While tomatoes and cucumbers require a high temperature, lettuce may be grown easily all the year round. A good method is to grow three crops of lettuce during the fall and winter, and follow with tomatoes and cucumbers in the spring, when the high temperature required can be more easily maintained.

Lettuce is a low-temperature plant, and there is no reason why the small greenhouse owner should not be able with ease to supply his table constantly with this delicious salad. As with the carnations, and violets, if there is no part of a bench that can be devoted to the lettuce, a few plants can be grown in pots. If this method is used, the seedlings should be pricked off into small pots. When these begin to crowd they will have to be given six to eight inches of room, and the pots plunged in soil to their full depth. But it will be more satisfactory to devote a part of a bench, a solid one if possible and in the coldest part of the house, to the lettuce plants. Well rotted manure, either horse or mixed, and a sandy loam, will make the right soil. The first sowing of seed should be made about August first, in a shaded bed out-of-doors; the seedlings transplanted, as with spring lettuce, to flats or another bed. By the last week in September these will be ready to go into the beds prepared for them, setting them about six inches apart for the loose and eight for the heading varieties. The bed should be well drained, so that the soil will never stay soggy after watering. The soil should be kept fairly dry, as too much moisture is apt to cause rot, especially with the heading sorts. Syringe occasionally on the brightest days, in the morning. Keep the surface of the bed stirred until the leaves cover it. Keep the temperature below fifty at night, especially just after planting, and while maturing. And watch sharply for the green aphis, which is the most dangerous insect pest. If tobacco fumigation is used as a preventive, as suggested, they will not put in an appearance. The first heads will be ready by Thanksgiving, and a succession of plants should be had by making small sowings of seed every two or three weeks. If the same bed is used for the new crops, liquid manure, with a little dissolved soda nitrate, will be helpful.

If a night temperature of sixty degrees can be assured in part of the house, tomatoes and cucumbers may also be had all winter. If the house is only a general purpose one, held at a lower temperature than that, they may still be had months before the crop outside by starting them so as to follow the last crop of lettuce, which should be out of the way by the first of April. The seeds of either need a high temperature to germinate well, and may be started on the return heating pipes, care being taken to remove them before they are injured by too much shade or by drying out. In sowing the cucumber seed, pots or small boxes, filled about half-full of a light sandy compost, may be used, these to be filled in, leaving only two plants in each, as the plants get large enough, with a rich compost. If there is a solid bed available, a trench filled with horse manure, well packed in, will act as a hotbed and help out the temperature required for rapid growth. If fruits are wanted for the winter, the tomatoes should be started in July and the cucumbers early in August. They should be given a very rich and sandy soil, and the day temperature may run up to eighty degrees. Until the latter part of spring, when the ventilators are opened and bees have ready access, it is necessary to use artificial fertilization in order to get the fruit to set. With a small soft brush, dust the pollen over the pistils. With the English forcing cucumbers, this will not be necessary. While fruit is setting, the houses should be kept especially dry and warm.

The vines of both tomatoes and cucumbers will have to be tied up to stakes or wires with raffia. They should be pinched off at about six feet, and, for the best fruit, all suckers kept off the tomatoes.

The best varieties of tomatoes for forcing are Lorillard, Stirling
Castle and Comet; of the cucumbers, Arlington White Spine, Davis
Perfected and the English forcing varieties.

If you do not like to stop having lettuce in time to give up space to cucumbers or tomatoes, start some plants about January first, and have a hotbed ready to receive them from the flats before March first. With a little care as to ventilation and watering, they will come along just after the last of the greenhouse crops.

A point not to be overlooked in connection with all the above suggestions is that any surplus of these fresh out-of-season things may be disposed of among your vegetable-hungry friends at the same step-ladder prices they are paying the butcher or green-grocer for wilted, shipped-about products.

And don't get discouraged if some of your experiments do not succeed the first time. Keep on planning, studying and practicing until you are getting the maximum returns and pleasure from your glass house.

[Illustration: Tomato plants, started in pots, ready for transplanting into the bench]

[Illustration: The tomato plants in full bearing. The vines are severely pruned and tied up to sticks or twine]

[Illustration: Lettuce and cucumbers in the greenhouse. The cucumber vines are induced to climb the heavy strings so as to economize bench space]