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

It was fun trying to figure things out and finally finished the very first one.

I want to plant more and more. I get greedy.

↓↓↓↓Here is the video clip to see closer.　：）

my first design of window farm

windowfarm

This is coming from a completely genuine place of curiosity.  Sorry if it’s been covered elsewhere, I couldn’t locate any threads on it since the search function on here is kind of clunky.

Does anyone know why the window farms system (diy version) uses an air lift system as opposed to a water pump system?

Is it energy consumption?

Availability?

Weight?

Price?

It seems like the air lift system over complicates the system – adding additional parts and experimenting.  Wouldn’t it be more simple to get a larger water source (E.G. 5 gallon bucket) and drop the water pump in and use the rest of the setup the same?   This would obviously require you to use non-recycled materials – but I think most people are just buying water bottles anyway for the system, and a 5 gallon bucket would last forever with adequate care.

Is the reason aesthetics?

I guess a bucket on the floor doesn’t look nearly as visually pleasing as the hanging bottle version, but there has to be some kind of work around for this.

Really interested to hear other builder’s thoughts on this.

I have mine currently set up with the air lift system and it seems to work out alright – but in the spirit of the project I am on the lookout for alternatives to make everyone’s lives easier.

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?

I have one of the manufactured systems (I was a Kickstarter supporter) and have to say it’s incredibly awesome!! My older water bottle one made it’s way quickly to the recycling bin!!

My issue is that the output of water at the top of the airlift spews droplets all over my window. It makes one heck of a mess. I ended up taking a pill bottle, cut off the bottom half, then drilled a hole in the lid just large enough for the airlift tube, and this has helped stem much of the mess.

The issue is that when the bubble of water gets to the top/end of the tube it is actually a bubble and it *pops*, making a little mess of droplets (2-3 of them) spray out. I don’t see another way around this from what I’ve done, but it’s apparent you have to let the bubble burst, and containing it inside a larger sealed vessel as I’ve made is the way to go.

What have you done to help this issue?

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

No painting, I’m using socks to protect the roots from the sunlight.

Sock on.

Sock off

This place has no electric power near by.
I’m trying to let it work with just a solar pump.

Greetings from The Netherlands.

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.

Hey Fellow-windowfarmers!

I’d like to share some pictures of the design and progress of our first ever windowfarm where we are growing peas, mini tomatoes and cayenne peppers So far, so good! More updates will follow as our plants grow.

As you will see, the basic set-up of the windowfarm includes; an airlift system using a pump, a nice green hose, a t-joint, two valves, a plastic white cereal container as a reservoir (3.5 litres capacity), 3 plastic white plant pots, two chains by which to suspend the pots from the curtain rail, plastic white tubing to allow the water & nutrients to drain down through each pot and some bbq skewers placed horizontally to keep the white tubing stable and to give the plants something to grab onto! Please feel to add your comments, feedbacks and tips!

Photos

Very special thanks goes to my boyfriend Dmitry for his engineering, design and building contributions. It is our windowfarm and I couldnt have done it without him .

I’m working on my first windowfarm, and building each column iteratively so I can learn from what I don’t like about the previous one.

All columns use a t-joint lift system, which is working well now that I’ve got the hang of it. Each column has its own plastic bottle reservoir (held upside down in a large orchid pot) and I used a 4-way air valve to power everything off one Tetra Whisper 10 pump.

The first column (right) is made using 1.5L water bottles. The second (left) uses white plastic disposable cups. I’ve documented a lot of the basics on my own blog, but I’ll elaborate a few details here.

The reservoir bottles sit about 6″ off the ground, sitting in an orchid pot and held up by some scrap plastic. Each bottle has about 3 feet of 1/4″ OD tubing that coils at the bottom of the pot before heading up to the T-joint. The t-joint height comes to just below the bottom of the reservoir bottle. Airline tubing comes into the side of the t-joint, and black 1/4″ ID landscaping tubing serves as a lift tube.

To keep splashing at a minimum I ran cotton wicks between each cup. The plastic cups are considerably louder than the water bottles, I think due to the shape of the bottom of the cup.

Still trying to decide how to do column #3, but thankfully I’ve got a little time before those seedlings are ready.