March Garden Tips
There’s lots to be done outside, now the slower winter months have passed. Read about this month sowing and growing tasks here.
Timely Tips
Clear your garden paths before the plants really start to grow.
Fertilise your beds. Once your soil is workable, dig a 5cm (or more) layer of compost or well-rotted manure into your beds to prepare for the growing season ahead.
You can also work in a general-purpose fertiliser, such as pelleted chicken manure, or fish, blood and bone.
Put supports in. If any of your garden plants or climbers need supporting this year, put them in now, so plants can grow up through them.
Adding supports afterwards is trickier and often looks unattractive.
Move deciduous trees or shrubs. Now is the time to do this task, provided the soil isn’t frozen or waterlogged.
Resurface paths before plants start to grow and smother them
Cut back cornus to their bases in March to stimulate fresh growth.
Feed roses with special rose feed or balanced fertiliser as they come into growth.
Prune roses now to encourage strong new growth.
Prune clematis - prune early-flowering varieties once their flowers have finished and summer-flowering ones before they start into active growth.
If you have a rhododendron that needs a new lease of life, choose a frost-free day this month to cut the branches hard.
Finish cutting back cornus and salix cultivars, and other shrubs grown for their colourful winter stems. Cut them right back to their bases to encourage new stem growth for next winter.
Cut out the top rosette of leaves from mahonia shrubs after they have flowered, to encourage branching.
Finish cutting back dead foliage from perennials and ornamental grasses to make way for new growth.
Prune overwintered fuchsias back to one or two buds on each shoot. This will encourage a bushy growth habit. For more information about growing your own fabulous fuchsias,
Prune winter-flowering jasmine (Jasminum nudiflorum) after flowering, to encourage new growth for next year's blooms. Cut back the previous year’s growth to 5cm from the old wood.
Trim winter-flowering heathers as the flowers disappear, to prevent the plants becoming leggy.
Keep an eye out for slugs as the weather warms. Pay special attention to soft, new growth, which slugs love. Use nematodes for an effective organic control.
Cut the old leaves off hellebores to remove any foliar diseases and make spring flowers more visible.
Continue to deadhead winter pansies to stop them setting seed. This will encourage flushes of new flowers throughout the spring.
Deadhead daffodils as the flowers finish and let the foliage die back naturally.
Deadhead hydrangeas before new growth appears. Cut to about one third of last season's growth.
Plant native hedges to encourage wildlife.
Recut any lawn edges if necessary.
Install lawn edging to make future maintenance easier.
Mow your lawn if it needs it. Choose a dry day and set your blades higher than usual.
Lay new turf if the ground isn't frozen or waterlogged.
Prepare soil for growing new lawn from seed. Doing this now allows it time to settle before sowing.
Dig in green manures grown over the winter. Do this while stems are still soft.
Dig compost, well-rotted manure or green waste into your vegetable beds to prepare for the growing season ahead. Dig in a 5cm (or more) layer when the soil becomes workable. Weed vegetable seed beds before adding the layer.
Place the cloche or fleece a week or two before planting and the soil will have warmed up nicely as well as being dry and easy to work.
Water well into the drill prior to sowing and replacing the cloche. Do remember to water weekly or more frequently in sunny weather under cloches.
To hold down fleece without tearing, save plastic 2 litre milk containers and fill with sand or water although water tends to leak. The smooth surface will weigh down the fleece but not damage it. It’s surprising how just a layer of fleece can raise the temperature of the underlying soil.
Plant out your onion and shallot sets. If growing onions from seed started earlier in the year under cover these can also go out now. You can also direct sow onions, thinning to the eventual spacing. Cloching will help them establish and also stop pigeons from pulling them up.
March is the right time to establish an asparagus bed if you are starting from crowns. Do make sure you get it in the right position as it will be there permanently.
Mid March should let you start planting out those potatoes you’ve had chitting. If you want some really early potatoes, start some in a black polythene sack in the greenhouse or tunnel. Punch drainage holes in the sack and use a multi-purpose compost.
