Here, I am going to highlight the nitty-gritty parts of the operation.

This is where it all starts.

For the resevoir exit, I drilled a hole in a rubbermaid and secured a small piece of tubing into it with some waterproof caulk. This small piece of tubing is then connected to the rest of the line by that funny white connecter doo-dad. Having a removable connection point makes cleaning very easy.

I find that I don’t necessarily need a check valve since the T-joint is significantly lower than the pump. I used to have one check valve for each line, but I found that the check valve restricted the one line quite a bit, so I removed it. After doing that, I found that the check valve line was much quieter. It seems that without the valve, I experience the gurgling noise. Hmmm

 

T-joint

A very simple setup here.  The resevoir is about a foot above the T-joint. This creates more than enough pressure, even when the water level is quite low. After the T, the flexible tubing continues for about a foot and then connects to the rigid tubing. To make this connection, all I had to do was shove the flexible tubing into the rigid tubing. No leaks! Easy.

Here’s the top of the farm.  I used zip ties to secure the rigid tubing to the chain. To get the coiled up, rigid tubing to straighten out, I boiled some water and syphoned it through the tubing. This allowed me to bend it and straighten it with ease.
I used to have some serious gurgling sounds. I found that by lowering the T-joint, I was able to get rid of them. No need for a silencer. The key is to make sure your tubing has lots of water running up it at one time.
One thing I really like about using these chains is that I can adjust the height of my pots at any time without disturbing the others.

Here is the bottom of one of the pots. You can see the net cups full of clay balls through the holes on the bottom. I thought I would have to plug up some of these holes so that water wouldnt be dripping everywhere, but (luckily) I was wrong!  By hanging the pots on a slant (see gallery), the water only drips out of one of the holes! This is another nice feature of the chain. I can change the angle or direction of slope for any pot at any time. So, what did I do about the bottom pot?…

For the last pot in the line, I poked a hole in a plastic bag, taped a piece of rigid tubing to it, and shoved a piece of flexible tubing in it. The tube connects straight back to the top of the resevoir. The net cup sits in the plastic bag. This is a simple solution that works like a charm. You can also see that the pot is hung at an angle.

This is where it all starts.

T-joint

The bottom of a middle pot

Pot-to-resevoir

Air Pump

Nutrient solution

Peter piper…

pot-to-chain connection point

resevoir connection point

Sideof the resevoir

Top of resevoir

Seedling Tray

Swiss Chard seedlings

Timer

A lovely tomato plant!

This is the whole setup

 

Hey everybody, I finally finished my first window farm (WF). It consists of an air lift and 2 rows of plant containers, with 5 containers in each row.

I put together a DIY guide, see it here (pdf).
I also made a Danish version of the guide (pdf), which includes prices and where to get the parts in Denmark.

I started figuring out how to build a WF, from scratch, about 3 months ago. I live in Denmark so buying a kit was out of the question. It took me a while to understand how the system was supposed to work, and then another while to figure out how I was going to build one myself. I had no experience working with the stuff needed to do this. Stuff like air pumps, tubes, and valves so it was all very confusing to begin with. I didn’t know anything about growing hydroponically either but ever since I saw the TED talk with Britta Riley, about a year ago, I have been interested in the project.

Now my WF is finally up and running and the plants grow bigger every day. So I want to thank this lovely community and the people behind the WF project for teaching me. It has been a lot of fun, and a little infuriating from time to time, when something just wouldn’t work the way I wanted it to.

I went through a couple of test systems, all of the air lift type, before landing on the one I am using now. At first I tried anchoring a tube on the bottom of a big water reservoir, but even though I knew this worked for others, I never managed to make it stable. The air from the pump kept flowing back into the reservoir, instead of lifting the water upwards. I then tried putting a small reservoir at the end of the row of plant containers. This worked very well; the reservoir had a tube in the bottom that went into a U-bend, which prevented air back flow to the reservoir. Unfortunately this setup forced me to reduce the number of plant containers I could have in a row, and I had to add water to the reservoir often, which was annoying. My current setup looks like this:

I put the reservoir, the air pump, and the U-bend below a shelf at my windowsill. There is a small gap between the shelf and the windowsill, where the tubes can get from below to above the shelf.

