Red Clover Seeds to Plant 5 Acres

I would like to know how many red clover seeds are required to plant 5 acres? How much would this cost?

Red clover should be planted at the rate of 4-5 kg per acre (9-12 kg/ha). The cost for the 5 acres would be $500 in 2010.

When should I plant it in the spring or in the fall? And will it bloom the first year in spring?

You will get better success with spring planting. They will not bloom the in the spring that they are planted, but next spring. If you plant in early fall, then some of the plants WILL bloom the first spring.