This instructable will explain household hydroponics, with the intention of growing edible flora.
In layman's terms, hydroponics is the science of growing plants without soil-- although the plants may or may not be suspended in a solid medium such as gravel, or expanded clay balls.
Soil retains minerals and nutrients, which "feed" flora, as we all know. Plant roots can't absorb dirt, however; when water passes through soil, it dissolves and collects some of the nutrient particles embedded. This "food" solution is absorbable as a liquid. As you can see, the soil itself is not an integral part of a plant's feeding cycle-- it is simply a stabilizer for the roots, and a convenient filter.

Why eliminate the soil?
Plants breathe air, just like humans. School children are taught a simple lesson: plants take in carbon dioxide, and release oxygen. The entire plant-- not just leafy material-- contributes to this process.
If not properly maintained, soil can retain too much moisture, effectively suffocating ("drowning") a plant's root system. Alternatively, if the soil doesn't contain enough moisture, the plant will be unable to absorb the nutrients it needs to survive.
The roots of a hydroponic plant have constant access to both air and water, and it can be much easier to maintain that balance since the roots are typically visible.
The average plant needs at least five things to survive. Air, water, nutrients, minerals, and light. So long as you can provide these things in plenty, your plants should stay healthy.

Growing your own food can be a rewarding experience. It's a good way to save money on pesticide-free produce, and you'll know it wasn't shipped from a third-world serf farm supporting bad business. If your hydroponic system is indoors, you can grow food during the off-season in winter, too.

That being said, there may be more efficient systems out there for the home grower. I created this instructable to inform, more than anything.
After all, if anything's worth doing, it's worth doing right. Gotta do your research, kids.

Step 1: Substrate 101

Although not necessary for the survival of a plant, substrate can help to support a plant physically and hold it upright, either by securing the root system, or by outweighing the plant itself. There are many kinds of substrates commercially available. Check your local greenhouse or hardware store. Alternatively, there are plenty to be found outdoors, especially near bodies of water.
Even simple rock can alter the PH of your system. When checking your PH balance, be sure to check it after it has circulated through your substrate.

In the moisture-rich conditions hydroponics typically provide, substrate can be generally classified into the following categories: sandy, granular, and pebbled.

Sandy environments consist of particles between .06 (fine) and 2mm (coarse) in diameter. Even coarse sand retains a considerable amount of water (except in comparison to soil), and is not generally considered appropriate for use in a hydroponic system. If you use a pump, for example, the small particle size may lead to clogging. However, it is cheap and readily available, and, when wet, is heavy enough to provide a reasonable anchor for plant roots.
There is some absorbable nutrient in sand. Typically speaking, the nutrients latent in sand culture vary widely on the substrate's color and origin. Most sand contains a large quantity of shell fragments, and thus has a high calcium content.
Black sand usually has a high magnetite content originating from volcanic rock, known for its fertility. Orange or yellow sand might be an indicator of a high iron content.
White sand tends to be very high in silica, which helps build healthy cell walls in plantlife. Diahydro, for example, is made from diatoms, a type of algae.
Sand is semi-reusable. Sterilizing it between uses can be messy. (Sand can be sterilized by boiling it in water for extended periods of time.)

Granular particles range between 2 and 4mm. This may consist of gravel, or plant mulch.
Stone gravel makes a heavy, non-biodegradable anchor for plant roots, and is highly recommended for use in hydroponic systems. Stone gravel contains very little latent plant nutrition, just like sand. There are several grades of gravel readily available to choose from.
Creek rock and Pea Gravel consist of round, shiny stones. The smooth shape of these stones allows for great aeration and root growth, although the drainage may be excessive.
Crushed rock is typically made by crushing large chunks of limestone or dolomite into smaller pieces. Crushed rock has sharper edges than creek rock, and tends to interlock better. This tighter knit makes for higher water retention, although limestone tends to weigh less. Limestone is a strong alkali. Check your PH, and balance accordingly.
Stone-based substrate is highly re-useable. It is considerably less messy than sand to boil for sterilization.
If weight is not a concern (ie: the plants you grow are not expected to reach considerable heights) you might consider using a plant mulch, such as peat mulch, cedar shavings, or coir (coconut peat). Mulches retain a high quantity of water, but also breathe very well. Mind you, they are also highly degradable, which can lead to clogged pumps, and wood shavings often contain aromatic oils which can inhibit plant growth. Mould and algae growth poses a higher risk when mulches are involved, but pose one considerable advantage over rocky substrate: they can be composted and replaced with fresh material. It does not need to be stored. I would n't suggest re-using 'em, anyway. This is especially convenient if you use hydroponic systems exclusively to start seeds, or grow during the off-season.

