Did JacOB really promise to give God a tenth of all his belongings?

JacOB made a vow, saying, "Of all thou shalt give me, I will surely give a tenth."

Interesting vow, which was not fulfilled by JacOB himself, but by his offspring. God promised to give JacOB the land JacOB was on.
Genesis 28:13-15 And, behold, the LORD stood above it, and said, I am the LORD God of Abraham thy father, and the God of Isaac: the land whereon thou liest, to thee will I give it, and to thy seed; And thy seed shall be as the dust of the earth, and thou shalt spread abroad to the west, and to the east, and to the north, and to the south: and in thee and in thy seed shall all the families of the earth be blessed. And, behold, I am with thee, and will keep thee in all places whither thou goest, and will bring thee again into this land; for I will not leave thee, until I have done that which I have spoken to thee of.

Some 300 years later, God held the children of Israel to their father JacOB's vow, commanding them to give a tithe of the land to Him. He explained to them what He meant by "tithe of the land" in Leviticus 27, when He said

Leviticus 27:30-33 And all the tithe of the land, whether of the seed of the land, or of the fruit of the tree, is the LORD'S: it is holy unto the LORD. And if a man will at all redeem ought of his tithes, he shall add thereto the fifth part thereof. And concerning the tithe of the herd, or of the flock, even of whatsoever passeth under the rod, the tenth shall be holy unto the LORD. He shall not search whether it be good or bad, neither shall he change it: and if he change it at all, then both it and the change thereof shall be holy; it shall not be redeemed.

The tithe of the land was agricultural... a tenth of what the land grew went back to God. "of all thou shalt give me, I will surely give a tenth of all." JacOB was not speaking of tithing money at all when he made his vow to the LORD God, he was promising the tithe of the land that God promised to him and his seed.