الجواب حامدا و مصلیا
Firstly, the lunar calendar is used for checking the day in which Zakat is due, not the solar calendar. For this reason, the questioner should specify a date to pay his Zakat in accordance with the lunar calendar. Moreover, since the questioner didn’t purchase the plot of land for trade (i.e. to resell it), but rather to build a house on it and then rent out the house, then in that case Zakat is not due on the value of the plot of land. Rather, it is incumbent to pay Zakat of 2.5% of the rent money achieved (from the house after it is built and rented out) on the day that Zakat is due.
And Allah knows best.
