Picture of Hydoponic garden - Gravity feed
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What are hydroponics?

Well quite simply, this is a method of growing plants with out soil, the plants roots are in direct contact with the nutrient solution. (nutrient minerals dissolved in water)

At their essential basic hydroponic systems are just another method by which to grow plants, but unlike the soil out doors, this method allows you to control and maximise the requirements of life in order to maximise end result.

How you maximise the conditions and requirements of the plants (food, pest and disease control) dictates whether you plants are truely organic or not. For the purpose of this instructable (and any thing I have my hands in !) it will be totally organic!

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Step 1: Outline - My Passive Gravity fed system

This instructable defines a system of hydroponics that is gravity feed, and provided you keep the nutrient tanks full, you only need to monitor plant health, occasionally maintain the system and chomp the end product. It is based in a small glass house, but has been run successfully inside on a window sill and in a conservatory also.

All references to "fig...." refer to the individual photos on below each page(each is labelled in the yellow squares)

In order for a plant to grow ( just like us..) it has 5 basic needs;
a.) Water supply (we supply)
b.) Food supply ( dissolved nutrient solution)
c) Light for photosynthesis ( Mr sun)
d) Temperature management (seasons + extension being in glass house)
e) Gas exchange ( Mrs nature)

.All instructions are based on my materials locally available - you will need to adapt them to yours.

You will need;

- Rectangle section hydroponic tray tube with end caps ( you can get it pre drilled too)
-(or standard guttering with end caps)
-Rubber grommets to suit tubing used 13mm & 4mm
- a grommet, and tap to match the size of pipe you wish to use for the drain pipe( 30cm of pipe) (hardware - irrigation supplies)(the pipe i use being 13mm irrigation hose)
- '''Autopot Smart valve Mk 11''' ( thanks to: Clive who read this instructable and found this far more reasonable supplier of smart valves!)
- 4mm tubing (Bunnings hardware irrigation supplies)
- 4mm tap (Bunnings hardware irrigation supplies or aquarium shop)
- 20 Lt plastic Jerry can
- Materials and construction tools to make a light prove box over Jerry (timber, screws, saw, drill, screwdriver in my case)
- Nutrient concentrate + tap I buy mine in 5 litre containers.(fit with a tap and decant in to one litre bottles for ease of us.)
- Hydroponic tray tube (100 x 75) you can also get tube tray with holes ready cut or standard house gutter.
- Plastic gutter PVC solvent cement
- File
-Hack saw / power saw
- Drill press ( ideal) or power drill
- Drill bits
- Drill saw (or method for drilling out circles of plastic)
- Inner tube band
- Gib board plastic corner lengths
- Self taping screws - four per tray
- Builders long level
- EC meter(Conductivity/TDS)
-Wooden wedges - 30 - 60 degree ( 4x per tray)
- Growing media - expanded clay balls
- Weight (quarter a brick )
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damn right u were lucky. other wise u would be named nine fingers.
sampson1114 years ago
wat chemical would i use for capsakin strawberries and tomato please reply asp thanks
agatornz (author)  sampson1114 years ago
hey there,

Not sure what you mean by chemical... or is it which solution of dissolved nutrients would you use? to grow capiscums, tomatoes and strawberries?

With all of these plants you would start off with the solution to promote leafy growth,(green) then as they flower - switch to that to promote fruit(red)

It is however the EC levels that will be different -while from memory the tomatoes and capisums will happily grow together on the same levels - i dont believe strawberries will... requiring a separate tray.
thank you that helped so much
Is organic fish dirt ( from under the bottom filter ) any where near as good as store bought fertilizer for aquaculture. This is what I was going to use, but I have no idea about the ppm, pH and so on. Interesting, instructional, answered many of my questions.
agatornz (author)  Brainchigger14 years ago
hey there.. sorry might be missing something..what is the reference to organic fish dirt under the bottom filter?
All the filtered dirt and Bactria found under the under gravel filter, Very fine and fluffy material.
Pizzapie5004 years ago
Where do you get nutrients and expanded clay balls?
agatornz (author)  Pizzapie5004 years ago
hi in New Zealand we get them from our local hydroponics store:-0 you can if you ultra keen make your own nutrients using raw minerals mixed in water but that's all bout getting the right amounts - i just get pre made fairform concentrate
anandsa4 years ago
hi, Some nice information, but can you tell me what chemical you used? i would like to maintain a pH between 5.5 -6.5. i wanna plant lettuce.
agatornz (author)  anandsa4 years ago
hi there,

i think when you refer to chemical you mean nutrient solution?( there are no inorganic chemicals used) 
I used commercially produced Green dream by flairform which is highly pH balanced an as such when measuring concentration (ppm) of the water solution i never needed to adjust pH, unlike the concentration that needed constant attention given the variations in climatic conditions and plant requirements.