For reservoir I am using a 10 l (2.6 gallons) water container with a tap that is big enough for 2 tubes to fit into it. I made a plug of silicone sealant around the ends of the 2 tubes, to make a water tight fit (see info. box 1 on the sketch). To make sure the plug stays in place I wrapped some duct tape around the joint.

After leaving the tap of the water container each of the 2 tubes goes into a U-bend. *The U-bend needs to be at least 30 cm (12 inches) from top to bottom to prevent air back flow. (Thank you, Brian White, for sharing this information, the diagram you made really helped me a lot: http://our.windowfarms.org/files/2012/04/contest-with-u-April-7th.jpg)

After the U-bend there is a t-joint, where the water meets the air from the pump. I put a check valve on each of the 2 tubes leading the air to the t-joint, to prevent water reaching the pump (see info. Box 2 on the sketch).

In an effort to decrease the amount of plastic in my WF, and because I thought it would look good, I tried using coconut shells as plant containers. I hollowed out 10 coconut shells, cleaned them, and coated them on the inside with mineral oil to prevent them from absorbing water. I made a braided rope and nets for them to hang in. It looked really good but unfortunately the shells cracked. I think it happened because the shells I got were very old and dried out. I bought them all the same place but later on I tried with a shell bought at another place and it did not react the same way as the others. So I still think it could work with coconut shells, but I grew too impatient and my seedlings grew too big for me to do it all again with other coconuts. I turned to the well known plastic bottle instead, and I am very satisfied with the result.

I reused the rope I used to hang the coconut shells from but had to find another way to attach the new plant containers to the rope. I ended up with a kind of button on system which allows each plant container to be removed without dismantling the entire row. This highly modular system has the advantage that I don’t need net pots in the containers. I couldn’t find any net pots that would fit so I had to do without. If I do get my hands on some good net pots I will use them, though.

So I wanted to use coconut shells as plant containers, partly, because I wanted to reduce materials that could leak toxins into the water and plants. About this I have now come to think that the plant containers are actually the least important part. Most of the time, the water is in the reservoir or the tubes, so it’s more important that these parts don’t contain anything that will leak into the water. As the water drips into a plant container it goes straight through the clay pebbles and into another tube. Most of the clay pebbles that come into contact with the container are dry, as the water runs through the center part. I therefore don’t think the plastic bottles will be able to leak anything into the water, and if it does it will be minimal, compared to the reservoir and tubes.

These are the things I used to make my WF:

1    Air pump: Sera air 275 R plus. It has 2 outlets, a power regulator, and it comes with 2 check  valves

2    Water container with tap: 10 l (2.6 gallons). (It has the glass and fork symbol, which     means it’s intended for food contact; http://en.wikipedia.org/wiki/Food_safe_symbol)

3    Tube: 4/6 mm (0.15 inches/0.23 inches). I used about 6 m in total (19.6 feet)

4    Tube close up: It has the glass and fork symbol too.

5    T-joint and check valve: I used 2 of each.

6    Water bottle: 2 l (0.5 gallons). I used 10 of these.

7    Twine: 2 mm. (0.08 inches). I used about 10 m in total (32.8 feet).

8    Hooks: I used 7 in total (2 for each row, 2 for the water container, and 1 for the pump)

9    Spray paint: 1 can

10  Buttons: About 1 cm in diameter (0.4 inches). I used 40 of these.

11   Wire: 0.3 mm (0.01 inches). I used about 2 m in total (6.5 feet).

12  Power drill

13  Drill bit (4 mm – 0.15 inches) and screw bit (6 mm – 0.23 inches).

14  Hobby knife

15  Scissors

16  Belt punch

17  Duct tape

18  Silicone sealant

19  Clay pebbles (Leca): I used about 5 l in total (1.3 gallons).

20  Nutrients: Biosevia grow and Biosevia bloom

21  PH test kit (I didn’t use this to make the WF but it’s good to have afterwards)

22  Seeds, soil, egg shells, and egg tray.

23  Planted seeds in egg shells. This is how I grew my seedlings.

The essentials for making an air lift type WF: air pump, water container, tubes, valves and t-joints, grow medium, and nutrients.
The rest (tools, plant containers, plants) can be improvised.

