Windowfarms recommend a 4 outlet pump but many people already have a 1 outlet pump and probably would like to use the one they have.  So here I have a video about a method to split the air stream to work 2 or more columns. If you just split the air with a Y or T splitter (even if both airlift tubes are exactly the same), the air will “choose” one tube (or the other one) and then all or most of the air will go up that one with zero or almost zero airlift happening in the other one.  This is because the “starting pressure”  is higher than the “running pressure” for any airlift pump.  So whichever one starts first will probably stay running really well at the expense of the second one (which will be either really slow or not running at all!)

The method I show to prevent this is to throttle both of them.  In the video, I use little “taps” to tighten and restrict the airflow to both sides until both sides run. AND stay running!   For this to work, both airlifts should have similar submergence (but they do not need to go to the same height).  You might also be able to see from the video that you can have one going a bit faster than the other.  So possibly, you can supply more water to some plants when they are big while in the other airlift supplying just a little to them because they are tinier.

There are other methods too but this one should be easy to do and to adjust.

2  airlift columns from a single outlet air pump!

I only did 2 columns because I didn’t have enough tubing to show 3 working.

3 columns  might work in my case (my pump is an old aquarium pump that I found dumped on the side of the road so it is probably not such a good model)

Update 2nd Jan 2012.  3 columns works too but in the case of my pump it is the limit.  Video Jan 3 2012. 3 airlift tubes working from a one outlet aquarium bubble pump

Youtube now allows you to edit videos so if I am not too busy, I will “upgrade” the video (and this post)  over the next week or 2 and show methods to measure the flow or at least compare flows under different conditions too. Brian

We built a starter window farm earlier this year, and now I’d like to build a bigger one to cover the entire window. (I actually have a really huge window.)

But I’m having trouble understanding the assembly instructions for plumbing, specifically at and after bottle cap assembly (methods A, B, and C).  At the end of the instructions for each method, it ends with putting the other end of the airline tube into the pump.

I must have missed something or am not understanding how this works, but if you have four or more columns, how do they share one pump? In the full assembly picture, it looks like each doesn’t plug into the pump but rather into something with a loop above it. I can’t seem to find mention of this in the instructions.

Can someone please enlighten me?

I did a little video today about lowering the airspeed through to windowfarm to vary (and sometimes increase!) the rate of airlift.  Depending on your tubes the rate can be quite slow and still give you good pumping. Check it out because I think it can help people to understand a bit better and to get things right first time.
Anyway here are some pictures that I took out of the video.

2 outlet air flow regulator valve

This is a little aquarium valve and bottom pic shows the adjustment knobs

You can either use it to regulate air to 2 t joints or just leave one open to the windowfarm and have the other one just a bit open to let some of the air escape.

Below is a head for connecting a tube under the reservoir. You might need a bit of gauze or window bug screen in the bottom to stop crud getting into the tubes.

Head for watering plants. Snip off the top and use the "neck" to attach tube

And you also can use this thing for aquariums as a bottom reservoir.

Aquarium attachment for tubing

And finally I am going to show you a pic of the bubble in the tubing.

plug of water

If you reduce the airflow into the t-joint and into the tube, sometimes the water flow increases. This is because the type of flow changes from churn flow to plug flow.

Plug flow can be quite slow sometimes. As the plugs of water rise, it changes from many short ones to a few long ones.

Watch the video to get more information.

Thanks Brian

Thanks for your suggestions and comments, everybody. I hastily made my reservoirs darker, but will have to address the issue more thoroughly in a near future. I used thick cardboard to make a niche for my upper reservoir and poster cardboard to cap the bottom one. Look at the photos.  Wouldn’t it be wise to cover the tubing as well, inside a sleeve of black fabric, for instance ?

I’m still looking into a sustainable pumpless system. I figure that I can live with the chore of climbing up once every three days to refill my upper reservoir. But I’d like to refine the design. And I thought about capillarity, this capacity of a spongy material to sip water up to a higher level. Still juggling with the idea. I have the habit to leave my plants at school with a very simple but very effective capillarity system to water them during Christmas vacations. By the way, I enrolled my younger daughter in this thinking process.

Meanwhile, I continued my experiments with the slow drip, utilizing the 600mL container, since I like the idea of suspending it directly above the plants. I doubled a simple string of unknown (synthetic) material, made a knot to tie its two ends together and squeezed the fold up into the silicone tubing. To my surprise, this slowed the flow  very significantly. (In my first attempt, using the enteral tubing with the slow drip system built in, the bottle was empty after 3 hours.) This last system lasted 84 hours (3 days and a half) during which it needed no intervention from my part.

