LandShare is a very active and useful site set up by Channel 4 to connect growers and landowners. It has a searchable database and a facility for adding your own listing.http://landshare.channel4.com/

The Yours2Share website has a searchable listings in the category 'Property, land, allotment sharing'

If you have any land and garden share resources or information for inclusion, please send to louisa@freshideas.org.uk