Oh! Thanks for the tip - I was just researching about this kind of thing!About 40 years ago we decided to attempt to grow morels in our yard in Adair County Missouri. We had read about obtaining spores and growing mushrooms ourselves. The source for obtaining spores at that tme was basically non-existent. So, this is what we did. We had always hunted morels with paper grocery bags.
When we got home from hunting we would pour the morels into a five gallon bucket and then rinse them with water into the bucket. We would them slowly pour the wash water into the paper bag and rinse the bucket into the paper bag.
When the water drained from the paper bag we would cut the bag open and place the inside of the paper bag down on the ground and weigh it down with a rock and leaves in the shade of the north side of our house. We let the grass grow up arround the bag and did not mow the area until the bag rotted away.
We did this for about five years and by the end of the sixth year we had morels growing everywhere we had placed the bags.
It's amazing to watch the morels grow from the small grays into the big yellows/whites. The largest we ever had was about 12 inches tall. Also, we never had to go to the woods to see if they were up yet as we just cheked our yard. The most we ever harvested was a paper grocery sack full.
I had to demolish our old house last year and a lot of the grow areas are now covered over with dirt, but there are still areas that are not covered and should still produce, no morels up this year yet, but I am still checking.
It was my understanding at the time that we tried this trick was that when a morel emerges from the ground it is fully developed and spores are released from the cavaties within the morel. It figures that not all of the spores are released from the morel and that there would be spores still attached to the morel. I was right and we had our own patch to pick from.
Give it a try, it works and just keep adding to the patch and your whole yard will be a patch of morels.
Good Luck, Missouri Bob