Tomato stand-alone or multiple-bay greenhouses is on the increase, providing fruit during those times of the year when field-grown fruit is not readily available. Smaller sized fruit (cherry and grape), or cluster tomatoes (fruit-on-the-vine) are the fruit of choice for the large commercial greenhouse operators while the beefsteak varieties are the choice of owner-operator growers. Hydroponic technique is often used in hostile growing environments, as well as high-density plantings. To facilitate transportation and storage, tomatoes are often picked unripe (green) and ripened in storage with ethylene. Unripe tomatoes are firm. As they ripen they soften until reaching the ripe state where
Plum the Balkans, plum is converted into an alcoholic drink named "slivovitz" (plum brandy) (Serbian: "šljivovica"). A large number of plums, of the Damson variety, are also grown in Hungary, where they are called "szilva" and are used to make "lekvar" (a plum paste jam), "palinka" (traditional fruit brandy), plum dumplings, and other foods. As with many other members of the rose family, plum kernels contain cyanogenic glycosides, including amygdalin. Prune kernel oil is made from the fleshy inner part of the pit of the plum. Though not available commercially, the wood of plum trees is used by hobbyists and other