March in the vegetable garden- time to sow seeds


Growing veg in March

March is the first month of spring – and the start of the main gardening season, so there is a lot to do in the garden. But the weather can be very variable, so be guided by the conditions rather than the time of year, especially when it comes to things like outdoor seed sowing.

Sowing seed indoors?

If you want early crops, you can sow your seeds indoors. Although it may be easy to take advantage of the warmth inside your house to germinate seeds like for instance tomatoes, they will very quickly need plenty of light and space and it may be still too cold  in a greenhouse outside or even a conservatory (not many of us can afford heating to the levels required by these plants and they need it steady and in plenty).

So don’t be too hasty – resist sowing if you don’t have the warmth to grow on the plants – a minimum of 10C (50F) in a brightly lit place – and the facilities to harden them off properly before planting out. Sowing too early in the wrong conditions can lead to straggly, unhealthy plants that never perform well. I have to leave sowing until the conditions are better in April or even early May partly because we high up on the side of a hill. The blackthorn has to finish flowering before we put out any frost tender plants because there is always likely to be a ‘cold snap’ before then. The ‘Blackthorn Winter’ we call it when the wind blows in from the east at the end of March. Late sowings will nevertheless result in stronger plants and these soon catch up and out-perform those sown too early in poor conditions.

Seeds should be sown in small pots or trays of a good seed sowing compost, such as NEW Levington Original Multi Purpose Compost or Levington John Innes Seed Compost, and germinated in a warm place. A heated propagator will provide good bottom heat and usually produces the best results. A warm windowsill is fine if that’s all that’s available – just make sure to turn the plants daily to prevent them becoming tall, spindly and lopsided.

If you don’t have much success with seeds, it may be better to buy plug plants and seedlings for growing on. By starting now, and potting them up into suitable-sized pots of good compost, you’ll have well established plants ready to plant out and burst into colour at the end of spring.

Before you sow seeds indoors, transplant or pot up young plants, make sure that the compost has been warmed to room temperature. Cold compost will prevent seed germination and lead to rotting and prevent strong root growth, which will affect subsequent growth and performance.


In cold, exposed areas, it may be better to delay sowing until the end of the month, unless the soil has been pre-warmed with clear polythene sheeting or cloches. The seeds of most outdoor spring-sown crops won’t germinate until the soil temperature reaches 7C (45F).

Good crops to sow now include beetroot, broad bean, carrot, cauliflower, kohl rabi, leek, lettuce, onion, pea, radish, salad leaves, spinach, summer cabbage, Swiss chard and turnip.

If the seeds have germinated fleece, cloches and polythene can be used to protect early outdoor sowings if the weather turns chilly. Many vegetables can bolt (go to seed prematurely) if sown outside too early without protection – beetroot being a good example.

If you grow peas, beans and celery, make a trench and fill it with kitchen vegetable waste, torn up newspaper, compost and anything similar. This will help hold moisture in the summer and so produce bumper crops. Dont sow the seeds just yet.

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