I did have some chemicals that were designed for pH balancing, in fact if i recall rightly they were actually a common household substance or medication - ill dig it out and tell you ..

do you have the recommended nutrient concentration for lettuces, i should post the list up to the instructable too..:-) hope th

reitaka185 years ago
Hi; Just another question. I got some smart valves sent up to me from the manufacturer; but they didn't have any covers. Do the covers come with them? or do you have to buy them separately? Can the smartvalves work ok without the covers? Thanks
agatornz (author)  reitaka185 years ago
hey there, as far as i know they need the covers to work.. i tired getting away with out them too, but if you notice the bottom edge of the cover actually rests on a little tab foot on the valve that keeps it in position when you put in the water with a weight on top of the cover. (other wise it just floats and doesnt work) there is also a little breather hole in the top of a cover - which i guess must be linked to its function.. odd that they dont sell them to gether but i guess they could assume you already had some.
reitaka185 years ago
Hi; Thanks for the great instructible. I was wondering what do you do with the drain tube; ie how often do you have to drain it. Thanks
agatornz (author)  reitaka185 years ago
thanks for that comment - ill make some adjustments to the instructable to reflect that. i drain the trays when ever they need cleaning - such as when aglae takes hold - this happens when sunlight is allowed to reach the nutrient water, having the drain pipe in place makes it considerable easier to get the water out of the tray with out having to remove it from the setup.
ranger245 years ago
If you go to this site you can buy the smart valve for $20.
agatornz (author)  ranger245 years ago
Hi, Thanks for that... however since i Live in New Zealand, that would still work out as more expensive by the time i have changed the currency and added postage...:-) thanks
agatornz (author) 6 years ago
well the strawberries are nice and juicey and fat, so i thought i would run a little test given the depth of feeling with some of you about earth grown. Take 5 strawberries each from my set up , from the shop , and from another bush grown in the earth, add different coloured paper clips representing the group they came from... take 4 friends, faciliate the selection of strawberries in to their mouths, ask them to return the paper clips they didnt like..... mmmm no prizes for guessing which were regarded as the best - perhaps smaller than the shop ones but still the best....:-)
jovation6 years ago
Hydroponic has its advantages - but if you're looking for taste, plants grown in fertile soil in season, with the right amounts of compost or humus, are superior. Even potted plants with this mix (if you don't have a garden) will give you better results in this respect.
I totally agree. Since I work in the green industry I've been privy to different growing techniques and from personal experience NOTHING tastes better than a fruit/veggie that has been grown in contact with the Earth...
agatornz (author)  firemosca6 years ago
and like i say i totally agree with you, love to see NASA with an earth garden however hehehe - thanks for your commment though, makes interesting thought if the only thing different from this style of gardening is that there are no restrictions on the needs of the plant....
agatornz (author)  jovation6 years ago
(removed by author or community request)
As I said - hydroponics has its advantages. The fact that you live in an urban area does not necessarily mean you can't set aside some room for potted plants (in the same way you do for a hydroponic system) - the question is always priorities. And yes, I have tasted hydroponic vegetables that have been grown in mixtures such as you demonstrate - I have not found them to be as good as same grown in fertile soil. But perhaps I will yet encounter an excellent hydroponic grower that will persuade me otherwise. Taste is a subjective matter, anyway, and will always be something to argue about... Thanks for the instructable!
static jovation6 years ago
LOL "taste", is a subjective matter I agree. In regards to hydroponically grown vegetables, have any blind taste comparisons ever been conducted? That should take the subjectivity out of the issue.
agatornz (author)  static6 years ago
ditto, the instructable is merely and option for those of us in the urban enviroment.... i am sure not getting to hung up about what it tastes like - my straw berries are sure nicer then the shops...
agatornz (author)  jovation6 years ago
as i said - its merely and option. if this is not your "cup of tea" thats cool....
digital01296 years ago
Hey, very nice Instructable. When you start the flow of water, how thick is the stream of water? Also, do you find that the plants have a hard time being transported from soil into a water environment?
agatornz (author)  digital01296 years ago
hi there, well giving i am using four mm irrigation tubing routed through the smart valve - it comes out the same size as the hole in the smart valve - you can just see it in the video 1 - is this what you wanted to know? not quite sure what you are getting at. roots - the only reason plants in the ground dont grow as well as hydro's is they have to compete for nutrients and water, as well as find them... in hydro all the nutrients and water is right there at the back door - so as long as the roots make it to the "water line" they adapt fine.... so in theroy the plant needs to put less effort in to roots in water than on land - all though i have notices that many of mine still have huge roots - to the point where i often need to prune them.... taking plants from hydro pack to earth hasnt been quite as successful - but ihave had some success also - about to do so with some of the sunflowers in thelast pictures of the instructable
Sorry I wasn't clear. I was asking about the water level in the bottom of the gutter.
agatornz (author)  digital01296 years ago
oh ok - the valve design brings the water level to approx. 1 inch
Ceefa6 years ago
Hi Agatornz, I enjoyed your instructable. Well done. I have been growing in hydroponics for some time but never heard of the smart valve. Your instructable makes me want to experiment with them. It make the whole job so easy. I am in Christchurch NZ and from your name I guess you're in NZ too. Do you still have to buy the valves from Aussie or are they available in NZ. If so how much are they and where can they be purchased.
agatornz (author)  Ceefa6 years ago
hi Ceefa, Well currently yes the only place i can get smart valves is from melbourne (where i was living when i found them.) I searched all the hydroponic suppliers in NZ, most had never heard of them and didnt believe there was a market for them here in NZ ( ? they seemed to be suggesting to me that people had more interest in more control as there crop of choice was worth something....? ) SO I currently get them through a friend who lives in Melbourne - i tried to get them direct from the company but they were charging horrendous postage ( which i cant figure out given we can do it far cheaper....) short of convincing your local guys to import them.... ( i havent managed to )
agatornz (author)  agatornz6 years ago
the valves design is a registered patient.... so i guess that rules out finding some smart kiwi brain ( kiwi ingenuity) who can build a simply version of what they do...
MikePri376 years ago
ok no offense but itsnt the point of a hydroponic garden to grow using containers and watter not soil or clay
agatornz (author)  MikePri376 years ago
i think perhaps you are confused with Aquaponics - this system uses bare roots in a darkened container which are perodically sprayed with nutrient solution.

