This Month in the Garden - March
Sowing and planting:
Hardy annuals can be sown in pots 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.
Plug plants can be purchased now and grown on for summer colour in containers, baskets and the garden. (Please note that these plants need protection from frost.) Click here to visit our Kinder Plug Plants page.
Sweet peas can be sown outside this month. Autumn-sown sweet peas will need a sunny position such as a high shelf in the greenhouse to get 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.
Plant summer-flowering bulbs for the summer border and patio containers. Click here to visit our Summer Flowering Bulbs page.
Sow native wildflower seeds in trays or modules to create your own mini meadow.
Cutting back, pruning and dividing:
Cut back perennials and ornamental grasses left for winter interest if you have not already done so to make way for new growth.
Cut off old leaves of hellebores that produce flowers from ground level to expose the flowers.
Divide clumps of herbaceous perennials if they have become too large for their allotted spaces.
Finish pruning roses in early March. Click here to find out more about pruning roses on the RHS website.
Seedheads on daffodils and other spring bulbs should be picked off, but leave the foliage to die back naturally.
Dogwoods, willows and cotinus should be cut right down to the base to promote vigorous new growth.
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.
Mow established lawns if the weather is mild enough and the grass shows signs of growth. The first cut of the season should be light, raising the blade 0.5cm (0.25in) higher than the usual cutting height.
Apply a high nitrogen lawn fertiliser to encourage good, strong growth and help the lawn recover after the winter. You can pick up a copy of our Spring Lawn Care Guide in store for further information.
Turf can still be laid providing the soil is not too wet or frozen. Once laid, the turf should be left 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.
In The Greenhouse:
Continue to prick out and pot on new seedlings and cuttings.
Check plants regularly to see if they need watering. Seedlings will need daily attention.
Give greenhouse plants more space as they put on new growth, which will help to prevent disease and early pest infestations.
Open doors and vents to increase ventilation on warm, sunny days.
Regularly inspect plants and the greenhouse structures for pests such as vine weevil, red spider mite and whitefly etc. Control with approved insecticides and biological controls. Click here to visit our Pest, Weed & Fungal Control page.
Brush up fallen compost and debris and pick off dead leaves from plants, clean tools, pots and greenhouse staging. This will help to prevent pests and disease spreading.
Continue to deadhead winter-flowering pansies and other winter bedding.
Feed borders with a general-purpose fertiliser at the manufacturer’s recommended rate. Click here to visit our Fertilisers page.
Improve the drainage of heavy soils by working in plenty of organic matter.
Check to see if containers need watering. Pots in sheltered positions can miss out on rainfall. Aim to keep pots moist, but not wet. Do not let them dry out.
Deadhead the flowers of Narcissus (daffodils) as they fade, but allow the foliage to die down naturally.
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.