3,523. Can You Redeem Second Tithe Before It's Been Separated?

Hilchos Maaser Sheini and Neta Revai 4:16

If someone declares that second tithe sanctity is transferred to a sela in his son’s possession, the sanctity doesn’t transfer because maybe the son didn’t have the sela at the time.

Hilchos Maaser Sheini and Neta Revai 4:17

If someone redeems second tithe before separating it, such as by saying that the second tithe of certain produce is redeemed with certain money, his statement is ineffective and the tithes haven’t been designated. However, if he declares the second tithe of that produce to be in the north or in the south of it and its sanctity transferred to the money, then the second tithe has been effectively redeemed.