We just got our first windowfarm going, but it was not without a bit of experimentation, and in particular, getting the airlift working. We started by downloading the MAMA v3.0 design, and was eagerly looking forward to our windows going green. However, living in Malaysia we quickly realized that pretty much none of the listed components were available.

We went to the hardware and aquarium shops to find out what WAS available. To make a long story short, we did over 30 design variations and experiments over the course of two weeks, learning LOTS in the meantime, and below is what we currently have. As always, it’s work in progress, but at least it shows some variations that can be tried out.

The major realization I had after failing miserably in the beginning is that the core design principle in a windowfarm is basically “use an airlift to feed a series of water bottles nutrition and water”. Everything else is optional and variable (which it what makes this so much fun!). Here are the major variations we made, to the suspension and airlift. Here is the big picture of what it looks like right now:

There’s a tiny airpump to the left, and we found out that we HAD to keep it on the “low” setting. Too much air will disrupt the flow of water. There’s four bottles right now, and they are not screwed together. Instead the top of each bottle is cut out, and each bottle leads to the other. At the bottom we have a reasonably high and narrow bucket for the water and nutrition. As others have found out having a high pillar of water is key to getting the airlift to work, and this way it’s easy to refill as well. The end goal is to use this single airlift and bucket for the whole window. We’ll see how that works out.

Suspension

We couldn’t find any of the suspension components from the original design, but got real lucky in one hardware shop (Ace Hardware in Kuala Lumpur) where we found a one-foot pot hanger. Our window also has a a metal grille (in Malaysia pretty much everyone has grilles for the windows due to breakin risks, perceived or actual), where three metal bars account for one foot. One bottle also turns out to be approximately one foot. So, put this together and you get what is shown in the picture. One end of the hanger is attached to the grille, and the other is put through a small hole in the cap. We also have a triangle cut out for the water to run out, so it doesn’t go through the hole for the hanger. Now we can easily put it and take out bottles. We also experimented with skipping the net cup for the plant, but I think in the end we have settled for having it in. Then we don’t need to duct tape the whole bottle, so it just looks nicer.

We then have four of these bottles in each line. All in all we should be able to put in a maximum of 36 bottles like this in this single window, and each is easy to put in or take out due to this suspension system.

T-airlift system

The second major problem we had was with the airlift. We couldn’t quite find the components shown in the MAMA version, and there was just too many places where it could leak. A bottle also has too low of a water column to consistently get the airlift technique to work. After LOTS of experimentation with various designs (including using straws for tubing, which was awesome but leaky), and looking at how others have done it, we settled for a dead simple version: the T-airlift.

In the middle of it all is a T-joint. On the left we have air coming in from our airpump. On the right we have water coming in from a 3-foot soft tube. At the top there is soft tubing going up to the plants. We have taped the soft tube to the wall, which makes it straight enough. Because the tube for the water intake has a natural coiling effect, and is quite long, that is what keeps it down in the bucket, so we don’t need to tape it down or anything like that. We could make it even longer to increase that effect. I think that having a reasonably long one also helps in not getting the air to exit that way. Sometimes the air will push evenly upwards and into the water tube, but as soon as the pressure is released by the first water dropping into the bottle line, the air seems to prefer going up rather than out the water intake tube.

This system does not require the one-way valves, or needles, or somesuch, and allows for a high water column and easy adding of water. There’s no air leaking going on since the T-joint handles that quite well. It’s not as pretty as other versions, but this is in our basement (with window to outside, since we have a terrace house), so that’s ok.

So that’s it! Now we want to add more lines, maybe reusing the same airlift, and also maybe experiment with using a solar panel to drive the pump for the ultimate post-apocalyptic-nothing-works DIY experience.

New plants in the farm!

So we had a little problem.  Our strawberries died.  I’m not sure what happened, but we could never make them happy.  So after changing out the old plants with new ones and doing some changes, everything is growing well.   We are growing mint, peppers, and nasturtiums.  

Check out our last posting that shows the detailed explanation of how we put our farm together.

http://our.windowfarms.org/2010/04/26/our-hydroponic-window-farm-experience/

Now that we have had our window farm up and growing for a few months, here are some things we have learned. 

Use net pots.  We decided not to use net pots and had major clogging issues.  The roots grew to the bottom of the bottles and bunched up creating water flow problems.  Also, airflow could be restricted making your plants unhappy.

Control the dripping.  By using short tubes to direct the drip from one bottle to the next, we are able to control what gets wet.  The top of the strawberry plants hated getting wet and sometimes the drip was too far away from the other plants making them dry out.  Now we control right where we want the drip to go.

