Pot plants from seed

by Alan Titchmarsh

When you want masses of colourful pot plants to fill your conservatory or indoor windowsills this season, keep costs down by growing your own – from seed. Nowadays all sorts of popular annual species are available in economical packets, which will produce more than enough for your needs, and probably provide spares to give away to friends – or to use for fund raising on plant stalls this summer. Seed catalogues (and the seed firms’ websites) offer a huge selection, but you’ll find quite a few on the seed racks at garden centres.

Good sorts to sow now include begonias, coleus, zonal pelagoniums, heliotrope (the deliciously scented Victorian favourite aptly known as cherry pie), feathery-flowered celosia, exacum (Persian violets) and dwarf gazanias. Sow them all now, one variety per pot, on a warm windowsill where it’s easy to keep an eye on them. Since the seeds are usually quite small (and begonias are more like dust), use a technique known as surface-sowing.

Three-quarters fill each pot with multipurpose compost, then top each one with a thin layer of horticultural vermiculite or silver sand, smoothing if off so its perfectly flat. Then carefully sprinkle the seeds thinly and evenly over the surface. Don’t do anything more in the case of fine or tiny seeds; anything larger can be very carefully covered but only to its own depth with more vermiculite or silver sand. Then water, but so there’s no risk of washing away tiny seeds, simply stand the pots in several inches of tepid water for a few minutes, till you can see the surface ‘topping’ turning a slightly darker colour, showing that it’s damp.

Then after letting surplus drain away, stand the pots in a drip tray or saucer on your warm windowsill to germinate; they’ll do very well over a radiator. Use the same technique to water again any time the compost starts drying out, which again you can tell as the topping turns a lighter colour.  Prick the seedlings out when they are big enough to handle, but that won’t be for quite a while yet.