Pebbled substrate measures between 4 and 64mm.
Stone pebbles have the basic characteristics of creek rock. They are typically smooth, often shiny, and the gaps between the stones make for low water retention and high aeration. The shinier the stone, the worse the water retention will be. A matte or pockmarked surface indicates a porous stone, which will stay damper, longer, whilst still providing excellent aeration. Pebbles-- especially the porous variety-- can explode when heated for sterilization.

A common alternative to these substrates is mineral (rock) wool. You've probably seen it used as insulation in housing. Rock wool contains fiberglass, and it can be absorbed into the body by inhalation-- irritating eyes, skin, and lungs. It needs to be treated before it is a tolerable substrate for plant growth. Altogether, I don't recommend its use.

As I've said, you should boil your substrate between uses to sterilize it. Bacteria love warm, wet environments and will probably thrive in a hydroponic system.
Just a heads-up, here... algae loves wet and warm (and lukewarm... and cold) systems, too, and it can look unsightly. If you care about appearances, boiling your substrate between uses will discourage blossoming, but if you use grey (recycled from previous use) water you'll be fighting a losing battle.
<p>Hey, lots to add here about watering - what type of water to use, etc! I have a few pieces already on my blog that cover this more in depth if you want to add them or update the Instructable:</p><p>Tap water: http://www.epicgardening.com/can-you-use-tap-water-for-hydroponics/</p><p>Distilled water: http://www.epicgardening.com/distilled-water-for-plants/</p>
the problem with using anything is how it will effect the PH of your system short term and long term. as minerals degrade they change your PH. I think it would be harder to maintain a constant PH with mineral water. Personally I use filtered water and then let it sit for a few days to equal out. Also with anything you use it should be cleaned thoroughly and soaked for a day or two before nutrients are added. In fact NEVER add nutrients or start plants until you have successfully balanced you systems PH for a day straight running then add your nutrients and finally your seed or clone, If you are very carfull you can start your seeds conventionally in soil until they have good roots then soak it in pale of water to gently wash ALL the soil off and then put it into the media. I use perlite and peagravel. PH is the key to perfect Hydroponics and deep water culture, Know the proper ph for your plant growth and also MAKE SURE YOU USE THE RIGHT NUTRIENTS!!!!!! NO NO NO MIRACLE GROW
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Would mineral water help with anything?
Just curious if anyone has used the liquid byproduct of a biogas digester as a solution for hydroponic gardening. I am building a digester into which I plan to use kitchen scraps (no animal products) and am looking at grass clippings from the lawn. once this is broken down it would be great if I could use the resulting liquid fertilizer to add to a hydroponic garden. kind of completing the cycle... Any thoughts?
This Instructable has lots of top-notch info on hydroponics. will you permit me to add it to my &quot;<a href="http://Instructables.com/groups/plants">Plants</a>&quot; group?
Just to dummy-proof the water thing... That's the formula for photosynthesis. Food making. That's all. Totally different from mineral collection necessary for cell construction. All that formula is for is making sugar to fuel the plant. It still needs basic building blocks. Also, excellent plan my friend. I'm going to build my own system soon, though a bit modified to fit in a cramped space. Hopefully hydroponics catches on as mainstream and more people will become self reliant and healthier. But enough daydreaming lol.<br />
As our planet rotates, the east-west location is not only irrelevant but placing plants anywhere but facing north or south reduces the light that reaches the plants. Placing them in south(north)-eastern facing rooms will block out the evening sun, which will allways come in from south(north)-west to west (depending on season and distance from the equator), as does placing them in south(north)-western facing rooms with the light of the morning sun.<br />
&quot;water is not enough &quot; , why not ? everything is there and the sand and crap just holds the plant up.<br/><br/>the symbol equation for photo synthesis is 6 h20 + 6 C02 ----------&gt; c6 h12 06 +6 o2 <br/><br/>with chlorophyll and sunlight above the arrow . all the reactants are there , h20 is the main ingridient and c02 is worryingly plentifull<br/>
I challenge you to produce healthy, edible growth from a plant using distilled water. Go wild, sugar. I'll wait. The results are going to be pretty sad, though. As much as I'd love to cite a formula, I'm just going to let experience speak for me. Yes, the math is there-- a plant can subsist off of air and water alone. It will not thrive.
