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I’m considering making my bottom reservoir with an assembly of old soy milk cartons. (I have a window sill that it can sit on.) However, one of the soy milk cartons I’m using wasn’t cleaned out properly, and had some mold growing on it. I was able to scrub most of it off, but I’m afraid trace amounts of mold are left. I could use some sort of cleaner (vinegar would probably be my choice) to get rid of it, but I’m not sure if introducing that (would it leave trace amounts?) would be any better than the mold in the first place.

So my question is: how sensitive are the plants to what the water may be in contact with? Is there something I should do to minimize any risk, or should I just abandon this idea?

Derek Stobbard wrote me an email with this idea for nutrients:

“Here’s an idea for natural nutrients: Keep fresh water fish – goldfish, for instance. Once a week empty one fifth, to one third of the water from your fish tank and replace it with new water (preferably water that has sat in a bucket for a day – to get rid of the chlorine). Empty the water you took out of the fish tank into your watering reservoir. This water will be rich in nitrates from your fish’s “waste” which plants love, and if you feed your fish sustainable and organic food, so much the better. As long as you are doing this regularly, your fish water should not smell. Beware of algae, keep your fish tank out of direct sunlight, as algae will consume the nutrients and the oxygen from the water.

If you grow anything other than green leafy plants you may need to add very small amounts of calcium, iron and potassium from time to time (once a month). However, you may get away without it since you use clay pellets as a solid medium in your pots, and this has trace amounts of these necessary elements. Also, depending on the food you give your fish, some of these may already be present in the uneaten food, and will make their way into the water. ”

I love the idea and generally love the idea of aquaponics (fish + plant system). I continue to remain skeptical about incorporating fish into the windowfarm because forcing symbiosis between two different ecosystems is pretty complicated stuff and the balances can get out of wack really quickly meaning you could end up with a bunch of dead plants and fish really fast.

I like that he proposes simply using the fish water as a nutrient source and moving that water to the windowfarm after a simple filtration process. Anyone want to try it out? We would need a control group as well. Build two airlift systems- one using fish waste and the other using the recommended (Sugar Peak Organic Hydroponic Vegetative Nutrients) commercial nutrients? That would be rad, guys.

Remember everyone, creating nutrients is a pretty sophisticated biochemistry application so you gotta be ready to be super experimental. You probably will lose a lot of plants along the way. If you just want beautiful veggies you can eat asap, start by experimenting with existing hydroponic nutrients and only make slight modifications to start with.

My husband and I are excited to start our window farm! We’re starting small with the central pane of our three-pane bedroom window. We have to keep it all pretty high up since we have a toddler, so we can’t have anything at a height that he can reach and destroy.

One thing we’ve already noticed is that while we are going to be doing a “C” style window farm, our window sill is just not wide enough underneath to hook the bottom reservoir, and our air conditioner is also in the way. So we’re going to set the bottom reservoir on top of the sill. This will take away a little bit of window space, but it’s a tall window so we think we’ll still be OK.

Today we made our initial foray to Lowe’s to see what supplies we could get there and how much they would all cost, as well as get an idea of what kinds of things we want to grow. In February our son is going to stay with his grandparents in Miami for a week so that’s when we’ll do our shopping and start our garden!

I’m attempting to build a version of the Airlift Window Farm without plastic parts.

The initial version uses stainless steel tumblers, sisal rope, metal crimps, a glass reservoir, and natural latex tubing. The only plastic part is the air pump. Everything was purchased fairly inexpensively (mostly on the Bowery in NYC).

You can find images of the project in progress HERE.

If I can get this one to work, I will build a second system next to this one using Chinese bottle gourds, coated in beeswax (see diagram). We’ll see.

PROBLEMS:

1. I’m currently having problems getting the pump to push the water up the airlift tube. I’ve noticed others have had this problem and see that Britta posted some suggestions, which I tried– but they haven’t worked. The air forced into the air lift tube doesn’t seem strong enough to move the water up vertically. It goes for about 6 inches and falls back down again. It also makes a loud bubbling/spattering noise. The pump tubes are dry and the air lift tube is fully submerged and mostly straight. I have an ActiveAqua AAPA7.8L pump. — ANY SUGGESTIONS?

You can grow edible plants with 100 or 150 watt CFL bulbs. Even fruiting plants. I have done it successfully in several windowfarm systems. You must use CFLs with the proper color spectrum. The “daylight” bulbs you get at Home Depot in the blue package work. Arrange your plants so they are no more than a few inches from the light. You will need to move them frequently or they will grow into the light and singe themselves. I highly recommend putting them in a window so they are also getting at least some indirect natural light because I highly doubt that these CFLs really provide the complete spectrum of light that plants need. You can put them on a timer so that they are only on a few hours during the day to supplement natural light. This keeps them from blinding you at night.

Until plants reach the adult phase, they require more light. I generally supplemented seedlings light for 18 hours per day. Then, once they reached maturity, I decreased to 12 hours.

Hi all,

I love the idea of urban farming. I have previously owned an AeroGarden but I am looking forward to going DIY. I am just in the research phase of getting started, and I have some questions/concerns about hydroponics.

I would very much like to proceed as “low-energy” and using as many “low-impact or recycled local materials” as possible. This is what appeals to me most about the windowfarming concept. However, most of the hydroponics solutions I’ve read about do not fit those qualifications. Most low-cost pumps are presumably manufactured somewhere far like China. I’m also against running a pump continuously, and even a simple timer requires electricity (and is also probably imported from somewhere).

