The Encyclopedia Hydroponica

Your Hydroponics Compendium

Better than Free Hydroponics 21 July, 2008

Filed under: Blog — E.H. @ 1:26 am
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Here it is, as promised, my MacGyver-style home hydroponics.

Unfortunately, as I’m prone to do, I built this thing in a obsessive-compulsive rush and didn’t pause to document the process so we have to make due with photos of the finished product and my descriptions of how it was built. Let’s begin with an overview.

Let’s say we want to grow a small tomato plant (or something similar) with a minimum of fuss and using only items of little or no value that are laying about. Now a wick system would probably be the easiest way to do this, so of course I dismissed that out of hand. No sense in making the problem too easy to solve, right? Instead let’s take it a step up – DWC. This requires some kind of air pump, and barring some MacGyver’ed version of an air pump we’ll have to actually get one of those, but we’ll dismiss that for the moment. (Besides, a basic Wal-Mart air pump only runs about $10.)

Parts List:

2L bottle

Empty yogurt cup (style with an outward upper lip and narrow bottom than top)

Spare airline tubing

A bit of aluminum foil (perhaps 1 square foot)

Duct Tape (can’t MacGyver without it)

Super glue or silicone sealant

Some kind of hydroponic medium

A plant


a knife (preferably a Swiss Army knife like MacGyver’s, but as long as it’s sharp any knife will do.)

a drill (preferably with a drill bit slightly smaller than your airline

a pair of pliers

a needle or pin

a source of fire


So the first order of business is to create a substitute for the airstone. If you’ve got a lot of extra airline laying around (say a couple feet or so) skip down a bit and see what I suggest you do instead of what I did.

Anyway, you can make a decent amount of bubbles with just the airline sticking into the bottom of the reservoir, but we can do better. Get your airline, fire, pliers, and the needle/pin. Now you want to heat up one end of the airline a bit without really burning it or melting it too much. Just get it soft. Then mash down on that end with the pliers, sealing the end completely. Then stab that end over and over with the pin around the last inch or so.

This makes our “air stone” by allowing a few dozen little sites for the air to escape as small bubbles.

You can kind of see the “airstone” at the bottom of the bottle, at right.

Fill up your bottle with hot water to soften the glue on the label, and strip the label off. I like to pull down on it like I’m trying to peel off a sock, but it doesn’t really matter how it gets done as long as it gets done. Empty the bottle afterwards.

Next, drill a hole in the side of the bottom of the bottle using a drill bit that’s slightly smaller than the airline so you get a nice, tight fit. It may fight tight enough that you don’t need to seal it, but you ought to anyway. (Especially if, like me, you get a couple small radial cracks in the plastic as you drill through.) To make drilling easier, I recommend leaving the cap on so the bottle is firmer.

If you have extra airline, as I mentioned above, drill your hole before you crimp the end shut. Then feed the airline through the hole and out the top of the bottle, then do your crimping and stabbing full of holes stuff that way. You can then draw the line back out, pulling the “airstone” into the bottom of the bottle.

If you don’t have extra airline (like me) it won’t matter how neatly you drill the hole since you’re going to have to cut a slit out from the hole to let the crimped end fit through. (You can’t feed it through from inside since your hand won’t fit down into the bottle.)

Once you have the “airstone” roughly centered at the bottom of the bottle, glue all the cracks/gaps/edges with superglue and/or silicon sealant so you won’t have any leaks. I recommend filling the bottle once that’s done and dry to make sure it’s water-tight. Keep in mind that water will seep into the airline and drip out that way, so keep the outer end elevated to prevent that. (You can see in my pictures below that I have it taped up for this very reason.)

Now the reservoir is built, we need to create some way for a plant to be installed. We could simply make a collar for the plant to fit into the neck of the bottle (a little piece of sponge would work decently well, cut a groove in one side, slide the crown in, then “cork” the bottle with the whole thing. That will work, but be harder to refill.

Instead, take your empty yogurt cup, turn it upside down, and fit it over the nozzle of the bottle as straight as you can. Then mark the bottle around the cup where the bottle and cup meet. Use the knife to cut along that line, just below it so the hole is slightly bigger than the cup. It should now fit down into the top of the bottle and be supported by the lip of the cup.

Next, drill a bunch of holes in your yogurt cup, sides, bottom, etc. You don’t need to turn it into complete swiss-cheese, but you want plenty of holes for roots. Now we’re almost done.

The final step of construction is to make the bottle light-tight. Light + hydroponic solution = bad microbes (fungus, algea, and other crud). So we don’t want light getting in. If you have metal tape that works best, but most people don’t have that just laying around. Duct-tape and aluminum foil, however, are commonplace. First tear your aluminum foil into narrow strips as long as the bottle and about an inch narrower than the tape. To do this I took a ruler, pressed it down hard on top of the foil, and then pulled the foil upward in a smooth motion to tear it neatly in a straight line. This doesn’t have to be perfect, but the neater the better.

