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building a system 8x4 feet


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Old 06-17-2011, 10:05 PM
animus_divinus animus_divinus is offline
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hey everyone.. im building a hydroponics system in less than a month... its going to be 8x4 feet in size, 32 square feet, about 10-11 cubic feet in total

im buying a 600w ballast kit for $100, plus a 600w bulb.. ill make the reflector myself to cover the entire table

well, id like to go with an ebb and flow system.. put a 1/2 inch PVC pipe through the bottom of the tarp-lined table, glued in to make a seal.. 8 of them, each one supplying a 4 square foot area and linked together 4+4 and then a 2 into 1... nutrients will be pumped through all of these drains and then released in a typical ebb and flow setup

what i need help determining is the grow medium... i have to fill a 96x48x4" area with grow medium for this system to work as planned, or plan a new one... frankly, this seems the least expensive route having all plants grow side by side on a table filled with the medium...

if anyone has any better ideas to set up an ebb and flow system of this size, id love to hear it

however.. gravel and sand is heavy... i think for sand or pea gravel im looking at the table holding 1,000lbs in medium alone

if i use perlite, then i have the issue of the stuff floating, though i could stretch a mesh screen over it and staple it down... the loose leaf lettuce would probably find its way through holes in the mesh? and holes could be cut to make room for the stem of other plants

ive thought about using tubes with holes cut out to fit a styrofoam plug holding the plants inside a pipe which can be flooded and released like a typical ebb and flow system.. but it would be too difficult to get this to work on smaller plants too

basically, im looking to go as simple as i can while being able to accomodate larger plants, and small herb/spice plants too

any suggestions will be helpful

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Old 06-17-2011, 10:18 PM
animus_divinus animus_divinus is offline
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hey... i was wondering what size flour pot a tomato plant actually needs?... if not too big.. i could build my 8x4 foot table, line it with the drains for ebb and flow.. and then cover it with a thin 1/8 or 1/4 inch thick piece of plywood painted white so to not absorb light... then cut out a hole just large enough for the pot to fit in and drop it in..

then for other, smaller plants like the herbs and spices or leaf lettuce which is many, many plants per square foot i could get a 1x1 foot square pot with the holes in it, or drill them myself to grow this stuff in.. use pea gravel as a medium.. and this will significantly reduce the weight in pea gravel that i will actually need.. making this system much lighter, and even cheaper

should i do this with the pots set into a top over the entire table... what other kinds of systems could i employ with ebb and flow?... i could potentially position PVC pipe under the canopies of the larger plants or in between smaller ones to drip nutrients i bet..

i might even be able to have a solution of water under the table at all times... a passive system, i might look into those more....

if i had a system that continuously drilled solution.. i think my best bet would be to put the nutrients solution on a table above the plants.. so that gravity would feet it.. and when the upper resovoir got to a certain level (using a float as a switch).. it would turn on a pump and pump all the nutrients back up to the top.. this way the pump wouldnt run constantly.. and should there ever be a power outage i could atleast keep them fed

one question with this setup... what would be the best medium in a drip setup?.. probably something that retained water

so im liking this individual pot idea ive just thought of using.. so im wondering what you guys think would be the best system for it?

Last edited by animus_divinus; 06-17-2011 at 10:22 PM.
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Old 06-18-2011, 12:29 AM
GpsFrontier GpsFrontier is offline
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Hello animus_divinus,
You mention your looking to go as simple as you can, but from what I here your plans are overly complicated to me. I think it's mostly because you are trying to grow everything in one system. As I mentioned in the other forum, I would definitely use different systems for different plants for various reasons. Here is some examples of simple setups that I have built for both small as well as large plants.

Here's a simple water culture system I built for growing lettuce,
http://www.hydroponicsonline.com/for...th-system.html
A water culture system is just about the simplest systems you can build, and this one cost me all of about $20-$25 to build. It's easily expandable to accommodate as many plants as you want too (as long as you provide enough air bubbles). But you can use a lot of different materials to build a slimier water culture system setup.

