You could try using a search engine (Google or something else) to look up the names of the nurseries and see whether they have new web addresses, in which case you'd edit the address and perhaps the telephone number. This probably would also let you know whether the nurseries have gone out of business, in which case the entry can be deleted. If the nursery was reviewed by any of our members before it went out of business, you could delete the contact links and add a note saying that the company has gone out of business.
