The entire month of Ellul one may not blow Shofar at nighttime

The Aruch Hashulchan (O.Ch.581:12) writes,

“It is forbidden to blow Shofar in the month of

Ellul ,in the nightime, even if it’s done just for

practice. (not to awaken the negative forces

of the night.)”

The Tur (O.Ch. 581) writes that in Ashkenaz

the Minhag is to blow Shofar every morning

and evening (בכל בקר וערב )

R. Moishe zt”l (Igros Moishe O.Ch. 4, 21,) writes

“It is Mistaver (makes sense) Erev is not in the

nighttime, but  during the daytime,

either after Mincha* or after early Ma’ariv.(They

used to Daven Ma’ariv in the daytime).”

*The Chaya Adam, brings the Minhag of blowing

after Mincha