im not saying that it would produce good plants , but it would produce a plant . cetainly fertilizer , mineral aditives and substrate would produce a better plant . but just water would produce a small , withered under nourished plant. and who said anything about it being distilled water , especially in my area , tap water contains more minerals and vitamins than a plant could ever want , ever! and no one would buy really expenive distilled water when tap wtare by its very nature is better . satisfied stressy knickers ? way to over react , i made a (valid) statement , that was all...
I tend to disagree with this statement beyond the nutrient factor as tap water by it self in a hydroponic system attracts diseases and infestation. This is a big reason for using distilled water. When it comes to hydroponics cleanliness is next to godliness and one cannot obsess. <br /> <br /> On the nutrient level, the trace elements in your water might be JUST enough to keep a plant alive( for a bit ) but once the plant starts taking up nutrients and the PH swings with it you have to adjust your PH almost daily in order to prevent nutrient lockout. Plant require 3 main N-P-K and 12 micro nutrients to thrive. They take up these different nutrients at different PH levels. (around 5.8 to 7.0, plant dependent)&nbsp; There are more obstetrical to what you have said which in all reality makes it very impractical to state that water alone will grow a scawny plant, Not to term. Why would someone want to grow that.&nbsp; But I would be willing to give it a shot to see the out come. If so just shoot me a analysis of your water so I can produce to the same. We could use either my DWC or top drip bucket systems.<br /> Be safe, Acanna<br /> <br />
Photosynthesis only requires the given formula, however the structures of every cell in the plant require all kinds of minerals. A large blend of different things creates more vitamins for you to eat.
Please tell me that your going to enter this into the garden competition. It is an excellent instructables (*****) and I can't wait to use the worm composting idea (I tried before and it didn't turn out well). One question though, how much and how often do I put the food and newspaper in?
Hey, thanks for the rate, and your lovely compliments! I don't think I qualify for the garden competition, as this instructable was published last year. I'll have to look at the rules. As for your question: I use a rule of thumb. Time is not an issue, here, but for every three inches of food I add to the composter, I throw down a layer of newspaper. Sometimes that takes a day, sometimes a week.
I Like the guide! am getting the bug to do something like this. Can you remove seedlings from potting soil to transplant into a hydro medium? I have a bunch of perlite still in the bag, will this work for a medium? If not I guess I can go get me some gravel some where or a bag of river rock at lowes. And also a great worm container! My old plastic tote of crawlers will love the new home once I find a thermos like that one ! One last question, will a nursery carry a commercial hydro food? if so will they help me decide on what kind I need for which veggies I want to grow?
Oh, dear! I totally missed this comment. My appologies. I've had success moving potted seedlings to a hydro system, but very little moving hydro seedlings to pot. Perlite makes a fine medium, yes. I may have mentioned it, or a non-brand version of it, in the substrate chapter. I'm not fond of commercial hydro food-- labelling standards for this sort of product are poorly standardized, and you're working on a 50/50 chance, hoping that the staff are properly educated. I know my local nursery is fairly clever, but I can't promise the same for yours. Thus, the recipes provided. Thank you for the positive comments!
Healthy urine IS sterile - so why would you want to sterilise it ? Steve
Good point!<br/><em>Treating</em> the urine is the important part, obviously, otherwise you'll give the plants a nasty case of fertilizer burn.<br/>I hear now that simply allowing a bucket of urine to sit for a month is sufficient to break it down, and render it safe to use on plantlife. But that's just hear-say, alright?<br/>I mentioned sterilization because, obviously, not everyone's urine is healthy. It's better to be safe, than sorry. Even if it's just 1% of the time.<br/>
You are pretty ill if you have infected water - I don't think you'd want to pee for your plants ! Steve
A great beginner guide! Your PH suggestions seem a bit high though. A 7.0 PH is going to significantly reduce nutrient uptake is a large number of plants. Perhaps editing to mention that different plants required different PH levels, and some go as low as 5.0?
