Cotton and Polyester Tzitzit

Hi,

According to the Rambam and Shulchan Aruch, four-cornered wool or linen garments require tzitzit biblically, but garments of other material do not require tzitzit biblically. Therefore, one should not use garments of other materials, like cotton and polyester, for tzitzit, since he is not fulfilling the biblical mitzvah.

On the other hand, the Rama ruled that these other woven materials do require tzitzit.

Therefore, one who is suffering from heat would be permitted to rely on the Rama and use garments of these other materials, but this is not ideal in general.

(Rav Moshe Feinstein, Igrot Moshe Orach Chaim 2:1)

המצפה לישועה,
Mordechai