Here is a simple drip system that I built for growing large plants,
http://www.hydroponicsonline.com/for...w-systems.html
A drip system is the second easiest type of system you can build, and I simply wouldn't grow tomato's with anything less than 5 gallons of root space. This system only cost about $80 to build, and that includes everything (even the pump and growing medium). It is also easily expandable to accommodate many more plants even with the same pump, although I would use a larger reservoir.

Here is another simple drip system that I built as a makeshift system to hold some Mellon plants
until I was able to build their permanent home, but I didn't have the money to build it in time before they got to big to transplant. It would have cost about $150 complete with two 6 foot troughs and growing medium, a "A" frame trellis for the vines to grow on, and an in ground reservoir and pump to keep the nutrients cool.
http://www.hydroponicsonline.com/for...26-melons.html
I built this make shift system with all left over parts, but you could easily build the same thing with new parts for about $50 including a pump reservoir anf growing medium. You could also easily expand it to more than one growing container using the same pump for multiple growing containers. I use nothing more than regular tubing that I poke holes in with a hot paperclip to make the drip holes with. Not much simpler or cheaper than that. And you don't need to worry about clogged dippers or spraying heads.

Here is a drip system I built for growing root veggies using sand and perlits similar to what you want to use.
http://www.hydroponicsonline.com/for...en-onions.html
No mater what you use as a growing medium you will run into a problem if you want to use this type of a system to everything at once in. One of the biggest issues id harvesting the plants like lettuce that don't take long to grow. As much as you try you wont be able to get the entire root system out, and the roots will intertwine with the other plants, making pulling them up much harder also. But the roots that break off and are left in the growing medium will die and begin to decay. These decaying roots will feed pathogens and fungi that can cause root rot, and plant diseases for the plants left in the system. This type of thing is what I am referring to when I mentioned plant and system maintenance being much more difficult when you try to grow everything in the same system.

Here is another simple flood and drain system I built for growing medium sized plants, but can be used for smaller plants as well.
http://www.hydroponicsonline.com/for...rd-system.html
Again this system was inexpensive and yet easily expandable, even using the same pump. I would just increase the size of the reservoir depending on the type of plants used if growing in more than one tube. The larger the plants the more water they will drink up daily.

I prefer to use coco chips for a growing medium most of the time. It retains water real well, and is fairly inexpensive running about $10 for 2 cubic feet (assuming you don't need to have it shipped to you). That also makes it about half the price of perlite or vermiculite I can get locally that runs about $20 for a 2 cubic foot bag. As I do with my drip systems I like to use rock on the bottom of the growing chamber for weight, and to aid in good drainage. That also takes up space so I don't need as much growing medium.

P.S.
Anytime you use wood in an area where it will be subject to getting wet, you run the risk of mold and rot. So if you do so make sure it's completely 100% waterproof. Also from reading the posts in both forums, I think your underestimating the size of the plants. That will cause problems for you. But we all learn from experience, and that experience just helps us in the future.
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Old 06-18-2011, 03:16 AM
animus_divinus animus_divinus is offline
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given the size im working with.. ebb and flow might be too expensive to set up... so what i think ill do is cover my 4x8 foot table with a piece of plywood, cut holes in that to fix the net/basket pots so the roots will hang out into the solution, and run an aquarium air pump possibly through a length of PVC pipe with tiny pin holes drilled in it to aerate it all

what i like about this system, is that if i grow anything where the roots perhaps arent long enough to reach the water source.. like some herbs and spices, i could go with a wick method to supply water to the smaller plants, which will allow me to use two systems in one without complicating anything at all

so, 8x4 feet, maybe 6 inches deep, lined with a tarp and sealed in.. in the bottom will be the PVC tube with holes in it to supply air from an aquarium tank made for a 75 gallon aquarium... and the top piece of plywood will have holes cut in it to set the net/basket type pot... and really, thats all there would be to it... except the light of course

