"March is one of the most exciting months on the gardening calendar. The sights of spring are hiding slowly in South of Norway and you can really start to get going in the greenhouse."
The first thing to bear in mind is the unpredictable weather that March brings. Early spring can see wide temperature fluctuations which can be a proble. You must keep the air temperature at around 7 – 18°C (45 – 65°F); this will involve heating the greenhouse at night and also ventilating and damping down the structure on cloudless days if required.
Large-seeded and leaved vegetables such as cucumbers zucchini and courgettes can be planted into their own individual pots and placed in a propagator. In almost a month from now, the pots can be moved into the main body of the greenhouse for an early July harvest. Seedlings need good light but young ones will still need protecting from the mid-day sun.
These are the flowers you can sow and grow this month:
Sow half-hardy annual seeds inside now, ready for planting out in June. Start ageratum, aster, brachycome, cosmos, celosia, petunia and salvia in a heated propagator or on a warm windowsill for summer and autumn border colour.Sow dahlia seeds indoors to plant out in summer and provide tubers for lifting in the autumn.
Pot on rooted cuttings of tender perennial plants and hardwood cuttings taken last year.
Sow cleome seeds on a windowsill indoors or in an unheated greenhouse — they need fluctuating temperatures to germinate and this ensures they’ll get a drop in temperature at night.
Plant begonia tubers in the greenhouse this month, positioning them just below the compost surface with the indented side facing upwards.
Repot orchids and other house plants before they start into active growth again.
These are the veggies you can sow and grow this month:
Start off aubergine, sweet pepper, cucumbers, gherkins and mild chilli seeds in the propagator — these plants can stay in the greenhouse over summer.
Plant a variety of tomato seeds under glass for greenhouse cultivation. Check out our tomato selector guidebefore ordering your seeds to help you choose from a range of sizes, colours and flavours.
Start tender celery in seed trays in the greenhouse.
Sow celeriac seeds under cover — they need a long growing season.
Start winter brassicas like cauliflower and Brussels sprouts in a cold greenhouse ready to plant out later in spring.
Sow salad seeds in pots and place on the windowsill for fresh, healthy leaves. Try recycling yoghurt pots to use as containers.
Start basil seeds on your kitchen windowsill. They can stay indoors or be planted out when the risk of frost has passed.
Sow seeds for perennial herbs such as lemon balm, rosemary, sage, oregano and thyme under cover.
Begin chitting (sprouting) seed potatoes on delivery.
In the cold frame/ under cloches
Sow lettuce and radish seeds into the garden under cloches for your first salad of the season.