How To...Sow Annual Seeds

It’s less than 8 weeks now until we can expect the last frost at the end of April for this area, this means we can really crack on with lots of sowing. All annual seeds can be sown now, but some need a little more care than others. There are three main different types of annual plant, and each have slightly different requirements for sowing:

Hardy Annuals – plants which tolerate frost and can be sown directly into the ground or in pots in the autumn or early spring, for example sweet peas and calendula. These do not need additional heat to germinate and grow.

If you have well worked soil without many weeds then sowing directly into the ground is a good option. Flowers such as nigella (love-in-the-mist), ammi majus (Bishop’s Weed) and centaurea (cornflowers) do better if sown directly into the soil in autumn. You will get bigger and earlier flowers if you do it this way.

Half Hardy Annual – plants which can take a light frost and can be sown directly in the soil before the last frosts, but as the soil begins to warm up, these may need a little protection if very bad weather is expected. Examples are snapdragons, cosmos and nasturtiums. These are suited to growing in an unheated greenhouse.

Tender Annuals – these cannot tolerate any frost at all and must be sown either after the last frost or kept somewhere warm, such as basil. It is best to sow these in pots and kept in a propagator, on a windowsill or a heated greenhouse.

Half hardy and tender annuals are generally not worth sowing before April. You’ll find that unless the weather is abnormally warm they resent going outside until it has properly heated up. Nicotiana and zinnias can sulk if transplanted outside too soon, and if you keep them in pots for too long you will check their growth. All this means it’s best to leave sowing for a little bit longer.

Mostly sowing into pots, trays or cells is the best way to start flowers off. To do this use clean pots and ideally fresh seed compost – although sieved general purpose compost will also give you good results. Fill trays to 1cm from the top and water, then leave the compost to drain. Sparsely sprinkle your seeds across the surface, then cover with a layer of sieved compost or vermiculite. shaking compost through a small pot over your tray does this well. Do not water again as you risk washing away the seeds.

In general, the smaller the seeds the less compost they want on top. Some seeds do require light (such as scabious) to germinate and should not be covered in compost. To find out if your seeds have any special requirements just read the back of your seed packet.

Tips for success –

· Always read the seed packet to check specific requirements before sowing

· Keep seeds slightly damp, either water by putting in a tray with a few centimetres of water in and allow the water to wick up the compost or spray with a misting bottle.

· Keep somewhere with high light levels. Once your seeds germinate you do not want them reaching for the light and growing tall and weak – known as etiolation.

· Once seeds have germinated and their seed leaves are up then any covers such as propagator lids can be removed.

· Label your seed trays and include the date.

38 views0 comments

Recent Posts

See All