many of these deep water culture systems i see dont even have a medium for the plants.. which is fine.. and for those few plants that may not be large enough... i can plant them in some perlite mixed with coconut husk fibers to absorb the nutrients from the wick

so far (for the size im working with)... this sounds like the least expensive and simplest way to build a compact system
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Old 06-18-2011, 06:04 AM
GpsFrontier GpsFrontier is offline
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Well you can try it, but I can see a few problem. First is one 75 gallon aquarium air pump wont be anywhere near enough air for the amount of plants your planing. Especially for the large ones like tomatoes. You'll want a high volume air pump, something like this: Super Luft Pump - 3.9 psi - 66W (Output 2.3 CUBIC FEET PER MINUTE). Second a PVC tube with holes drilled in it wont be able to create all the tiny air bubbles needed like an air defuser (air stone) can, I've already tried it. Bottom line you'll want the air bubbles to be as small as they can be in order to create as much surface area between the air bubbles and the water. That's what allows the oxygen molecules to be absorbed by the water. That also allows them to be distributed thought the water and through the plants roots much better. You might try soaker hose (like for drip irrigation), it's my understanding it works well for a air stone replacement. Providing the tiny bubbles, it's also flexible so you can cover the bottom fairly inexpensively. I haven't tried it yet, but I'm told it dosen't clog like the the regular flexible air stones do.

Next is the weight. You said you didn't want your table to weigh 1000 pounds. A 8 foot long by 4 foot wide table that is 6 inches deep in water will be heavier than 1000 pounds. That will be 16 cubic feet of water. There are 7.48 gallons of water in a cubic foot. 7.48x16= 119.68 total gallons. A gallon of water weighs approximately 10 pounds. That means your table 6 inches deep full of water will weigh about 1200 pounds (without the plants). it can be done, but make sure the base is very sturdy.

Next problem is the top section you plan to place the plants in. I don't know how you plan to construct it, but there are a few design issues you will want to think about for maintenance. First You'll want to make it in sections instead of one piece. If not you will have an extremely hard time taking plants out and replacing them. The roots will also become intertwined with other plants, and cause you problems when it comes time to move them around. Also if you made it one piece you will never be able to lift it with the weight of the plants in it, even if you could or had people help you, it would collapses under the weight of the plants (when growing large plants like tomatoes, beans, peas, peppers and herbs etc.). Witch leads me to the next point, you will want to create a support system for the top spanning across the water to support the plants weight as they grow heavier daily.

Another maintenance issue is nutrient changes. You will want to at least build into your table top water culture system a "draining system." Otherwise nutrient changes will be too difficult to do. But you should really have a table to place the plants on so you can clean the water tray as well, if not you wont be able to clean it if there is a problem without killing your plants.

But if it were me and I was going with a large water culture system like that I would also use a secondary reservoir (with at least one third the water volume of the system). Pump it up through the system, and have it overflow back down to the secondary reservoir. Not only would that provide better water circulation, but make nutrient changes much easier. Instead of completely changing it, I would just empty the secondary reservoir, clean it and fill it with fresh nutrients, and only clean the main system if/when it needs it. Then let the fresh nutrients cycle through the main system. Basically that would replace 1/3 of the volume of water with fresh nutrients each time, and I wouldn't need to worry about the water level in the main system either, and/or how to add replacement water that the plants drink up (simply add that to the secondary reservoir).
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Last edited by GpsFrontier; 06-18-2011 at 06:48 AM.
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Old 06-18-2011, 12:22 PM
animus_divinus animus_divinus is offline
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hmm.. youre math is a little wronga gallon of water weighs roughly 8.34lbs, and the entire container would be 6 inches deep but if it was filled all the way to the top, it wouldnt leave much room for good aeration, so even if it was filled up to the 6 inch point, it would not weigh anywhere near the 1400lbs of gravel, and the 8x4 by 4 inch area will only weigh roughly 600lbs...

