Sowing Seeds for Summer Flowers

This winter has felt like a long one, particularly with the third lockdown which started in January, heavy rainfall almost twice the normal average for Norfolk and then freezing cold temperatures and snow in February.

The last week of February brought more sunshine and warmer temperatures and I could start seed sowing annuals in earnest, albeit a week or two later than normal. Annuals are plants that flowers the same year as sowing and are used for lots of summer colour.


I really enjoy sorting through the seed packets that I invested in in the late autumn, a time to plan what to grow the following year, each packet holding a promise of colour and scent to be enjoyed in the warmth of late spring and summer.

My seed box had become too small as I can’t resist the catalogues in the autumn, seduced by the lovely pictures I end up buying lots of packets for the following season. Over winter I put in a request for a new seed box and Andy obliged, so now I have lots of space including dividers to separate the packets!

In late January I sort the seed packets into weekly sowing times, divided further depending on whether the seeds need bottom heat or will germinate in the polytunnel. Then in mid-February I can begin sowing in earnest.

I prepare trays of fresh seed compost slightly tampered down to make a flattish surface and watered well and then the seeds are sown very thinly on the surface. Some seeds such as Nicotiana (tobacco plant) and Lobelia are left on the surface as they need light to germinate. Most seeds however need a light covering of compost and a mini gardening sieve is the ideal tool for this job. I water the surface again lightly and put the labelled seed tray into the propagator.

My propagator uses a thermostatically controlled electric heat mat under polythene with a clear polythene lid and a grow light suspended above. The light is kept on during the day and the heat on constantly.

Once the seeds have germinated and have a grown to a green carpet of seedlings the tray is transfered to a bench under two more grow lights to continue growing until they reach the stage when they can be pricked out into fresh trays of compost.

Now for a technical science bit – it’s best to wait until the seedlings have a set of true leaves before pricking them out, the first two leaves that appear from the seed are known as ‘seed leaves’ or ‘cotyledons’ and use stored nutrients from the seed to promote the growth of the seedling and the first set of ‘true leaves’ which can then photosynthesize for growth. That’s why seed leaves all look pretty much the same regardless of the plant being grown and it is the true leaves which have the characteristic leaf shape of the plant.

Okay, once the seedlings are at the pricking out stage I then have to decide how many seedlings to grow. In the past I couldn’t bear to throw any away but now I’m much more disciplined. I work out how many of the particular flower will be used in the garden, add on an extra dozen or so for my local gardening club plant sale (cancelled in 2020 because of Covid, but I’m hoping may happen this May), some for garden gate sales and a few extra in case of failures. The baby plants are then transferred to the polytunnel, given a pep talk to reassure them and then checked daily. If the night is going to be very cold (and we can get frosts into early May) the seedlings are protected with horticultural fleece overnight.

Once the seedlings are growing well they are potted on, protected in the polytunnel until all danger of frost has gone (usually early-mid May) and then planted out in the garden or in pots.


This all sounds very labour intensive and it does take time, but I grow a lot of plants and always have done and so it has become routine. This can all be done just as successfully using a mini propagator on a windowsill and a small cold frame in the garden and just choose the flowers that you really like and want to enjoy through the summer months.


February through March is a lovely time of year, the days are getting longer, spring bulbs are starting to flower, the air is a little warmer and has that fresh scented feel telling us that spring is almost here. Seed-sowing continues through March and April too so there is still plenty of time to visit a local nursery or garden centre and choose some flower seeds for summer colour for your garden.

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