Echinacea Culture

I have heard that Echinacea angustifolia requires a cold spell to germinate. 3 degrees Celsius for a week in the fridge by the sounds of it - I hope this is correct. Is Echinacea purpurea the same? Things are getting a bit late, and I'm also considering direct planting. Is this refridgeration still needed? We are in spring now. Outside of germination my main concern is the crawing grass we have here. I've been told to use weed matting, but the cost is considerable. Have you any advice as to the ways and means? There is the possibility of planting closer- is this going to inhibit weed growth?

The echinacea seeds need 4 to 10 weeks in moist sand kept at about 5 degrees Celsius, but 3 degrees would be perfectly OK too. If you are having spring right now, it might be a better idea to keep the seeds in the fridge in moist sand and then you will be sure they had enough of a cold , wet spell to germinate when they get under field or garden conditions. Since the seeds have to be surface sown and just pressed into the soil, it would be best to expose them to outside conditions for as short a time as possible to minimize the chance that they get eaten by some hungry bird or insect.
To get weeds under control, I would suggest plowing once a week until you have to use the field for the crop. If the weather is fairly dry it will kill the weeds quite well. If it is too dry, I would suggest planting a green manure such as rhye or clover and plowing it under a bit before planting the echinacea.
If the area to be planted is fairly small, then spreading a sheet of clear plastic over the area weighing down the edges and letting the sun heat up the soil beneath to such an extent that any weed is cooked under it. Using black plastic to cover the soil between rows shades out any weeds trying to grow there. Planting the seeds close together is a good option for trying to crowd out the competition.