بسم الله الرحمن الرحيم
(Fatwa: 268/225/D=03/1436)
It is makrooh to stand in new saf (row) alone; hence you should take someone to join the first row with you. Nowadays, since people are not aware of Shariah rulings, so if you will ask someone to join from the first row, it is very much possible that he will turn away from the Qiblah direction completely or make his salah invalid. So if you are sure that this condition might take place then you must not take someone from the first row, as people keep on coming hence you should wait till ruku. If someone comes then you should start your salah. In case, none comes till ruku then you can start your salah alone. هكذا فى امداد الفتاوى و حواشيه عن الشامى
Allah knows Best!
Darul Ifta,
Darul Uloom Deoband