of water hit the growing media they explode into tiny dropletts of water catching oxygen from the air and carrying it with them as they collect back into drops that run down into the root zone. These tips are just my oppinion of one way to do things. As you start playing with your hydro garden you will learn your own way of doing things that may be completely different from how I or anyone else does them. there are very few hard and fast rules about what is correct or incorrect in hydroponics so my most important tip is- keep an open mind and experiment with different things until you find what works for you.