After making the plant containers and assembling the system I transplanted the seedlings into the WF by carefully uprooting them, cleaning the soil from the roots, and putting them into the clay pebbles. The seedlings I have transplanted have all survived, it’s been about 2 weeks now. I also tried transplanting some cuttings from grown plants into the WF. One cutting was from a tomato plant and the others were from a basil plant. The tomato plant cutting had been growing in soil for a while and had become rather large. I thought it had grown too big to survive the transplantation and for a couple of hours it looked like it would die. Then it suddenly started getting better and the next day it was definitely on the mend. After 2 days it was back to normal. (The bend on the stem is caused by the way it has been growing before being put in the WF).

1 hour after transplantation

The next day it looks better

2 days later it's back to normal

The basil cuttings (3 in total) had different reactions: the first had grown pretty big in soil but it had no problem adjusting to the new environment. The second had not developed roots yet and for a long time, after putting it in the WF, it looked like it was dead. All the leaves fell of but I just let it be and now it has developed new leaves and looks like it will survive. The third already looked rather droopy when I put it in the WF and like the second one it dropped its leaves and looked like it was dying, but now it has developed new leaves too.

Besides tomato and basil I am growing chives, thyme, chili, and lettuce.
Row 1, from the top: chili, basil, thyme, chives, and tomato.
Row 2, from the top: chili, basil, thyme, lettuce, and chili again.Later I want to grow more lettuce and some strawberries, cilantro, mint, and pepper.

I don’t have a timer on my system at the moment but I will probably invest in one later on.

Pdf guide (English)
Pdf guide (Danish)

Thanks for reading and happy window farming.
Maj

Hello, I’ve attempted my first window farm this week as a prototype for class. It’s been a bit difficult to find proper supplies in Hong Kong due to language barriers. Challenges and questions I’ve come across while exercising my poor engineering skills. I will be using black socks to cover the bottom of the bottles.

1. My seedlings have already been attacked twice with aphids and fungus gnats in it’s growing plugs. I had to start a fresh batch. If the seedlings are already so sensitive to the  moisture and humidity, how soon will my window farm be attacked by these pest? Anyone have experience with handling this in a humid country?

2. My tubing is too stiff to direct it away from the seedling. I’ve seen some systems using a toothpick or wooden chopstick, but my result was a moldy chopstick. I ended up using a fishing wire just to hold it down and a tape to keep the tube in place. I obviously need to find a better alternative. 

3. Reservoir problem. Due to the limited space in HK, I don’t have the luxury to have a big bottle for reservoir so I attempted to use a ketchup bottle on the bottom. I found the tip was a good way to plug the tubing in (I still need to reinforce it with plumbers tape, but haven’t found it yet).

4. Cutting through plastic was the biggest challenge.  I am not a very handy person, but I attempted to use the drill to make some holes on the bottom of the bottles but the bottom is thicker than the rest of the bottle, so I am not able to cut through it. In the end, I made a big circle but the bottles don’t fit perfectly. Any suggestions? I thought about using sticks to reinforce it.

5.I wanted to try out using water beads instead of clay pellets. Anyone have any success in it?

Hello fellow windowfarmers!

I finally completed my first single-string, 3 container attempt at a windowfarm, and it’s .. well, it’s very basic and Frankenstein-y, so I’ve taken to calling it my ‘ghetto farm’. I started with one set of components and am basically upgrading as I go along. It’s a T-joint airlift, because I wanted something fairly simple. (HA!) My duplex has a central furnace, not forced air, so the big picture window I can use in the spring/summer is in a room that is far too cold in the winter months – and of course, I get the bee in my bonnet to start this project in December… So, the first thing I needed to do was find a way to hang the windowfarm above the heater at a position where the plastic bottles/tubing won’t melt and the plants won’t cook, and then get a source of light. Due to my seasonal affective disorder, every bulb in my house is a 100w full spectrum, but I’ve found with plants in dirt, the ceiling bulbs are too far away, so I purchased a SunBlaze narrow footprint light for this purpose.

