If cold frames are used and the seeds are sown in pots, pans or boxes and placed inside the frame to germinate, the procedure is much the same as already described; the only difference being that there is no artificial heating and therefore the germination and growth of the seedlings may be slower.

When large numbers of young plants have to be raised as is often the case with biennials and perennials, for instance - a seedbed may be prepared directly in the cold frame, thus dispensing with the need for pots, pans and boxes. If the seed-bed is carefully prepared and the cold frame is properly ventilated, a great variety of plants can be propagated in this way. The advantage of this method as compared with sowing in unprotected outdoor beds is that because there is little interference from the weather and pests, the operation is under better control and earlier crops can be obtained.

Sow the seeds directly into a bed of soil with a reasonably firm, fine tilth, prepared in much the same way as an outdoor seed-bed. Seed-drills can then be drawn from back to front of the frame or the seeds can be sown broadcast. Afterwards the covering sash is placed in position, with adequate ventilation afforded if the weather is hot, and the glass (or plastic) sash shaded. The shade is removed and the ventilation is increased as soon as the seedlings show through.