Question
I live in Toronto, Canada. I need a way have my window boxes  be watered while I am away for 4-7 days. There is coir (coconut bark) in every box, so that helps. I know you can buy water bulbs and so on, but is there something I can make? I don't want to buy anything expensive as I have a LOT of window boxes. I saw something once where you take an empty water or pop bottle, and do something with it -punch holes in it,or put a cork in the opening with a wick hanging out...I don't remember..and put it upside down in the soil and it will wick moisture to the soil --hopefully in adequate amounts--on hot, windy summer days it gets mega-dry  up here on the third floor. Can you suggest an inexpensive watering method for me?

Answer
There are many ways to vacation-water house plants. But, you have window boxes in the hot, windy, sun, on the third floor. Much, much more difficult.
The best method is a reliable plant sitter to come in, and water, following your detailed instructions.
The second best would be a 32oz bottle of water with several small cotton rope strings, enough to wick the water out around each plant. The bottle should be higher then the window boxes, so that the water will wick down. If the boxes are large, it may take more the one bottle for each box.
If the temperature is too hot, like in the 100's, the string may still dry out before it is able to give out much water. If you can bury it in the soil, to keep the sun off of it, it may help keep it moist.
Shading the boxes, and blocking the wind would also help. This might be done by tacking cardboard, or a wood "wall" around the boxes for  temporary protection. If the boxes are wooden, try wrapping them in plastic to hold in moisture.
You can also buy wicks from the garden centers that come with instructions. for about $2.50 for 5 of them.
There is a product called DriWater Gel Pacs for $2 each at www.driwater.com
And the Terra cotta cones that have cork in them, and are placed in a soda bottle, and inverted are about $12.50 at Gardener's Supply Company.
Water the boxes thoroughly just before you leave. Make sure the coir is wet. Don't fertilize. Cross your fingers.
Enjoy your vacation.