Check for leaks.  We had to refill our reservoir at least once a day.  But after we used the short tubes to control the dripping we noticed we were using less water.  Water was splashing out the sides.  Also with the clogging water was getting stuck, using the net pots solved this.  We now refill only about a half a cup a day.

Grow mint!   The mint we are growing could not be happier!  And it makes the whole apartment smell nice.  No more chemical fresheners!

And try not to get the clay pellets in your garbage disposal. It doesn’t like them.

Hope you like the pics!

This is a summary of our build and experience so far.

Our window frame measures 75” x 31” so we thought two columns with five rows (ten containers total) would work well. We decided to use the recommended 1.5 liter water bottles for the containers, but instead of cutting one outlet per bottle, we decided to cut two on opposite sides and have two plants in each container. Each column is attached to a single wire cable that hangs from its own plant hook, loops through the bottom container, and back up. Wood dowels are inserted through each bottle (except bottom bottle) and alligator clamps hot glued to the wood dowels attach to the wire cable. Duct tape covers the bottom of the bottles to prevent the roots from drying out and minimize algae and mold growth. Rather than filling the net pots with clay pellets and then inserting the pot into the bottle, we eliminated the net cups, filled each bottle with the clay pellets, and the plants go directly into the bottles.

After reading about other farms, we first decided to go with the upper and lower reservoir system utilizing a water pump. After getting our supplies, the next step was to set up the watering system. We soon realized that to pump water over six feet vertically was going to require a heavy duty and more expensive water pump. We returned to Home Depot to purchase a fountain pump capable of 400GPH at 1’ lift, with a maximum lift of 7.3’ at $40.00. We then realized that due to the size of the pump, it would have to sit outside of our bottom reservoir, meaning we were going to have to consider the sealing aspect of our system to prevent water leakage. Our other thoughts about the water pump were the noise of the pump, the power usage, and fear of running the pump dry, which would mean we would have to go to a clear bottom reservoir to know when the water level was getting low to shut the pump off. With all of this adding up, we decided to ditch the water pump system, and move to the air pump system.

We purchased a Top Fin Air Pump 4000 with two adjustable airflow outlets for use with up to 80 gallon aquariums. Without looking at any diagrams or suggestions for the air lift system, we started experimenting with different ways to get the system to work. After days and days of different setups, numerous trips to Home Depot and PetSmart purchasing and returning products, and frustration beyond belief, we finally broke down and read other posts on the setup. After reviewing the recommended airlift setup and combining what we had already learned, and a bit by accident, we came up with a new airlift setup that works incredibly well and reduces gurgling. See our diagram below. As others have mentioned, the depth of the water is the greatest factor in achieving lift. Our bottom reservoir is a glass cylinder measuring only 4” diameter, however, the container stands 13.5” tall. When this is filled to 9.5” the max lift we recorded was 5’ 4”. When filled full at 13.25” we achieve an 8’ 3” lift, though 7’ 3” appears to be the optimal level for this water depth. Also as others have stated, keeping the air lift tube as straight as possible, especially into the reservoir helps achieve better lift.

What is excellent about the air lift system (once working) over the water pump system is the reduced cost of the setup, simplistic design and setup eliminating the top reservoir and having to seal and water proof the system, virtually noise free (no loud water pump), not having to worry about running the pump dry and damaging the unit, and the reduced operational cost (water pump consumes 80.5Watts versus air pump at 3.5Watts). Not only this, but the water pump system also suggests using an air pump in addition to the water pump to aerate the water so it does not become stagnant and reduces mold/algae from standing water in the bottom reservoir.

Our Plants

We decided to grow strawberries in 8 of the 10 containers, and peas in the other 2.  Using clay pellets with no soil, we purchased organic plant nutrient (liquid form) that says it is designed for soil and soilless gardens. We mixed the recommended amount of nutrients to water and filled our reservoir. During the day we would leave the air pump running and the water/nutrient solution would trickle down through our plants, and turn the pump off at night. Everyday we added about ¾ cups water due to plant use and evaporation. After about 4 days our mixture had become clearer indicating a higher water base than nutrient. Though our peas are fine, the strawberries after about the fourth day began to show a little black on the ends of the leaves, and after six days, some of the leaves were yellowing. What is interesting is that the strawberries closer to the top of the window farm show little to no signs of the discoloration. This indicates that the problem might be from a lack of nutrients to the lower strawberries.

