10:40 - 04 March 2011
March is the beginning of the gardening year in the UK and although many greenhouse gardeners will already have plenty of things growing in their glasshouses, March is the signal to get growing.
If your greenhouse is frost free then the scope of what you can grow now is enormous, but even if you are restricted to a heated propagator there are lots of things you can start sowing and growing now.
In March you can keep sowing hardy annuals and biennials, which will not mind a degree or two of frost. Actually you can even sow these outside in March, but if you want better control over them, then sow them into pots of quality seed compost in pots in the greenhouse.
Getting Started
March really does signal the start of the sowing season. You can start sowing half-hardy annuals with basal warmth in March. Sow them into pots of quality seed compost and place the pots into a heated propagator to entice them into growth. Although you can sow many things in March it is important to look at the prevailing weather conditions, it may be exceptionally cold for the time of year, in which case it may be better to wait a few weeks before you start sowing.
Late Starters
Don’t forget that seeds sown in April will quickly catch up with any slowcoaches sown in March. And it’s important to consider that seed sown later will mature, flower and fruit later, this extending the season into the autumn. This is really vital for crops such as beans that run out of steam by mid to late summer when sown early. Getting an early crop is the objective of most gardeners, but having plants that are still cropping when the others have finished is also very valuable.
Fruiting Plants
You can also start sowing fruiting plants like aubergines, French beans and runner beans, sweet corn and sweet peppers as well as chillies, but all of these will need propagator warmth and warmer conditions to grow on. Greenhouse tomatoes should have already been sown, but you can sow more in March and March is also a good time to sow outdoor tomato varieties, especially varieties that you can’t buy as ready grown plants.
March is also a good time to sow lettuce and salad plants, leeks, spring onions and carrots.
Plants and Cuttings
If you have over wintered cuttings in the greenhouse these can be potted up in March ready to plant out into the garden, when their roots have filled the pots and they have spurted into growth.
Use the cold greenhouse to bring strawberry plants into early crop. Potted plants or those in growing bags can be moved into the March greenhouse, fed and watered until they start to flower. You need to allow pollinating insects access when the plants are in flower, or move the plants outside.
Summer Bulbs
As the weather improves and the greenhouse warms up you can start potting up summer bulbs such as lilies and dahlias, tuberous begonias and more. Keep them protected from a sudden chill and allow them to grow on. You can also take soft wood cuttings from dahlias, fuchsias and pelargoniums as they start to spurt into growth.
The greenhouse in March is a wonderful place to potter and spend some time. Keep it well ventilated during sunny spells but don’t forget to close it up by mid afternoon before the temperature drops. Keep an eye out for early pests such as aphids. Don’t forget that plants brought in for forcing such as potted strawberries may harbour slugs and snails, so be ready with your preferred control, or visit the greenhouse at night by torchlight and collect any offending beasties that are munching on your prized plants.