The plants right now are from the few packets of seeds I had available that weren’t flowers or root vegetables – spring lettuce mix and Alpine strawberries of the Mignonette variety. They were started in rockwool, in the net cups with hydroton, sitting in a water + fish nutrient bath with the light right above the container. See second picture below – you can see the container with the new baby plants in it on the shelf. The lettuce sprouted and is growing but not terribly well – hoping the new nutrients will help. The Alpine strawberries sprouted so fast you could almost see the growth minute by minute. Because I fail at math as well as physics, I started two more net cups of strawberries so will have to set up a second string of containers next. I think window farm strings are like potato crisps and cats – it’s not possible to have just one. I also found more last-season herb seeds at the hardware store, so I can try my hand at heirloom basil, peas and beans. We’ll see how that goes.

Materials:
Modular wire cube shelving like these   ($25)
Topfin Air 1000 air pump from PetSmart. It has two output nozzles, but I have one blocked off by a piece of tubing with a knot on the end. There’s no way to change the air pressure, and a new pump has been ordered and should be waiting for me when I get home tonight. (already had, but website lists for ~$10)
25′ of 1/4″ vinyl tubing from the hardware store (this does not fit standard aquarium equipment like t-joints. Will eventually be replaced.) ($2.50)
8′ of black pvc tubing from the petstore (I already had this, unused, from a Betta setup, wound up cutting it into 2″ pieces and using it as connectors because it fits perfectly inside the vinyl tubing. Website lists it as ~$5)
Metal T-joint ($1)
Discard A Stones – air filter stones, but I really wanted the plastic part. The white filter stone is not attached in the package. The picture lies. ($2)
3-1.5L Evian water bottles, because they’re the only kind that had any curvature in the center to hold the pots. ($1.25ea/$3.75 total)
3-3″ mesh pots. ($1ea/$3 total)
Rockwool cubes to start plants in. (Way more than I need – $10)
Hydroton (Way more than I need – $6)
Chrome duct tape (because more reflective surfaces for light = good thing, right?) ($1.50)
Velcro ties (aren’t long enough, going to be replaced with 12″ zip ties this week – they hold it but not as securely as I’d like.)
1.5gal Brita water dispenser like this one  – mine is not electronic and I’ve taken the white plastic insert out of it completely, so it holds more than the “1.13″ gallons it claims. (already had – $25 if you had to buy one)
SunBlaze T5 21″ (need a longer one, will probably replace with 2-48″) ($25)
Zoo Med AquaSun 24 hour timer. ($15)
Started with Lilly Miller Alaska Fish Fertilizer, because it was the only ‘non burning’ fertilizer I could find locally. (I’ve ordered Botanicare CNS17, and Botanicare SeaPlex, which should hopefully arrive tonight. The Alaska stiiiiiinks.) ($10)
1-silicon potholder I bought at the dollar store, cut up into small squares and placed under the plastic connecters of the wire cube to prevent melting. (not pictured, it was added after the first set of pictures) ($1)

Total potential cost: $144.75 – I had many of the parts already, so didn’t pay that out of pocket for this setup but it is probably about that when I factor in the cost of the replacement parts I’ve ordered.