Just thanks for the instructable! (5starred, faved of course!) I actually know understand hydroponics! And now comes teh questions... Hydroponics consists of growing plants "In Water." Isnt using a substrate, well, cheating? Does the substrate contain/hold any nutrients? How is the growth of a plant affected by the nutritional absorbence of the substrate? What substrate absorbs the most nutrients? water? toxins? Does PVC affect the plant growth? Are there certain pumps you can use to filter the NutrientWater? Do you think you could filter a sand substrate, that is nutrient induced would grow a plant? Am I revers engineering hydropnics using only filtered sand? Is that the equivalent of regular growing? Perhaps im overthinking this? Ah screw it, its just starting spring, might as well start. Thank! -PKT
It could be cheating, sure-- but until somebody comes up with a better plan for supporting long-stalked plants without substrate, I'll be using rock. I use a variety of substrates, depending on, well, what I have on hand. To be honest, at the moment-- most of my plants are supported by river stones I stumbled across at the local creek. Clay substrate is HIGHLY absorbent, and so is sand. Clay pellets are much easier to boil and clean. Yes, when PVC is exposed to light, it leeches chemical over time. Although I haven't noticed any negative effects, there's a scientific argument for not using it. I have plans to build a hydroponic system out of clay-- but that's going to be an expensive and time-consuming process. I'll make do with what I have, in the process. I use a fish-tank pump, because it was accessible and cheap. There are specialty stores you might find something more suitable at, of course. There are pond pumps which you might find beneficial for a large system. Sand is made up of smaller pieces of rock, which contain nutrients. Filter to your heart's content, but you're still going to be leeching. I am under the opinion that growing a plant in sand is not true hydroponics, but it's a matter of opinion.
The answer is-- yes! If you don't use rock wool, the seedlings can be placed directly in the substrate of your choice. I sprout my seeds by stickin' them in a moist baggy of substrate on top of my fridge, where it's warm, until something green pokes out. Hardly scientific, but I've had great success with the process, thus far. I usually wait 'til the sprout is about an inch long before moving it into my hydroponic system. As for the bucket o' worms-- although I have enjoyed great success with my own bucket, I'm in the habit of leaving the lid off for days at a time. Several of my commenters have suggested drilling holes in the top, to allow for better ventilation. Use your judgement.
Firstly, thank you so much for cramming all this info into one place for me. Substrate mineral content would have been an after thought to me. This entire instructable is well-organized and is going to be incredibly useful. I can’t wait to try the Bucket O’ Worms. Ok, so I’ve just gotten into hydro and I have a question based on this step. I am currently set up with rock wool sitting in expanded clay with felt wicks (it was a kit I got for xmas). So, if I don’t use rock wool, which isn’t readily available here anyway, do I just put the seedling directly into one of the substrates that you mention? And if that is the case how big should the seedling be before its put in?
I am sure that you are right about all details, and it seems to me that the whole system is planned to be perfect in every detail. On the other hand, I have 3 fish tanks, the biggest one holds 250 liters of water. I think that I cleaned it the last time about 6 years ago. The thing is that we "clean" the fish thank about once a month by siphoning out about 50-75 liters each time, and refilling the same volume with fresh water. Now to the "thing": The "old" water is reused to water our plants, as it contains enough of nutrients to make our plants grow happily. Why not use this water in a hydroponic system? It would surely do the thing?
I did make a brief note about this: "If you already have a fishtank, you could simply use the water you would normally siphon off and discard during cleaning, and use it to top off your hydroponics system." The answer is-- yes. Kind of. I wouldn't run a hydroponic system EXCLUSIVELY off the leavings of a filtered fish-tank, because the resulting veggies might not be very tasty. Not much salt in fishtank water, eh?
i'm another one who has been looking (for ages) for a simple and easily available nutrient recipe; Epsom salt and Miracle-Gro i've already got. thanks so much for that alone, not to mention an excellent instructable! wouldn't it be great, though, if a body could get enough of that worm tea going to grow some nice hydro-edibles?
If you put the lid on the cooler would't you suffocate the worms? Or could you leave it loose, but then would the worms escape?
