Crown Vetch Seeding Rate

I would like to know how much seed I would need for an area approximately 3000 sq ft. What is the ideal time to seed and is it possible to seed at the end of summer?

The direct seeding rate for crown vetch is 17 to 23 kilograms of seed per hectare. For indirect seeding (growing them in a seedbed and planting in their permanent spot when of reasonable size) you need 10 grams of seed to produce 1000 plants. Since the plants should be spaced about one foot (30 centimeters) apart each way, you would need 3000 plants or 30 grams for indirect seeding and about 10 times that amount for direct seeding.
Fall seeding would be best, since this is when the seed is produced naturally. However I have seeded my own sloping roadside with this plant and early spring seeding worked quite well. In a roadside situation it would be a good idea to make shallow troughs parallel to the hill about i foot (30 centimeters) apart and sow the seed in them. Cover lightly with soil, tamp down and water. Rewater anytime the soil seems to get dryish. If you sow in the fall, the natural precipitation and snowmelt will greatly reduce the care needed.
By the way, my roadside was lovely with crown vetch until the roads department decided to redo the ditch and scraped all the vegetation off to do it!!!