The Setup:
I have the cubes configured in a 2-wide, 3-tall setup. On top of the heater, it puts my top container at about 6′ from the floor. The air pump sits on the water reservoir, on a table to the left of the heater, about level with the bottom of the cubes.
I cut the front hole in all three Evian bottles before I cut the hole in the bottom for the cap to fit in – don’t do this. It makes the plastic much harder to work with. I wound up cutting the top container opening too high, resulting in water spitting out the front from the air lift. This was fixed by putting a cheap plastic sandwich baggie over the top and tucking the ends into the hydroton, which works as a splash guard. I’ll probably end up replacing this bottle and using it as the middle or bottom container when we set up the second string. Drilling into the caps was super easy and I accomplished that with a pen knife. The bottom container’s cap was fit with the clear vinyl tubing, which was originally attached to the black aquarium tubing and set in the bucket, but now it’s all just the clear vinyl and feeds back into the top of the water dispenser.
Bottom half of bottles were wrapped with chrome duct tape, mostly because oooh shiny but also because I thought having more reflective surfaces would be a good thing, since I’ll be using grow lights this winter.
Stacked them and velcroed to the center line of the cube unit. Found out that the velcro wasn’t nearly long enough, so there’s two per unit for top and bottom with nothing supporting the middle container but pressure of the other two containers and gravity. This will be rectified as soon as my long zip ties arrive. It’s stable, but not as stable as I’d like.
The vinyl tubing was run and leak tested and boy, howdy, did it leak. It’s just slightly too big for all of the aquarium fittings, so I scrounged up my old black airline tubing and imped it all together, which made it watertight. I wanted the clear tubing so I could see any problems with water pressure when starting out, so I could correct it before replacing with the black tubing.

The original reservoir had the bottom tube running into a 2gal bucket sitting on the floor. This worked for about 2 hours and then lost pressure to the point where the water only made it halfway up the tubing. Because I fail at physics and apparently didn’t grasp that the water supply should have, y’know, pressure.

After much more reading on here, I was intrigued by Lincoln Jones’ post detailing his use of a water dispenser. We went to the store and purchased a 1.5gal container of water with a dispenser spigot, took it home, and aquarium-caulked tubing into the spigot. Failure – it kept leaking, no matter how much caulk was globbed into it. There was no way to thread the tubing through the dispenser, and the second time it dumped water all over my floor, I was hard pressed to not take it outside and see how far I could drop kick it.

Then I recalled that I had an old Brita dispenser sitting on top of the kitchen pantry. The white plastic insert lifted right out, leaving me with a clear dispenser much like the one in Lincoln’s picture. The top of the spigot also unscrewed, joy of joys.

Took one of the plastic bits from the Discard A Stone set, and cut one prong off it. Using aquarium caulk, I glued it into a 8″ piece of vinyl tubing. When it dried, I dropped it into the spigot, and then screwed the spigot top back on to see if it fit. It did. I now had a spigot I could turn on and off. Unscrewed the top of the spigot, put more aquarium caulk down the spigot, let it dry, checked the seal to make sure it was water tight – and it was, yay for that. Screwed the spigot top back on a final time, and then filled it with water to check that the seal was still water tight – and it was. We were in business.

Used a piece of the black aquarium hose to connect the 8″ from the dispenser to the water supply hose of the airlift, which is about 7′ of hose coiled on the floor. The air pump is sitting on top of the water dispenser to ensure it was higher than the water supply. This works, but is obviously not the most ideal setup. Due to the electrical outlet and lack of extension cord, it’s my only option at the moment.

Turned the spigot on and let water run down into the water supply side of the hose. Then turned on the air pump. I was very glad I had a drip shield on the top container, because the pressure sent the bubbles of water spitting out at force. It is, in fact, giving my plants too much water. I’ve purchased a new pump with adjustable air flow (should be waiting for me when I get home today), and purchased a timer.

The problem with the timer is, when the water starts up again, it bubbles back into the reservoir. We’re going to try a longer length of tubing on the floor because I suspect the airlift is less high than the water supply hose at this point. So for now, the timer isn’t being used. The light is still in its horizontal placement over the baby plants, but the plan is to buy longer SunBlazes and put them vertically on either side of the containers, held to the wire cubes with zip ties. The nice thing about the SunBlazes is that they come with a connector to daisy chain, so they only require one electrical outlet. I have absolutely no information about water pH or nutrient content or anything at this point – this was the ‘can I get it running?’ stage. The next stage is ‘can I keep the plants alive in it?’

