Wondering what to do in the garden in March? Here are 10 essential jobs to tackle now to get your garden into shape.
01 Pot up dahlia tubers
Dahlias are enjoying a resurgence in popularity. These easy-to-grow plants emerge from odd-looking ‘tubers’ which, if planted in pots indoors now, will provide spectacular colour in the garden from June until autumn frosts.
Fill pots with multi-purpose compost and plant the tuber just below the surface, so it’s covered with a few centimetres of compost. Water lightly and keep on a windowsill or in a frost-free place. Shoots should emerge within a month, but they can’t be planted outdoors until all risk of frost has passed.
02 Fumigate greenhouses
Plant pests love winter warmth under glass – so give them the boot before they emerge in spring and feast on your flowers and veg. Empty the greenhouse of any plants, give it a sweep and scrub the glass – better light transmission means improved plant growth.
Empty plant pots are a great hideaway for leaf-munching slugs and snails, so brush pots out and wash them with a disinfectant such as Jeyes Fluid.
Then close all windows and doors and light a sulphur candle (often sold as greenhouse fumigators) to get rid of any nasty bugs. Exit the greenhouse as soon as the sulphur candle lights and let it burn overnight, then ventilate well for a day or so before introducing any plants.
03 Plant onion sets
It pays to know your onions, whether you plan to sizzle them in fajitas, add flavour to casseroles or help your salads pack punch. Onions are one of the easiest crops to grow at home, and the simplest way is to plant onion sets – mini onion bulbs in an arrested state of growth.
For best results, choose a variety with a Royal Horticultural Society Award of Garden Merit (AGM) and look for types that are slow to bolt (that’s where plants produce a big flower stalk instead of developing a full onion bulb – pretty, but useless).
Plant sets in a sunny part of the garden with well-drained soil, because onions hate sitting with their roots in the wet. Plant in rows by pushing each set into the soil, so just its neck shows, spacing the sets 10cm (4in) apart.
If birds try to uproot the sets, you may need to cover them in horticultural fleece (available at garden centres) until the crop is established. Keep onions weed-free and water well during dry spells.
Learn more about growing your own with the Haynes Home Grown Vegetable Manual.
04 Top-dress container shrubs
Are your shrubs in pots looking worse for wear? Yellowing leaves? Sluggish growth? Chances are they’re sitting in old, exhausted compost that’s run out of nutrients.
Before you contemplate the back-breaking task of tipping out and repotting, there is a simpler way: top-dressing involves scraping off the top couple of centimetres of compost and replacing it.
For trees and shrubs in pots, top-dress with a quality John Innes No3 compost and water well to carry nutrients down to the roots. Your plants will show their gratitude by putting on a new lease of life.
05 Buy plug plants
Garden centres and mail order suppliers have huge stocks of plug plants – ready-germinated seedlings in small cells of compost. It’s a great way to get a head start with summer favourites such as geraniums, petunias, busy Lizzies, begonias, snapdragons, verbena and salvia.
Plant them up as soon as you get them home, by pushing each plug into a small pot of multi-purpose compost. Water lightly and grow on a window sill or in a frost-free greenhouse. They’ll need potting-on into bigger pots when growing strongly, but can’t be planted in the garden until after the frosts.
06 Prune roses now
March is a good time to get roses into shape, before plants begin growing. Use sharp secateurs as they’ll make clean cuts that stand less risk of becoming infected with diseases. Cut out dead, damaged and crossing growth.
If dormant buds are visible, cut no more than a quarter of an inch above a bud, and cut at an angle, so rain water runs away from the bud. Many gardeners prune shrub or bush roses to within a foot or two of ground level – plants will grow back with extra vigour and flower power come spring.
07 Go on slug patrol
As temperatures begin to rise, out come the slugs and snails, in search of tender young plant growth to feast on. Don’t let populations rise: control them now. Chemical slug pellets are effective but never endanger wildlife by leaving pellets in heaps – one pellet spaced every six inches works best.
Organic pellets are available, too. If you prefer not to use pellets, beer traps offer a degree of control. Set the traps in the ground, fill with cheap lager and thirsty molluscs will make a beeline for the trap. Cheers!
08 Control weeds
As if to herald the arrival of spring, weeds are infesting paths, patios and lawns. The key is to nip them in the bud before they set seed in summer and multiply faster than a family of rabbits. For best effect, spray weeds on a warmer day when they’re actively growing.
For paved or gravel areas, buy a systemic weedkiller – that means it’s absorbed by the leaves, taken through the plant and kills the roots. Products containing glyphosate, such as Roundup, work well but avoid any overspray onto nearby plants, or they’ll come a-cropper.
For lawns, always use a lawn weedkiller, because such products are designed to wipe-out broad-leaved weeds and not narrow-leaved grass. General purpose weedkillers will damage your turf.
09 Sow tomatoes indoors
Tomatoes are Britain’s favourite crop and they’re easy to grow. Fill a seed tray with seed and cuttings compost and sow the seed at the depth indicated on the packet. Dampen the compost with a water mister and place the tray in a propagator or clear polythene bag. Place on a windowsill at 15-20C until seeds germinate.
10 Start feeding fish
Towards the end of March, pond fish will become more active, if the weather is warmer. Start to feed a little, and switch on fountains and waterfalls to help oxygenate the water.
Pond netting used to stop autumn leaves entering the water should now be removed, before aquatic plants start growing and become entangled in it.