Is the Lord made harvest grown

Leviticus 23:1-22
The appointed feast of the Lord, which you are to proclaim as sacred assemblies.
There are the Sabbath, the Passover and unleavened bread, First fruits, feast of Weeks, feast of Trumpets, day of Atonement, feast of Tabernacles.
The Sabbath: one day of rest in seven
The Passover: (1/14) seven days. followed by the seven-day
The Firstfruit: followed by seven weeks later by, together with its grain offering of two-tenths of an ephah of fine flour mixed with oil.
The feast of weeks: the harvest festival (June). Count off fifty days up to the day after the seventh Sabbath. The day brought the sheaf of the wave offering, count off seven full weeks.
Bring two loaves made of two-tenths of an ephah of the finest flour, baked with yeast, as a wave offering of firstfruit to the Lord. And bring a sin offering, fellowship offering, wave offering.
Why?
The seasons of the year, seed time and harvest are marked with special festivals. 
Like the weekly sabbath, they reflect a pattern of sevens - pointing back to God setting the seventh day apart as a special day at creation.
Only in the feast of weeks for celebration so the bread may baked with yeast.
How?
People put seek in the land, and God let it growing up. The harvest is the grace of the Lord, so had feasts to thanks the Lord.