Tear yourself some strips of tape a bit longer than you need, and affix the foil carefully down the center of the tape. Then cut one end off flush with the end of the foil (this end will match cleanly with the top edge of the bottle that way) and apply it as smoothly and cleanly to the bottle as you can. Repeat this with just enough overlap to ensure the entire bottle is encased not only in tape, but aluminum foil as well. Duct tape doesn’t block light, foil does. If you like, leave a narrow gap in the tape in one spot so you can see the water level inside. If you want to do that, the spot where the airline is installed is a good place to do it.

Now you can fill your cup with the hydroponic media, put in your plant, and hook up your air pump.

My system has a Micro Tom hybrid tomato plant started in it. It’s a type of tomato plant specially bred to remain very, very small. This system is much too small for most any other kind of tomato plant. If you’re interested, I got my tomato seeds from Totally Tomatoes, and here’s a link to the Micro Tom. I haven’t grown one before, but it’s supposed to grow to be only 6-8″ tall, which means it should be the perfect size for our 2L DWC.

So far my little seedling hasn’t gotten its roots past the cup, so I haven’t had the airline attached (it’s basically just a wick system right now with water in it.) It will need aeration soon, though.


Hydroponics Upgrade 2 July, 2008

I think I mentioned earlier that my plants were starting to seriously outgrow the enclosure I had them in, but in case I neglected to say so, my plants were starting to seriously outgrow the enclosure I had them in. So I got a big cabinet thing off of Craigslist.

I’m pretty sure it started life as one of those generic pressed-wood armoir things with shelves and a center divider and so forth, and then somewhere along the line someone modified it into a large portable closet, but the important thing is that it fit my needs perfectly. Heck, it was even white already. I’d been meaning to modify the reservoir on my DWC to include a drain valve and a solution level indicator (neither of which you can do while the reservoir is full). What better way to do everything than to combine a relocation, upgrade, and reservoir change all at once?

To get started I went out and bought another Sterelite bin just like the one I used to make my DWC. Why mess with trying to modify the existing DWC when I can swap parts?

As you can see I simply drilled holes top and bottom, making sure they were just barely big enough to jam a bit of aquarium air line through (I used a 3/16 bit). Then I simply forced the airline in and taped the bottom, both to keep it tucked in neatly and to cut down slightly on the amount of light that gets in. The airline fits tight enough that it seals itself without any help from me.

The idea is that once the new reservoir is complete it gets put into the new grow cabinet, filled, stabilized, and then the lid with plants from the old reservoir gets moved in.  Then the old reservoir can be drained manually (solution scooped out with a big pitcher and fed to the backyard garden).  Then it can be cleaned out and used as an ordinary storage tote or whatever I want, since the only modification to it was an extra hole for an airline in the inside of the handle.

Next I installed a drain valve I bought from Stealth Hydroponics. This probably isn’t the cheapest way to do it, but it works and works easily. I cut the hole by hand, after tracing around the inside of the rubber washers that come with it, but I’d recommend using a drill as the instructions suggest. (It worked for me, but it’s easy to mess up with a knife.)

You can just make out the valve in the bottom of the picture to the right, which was taken mainly to show how the water level indicator works. The level of water in the tube is exactly the same as the level of water in the tank. Note that in order for this to work the tube must be free of obstruction all the way through (water goes in the bottom, air comes out the top). Simple laws of physics dictate that the water levels must match.

I kicked around a lot of ideas on how to check the water level without opening the reservoir, but this is just the simplest and least likely to break down.

Here’s a shot of the completed system. Note that since this picture was taken I’ve resolved the rat’s nest of wiring on the left by mounting the power strip to the left wall (power strips generally come with screw mounts molded into the back), added a second air pump and two more air stones in the reservoir, and some extra 100w equivalent CFLs.

Mounting a power strip is easy. Just grab a scrap piece of paper about the size of the strip, lay it on the back, and poke holes through where the holes for the screws are on the back. Then put that paper (don’t flip it over! the side that was facing you faces the wall!) against what you want to

mount the power strip to, mark the holes, drill some pilot holes for the screws, and then mount your screws. Leave them sticking out a bit and the power strip should fit onto them perfectly and then slide down snugly.

Another advantage of the drain plug is it makes testing the pH and TDS of your solution easier. You can’t see it in these pictures but there’s a 2.5″ hole cut into the lid just behind the collard plant in the bottom left position. The hole is covered by an ordinary 3″ bathtub drain plug to keep light out, and is what I use to add solution to the tank and take temperature readings. (I have a floating aquarium thermometer with some fishing line tied to it. The line sticks

out of the hole and is trapped by the rubber plug. So I can fish it out easily anytime I want to take readings, but the hole is small enough to make it annoying to try to stick a tester down in there to get a reading. (I use the top of a 2L bottle as a funnel for filling.)

