Greenhouse
Grapes have been grown in both heated and unheated greenhouses in Scotland since Victorian times. These tended to be in the gardens of estate houses although there were also some commercial enterprises. William Thomson established Tweed Vineyards, the first commercial greenhouse vineyard in Scotland at Clovenfords in 1869. The main varieties grown were the table grapes Muscat of Alexandria and Gros Colmon both of which are very late ripening and require extra heat. The location was chosen for supply of coal (along the former Waverly route railway line) rather than climate as the Clovenfords area is characterised by cool mean summer temperatures of 13-14C (see map, Background section). Another notable enterprise was Forth Vineyards at Kippen, establised around 1890. Again Gros Colman was one of the main varieties grown, with one vine becoming the world's largest, the Kippen Big Vine, eventually reaching a size of 300ft by the 1960's.
Heated greenhouses are now long gone, but the unheated greenhouse is no longer restricted to the homes of the rich. It would be quite feasible to grow the same table grapes as in some the unheated Victorian greenhouses, and one such variety, Fosters White Seedling, does quite well here. Most though, tend to be quite slow ripening and mildew-prone. However, there has been a lot of development of new varieties over the last decades with an emphasis on early ripening and disease resistance. Several of such varieties are being trialled in the greenhouse and polytunnel. The main difference between these environments is in the length of growing season. The inaptly named toughened 3mm glass of the greenhouse, now replaced in many places with polycarbonate where it has broken, provides better insulation than the thin plastic of the polytunnel. The growing season in the greenhouse therefore starts about two weeks before the polytunnel. The traditional use of a long season growing environment would be for growing slow ripening varieties, but the option also exists to include fast ripening varieties to get a long cropping season. Some of the newer varieties of grapes developed in the Ukraine and Russia are currently been trialled. These are billed as requiring only a 90-110 day growing season, but it is expected this will be considerably longer at this latitude because of lower light levels (often cloudy) and a usually protracted start to warmer temperatures in April and May.
Right: The main greenhouse is 16x12 ft and houses 9 vines: Arkadia, Boskoop Glory, Concord, Dikson, Foster's White Seedling, Juodupe, Moore's Diamond, SV18315, and Stella. A smaller 10x6 ft greenhouse is used for vine propagation.
Left: Juodupe, August 2020, has pleasant-testing fruit like large blueberries (and in the greenhouse crops at least a month before the blueberry season). Spraying with water is enough to keep mildew at bay.
Right: Concord, October 2020. Disease-free and productive as a table grape. When other varieties are struggling in cold cloudy years, Concord keeps going.
