Close attention is required in the management of hotbeds, to insure that they do not become too hot when the sun comes out suddenly, and to give plenty of fresh air.

Ventilation is usually effected by raising the sash at the upper end and letting it rest upon a block. Whenever the temperature is above freezing point, it is generally advisable to take the sash off part way, as shown in the central part of Fig. 199, or even to strip it off entirely, as shown in Fig. 197.

Care should be taken not to water the plants at nightfall, especially in dull and cold weather, but to give them water in the morning, when the sun will soon bring the temperature up to its normal state. Skill and judgment in watering are of the greatest importance in the management of hotbeds; but this skill comes only from thoughtful practice. The satisfaction and effectiveness of the work are greatly increased by good hose connections and good watering-pots (Fig. 209).

Some protection, other than the glass, must be given to hotbeds. They need covering on every cold night, and sometimes during the entire day in very severe weather. Very good material for covering the sash is matting, such as is used for covering floors. Old pieces of carpet may also be used. Various hotbed mattings are sold by dealers in gardeners' supplies.

Gardeners often make mats of rye straw, although the price of good straw and the excellence of manufactured materials make this home-made matting less desirable than formerly. Such mats are thick and durable, and are rolled up in the morning, as shown in Fig. 199. There are various methods of making these straw mats, but Fig. 210 illustrates one of the best. A frame is made after the manner of a saw-horse, with a double top, and tarred or marline twine is used for securing the strands of straw. It is customary to use six runs of this warp. Twelve spools of string are provided, six hanging on either side. Some persons wind the cord upon two twenty-penny nails, as shown in the figure, these nails being held together at one end by wire which is secured in notches filed into them. The other ends of the spikes are free, and allow the string to be caught between them, thus preventing the balls from unwinding as they hang upon the frame. Two wisps of straight rye straw are secured and laid upon the frame, with the butt ends outward and the heads overlapping. Two opposite spools are then brought up, and a hard knot is tied at each point. The projecting butts of the straw are then cut off with a hatchet, and the mat is allowed to drop through to receive the next pair of wisps.

In making these mats, it is essential that the rye contains no ripe grain; otherwise it attracts the mice. It is best to grow rye for this especial purpose, and to cut it before the grain is in the milk, so that the straw does not need to be threshed.

210. The making of straw mats.

In addition to these coverings of straw or matting, it is sometimes necessary to provide board shutters to protect the beds, particularly if the plants are started very early in the season. These shutters are made of half-inch or five-eighths-inch pine lumber, and are the same size as the sash - three by six feet. They may be placed upon the sash underneath the matting, or they may be used above the matting. In some cases they are used without any matting.

In the growing of plants in hotbeds, every effort should be made to prevent the plants from growing spindling, or becoming "drawn." To make stocky plants, it is necessary to give room to each plant, to be sure that the distance from the plants to the glass is not great, to provide not too much water in dull and cold weather, and particularly to give abundance of air.