Easy propagation
SOW BIENNIALS
Get them started now and they’ll make good-sized plants ready to flower next summer
Wgreenhouse indowsills and shelves are looking a little spartan now that spring-sown annuals have been planted out in the garden. But if you’re keen to sow more, now’s the time to sow biennial seeds. These plants produce foliage one year, flower the next, and then die – though they often self-sow along the way. They’re hardy, but need to have grown into reasonably large leafy plants before winter arrives. This versatile group will provide extra colour in a spring garden and some, such as forget-me-nots (Myosotis sylvatica), make excellent groundcover. Late-flowering biennials can bridge that tricky gap between spring-flowering bulbs and summer-flowering herbaceous perennials. They also make longlasting cut flowers too. Biennials are often available as plug plants in early autumn, but the choice is often limited to dwarf cultivars bred for the bedding-plant market. If you grow your own, a whole world opens up – especially among cottage garden favourites such as sweet Williams, honesty, foxgloves and campanulas.
How to do it...
1. Prepare seed trays. From June to mid-July, fill module trays to just below the rim with seed compost, or multipurpose compost with perlite. The one exception is honesty, which needs sowing in May to guarantee flowers the following year. 2. Scatter seeds evenly. Sow on the compost surface. Some seeds need a sprinkling of compost, others should be left uncovered – check instructions. 3. Water them in. Use a watering can with a fine rose attachment so the seeds aren’t disturbed, or water from the bottom. Place the trays somewhere warm and sunny but shaded from the midday sun – an east or west-facing windowsill is ideal. 4. Grow them on. Pot on seedlings into 9cm (3½in) pots. Keep them watered throughout summer and be vigilant for slugs and snails. 5. Plant them out. In early September plant out into their final growing position, except for Iceland poppies, which don’t like sitting in wet soil. Keep these in pots, in a cold frame or cool greenhouse until spring.