Solution? Simple – you just get a little tray (I use the bottom of a 2L bottle, I told you I use them for everything) and just fill it partway from the drain valve. I can take my readings from that and then dump it back in through the fill hole. Keep in mind, if you use a similar system, that your readings can be thrown off if your collection tray isn’t clean (and even then it’s still not quite as reliable as testing directly in the reservoir.)

In the picture to the left you can see how I hung the light. It’s hanging from a chain attached to a hook attached to some twine, which is tied to some kind of cedar hanger-thing that came with the closet. The chain/hook combination gives me height adjustment during growing.

Here you can see the clip fan that blows air around in there.

I relocated the cord for the light so that it goes up over the bar and then across it before dropping down along the wall. Less chance for tangling = better. The lights I added after this picture are tied by the power cord to the bar so that they hang even on each end of the big light, and all three lights are plugged into the timer with a splitter. (Since they’re CFLs they don’t pull enough watts to exceed the timer’s safety rating. Fire bad.)

It’s mildly ironic that I accomplish all this near the end of this crop’s life. These plants could go on producing for quite some time, but they’re just not filling the gaps in our diet they way we want. For example, the basil absolutely explodes. I can hardly trim it back fast enough, so I’ve got new plants started in soil where they will (hopefully) grow slower and smaller. We just don’t need that much basil. One of the spinach plants is going into flower, but hasn’t become bitter just yet. Also, the collard just isn’t a big winner in our culinary opinion. Don’t get me wrong, I like collard greens. Just not every few days.

By the way, if you want to eat collard, I finally nailed down a good recipe. First, boil it for 5-6 minutes. You’ve gotta really cook them hard to make them taste good. Then, I like to pan fry them with some bacon or ham or something (chopped up into small bites so it mixes up with the greens nicely). Use some oil or (my favorite) butter to lubricate the frying and season to taste. I can’t explain why, but collard and ham are a perfect match.

But anyway, the point is that we’re not going to be growing these specific plants much longer because we want to optimize our crop to our individual needs. So I’ve started new seeds germinating and when they get big enough they’ll usurp the current plants in the DWC who’ll submit to one final, complete harvest. We’re going to have the Grand Rapids lettuce again since it was such a prolific producer and the spinach (because you can never have too much spinach) but we’re adding in Romaine lettuce as well. Two of each plant with mirrored front and back rows.

The extra room in the closet? Well I’ll probably end up needing more lights but the plan in progress is to add some tomatoes and bell peppers. The one problem with this closet is that it builds heat if the doors are closed (I keep one propped open a few inches right now) so I’m working on getting a small exhaust fan for waste heat first. More lights is more heat, so if I can’t get rid of what I’ve got so far adding more lights will just cook the plants before I’m hungry.


Another Harvest – Pics This Time 20 June, 2008

The hydroponic garden is just growing out of control.  Ideally it would be good to space the plants out some more, but realistically that’s just way more work than I want to get into at the moment.  So instead the wife and I have the delicious burden of having to eat fresh salads frequently enough that we keep the growth in check.

Here’s a nice before picture:

Above you can see starting at the top left and going clockwise, spinach, spinach (both are Bloomsdale Savoy), Sweet Basil, Grand Rapids Lettuce, Simpsons Curled Lettuce (hiding under the…), and Georgia Collard.

Those with sharp eyes may spot some tell-tale nute burn on the lettuce near the center.  It’s mild and I just added about a gallon of water so it should be fine.  Also, the Simpsons Curled lettuce in the bottom middle is not actually that yellow.  The camera makes everything look less green and more yellow than it is.  Yes, that means the spinach is frighteningly green.  It’s so succulent that the leaves will literally make your fingers wet.

Here’s a better shot of the Georgia Collard.  I don’t think I’ll be growing it ever again in a DWC like this.  It’s just WAY too big for this system.  I’m eating Collard greens every couple days just so the other plants can get some light.

Here’s the two spinach plants.  Most of the leaves are the left one, since it’s a few weeks older.  The leaves curl a hell of a lot, but seem obscenely healthy.  Not sure if that much curling is normal, but at the moment it doesn’t seem to matter.  It’s growing fast and seems happy.

This is mostly the Grand Rapids lettuce.  The Simpsons is slightly yellower, so it’s easy to tell them apart.

Here’s a decent shot of the Simpsons Curled which, as I said above, is not actually that yellow.  You can also see in this shot some of the stalks I’ve pinched off on the Collard to harvest leaves.  I just pinch in with my thumbnails, which I keep long-ish for this kind of thing, to sever the stems.  These plants are so vibrant and turgid they crisply snap off cleanly.

