Spring usually arrives by mid-March and the frequent sunny days provide the opportunity for an increasing range of gardening tasks. It’s time to get busy preparing seed beds, sowing seed, cutting back winter shrubs and generally tidying up around the garden. The month can also be a difficult one with sunshine one day and frost the next, so keep an eye on emerging young shoots and protect with fleece where necessary.
Sowing and planting:
Hardy annuals can be sown in pots or modules to provide colour in the garden. In mild areas you can sow directly outside. Marking out irregularly shaped seedbeds and broadcasting drifts of different seed gives a more natural look. Click here to visit our seeds and propagation page.
Sweet peas can be sown outside this month. Place autumn-sown sweet peas in a sunny position, perhaps on a high shelf in the greenhouse that gets plenty of light. Sow summer bedding plants in a heated propagator or under glass.
Early spring is an ideal time to plant herbaceous perennials, including Geranium, Astrantia and Oriental poppies. Click here to visit our perennial plants page.
Plant summer flowering bulbs. Prepare the soil first, to ensure that drainage is sufficient to prevent the bulbs rotting. Click here to visit our summer flowering bulbs page.
Cutting back, pruning and dividing:
Cut back ornamental grasses and other perennials left for winter interest, if you have not already done so. Even if they still look good, you need to make way for the new growth.
Cut off old leaves of hellebores that produce flowers from ground level to expose the flowers and remove possible foliar diseases such as hellebore leaf spot.
Divide clumps of herbaceous perennials that you wish to propagate, those that have become too large for their allotted space and those that are flowering poorly or have lost their shape. Click here to visit the RHS website dividing perennials page for full details.
Cut back Cornus (dogwood) and Salix (willow) grown for colourful winter stems.
Prune bush and climbing roses. Click here to visit the RHS website rose pruning page for full details.
Plant onions, shallots and garlic sets, Jerusalem artichoke tubers and asparagus crowns.
First early potato varieties can be planted from around late March, but this will vary slightly depending on location. Potatoes need a sunny site away from frost pockets – the newly emerging foliage is susceptible to frost damage. You can prevent this by earthing up the soil around the shoots or by covering them with fleece.
Sow seed outdoors in mild areas with light soil, eg: broad beans, carrots, parsnips, beetroot, onions, lettuces, radish, peas, spinach, summer cabbage, salad leaves, leeks, Swiss chard, kohl rabi, turnip and summer cauliflower. Be guided by the weather, and sow only if conditions are suitable.
Sow seed indoors of sweet peppers, tomatoes, cucumbers, aubergines, celery, salads and globe artichokes.
Turf can be laid, provided the soil is not too wet or frozen. Work from planks, to avoid compacting the soil. Do not walk on newly laid turf, and leave it undisturbed for several weeks to allow the new roots to establish.
Newly-turfed areas can be mown with the blades set to the highest setting, as soon as the grass reaches 5cm (2in) in height.
Mow the established lawns if the weather is mild enough and the grass shows signs of growth. Ensure the first cut of the season is light, raising the blades 0.5cm (0.25in) higher than the usual cutting height.
Where lawns are to be grown from seed, prepare the ground for sowing by cultivating, levelling and then firming the soil. Doing this now will allow the soil to settle prior to sowing later in the month, or in April.
In late March apply a high nitrogen spring/summer lawn fertiliser to encourage good, strong growth to help the lawn recover after the winter.
Straighten lawn edges using a half-moon turf iron and a board, or use sand to mark out a curve, which can then be cut out with the iron.
In the greenhouse:
Open doors and vents on greenhouses to increase ventilation on warm, sunny days.
Check plants regularly to see if they need watering. Seedlings will need daily attention.
Continue to prick out and pot on new seedlings and cuttings.
Harden off half-hardy bedding plants that were started off under cover.
Give greenhouse plants more space as they put on new growth. This will help to prevent disease, and to contain early pest infestations.
Try growing on plug plants in your greenhouse. These top quality young plants are an excellent and economical way to buy all you summer colour for containers, baskets and the garden. Click here to visit our Kinder Plug Plants page.
Continue to deadhead winter-flowering pansies and other winter bedding. Pansies will carry on into the spring and even to early summer, if attended to frequently.
Deadhead the flowers of Narcissus (daffodils) as they fade, but allow the foliage to die down naturally.
Check whether containers need watering. Even at this time of year, they can dry out. Pots that are sheltered by eaves or balconies can miss out on any rainfall. If in doubt, check the compost at a hand’s depth to see if it feels dry. Aim to keep pots moist, but not wet.
Pots and tubs benefit from topping up with fresh John Innes compost. Old compost can be removed and replaced with new if there is not much room for topping up. Click here to visit our soil and compost page.