But I think I might have been too successful in slowing the whole thing. I’m afraid the plants wouldn’t receive enough water.  So, I thought of coupling two 600mL bottles side by side, and join the two strings together to double the volume of water, which I’ll try out no later than tonight.

Which brings me to my question : does any of you out there can tell me approximately how much water you need to put through your system over a period of 24 hours to sustain your plants’ needs ? What would be your estimate ? And did I understand correctly when I read that people put their air pump on a timer to make it work only 15 minutes at a time ?

Last thing : Somebody gave me 2 swivel curtain rods, a few years ago, which I kept intending to use them for another project. I stumbled on them by chance while looking for something else. And I think they are just perfect for what I have in mind. I want to be able to get the whole window farm to get out of the way when I want to access my window. These rods move just like window shutters and their tubing is square, so we think that they would be strong enough to sustain the weight. I’m posting a photo and will certainly try them. Only need to figure out a way to stabilize the different columns of bottles at the bottom, possibly by tying them to a wooden rod suspended underneath the last row of bottles.

As I succeeded in sending a first communication, here’s the information about my experiment. As I said,  two weeks ago, I constructed a starter system that could allow me to get familiarized with all this first hand. I didn’t use the plans provided on the site, just browsed around, read a lot,thought a lot and observed. The funny thing is that, besides the need to buy hydroton, I didn’t spend one dime on my small and crude installation. Here is what I used so far :

. 1   2L soda bottle

.1   1L soda bottle

.1  1L Pedialite bottle (an oral electrolyte maintenance solution to prevent dehydration during diarrhea and which is also very effective to stop heartburns as well, by the way). The bottle is nicely square and I could open four windows in it, one on each side. But the plastic is not entirely transparent. Rather a smoky white. It’s the bottle at the bottom of the line.

. 1 tubing for slowdrip enteral feeding (my students are mentally and physically disabled and some can’t feed themselves by their mouths, so this kind of tubing is very abundant in our recycling bin and never comes in direct contact with the person, just with the feeding solution). See third photo. The product is american. Don’t know its cost, but it should be quite affordable.

. 1  4L ice cream container as a top reservoir (see the top shelve in the 2nd photo)

. 1 small rock to anchor the tubing to the bottom of the reservoir. See second photo.

. 1 metal container as bottom reservoir (it’s coated with a cooked layer, but I don’t remember how it’s called). See at the bottom of the system in the second photo.

. 3 plastic flower pots instead of net pots (the type you find in gardening centers when you buy baby perennials. The plastic of the cheapest ones is very thin and so flimsy you can compress them into the bottles without breaking them. Poking holes or cutting slits in the sides is also very easy.) I didn’t post any photo.

. Instead of hydroton, I thought of using my husband’s old glass marbles collection from childhood days, but since we want to give them to our grandson eventually, I refrained from that. Glass is inert, after all, and the marbles are the right size, but then I realized how hydroton is light-weighted, how it absorbs water and is full of small holes, so I don’t think marbles would be a good substitute after all. Besides, hydroton is quite cheap.

. For making a dark room, I simply used an old paper bag from a boutique. The exterior layer (the side with the store’s logo on it) was black, so I put that side inside to face the roots, showing only the regular brown paper layer.

. To suspend the whole thing, my husband gave me a roll of electric wiring that was gattering dust in the basement. It’s copper covered with black plastic and should be very sturdy. Each bottle was then secured with gardening metal wire covered with plastic as well.

My first experiment to make water run through the system was with the small 600mL feeding reservoir you can see on the third photo, put directly over the line of bottles (fine, since it comes with a nice handle to suspend it). But the water pressure doesn’t ensure a regular flow. This means that you have to ajust the flow with the clamp about every hour. And after three hours, the bottle was empty. That’s why I came up with the 4L (1 gallon) reservoir. The flow is much more regular, needing adjustment only every 18 to 24 hours. Plus, it lasted 72 hours before coming to a halt. Much better.

I’m currently trying other experiments to see how the system can be improved and I’ll come back to you with this.

I’d like to preface this post by saying that if these issues have been dealt with before or the solutions appear to be self-evident, please bear in mind I lived through the 1960′s. I think that says it all.

