If you do a Google search for the word “tzitzit,” some of the top-ranking websites you see are maintained by Christians. We recently received the following email from a woman in the state of Washington:
I see, while browsing on the Web, many tzitzit made from colored cotton yarns, including beads, and already tied, just with a loop at the top. Are these in conformance with Jewish practice?
I have seen these websites, too. The vast majority of them are sites maintained by Christians who like to observe certain biblical commandments in their own way (“Messianic Jews”).
Kosher tzitzit strings must be spun with the intent to fulfill the mitzvah (see “Kosher Tzitzit Strings: A Matter of Intent“). And tzitzit must be tied directly on a tallit or garment, not pre-tied, since the verse says, “And you shall make tzitzit on the corner of your garment” (Bamidbar 15:38).
I noticed that one of these websites offers “installation instructions.”
A third problem with these tzitzit, although less severe, is that the custom, according to the Shulchan Aruch, is to make white tzitzit, not colored tzitzit. The techelet (blue) strings mentioned in the same verse cited above is the exception, of course.