Even with the high water output – it works. Of course, in the process, I’ve replaced a bunch of parts and already started enough plants that I have to start a second string of containers. So there will be an update to this post shortly, which will contain better pictures of the reservoir setup. Below are the camera pictures I took of the very first setup, which as mentioned only worked for about 2 hours.

But part of the fun of DIY is tinkering, right? Right.

Image of the top planter with its baggie splash hood

First two planters, containing lettuce, with the baby plant tray and light behind on the left. Light is not on. It is about 1.5″ wide. There’s no velcro on the middle planter because I ran out of velcro ties. Zip ties arriving (hopefully) tonight.

This was the first reservoir attempt, which failed utterly. The airline tubing wouldn’t stay in the bottom, even when I had it wound through a tupperware container full of rocks and a jar candle sitting on it. It was also not set up to put any water pressure into the tubing. This has since been fixed. It worked for about 2 hours and then lost pressure completely. We’ve redone the reservoir entirely – this is just a picture so you can all cringe at my completely horrible first attempt. I fail at physics.

-T

Hi everybody,

I’ve just about finished construction on a 2-column windowfarm, and I am just waiting for my seedlings to get big enough to put them in.  I’ll post some pictures when it’s up and running.  Anyway, I have some comments and reflections on the “official” instructions and parts list.

So, I followed the instructions pretty closely except for on two points: first, my windowfarm is suspended from a free-standing frame on casters (which doesn’t really affect anything), and I used a t-joint for the airlift system.  The t-joint (a.k.a. t-valve) design is really simple and easy to install and use, whereas I found the method(s) outlined in the instructions to be really complicated and, frankly, intimidating.  The fact that the size of the check valve included with the air pump determines some of the other parts is pretty inconvenient.  Anyway, I hope the instructions are changed soon to include this more user-friendly design.

Speaking of the t-joint design, there are some issues that I ran into with parts.  Mainly, I bought a t-joint off the Petco shelf with all three openings the same small diameter.  It’s made for three of the standard 1/4″ OD tubes that come with the air pump.  The problem is that this makes a bottleneck for the flow of water.  At least I think it’s a problem.  Brian White say’s that the airlift tube should have an ID of 1/4″ for optimal performance, and he seems to have done his research.  I ran the 1/4″ OD aquarium tubing from the reservoir bottle to the t-joint, and from the t-joint up to the bottom of the 3/8” OD 1/4” ID rigid tubing from the parts list (McMaster.com #9245K17).  It works, but maybe it would be better if I had bought a wider t-joint and used wider tubing.

Speaking of things that could work better, there’s the Petco pump (#9902).  It’s not adjustable, as far as I can tell.  I guess I can add a little adjustable valve in the airline, but if I throttle it that way I’ll be wasting energy.  I think an adjustable pump should be recommended.

Then there’s the tubing.   Two kinds of tubing on the parts list reference McMaster part numbers, but the 3/8” ID flexible vinyl tubing for some reason does not.  Now, McMaster has a ridiculously extensive selection of tubing, so we should be able to find one that works.  I used #5103K36 (Chemical-resistant Clear Tygon Tubing, 3/8″ Id, 1/2″ Od, 1/16″ Wall Thk).  It was okay for joining the two long pieces of rigid tubing, but it was not flexible enough for the top, to curve down into the top bottle.  Technically speaking, the “bend radius” is too big.  Maybe #5231K185 (Clear PVC Tubing Chemical, 3/8″ ID, 1/2″ OD, 1/16″ Wall Thickness) would be better.

Chains.  I think the ball/bead chain is a good way to go, and McMaster was a convenient way to order it.  Weirdly, though, the part number on the parts list (#3606T16) turns out to be stainless steel chain, whereas in the instructions photos it looks like they’re using plastic.  It’s not important, but what’s up with that?  I also ordered the specified couplings (#3606T41).  They are listed in the McMaster catalog as being the same size as the chain, but for some reason the chain does not fit through the center hole.  I had to widen the hole.  I’m not sure what to suggest here.

I think that’s everything.  I don’t mean to complain; I think the design is great and I really appreciate having access to it, but I want to help make it better and easier for windowfarmers who come after me.  I hope this post is the right way to give this feedback.  Sorry it’s so long and boring!