Here’s the basil.  You can see here that it too is curling under a lot.  Also, the chlorosis that appears in this picture is nothing remotely that pronounced.  It’s more like a variation between healthy green and really healthy green.

This is the biggest leaf that I harvested off the Collard with a Penguin mint tin as a size comparison.

Considering how much Collard I’m going to be eating I’m going to have to find more recipes for this plant.  I’m already getting tired of it steamed.

Here’s the whole harvest laid out.  This was 3 salads and a double portion of collards.

And finally we have an “after” shot of the DWC.  In 2-3 days we’ll be right back where we were, but this time I think that second spinach plant may be contributing to the harvest.  Good thing, I love spinach.  (Thus the reason I planted two.

I’m thinking about maybe just taking the Georgia Collard out altogether in a week or two, moving the Simpsons over one spot and moving the smaller spinach down.  That’d leave me an open spot in the back for a bell pepper plant I’ve started.  Not sure on that, but I’m toying with the idea.

If you’ve got an ideas about the leaf curl on the spinach and/or basil, or favorite recipes for Collard greens, let me know.


The Fruits of My Labors 14 June, 2008

Filed under: Blog — E.H. @ 8:49 pm
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I had a little harvest a few days ago because my Georgia Collard was getting too big and was blocking the light to its neighbors.  I cooked them up in a pan with some crushed garlic and butter – it was delicious.

Today I checked and my Grand Rapids lettuce was in the same situation – blocking light to the Simpson’s Curled and threatening to overtake the basil.  So I harvested about half of the leaves on the lettuce plant (the oldest ones) and a few leaves from one spinach plant along with another leaf from the Georgia Collard.  (This leaf, a few days ago, was the size of a 3×5 card.  Today it was the size of half a sheet of paper.)

Altogether the leaves filled up a medium-sized mixing bowl.  Everything but the collard got torn up into salad sized pieces and made two large salads.  My wife took one to work for lunch and I ate the other right then.  I also steamed the collard leaf and ate that.  It was rather strong flavored, so I’m thinking I probably undercooked it slightly.  Generally I like my vegetables fresh or only slightly cooked, but I think with the collard a little more cooking time might be best.

Unfortunately I didn’t take any pictures because I was just having too much fun.

Fresh greens are nice.  Fresh greens which were picked minutes before eating are just a completely different food.


More Mystery Seed… ling. 25 May, 2008

To relieve the earlier tension, I’ve been trying to avoid my computer.  I was doing pretty well up ’till now, but I just wanted to come in and punch out a quick blog to let the 3 interested people know what’s going on in my garden.

Yesterday (or was it the day before?) I planted the bottom part of a red onion.  I read somewhere that you could cut off the root part, plant it, and grow a new onion.  I’m not sure if that’s true, but I’m about to find out.  As an attempt to multiply my success, I cut the bottom off and then cut the root “nub” in half.  Maybe I’ll get two onions, maybe I’ll get no onions.  We’ll have to wait and see.

The upside-down tomato planter I did is doing pretty well for a plant that was honestly a bit too big to have its roots crammed through the spout of a 2L bottle.  It’s turning and twisting its leaves right side up and not really pouting or wilting at all.  I took a bunch of pictures, so the DIY on that will be forthcoming.

I’m now actually hydroponic-ing.  I put the Jiffy starters with the seedlings I’m happiest with into my pots and filled in the gaps with hydroton.  I’ll get pictures later.  I sprayed the extra Jiffys with water till they were nice and wet and put them along the lid between the cups so they can get some light and grow bigger before they’re transplanted outside.  At the moment I’m just running straight water in the reservoir, since I figure the Jiffy starters have plenty of food in them for the plants for at least a week or two more, and I don’t want to risk burning the little guys.

The Mystery Seed is definitely not a seed anymore.  It’s weird, it looks absolutely identical to the Georgia Collard I have, but about double the size.  Both seedlings have almost identical development and the first true leaves are different only in size.  I tried looking for pictures online, but didn’t have much success.  I’m thinking, though, that my mystery seed is most likely some kind of Collard, perhaps some freakishly large variety.  That’d make it two of my favorite things:  bragging rights huge, and edible.  (The only thing better than food you grew yourself is food you grew yourself that people are astonished by.)

I’m torn between putting it into the DWC and growing it outside.  One of my spinach plants is still hiding inside its Jiffy starter, but I know it popped the root before I put it in there so I’m still optimistic that it will appear.  On the other hand, the Mystery (Collard?) would definitely be fun to grow in hydroponics, if that is what it is.  Of course if it’s half the freak it seems to be in size, it might actually be too big for my current equipment.

I think I’ll give that spinach seed a few more days.  If it doesn’t poke through by then I’ll put the Mystery Seedling in its place, and put the spinach outside to either grow or not.

Gardening is a nice de-stresser.  I think I may be ready to tackle that email issue calmly tomorrow.