MATS are used in winter and spring for covering the frames and cloches to protect the plants from frost, and to retain the heat in the beds. Later in the season they are used to protect the plants from strong sunshine. They are best made of rye straw (see Chapter XXIII). The most useful size is 5 ft. 4in. by 6ft., with five seams. Before they are used they should be dipped in a solution of sulphate of copper (7lb. to 25 gallons of water), and this dipping should be repeated each season, both to preserve them--for it makes them tougher--and to destroy such spores of fungi as may be present. After dipping, hang them up to dry in the open if the weather is fine, or if the weather is wet on wire lines stretched under the roof of the packing-shed.
Good rye mats of the kind described can be imported from France at a cost of about 1s. 7d. each, delivered.
When mats are used for covering frames, they should be placed with the length of the mat running the length of the frame, and should overlap each other for two or three