Sincerely,

Bill

I have finally completed my windowfarm, and transferred my baby plants! So far it was neat watching the plants grow from seeds. I hope they bear fruit. I have 2 spinach plants, 2 different tomatoe plants, 3brocolli plants, and 3 mint plants, and 1 lettuce plant! I used the air T-lift system to get the water pumped to the top.

It’s easy to get a little greedy. Continuing to build and build. Now I have turned my two columns into four with the help of these instructions from @gaiatechnician (Brian White), I managed to use a pump with two outlets to provide four columns with water. I have used 6 T-connections and 4 air controls.



The pump is on a timer that is on every half hour between 09:00 and 22:00. The fluorescent lamp is running from 08:00 to 21:00. It was a bit difficult to balance the air flows, but now it seems to be fairly stable.





My system is generally quite unstable, probably because my water tank is so small (less than 1,5l) and the tubes have a tendency to float or move in the water tank.


Lettuce, paprika, pepers, tomato and basil. The paprika I got from a friend. All plants are grown from seeds.

I have now built and planted tomatoes in my windowfarm with a 200 l reservoir. I hope this will be able to keep the plants happy for long warm periods unattended.

My farm consists of 8 hanging pots that are supplied with water from a t-joint airlift and three large boxes that get water through some pieces of yarn. The reservoir can hold more than 200 l of water and I have added some liquid nutrient in the water.

I am growing tomatoes in the hanging pots and in the boxes I have an ash, rosemary, maple, rowan and white clover.

So far, the plants seem to be fine. Some of the leaves on the tomato plants have some white patches. I might need to adjust the amount of nutrients in the water, but that is just a guess.

My plants are doing reasonably well, considering I haven’t really had any time to mainain them. Until this weekend, refilling the reservoirs is about the extent of the care my little windowfarm was getting. I’m up to three columns now – two done using plastic cups and greek yogurt containers, and one using Deer Park bottles and net cups. So far, I’m finding my version to be a little easier to maintain and slightly more attractive. Very slightly. There are a few more photos of individual plants over on my blog.

My upside-down Deer Park bottles were leaking a bit, and looked a bit worse for the wear, so I put together new reservoirs using soda bottles (which are thicker plastic), and added a nice coupling on the top for me to attach the water return lines. Previously I’d just shoved the water return lines through a hole I stabbed in the bottom of the inverted water bottle.

A few other people were having trouble preventing the air from bubbling back into the reservoir, so I made a diagram of my set-up and included a few numbers for reference. The full write-up can be seen on my primary blog, but the cliffs notes version is that I’ve got a 1 liter bottle, suspended about 6″ above the t-joint, connected by a 5 foot long piece of clear 1/4″ tubing which is coiled at the bottom of the container it all sits in.

I do still get air bubbling back when the pump first turns on, but it corrects itself in about a minute.

A few days ago I noticed some problems with my setup: when the pump would turn on sometimes the airflow would go back down through the source tube and start bubbling up the reservoir rather than lifting water up the lift tube. I could fix it by releasing the air pressure in the lines and letting the water re-prime itself.

Over the weekend I didn’t have much time to work with it, but thankfully every time I peeked into my office things seemed to be moving smoothly.
Today when I sat down to do some work, I heard the pump click on and once again the bubbling sound of air coming into the reservoir. I was perplexed as to why it only seemed to fail when I was around.

I didn’t have time to debug / re-prime the system at that moment, so I just ignored it for a few minutes. Then to my great surprise, it suddenly fixed itself and started delivering water to my plants again.

My theory is that sometimes, after the pump shuts off, water runs back down the lift tube and sits stationary at a height above the t-joint. When the system first turns on, the pressure from this thin, tall water column is too much for the air pump so the air starts to backflow into the reservoir. In a few minutes, the water stuck in the lift tube flows back down below the t-joint, and which point air starts flowing up again. The system resets itself and everything works.

Since I use black hose for my lift tube I can’t quite see what’s going on, but I’m curious if anyone else has run into similar problems.