also, i intent to have a bit of a hatch on top where i can find some free space.. atleast large enough to fit my arm in

the plants would be setting in the holes, the lip of the pot would rest on the top surface while the rest of the pot sits in.. so they could me lifted out from the top...

i could put a 1/2" piece of PVC into the bottom, and plug it with a rubber stopper like in the back of a toilet.. so all i would need to do is pull that out from the hatch to drain it into buckets below...

a question for people that have built such large deep water culture systems... about how long does it take before the solution has to be changed?

since this will be set up in a basement, im thinking of installing a float inside the resovoir, that when it drops below a certain point it will light up an LED which will be wired upstairs, maybe in my living room so that i wont miss a refill
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Old 06-18-2011, 12:36 PM
animus_divinus animus_divinus is offline
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see, the trouble im having is when i look at other peoples systems, theyre usually small scale for single, or a small group of plants, none of them really seem to be tailored for this size.. and i will be confined to a 32 square foot area to do this with.. so putting in multiple systems would just take up additional space

instead of scaling up techniques for smaller scale hydroponics, i may want to scale down some industrial methods for this.

the table i will build will have four, maybe 6 4x4 legs, the bottom section will be 3/4" plywood and will have a border of 2x10s or 2x12s that will by fixed below the 3/4" plywood table, and extend 6-8 inches above the table to act as the dies as well

inside this a plastic tarp will line the bottom and sides, and then a rubber strip will be glued around the top of the walls so itll act as a gasket when the top piece (probably 1/2 plywood) is layed on top

ive seen drilled PVC used for large scale aeration before, works quite well...

if anyone things something other than deep water culture would be better for the project, let me know
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Old 06-18-2011, 10:06 PM
animus_divinus animus_divinus is offline
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anyway.. this isnt so immediately important, im going to start with smaller systems and build onto it so im not taking such a major initial risk in costs
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Old 06-19-2011, 03:42 AM
GpsFrontier GpsFrontier is offline
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Quote:
hmm.. youre math is a little wronga gallon of water weighs roughly 8.34lbs, and the entire container would be 6 inches deep but if it was filled all the way to the top, it wouldnt leave much room for good aeration, so even if it was filled up to the 6 inch point, it would not weigh anywhere near the 1400lbs of gravel, and the 8x4 by 4 inch area will only weigh roughly 600lbs...
I was just going by the measurements you gave on your system design. If you drop the water level to 4 inches, that will cut 1/3 the water and weight. As for the weight of the water, for some reason I still remember from way back when, when I worked as a courtesy clerk at a grocery store, a gallon of milk weighed 9 pounds, and I did say water weighs ""approximately"" 10 pounds. But going by your figure of 8.34 pounds, and cutting the water volume by 1/3, it does come out to a little under 700 pounds. Although I was already weary about using only 6 inches of water for such large plants as tomato's, peppers, beans, peas etc..

P.S.
While I'm thinking about it peas are legumes, and legumes secrete root extrudes. These root extrudes could cause problems when the roots come in contact with roots from other plants.

Quote:
the plants would be setting in the holes, the lip of the pot would rest on the top surface while the rest of the pot sits in.. so they could me lifted out from the top.
It sounds easy enough to just be able to pull the baskets up through the holes, but if you haven't grown them that way before, you would be surprised how fast the root system grows. If the baskets you use have slats on the sides of the baskets, the roots will quickly grow through them. Making lifting the baskets out of the holes without damaging the roots impossible the bigger the plants get. Just look at the root mass from my pea plants (picture attached), that was from only 4 plants, and completely impossible to lift the baskets more than an inch up through the holes without cutting the roots with a knife.