In my googling, I’ve come across a few approaches that are pump-less:

• http://www.csupomona.edu/~jskoga/dripirrigation/
• http://www.flickr.com/photos/c4g/3062627532/
• http://www.instructables.com/id/Solar_Thermally_Pumped_Hydroponic_System/
• http://www.instructables.com/id/Solar-Powered-Vertical-Drip-Hydroponics-with-Frenc/

Even so, the drip irrigation approach uses PVC tubing, which I don’t have and can’t make myself, and the ebb-and-flow approach uses materials such as perlite and rockwool, which I’d have to go out and buy. More importantly, such materials are seriously not low-impact if you look up where they come from.

I’m not against buying materials if those things are really necessary, but each purchase seems to go against the low-impact intent! I might as well buy another AeroGarden.

So as a newbie, I’m questioning why hydroponics is really necessary for a successful windowfarm. Could one not just use a little potting soil instead? And how well do perlite, clay pellets, etc. match up against more easily findable “urban” materials (sand, gravel, glass, styrofoam, sawdust, …)? Are there others out there who are thinking along similar lines and have tried any alternative techniques or materials?

/John

Stockholm, Sweden

This gets way nerdy on the pump/plumbing of the Reservoir System. Beware. If you are super nerdy, this is where you can jump in and start making this system better!!

Your reservoir system is a liquid circuit controlled by a pump on a timer. The pump needs to only pump water, not air. Running a water pump dry will kill it. The relationship between the amount of time your pump is turned on by the timer and the gallons per minute flow of your pump dictates a minimum amount of water in your system and, therefore, a minimum size for a sewer pipe reservoir.

However, there is plenty to tinker with here.

Here are notes from my thinking when I wrote that part of the Reservoir system How-to. They are notes that I have not really edited, so ask questions if something is unclear,

Theoretically, let’s say our pump pumps 500gph. That’s about 8.3 gallons per minute. We have decided that we lose about 25% to the curve at the top of the reservoir, and we probably lose about 10% to any remainder at the bottom that is too low for the pump intake. That means that when the bottom reservoir is as full as it can be, only 65% of the water in the tube can actually cycle through the system. So, 65% has to be at least = 8.3 gallons, which means the total pipe capacity if completely full has to be 12.8 gallons.

The pipe formula is

length of pipe = volume in gallons/0.00432900433 x Pi x radiussquared

so when the radius is 4” for the sewer pipe with 1/8” thick walls, the minimum pipe length formula is

GPM/0.21759949= min pipe length

For this 500 GPH pump, minimum pipe length for a one-minute pump-on cycle with the timer we have recommended is

8.3/(0.00432900433 x 3.14159265 x 16)=

8.3/0.21759949

= 38.14”

and if you want it to rest inside the window sill, that has to have the pump length added to it, which puts us at more like 40”

A typical window is 36” wide. So:

1- Maybe we don’t need this fancy a pump because we are only pumping up about 4+- feet of head. Maybe we could find one that would fit inside the reservoir so we don’t have to suspend it outside.

2- If we still want to use this pump, we should have people make them wider than their windows and suspend them outside the windowframe.

3- ??

RESEARCH—

Ecoplus pumps correlated with head and cost are here: http://homeharvest.com/hydroponicpumpssubmersible.htm

(CAUTION: BE of these pumps- several of the ones we ordered did not pump as high as they were rated to pump!! Go a size bigger if you’ve got a tall window and can mount it outside the windowframe!)

Ecoplus 633 – 7.87 feet of head- pumps 633 gph

Gpm=10.55

Absolute Minimum pipe length with our timer is 48.5” +pump, assuming it drains completely within 3 hours

Drip rate needs to be 3.5 gph

½ inch and ¾ inch hose connectors

7.2 inches long (with cover that we remove) by 3.1 inches wide by 4.3 inches tall-

won’t fit in pipe

$46.95 at home harvest

Ecoplus 264- 6.39 feet of head- pumps 264 gph

Gpm= 4.4

Absolute Minimum pipe length with our timer is 20.22”+pump, assuming it drains completely within 3 hours

Drip rate needs to be 1.5 gph

½ inch and ¾ inch hose connectors

6.2 inches long by 2.5 inches wide by 3.5 inches tall-

will fit in pipe $21.95 at home harvest

If you put the Ecoplus 264 pump timer on a two minute duration cycle, you’d pump 8.8 gallons and your pipe would have to be 40.44”+pump long.

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.

On October 2nd, we installed this windowfarm at the Whitney.

The next day, we hosted the Whitney’s Family Day for several hundred New York families.

We tried out some of the latest innovations, including:
- suction cups for suspension!
- new way of attaching airpump needles for increased height!
- new airpumps
- regular bottle used as the bottom reservoir
- new dried powder nutrients

Everybody be warned that the Ecoplus pumps are a bit of a hit or miss. It seems like sometimes you just get shipped a lemon.

We have been having a lot of trouble with the EcoPlus pumps and have had to return them 3 times. Agh! Seems like there are some manufacturer issues. Maria Ailova, the program director has almost given up on them.

The window we are using for our windowfarm is 6′ 10″ tall and the plan is to mount the pump right flush with the bottom of the window and have the tubing go up into the top reservoir about 6″ above the top for a total head (pumping height) of 7′4.”

The first pump we bought was the Ecoplus 1056, which is rated for 9.2.’ But it did not pump high enough and the attachment for 1/2″ tubing was broken. We replaced the attachment and it still did not work.  Even the next pump down, the Ecoplus 633 is rated for a max head of 7.4.’

We returned the 1056 and ordered the 1267, which just barely reached the top. However, it leaked! The back of the pump housing put out a rapid drip as soon as we turned the pump on.

We returned that one and told them the problem. The next one they send did the same thing!

We finally got one that worked and did not leak. Just plan that there is a possibility you will have to return your pump so definitely wait to get seedlings until after you are sure your system is working.