The holder is made out of so-called 3/4" PVC pipe. This pipe is actually about 0.9" inside diameter and about 1.05" outside diameter. The two ends are converters to male hose threads, and the end caps are those used for soaker hoses. The pipe costs about $0.40 per foot, the converters are about $1.50 each, and the brass end caps are about $3.00 per pair. If you don't already have some, you may have to pay about $1.75 for the smallest size can of pipe glue.

Cut a piece of pipe exactly 4" long. Mark it 0.8" from each end. Glue on the first thread converter, pushing the pipe into it only to the mark. Let dry about an hour. Glue on the second thread converter, pushing the pipe in only to the mark. Quickly check that the end-to-end length is right at 5.9" to 6.0", and adjust slightly if needed before the glue sets!