We found out several things and are currently correcting those to see if it makes any changes. First, although the nutrient mixture said it was for soilless systems, this apparently refers to mulch, and not hydroponics. It also contained only nitrogen, phosphorus, and potash, but no calcium or other minerals which we read can contribute to our problem. We have now switched over to a dedicated hydroponic nutrient formula containing calcium. We have also been told that consistent watering and then drying out can be harmful to the plants. We purchased a timer that turns the pump on 15 minutes of every hour during light, and 15 minutes every two hours when dark. We also purchased a pH tester, although we might also purchase a tester for nitrogen, phosphorus, and potash.

Below is a table of our materials and costs.  This is an approximate estimate and you will see it is a bit more than the $30 mentioned on the window farm web site:)

This list only shows what we are currently using. It does not take into account extra tubing, needles, miscellaneous aquarium supplies, and the first nutrient solution, as these were items we tried but did not end up using. 

Structural and System Costs

Plant and Formula Costs

Total build cost = $165

Additional tools needed:

• Hot glue gun
• Drill with drill bits
• Exacto knife
• Scissors

Thanks for the fun adventure windowfarm.org

We will keep posting updates as our system grows!

Hello.  I’m about to begin my window farm, but I had a quick question.  In the Reservoir System instructions , the minimum width for the reservoir is 47″.  Is there any reason that it must be that long?  If I only wanted three columns (instead of four in the diagram), could my reservoir be ~36″?  Also, is there a functional reason for the lower reservoir to be suspended instead of resting on the floor?  Thanks in advance for the advice.

Moveable hanging windowfarm we made for demos

This demo model was all about portability. It has much in common with a standard reservoir setup, but we needed to be able to move it out into the main space so we could show people how a windowfarm works while also being able to put it back in the window most of the time so it could get light (and grow HUGE!!) .

This model came before the move to sewer pipe reservoirs. We used the same suspended tupperware reservoir technique we used in the first prototype that we built in my apartment’s kitchen window.

You can’t see it in this picture but the “plumbing” is detachable and can be moved separately from the plants. We suspend a tupperware reservoir above this windowfarm and use a bucket on the right at the bottom to recapture the liquid and house the pump. We drilled holes through the side of the tupperware container up top  and attached individual tubes to the reservoir (tricky plumbing!). The individual tubes dangle down into the top of each column. The “recapture” tube you see at the bottom attached to the bottom dowel drained into a 5 gallon bucket that also housed the pump (on the right, not shown). The pump in the bucket is attached by a long tube to the reservoir up top, closing the loop. 

We made it portable by creating a removable frame for the bottle columns. We hung one dowel rod from another dowel rod with tension cable, creating a loose hanging frame. Then we hung each strand of bottles from a dowel rod at the top using the fishing wire technique. There are holes in the recapture tube, into which we insert the tube at the bottom of each column. We tied the recapture tube to the bottom dowel with zip ties.

 It was so exciting to just pick the whole thing up and move it down the hallway! It’s light enough for one person to carry even with these big plants.

These plants were all started from seed in February. The lettuce loved the cool early spring. Look at how bushy that blackseeded simpson got (mid left). There are also cucumber (the yellow flowers at top left), okra (maple-looking leaves mid right) , green beans (top right) kale (bottom right) and cherry tomatoes (bottom left), jalepenos, and Japanese Eggplant (bottom right big leaves) in this system. The cherry tomatoes,  jalepenos, and okra are just now ripe in early August. Beans keep coming- super tasty, crunchy, and sweet. The lettuce went to seed and started tasting better about after about 2 months of churning out georgeous new leaves constantly when we picked them.  Aphids and a weekend when I left the pump off (OOPS!) killed the eggplant. The cucumbers were a real mystery. Like Marilyn and James Dean, they died a young tragic death after a short, but full life. Read their sad story here. Someone else please try cucumbers!

A bunch of people got together to help Gabriel build his window farm in June. He choose to use a reservoir system (How To guide here), with 2 columns of plants to avoid blocking the light. This system was built in a day, and holds 10 plants, mostly herbs and greens. 

Top reservoir in Gabriel's system

We’ve figured out a way to suspend the water bottles from eachother, eliminating the need for fishing line or any other external means of hanging each bottle separately. Basically, the bottom of each bottle is drilled with a hole that the neck of the bottle above fits into perfectly. Screw the cap on, and you have a surpisingly strong connection. Check out more about our process here: http://hughswindowfarm.tumblr.com/