As a new year begins we’re often champing at the bit to start in the garden and the first place to start is to get sowing. However, it’s important to remember, that no matter how keen you are to get started, January is still a month where days are short and temperatures low. So it’s important to choose wisely on what to sow – sowing the wrong seeds can simply be an expensive waste of time if you can’t achieve the germination temperatures required.
Some seeds will germinate at low temperatures, so can be started now in an unheated greenhouse or cold frame. Here are a few examples:
Sweet Peas / Lathyrus Now is the perfect time to sow sweet peas as they will germinate at temperatures as low as 12*C (55*F). This means that they can be started off in an unheated greenhouse or cold frame and they should germinate in 10-14 days. Many gardeners recommend soaking sweet pea seeds overnight before sowing – but like many gardening methods, there is a difference of opinion between gardeners as to whether this is necessary or not. |
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The reasoning behind soaking the seeds before sowing is that because the seeds have a hard outer shell this can make them difficult to germinate. Soaking them overnight will soften the seed coat making germination easier. However, if you don’t sow them straight away the seeds can rot. Rather than soaking them in a pot of water overnight, the RHS (who know a bit about gardening) suggest placing the seeds on a layer of moist vermiculite or kitchen towel, in an air-tight container in a warm room. When the seeds begin to swell or sprout then it’s time to sow them.
If you don’t want to soak the seeds before sowing, another option is to slightly crack the seed's outer coating. Simply use a sharp knife to nick the outer shell on the opposite side to the seed's black ‘eye’ or scar. Or gently rub the seed with sandpaper in the same place.
If you’re unsure as to which method to follow, base your choice on previous germination success. If you’ve sown sweet pea seeds without soaking and had a good germination rate then you probably don’t need to soak them. However, if you’ve had problems with germination in the past, soaking the seeds should help.
As sweet peas will have long roots it’s best to plant them in deep containers – we highly recommend using 5” rootrainers.
These not only provide lots of depth of compost allowing the plants to grow in place until they are ready to plant out, but they are also shaped to train the roots to grow straight, helping create a strong root system. PLUS you can plant 32 seeds in their own ‘cells’ in a space of just 14” x 8” – that’s a lot of seeds in a compact space!!
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Sweet peas sown now should be blooming from May / June through to August.
There are some flower seeds which can be sown now but will need to be germinated in a propagator indoors or in a heated greenhouse as their germination temperatures are higher than the ambient temperatures early in the year. Here are a few that can be sown now:
Pelargoniums / Geraniums Sow now and you’ll be seeing blooms between June to October. Sow the pelargoniums in small seed trays in a mixture of 90% seed compost and 10% grit. Sprinkle a small layer of compost over the seeds so they are just covered. The compost within the tray now needs to reach a temperature of approx. 24*C / 75*F for germination to take place. To achieve this, we recommend you use a propagator or warming mat which can be thermostatically controlled – allowing you to set the temperature for the propagator to reach. |
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You can help to achieve high temperatures by fitting a cover to the seed tray. To keep track of the compost temperature use a simple Soil Thermometer which can be pushed into the compost in the seed tray to check the temperature where the seeds will be germinating.
From sowing the pelargonium seeds you should start to see seedlings appear between 3-12 days later.
Dahlias
For flowers between July to October / November, you should start sowing dahlia seeds in January. To make transplanting small plants easier when potting up, ideally sow the dahlia seeds in individual cells – so you could use plug trays, seed success kits, plant trainers or rootrainers. All of these allow you to raise a large number of seedlings in a small space.
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For germination to succeed you’ll need to achieve temperatures of 18-21*C / 65-70*F. You’ll need either a high ambient temperature – for example, if you start them off indoors – or they could be started off in a heated greenhouse or using a heated propagator. To get the correct germination temperature you'll need to use a heated propagator. If this is the first to you buy a propagator then the Heat & Grow Variable Temperature Propagator is ideal as it has an easy-to-set thermostat and comes complete with seed trays and pots to get you started!! |
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You can learn more about Dahlias by visiting the Eden Projects website. You’ll find some facts and figures and some lovely photos.