GARDENING: The perils of sowing too early

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THE days are lengthening and it’s time to get your seed trays and propagators out and buy seed and cutting compost.

However, for most plants, sowing too early is a recipe for disaster, especially if they’re given too much heat.

You’ll end up with weak, leggy seedlings which are more likely to fall victim to damping-off disease or attack by overwintering aphids.

I used to be terrible for sowing tomatoes in January. I just couldn’t wait. I did conduct an experiment about five years back, when I sowed some in January, February and March.

The first sowings had much weaker stems and were poorer plants all round, while the latter two ended up sturdier and fruited at about the same time. Nature has a way of catching up.

The average light gain per day after the Winter Solstice in the UK is three minutes in the UK. Plants need all the light they can get, and less heat than you would imagine, to grow strongly, so when in doubt, hang on.

Of course, there are exceptions to this rule. Sweet peas can be sown in autumn and overwintered in a cold frame/cold greenhouse, or sown outdoors where they are to flower in spring. The latter method doesn’t work for me at all – my soil’s yoo cold and damp.

I’ve had my best successes sowing them in a propagator in January, then after they’ve germinated, getting them out of the enclosed environment and giving them as much light as possible, with minimal bottom heat. This way, they grow slowly, but sturdily.

Some people soak sweet pea seeds in warm water overnight, others swear by filing one side with a nail file and yet others do nothing. I can honestly say I’ve tried all methods and haven’t really noticed a difference. I used to sow them singly in empty loo roll tubes, but they used to fall victim to black mould. I find 3-5 sown in a tall family yoghurt pot works best.

This year’s varieties are Hi-Scent (pale blue/white); Robert Uvedale (pink) and the mix Royal 

 It’s also a production line thing in my conservatory. I don’t have the room to sow everything in the propagators at once, so I’ve evolved a system to make best use of the three I have – Snow White’s thermostatically-controlled coffin, a 35-year-old base and a windowsill Super Seven, the latter two fixed temperature (mid 60s).

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