Is it recommend not to go to the cemetery on 15 of Shevat?
Answer:
I do not know of this recommendation. Although the 15 of Shevat is a semi-holiday, in that we do not say Tachanun and one should not fast, if one has a yahrzeit on the 15 of Shevat, it is fine to visit the cemetary, as customary for a yahrzeit.
Best wishes.