I’m an international user in Maastricht, the Netherlands (originally from the US). My windowfarm is now up and running, with basil, chamomile, cilantro, and watercress. I combined the older, simpler instructions from this site with the new more extensive ones.
Tips that I’ve found, in case they’re not already mentioned elsewhere:
1) Make sure to elevate your air pump! Instead of putting it on the floor, put the air pump on a shelf or stack of books. Even if you use a one-way valve, the air pump should still be above the top of your water reservoir. Otherwise eventually the water will flow back up the tube, wetting and ruining the pump. This happened to me, and I had to buy a new pump. Likewise, like it says in the instructions, be sure to always make a loop in your tubes and cords, and never put the garden above a socket.
2) I was able to quiet my air pump by tieing it firmly to a cereal box filled with old clothes or some other sound/vibration absorbant material.
3) The simple older method for cutting holes in the bottom of bottles (exacto knife), to connect the bottles, was much easier than the new method, and I didn’t need a special rotary saw.
4) Instead of net cups, I used emptied individual pudding cups. It took some trial and error to find pudding cups that were the right size so that they didn’t get lost in the bottle, but still fit inside. The upside to that was getting to eat a lot of pudding.
5) If you’re growing plants from seed, using grow cubes, then you don’t need clay pellets specifically to fill your cups. You can just use reglar gravel or rocks you find outside.
6) My water reservoir is large and never completely full, because it has the hole in it to let the tubes come in and out. This would seem to affect the dilutions for the hydroponic nutrients, because the instructions are per liter, but my reservoir has an unspecified amount of water (~1.75 liters) in it at any one time. To fix this, I dilute my nutrients in a separate 1.5 liter bottle of water, allow the water level in the reservoir to get as low as possible, while still working, then refill it with the water from the 1.5 liter bottle. It’s still not exact, but it cuts down on the margin of error.
7) At the very top, the water was spurting and spraying everywhere as it came out of the tube. Instead of making a silencer with a medicine bottle (old instructions), I just used a 4-inch piece of masking tape to partially cover the tube. The tape should be parallel to the tube. Stick one end of the tape onto the front of the tube, about 1 inch. above the end where the water comes out. Then, just let the bottom end of the tape just lie loosely on top of the grow cube or plant. The water will come out of the tube, hit the tape, and then quietly drip off the tape onto the top plant.
I’m excited to try the T-valve assembly (elsewhere on this site) for my next project. I used the new instructions for one of the airlift mechanisms this time, and it has two disadvantages: 1) Since the airlift (needle and tube) is underwater, in the water reservoir, it’s hard to clean and difficult to diagnose the problem when it isn’t working, and 2) It’s somewhat unreliable, so it regularly stops working for various reasons and requires tinkering; and 3) It allegedly can’t lift the water very far compared to the T-valve method.
Good luck with your window farms! If there are any other users in France, the Netherlands, Belgium, or northwestern Germany (Aachen area), I’d appreciate it if you let me know by commenting here so we could get in touch.
For those in the Netherlands, there are many hydroponic grow shops here which were very helpful throughout the process even though I’m only growing herbal tea and vegetables. I’m using Floragrow hydroponic nutrients, which are avilable in Europe, with good results.