You can raise your own plants from seeds or cuttings without using a greenhouse if you’ve got space in your home to place a propagator. From compact propagators such as the Windowsill Propagator which you’ll be able to fit onto your windowsill, to larger propagators that you could place on a work surface, as long as you can place the propagator where your seedlings will get sufficient light then you should be able to raise healthy plants. To avoid draughts use a propagator that either has a cover, or use seed trays and covers that you can place in your heated propagator.
Two Wests & Elliott (UK) - manufactures and suppliers of
greenhouses, greenhouse staging, fruit cages (netting and aluminium
tubing), a wide variety of gardening equipment and
accessories.