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This is the gardening job you need to do in January

Some plants pootle along at a snail’s pace, while others grow at dizzying speed. Sweet peas belong in the second category. These fast, fuel-guzzlers are the Formula One of the gardening world, writes Flo Whitaker.

Super-speedy sweet peas can be in flower by the end of May and many varieties will attain 2 metres in height. A massive root system is required to power this high-octane growth rate. If you’ve had limited success with them, insubstantial roots may be the reason why. Sowing early in the year gives extra growing time. Despite their fragile appearance, sweet pea seedlings are tough customers that tolerate cool conditions. 

gardening job you need to do in JanuarySeed can be sown in September and plants overwintered to flower the following season. However, this method requires a level of forethought and planning that most of us, frankly, do not possess. When the garden’s still full of autumn colour, it’s hard to start thinking about dainty summer characters. Also, an autumn sowing means seedlings have to endure gloomy November and December – plants may grow spindly in poor light. Sowing in January or February gives a head start, but with the additional benefit of increasing daylight hours. 

Seeds are best planted individually – the roots are difficult to separate when tangled together in a seed tray. Long pots specially designed for the purpose are available, along with ‘grow-tubes’, shaped to encourage deep rooting. Or, make your own paper pots using a tall jar as a mould, (herb/spice jars are ideal) or utilise cardboard loo roll tubes.

gardening job you need to do in January
Sow seeds 3 cms deep into multipurpose compost. Keep in a brightly-lit, cool, (but frost-free) place. An unheated greenhouse or enclosed porch is ideal – or a chilly indoor window ledge, away from radiators and heat sources. Warm conditions will encourage premature leaf growth - you want plants ticking over slowly and concentrating on root production.

When seedlings have developed three pairs of leaves, carefully pinch out the growing tips to encourage formation of side shoots, (making more flowers!) Plant out from mid-April onwards, covering with horticultural fleece if frost is forecast. Plants in paper pots can be planted directly into a border – the roots will quickly push through the pot sides into the surrounding soil. Sweet peas require a sunny spot in rich, moisture-retentive soil, so incorporate plenty of well-rotted compost or manure. Although they produce clinging tendrils, they’ll need a helping hand - use soft garden twine and gently tie them to supports. They are hungry plants and will appreciate a liquid feed of tomato food or seaweed fertiliser every 10-14 days. Slugs adore sweet pea plants - be vigilant!

gardening job you need to do in January
Pick flowers every day; preferably as soon as buds start to open – and be sure to pick every one. Fading blooms quickly develop into seed pods and plants will cease flower production, thinking their work is done. Give bunches away to friends and neighbours ¬– a glut of sweet peas is a lovely gardening problem to have.