the hydro in hydroponics refers to the method by which the nutrients are supplied to the plants ( hydro = water) they still need to be supported in some manner - hence the growing medium of choice ( which has quite different properties to soil.)


Aquaponics on the other hand does not use medium (ie cal
Reade6 years ago
Hey, this is a very detailed Instructable and it is clear you put a lot of work into the article but it could use some revisions to make it more accessible. For example, there are many parenthetical remarks; some of which that interrupt the flow of the sentence and I had to read that paragraph several times to get it. e.g.: "The key thing about this valve that makes it so darn annoying (wish I could think of a way to do the same thing) as I have to buy them from overseas currently)" Also, you have your own step sequence that contradicts Instructables numbering sequence (step 3Water Supply - step one) Finally, you could make some of the images clearer (not the one of your hand injury, thank you very much!)
agatornz (author)  Reade6 years ago
enjoy the instructable - it takes a hell of a lot of work to put one up :-) i think you get the general gist.
SteveGerber6 years ago
MAJOR TYPO: Your title has a misspelling: Hydoponic should be Hydroponic (Feel free to delete this comment after correcting.)
agatornz (author)  SteveGerber6 years ago
thanks for that i do make and effort to spell check but some always slip though... have always been and imaginative speller:-)
chalky6 years ago
WOW! this is more like the HYDROPONIC BIBLE:) im just getting into this and i find this 'ible' priceless so thanks. ps/what did your strawbs taste like?
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