A couple of weeks ago, I built several 34 inch long strawberry towers out of a 10 foot length of 4" PVC drain pipe. The fittings for capping the bottom ends cost me more than twice as much as I paid for the pipe! I think I paid like 8 bucks a piece for the end caps, then had to use zip ties thru drilled holes to hold them in place since the end fittings are made for the thick walled PVC - not the thinner outside diameter of the drain pipe.

Several days later, I had an epiphany while shopping at the local Publix grocery store. Eyeballing the 2 liter soda bottles, I splurged 89 cents on some Publix brand cola, then cut the empty plastic jug's bottom off. Though difficult to get it to slip over the pipe end, once you do, it fits nice and snug. 89 cents versus eight bucks! It's a no brainer! A little spray paint will render the clear soda bottle plastic opaque too, and the soda bottles have a built in nozzle to fit into holes cut in a return drain pipe! This afternoon, I added a couple more strawberry towers to one of my systems using this technique.

Hint: briefly soak the cut end of the soda bottle in an inch or two of hot water and it will soften the plastic enough to make it easier to slip onto the pipe!