Remember: "In Flanders fields, the poppies grow" and those poppy seeds could have survived under ground for over 1000 years. It has become fairly common over here for arable farmers to use ploughing contractors. A good way tolose a contract is to plough just that bit too deep and penetrate the pan of soil that has not been to the surface for years. I have seen an example where this happened and the farmer was irate. (There are special ploughs used from time to time to break the pan for drainage that do not bring the subsoil tothe surface.) Temperature appears to be the factor. It's warmer nearer the surface. Were the bottles set at various levels? Regards Hamish -----Original Message----- Michigan State University has had a weed seed germination experiment going on since 1879. Bottles with a mix of weed seeds were buried and are dug up on a regular basis to see which seeds will germinate. The latest bottle produced only Moth Mullein, Verbascum blattaria, from 120 year old seed. http://newsbulletin.msu.edu/july27/beal.html Five of the original 20 bottles remain buried, and the next one to be dug up and tested will be in 2020. Diane Whitehead