I am working from the ”new” 3-plant airlift sytem pdf file. I am in the process of assembling the items in the Materials List (ML) and have a few questions:

1. the ML requires 1 x 3/8 OD  – 1/4 ID Kuritec Reinforced

                                      2  x 1/4 OD – 1/8 ID vinyl tube

                                      1 x 3/8 OD – 1/4 ID (vinyl tube??)

      Step 6 of the assembly instructions tells me to, “fasten together the bottle stack, the rod, and the lift tube (3/8 ID rubber tube at 4’6″ long).”

Is the ML missing an item or is there a mis-print in Step 6?

2. The ML calls for 5 liters of clay pellets. I can fill a heck of a lot of 3″ diameter net cups with a 5 liter bag of pellets. Do I really need this amount?

3.  Should the vinyl tubing be clear or opaque? I’m thinking the tubing will be subject to “algae bloom” if it is clear. However, thinking is not one of my strong suits.

4. Does the size of the bottles used in the stack have to be 1.5 L? I didn’t realize that the 1.5 liter size was almost unheard of in this region, until i went looking for them.  

5. I don’t wish to seem critical but I have to say that the less than $30.00 cost estimate is way off target. In this little corner of the world, (Atlantic Canada), an air pump of the specifications detailed in the ML is going to run me about $35.00. A 1 liter (about 35 oz) container of hydroponic nutrients will run me the better part of  $25.00. (OK, they’re Canadian dollars but it’s all I’ve got to work with.) The actual cost really doesn’t matter to me, I like the concept. Plus anything that can give me fresh “sweet million” tomatoes in mid-winter is worth shelling out for.  However, I do feel that the stated cost estimate is a bit mis-leading.

Thanks in advance for the advice and assistance.

Ed

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!

OK Britta, here is one of my Zigzag windowfarms,

Zigzag v2

It is made from Polypropylene milk cartons (which should not have any Bisphenol A leakage problems) arranged zigzag so I can get them to mate together horizontally to make a “wall”

This arrangement will also provide mutual strengthening (the bottles are very thin/weak)

I have a twinwall plastic ceiling over the area where these will be so the window will not be the primary source of light, and given our long gloomy winters in the UK I will be artificially lighting these for much of the year anyway.

Proposed wall of hydroponics

A single line of cartons can use the ends of of the cartons as a location for netpots – I have one of these in the build too, but to form a wall I have to use the fronts of the cartons meaning that the netpots are horizontal – a bit precarious!

I hope that once the roots get established they will pass through the netpots and go down the bottle helping stabilise them.

Given the number of growing sites and the weakness of the bottles I am only expecting to grow small (6 inch round) plants – herbs and cut-and-grow-on greens.

(Basil, Corriander, Oregano, lemon Balm, Garlic chives?, Mizuni, Cale, Mustards, Rocket )

The main problem has been getting a consistent nutrient supply from the 6 foot air lift (keeps stalling) – not helped by the fact I’m using thin pipe (6mm),and a fairly weak aquarium pump (one output)  - a thicker pipe (10mm.) is on it’s way – but the beast is working… just…

I think the nutrient pipes need to be black (can’t find any) or blacked (tape lengthwise!) to stop algae growing in them – I notice a lot of people using clear pipes, could be problems down the line…

Minimal airlifts

The airlift was originally  a “T” juction as above – (got no ball inflation valves!) – then I tried a straw with a pipe and a tiny hole in the straw side.

Minimal airlift detail - just add silicone and tape

I will try the same technique with a thicker pipe when it arrives…

You can just see the reservoir bottle in the distance!

I’m guessing that there is an optimum width for the nutrient pipe – too narrow (like mine) and the bubbles are too tight in the pipe and the airlift tends to go into reverse just bubbling the air out of the bottom of the airlift, too wide and the bubbles won’t make contact with the sides of the pipe and act as air pistons forcing the water up the pipe.

Just a note some organic nutrients (bio biz gro) seem to froth and the bubbles play havoc with the airlift! – frothing out of the top.

I think after experiences with various seedlings dying off/breaking at the stems/being too leggy that a fan(or other source of air flow) is a vital component in our setups.
Maybe you can get away with the window being open a little.
The increased airflow may prevent early mortality (is it stem rot?) and the constant flexing of the stem certainly stimulates the seedlings to produce thicker stronger stem walls.

Ok, 3-plant airlift system.  I am not seeing the lengths of tubing needed.  For those of us not in NYC could we get an online source for the tubing in the instructions as well as lengths of tubing needed?

Thanks.

Images

See some initial research here