I will now say a few words on the _greenhouse plants_ that you will want for planting in the open ground in your flower-garden. Petunias may be all raised from seeds with the other half-hardy annuals; as seedling plants both grow and flower much more vigorously when planted out into the open ground, than plants that have been raised from layers or cuttings. Célsia or Alonsòa urticifòlia may also be raised from seeds; as may Thunbérgia alàta, and its white variety. Phlóx Drummóndi is almost always raised in this manner; as are the beautiful climbing plants, Lophospérmum scándens and its varieties, Maurándya Barclayàna, Cobœa scándens, Eccremocárpus or Calámpelis scàbra, Rhodochìton volùbile, the beautiful canary-bird flower (_Tropœ'olum peregrìnum_), the most splendid of the ipomœas, and several other well-known plants.
Geraniums, or pelargoniums, as they are now more properly called, being half-shrubby plants, require to be raised by cuttings. These are generally taken off the points of the shoots in autumn; and, a good many being put into one pot, they are plunged into the hotbed till they have struck root, and then gradually hardened and placed on the back shelf of a greenhouse, or in a cold frame, till the spring, when they are removed to separate pots till they are wanted for planting out. Some gardeners do not put themselves to the trouble of potting them, but keep them in the same pots in which the cuttings were struck till they are wanted for planting out; but this is a slovenly mode of culture, as, when the plants are kept so long in one pot, they become drawn up, and never have the compact bushy appearance that they have when they are properly transplanted early in spring. Verbenas may be either preserved by cuttings or layers, or raised afresh from seed. The usual way of propagating them, however, is by layers, as they strike root readily at the joints, if the joints are covered with a little earth. All the other greenhouse plants which you may want to grow for planting out may be treated in the same manner as those I have mentioned.
A _cold frame_ is a bottomless box of the kind described for a hotbed, but formed of brick or stone instead of wood. These frames have a glass sash at the top, but contain no manure; and they are generally sunk in the soil, that the warmth of the earth around may aid in protecting the plants they contain from the frost. These frames, if they have only one light, are generally five feet in width; that is, from the back to the front; but, if they have two or three lights, the width is generally seven feet, as these are the dimensions of the frames used for hotbeds in kitchen-gardens. The greenhouse plants that are to be preserved in the cold frame are merely set in their pots close together, and, the glass sashes being then closed, mats and other coverings are laid on to keep out the frost.