What about potential suffocation of the worms? Water tight generally equals air tight. I've seen the apartment dweller Veriform composter (somewhere)in a common storage tote with wholes in it.
I've been looking all over for a nutrient solution recipe. I don't care (yet) that miracle-gro isn't that eco-friendly, I just need a simple place to start. Once I get things going, then I'll look at alternatives like worm-tea. Nice instructable, I'd love another one with more expert advice!
Hey, Quailman! Thanks for the positive comment. I'm glad to hear you found something of use, in the miracle-gro solution. I wanted this instructable to be accessible-- it's nice to hear when it actually helps somebody. When you get your garden up and running, I'd love to see pictures of it!
What do you know about aeroponics? or do you have a good info source? It seems like everybody wants to keep their methods secret on the subject. I'm going to try and set up a little hydro setup soon. Little apartment doesn't allow for much... but I'm really interested in aeroponics. Hopefully I'll wind up with slightly more room in the next year or so, then I really want to experiment with the two processes. Thanks again!
Here are a couple of sites that you might like to view on the subject:<br/><br/>www simiplyhydroponics dot com/system.htm<br/><br/>This is a nice site showing how to build systems<br/><br/><a rel="nofollow" href="http://www.jasons-indoor-guide-to-organic-and-hydroponics-gardening.com/homemade-aeroponics-system.html">http://www.jasons-indoor-guide-to-organic-and-hydroponics-gardening.com/homemade-aeroponics-system.html</a><br/><br/>Hope this helps<br/><br/>
Frankly speaking, the science of aero-- and hydro--ponics are damn near the same thing, IMHO. Instead of having their roots suspended in a substrate, the roots are typically allowed to "hang" in the air, while constantly being misted by a water/nutrient solution. This gives the roots access to air and water. I have a problem with aeroponics. Outdoors, they're fine. Indoors, the room the unit is in gets... moist. The constant misting makes for a very humid environment. Sure, you could use dehumidifiers to keep the mildew off your walls, but who wants to use that much energy? I think the process is a little too invasive, and not particularly cost effective. It could be done with great success in a repurposed shower or commercial fridge, but... eeeeehh... where the heck are you gonna find that?
PS; if you want to see another instructable from me, feel free to request something. I dib and dabble all over the map.
Great instructable, I was with you right up to the picture at the end of step 3. You do realize that the Earth rotates on its axis, right? If you live in the West, the Sun will only be in the East for half the day.
Thank you!
Thanks for this very informative, all encompassing instructable and excellent links. The vermicomposter and LED lighting are very useful...and did I mention cool? I'm just a beginner and have been researching and experimenting to find something cheap and reliable and you've really gotta look to find useful information beyond the basics. Thanks to people like you and sites like this, the world will be a much better place! Okay, I'll stop know..............................
Great post, only on question, do you have to dilute the worm fertilizer in water for your final product.
I would like to SEE a vermicomposter capable of spewing enough worm tea to maintain a hydroponic system. You can't water a plant with undiluted fertilizer without fear of "burning" the plant. Despite worm tea's decided lack of harsh chemicals, and relatively safe PH, it probably shouldn't be the only thing your plant absorbs. I highly recommend diluting your solution. The important part; your water/nutrient solution should have a final PH between 6.0 and 7.0.
Very informative for a novice, i.e., ME! I bounced here from Wiley Coyote's "mosquito" hydroponics instructable, looking for more information on the topic in general. BTW, the big coolers you mention are often available at season shift (fall-winter) in big box stores for relatively cheap (<$10, if memory serves)
I'm going to cite this comment in my instructable, as you've brought something useful to the table. If it bugs ya, just let me know so I can edit it out. I'm glad you found something useful here, too! As always, if there's any point you'd like clarification on, or you have any questions, I'd love to help.
No objection :o)
The use of this container is excellent. I had worms in plastic containers just for the castings and never did get the tea. The bottom of the container given me with the worms was not prepared properly as you have suggested. Now I know, and thank you for that. This is wonderful info, and I will give it 5 stars.
So far as first commenters go, I'm gonna have to give YOU five stars. Thanks for being remarkably positive and encouraging! There's a li'l something in here for everyone, I hope.

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