Staying with root crops, you can plant Jerusalem artichoke tubers now. Be aware that getting them all up at harvest time is very difficult and any tubers left in the ground will grow, so effectively you’re creating a permanent bed.
Many of the crops you can sow directly will also benefit from cloching, especially as you move northwards or started off in modules in a cool greenhouse or coldframe and then planted out later.
Cut autumn-fruiting raspberry canes to the ground to stimulate new canes, which will fruit in the autumn. Cut the tips of summer-fruiting raspberry canes that have grown beyond the top of their supports; cut just above a bud.
Feed blueberry plants with ericaceous plant fertiliser.
Protect the blossoms of apricots, peaches and nectarines from frost with a screen or horticultural fleece.
Mulch fruit trees with well-rotted manure or garden compost. Take care not to mound mulch up around tree trunks.
Cover strawberries with a cloche to encourage earlier fruiting.
Mulch rhubarb with a thick layer of well-rotted manure to keep it healthy and reduce moisture loss through the soil. Take care not to cover the crown, as this is where the growth happens.
In the Greenhouse
March is a good time to clean, tidy and reorganise your greenhouse, while it is relatively empty and there are fewer jobs in the garden to take up your time.
Cleaning the greenhouse will maximise light levels, clear blocked guttering, banish any pests and diseases.
Tidying it will make sure that you have an ordered working environment in time for the growing season ahead.
Get crops off to a good start indoors to transplant into the garden later, such as celeriac, celery, lettuces and parsley
Take down bubble insulation in the greenhouse once temperatures start to rise, to let in more light
Buy good value young bedding plants for growing on to a larger size under glass, or sow your own in a heated propagator
Sow dwarf French beans in a large pot for an early indoor crop in June
Plant prepared freesia bulbs in pots of rich, loam-based compost, for fragrant flowers indoors this summer
Pot up overwintering cannas into fresh compost, water in, then place in a warm spot to spur them into growth
Sow sweet peas in deep pots and keep them frost-free in a greenhouse or on a sunny windowsill
Take cuttings from dahlia tubers planted last month to raise new plants
Protect greenhouse sowings of beans, peas, mangetouts and sweet peas from hungry mice
Be vigilant for greenhouse and houseplant pests, such as mealy bugs, and treat straight away
Open greenhouse vents on sunny days to prevent humidity building up
Sow coleus on a warm windowsill to enjoy their vibrant foliage indoors or in tropical-style displays outside
Take basal cuttings from perennials, such as delphiniums and lupins, to root in a pot indoors
Other jobs about the garden
Install a new pond or water feature.
Remove any pond netting left over from the autumn/winter.
Get rid of slimy patches on patios and paving by scrubbing with a broom or blasting with a pressure washer.
Install water butts for the season ahead. Position them under a downpipe to make the most of rainfall.
Scrub watering cans with hot soapy wate to prevent fungal diseases.
Build a compost bin before the growing season gets underway. If you already have one, check to see if there is any compost ready to use on vegetable beds.
Move bags of compost into the greenhouse to warm up for a week or two before using for sowing.
Create a comfrey bed to make your own organic fertiliser. Sow into a seedbed in an unused corner of the garden.
Invest in a soil-testing kit if you don't already know what type of soil you have. It will help you choose the right plants for your garden.
Top up veg planters and raised beds with compost and good quality topsoil.
Begin weeding as the weather warms — it’s easier to control weeds if you remove them while they’re still young.
Check containers to ensure the soil hasn't dried out.
Top-dress containers by removing the top 2.5cm (1") of soil, and replacing it with fresh compost.
Start ventilating greenhouses and cold frames on warm sunny days. Don't forget to move plants from the greenhouse to a cold frame for at least 7 days before planting out into the garden. This allows them to harden off.
Give your wooden shed a spring clean before the sowing season really kicks off - you won't regret it!