Quote:
a question for people that have built such large deep water culture systems... about how long does it take before the solution has to be changed?
There are quite a few variables, and there is no set time. That is also one of the difficult parts when you are growing everything from small to large plants in the same water culture system. The individual plant needs cant really be accommodated. But small plants wont drink up nearly as much water and nutrients as the larger ones will. In contrast just one of my broccoli plants could drink as much as 2 gallons of water a day when it got big, but I had 8 lettuce plants and they would only require about 1 gallon a week (all of them combined) when they were big.

The bigger the plants the faster they will take up the nutrients, and thus leave the nutrient solution unbalanced. But I generally let my plants go between one week, and 3 to as much as 4 weeks (in some cases) between nutrient changes. But the amount of water volume in comparison to plant size and root mass is a huge factor in how fast the nutrients are depleted from the water. In the cases where I let it go for over two weeks, the plants were not full size, or there was a large volume of water in comparison to plant mass. General rule, large plants like tomatoes need a "minimum" of 2.5 gallons of nutrient solution per plant, medium sized plants like herbs or peppers need a "minimum" 1 to 1.5 gallons per plant, and small sized plants like lettuce need a "minimum" .5 gallons per plant. If you use the minimum amounts, you'll need to change your solution often like every week. If you use double the minimum volumes, you can probably go two weeks fine. If you use double the minimums, and your plants are less than half size, you can probably go longer than 2 weeks. But when you have various types of plants, and of all different sizes, as well as in all different stages of growth, there's no real guidelines to fallow. It's just more of a guessing game, as well as trial and error.

Quote:
since this will be set up in a basement, im thinking of installing a float inside the resovoir, that when it drops below a certain point it will light up an LED which will be wired upstairs, maybe in my living room so that i wont miss a refill
This is a good idea, although I would just use a float valve connected to a water line. Let the water line automatically fill the reservoir to the desired water level automatically. It won't provide water circulation to the main reservoir, unless you use a secondary reservoir as well. But it will keep the right water level. You can get a simple float valve at wal mart for about $4 (it's a replacement float valve for swamp coolers), or anyplace that sells swamp cooler parts.

Quote:
see, the trouble im having is when i look at other peoples systems, theyre usually small scale for single, or a small group of plants, none of them really seem to be tailored for this size..
Well there's a pretty good reason for that, and it's not really the size, I don't consider that large at all. The reason you don't really see systems like what your planing is because like I mentioned, different plants have various different need. And trying to combine various different plants into one system, tends to yield poor overall results in comparison to using separate systems. So that's just not the route most people take. I know you have your hart set on creating a one system for everything setup, that's fine and I wish you luck if that's what you want to do. I would just suggest to be prepared for a "lot" of trial and error, as well as on the fly problem solving with such a system. Especially if you don't have experience growing things hydroponically yet.

Quote:
ive seen drilled PVC used for large scale aeration before, works quite well...
Yes for large scale PVC works (provided you have enough holes, and their small enough), although I still like the soaker hose idea because it dosen't cost much (if any) more than PVC tubing. But large scale operations have some very important factors that set it apart. First is the very large volume of water compared to plant size and root mass. This is a very important distinction, because if not the plants would use up the dissolved oxygen faster than the air bubbles can replace it. Second is water circulation, commercial operations have water pumps that circulate the water in water culture systems. And lastly commercial operations don't use aquarium pumps, they use air compressors to be able to get the large volume of air required for such a system, as well as the higher PSI to create small bubbles through precisely sizes and spaced tiny holes in the PVC tubing.

P.S.
I would also guess they also employ another method of oxygenating water as well. I believe it is called an "air lift." That combines air bubbles to lift water in a tube, and allows it to overflow creating falling water that also oxygenates the water. It's used especially in large volume fish tanks. That is fish tanks that hold thousands of gallons of water. Here is a link to a thread where it was briefly discussed. There are a few pictures that basically show how it works. You can always build a smaller scale one. Basically it churns the air bubbles and water as the water rises to the top of the tube, before it falls back down, churning some more.

http://www.hydroponicsonline.com/for....html#post3666

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