Almost every imaginable glass structure can be employed for growing Tomatoes, from the small suburban greenhouse to the vast span-roof, hundreds of feet in length, devoted to their culture in the Channel Islands.  And it is not essential that the crop should be grown alone.  Potatoes, French Beans, Strawberries, and Vines may be forced in the same building, provided there be no obstruction to light and air, nor any interference with the conditions which experience has proved to be imperative for sustaining the plants in vigorous health.  For winter and spring gathering there must be a service of hot-water pipes, but as the season advances it is easy to ripen fruit in cool houses, and later on plants outdoors will in favourable seasons yield an abundant return without artificial protection of any kind.

==Indoor culture—­Sowing and Transplanting.==—­Seed may be sown at almost any time of the year, but the most important months are January to March, August and September.  In gardens favourably situated in the South of England and furnished with the most perfect appliances, seed is sown in all these months, and in others also; but in smaller gardens sowings are generally restricted to February and March.  Whenever a start is made sow thinly and about half an inch deep, in pans or boxes, and do not allow the seedlings to remain in them for an unnecessary day.  Immediately two or at most four leaves are formed either prick off into other pans or boxes, or transfer singly to thumb pots, and as a rule the pots will be found preferable.  The soil for these pans or pots should be stored in the greenhouse a few days in advance of the transfer, so that the compost may acquire the proper temperature and save the plants from an untimely check.  In small houses place the plants near the glass that they may remain short in the joint, but on cold nights they must be taken down to avoid injury from fluctuations of temperature.  In large houses, where the light is well diffused, there is no need to incur this trouble, for the seedlings will do equally well on the ground level.  In due time shift into six-inch pots, from which they can go straight to borders, or into a larger size if they are to be fruited in pots.  About fourteen weeks will be required to prepare the plants for borders in the winter season, but a shorter period will suffice in spring and summer.  Plants from an August or September sowing will not mature fruit in much less than six months, while a March sowing will yield a return in four months or less.  A great deal depends on the character of the season, and more on skill and attention.  Those who sow in January or February should sow again a fortnight later, and onwards until the end of April, according to requirements.  For winter supplies a first sowing may be made in June, in a cold frame, and prepared for transfer to fruiting pots in September.