March Garden Diary



Our March Garden Diary is brought to you by Geoff Hodge of the  Scotts Miracle-Gro Company.

March is the start of the main gardening season and there are lots of things to get on with in the garden. But keep an eye on the weather, as frosts and cold winds can be prevalent, which can be damaging to the new growth of plants and young plants.


This is a great month to sow seeds of all your favourite annual bedding plants. The seeds should be sown in small pots or trays of compost specifically formulated for this purpose, such as Levington Original Multi Purpose Compost or Levington John Innes Seed Compost, and germinated in a warm place. A heated propagator will provide bottom heat and usually produces the best results. A warm, bright windowsill is fine – just make sure to turn the young plants daily to prevent them becoming tall, spindly and lopsided.

But don’t be too hasty – resist sowing if you don’t have the warmth to grow on the plants – a minimum of 10C (50F) in a brightly lit place – and the facilities to harden them off properly before planting out. Sowing too early in the wrong conditions can lead to straggly, unhealthy plants that never perform well. Leaving sowing until the conditions are better in April or even early May, may result in stronger plants and these soon catch up with and out-perform those sown too early in poor conditions.

If you don’t have much success with seeds, it may be better to buy plug plants and seedlings for growing on. By starting now, and potting them up into suitable-sized pots of good compost, such as Miracle-Gro Potting Mix Root Boosting Compost, you’ll have well established plants ready to plant out at the end of spring that will burst into colour in summer.

side-Miracle-Gro-Bone-Mea#CB1B1CBefore doing any indoor sowing, transplanting or potting up young plants, make sure that the compost has been warmed to room temperature. Cold compost will prevent seed germination and lead to rotting and prevent strong root growth, which will affect subsequent growth and performance.

Fibrous-rooted herbaceous perennials can decline in vigour over time, and are best split and replanted every five or six years. This will improve their flowering and overall health.

Carefully dig up the plants and divide them into smaller sections and replant straight away in well-prepared soil with added Levington Organic Blend Soil Conditioner, or similar material, and Miracle-Gro Bone Meal Natural Root Builder.

Those that form large clumps, such as Michaelmas daisies (asters) and phlox, produce new growth around the outside.

The inner portion is the oldest, least vigorous and most disease prone, so is best discarded.

Fleshy-rooted plants, such as hostas, are best divided with a sharp knife or spade, ensuring each portion has at least a couple of growth buds.

Topical tip
Buy pansy, primrose and polyanthus plants plus potted spring bulbs for some instant colour to fill gaps in borders.


This is a great time to look at your patio, see if it’s missing some structure and plant up large containers with trees and shrubs. Just about every shrub and most small trees – including dwarf fruit trees – can be grown in containers. Just make sure you use the right size pot that matches their growth and a good potting compost. As these plants will be in their containers for several years, it pays to use a compost that contains loam, such as Levington John Innes No 3, Levington Multi Purpose Compost with added John Innes or Levington John Innes Ericaceous Compost for lime-hating plants, such as rhododendrons and camellias.

Established plants will be coming into growth now and should be given a good feed. Miracle-Gro Rose & Shrub Continuous Release Plant Food or Miracle-Gro Azalea, Camellia & Rhododendron Continuous Release Plant Food will keep plants well fed throughout spring, summer and into autumn from just one application now.

Topical tip
If you spend a lot of time watering your container plants in summer, it would be worth considering an automatic drip watering system.


Grass will start to grow strongly this month, so the lawn will need regular mowing from now on. If you haven’t been mowing through the winter, you’ll need to set the blades at their highest height and then gradually reduce this with subsequent mowings. You could stress and weaken the grass if you make the first cut too low.

side-EverGreen-Extreme-Gr#CB1B38Most people mow their lawns too short, scalping the grass, which weakens it. For best results, keep the grass at more-or-less the same height all year round. For normal lawns that take a lot of wear and tear the height should be around 5cm (2in). For ornamental lawns of fine-leaved grasses this should be about 2.5cm (1in). For lawns growing in shaded areas, mow at a height of around 7.5cm (3in).

This is the time to start feeding lawns, to ensure they look green and lush and the grass grows strong and healthy. At this time of year, the best feed to use is EverGreen Extreme Green, which will start to green up the grass in just three days. If you have a small lawn or prefer to use liquid feeds, feed with NEW EverGreen Extreme Green Lawn Food.

Now is a good time to rake out dead grass and other debris (called thatch) with a spring-tine rake to improve conditions for grass growth. And, if the soil is heavy clay, aerate it to improve drainage. The Joseph Bentley and Yeoman ranges contain numerous essential lawn care tools.

Topical tip
Re-cut lawn edges with a half moon edging iron to give them a crisp and even look.



Many vegetables can be sown outside this month. In cold, exposed areas, it may be worth delaying sowing until the end of the month or even April, unless the soil has been pre-warmed with clear polythene sheeting or cloches, such as the Botanico Sun Tunnel. The seeds of most outdoor spring-sown crops won’t germinate until the soil temperature reaches 7C (45F).

Good crops to sow now include beetroot, broad bean, carrot, cauliflower, kohl rabi, leek, lettuce, onion, pea, radish, salad leaves, spinach, summer cabbage, Swiss chard and turnip. Fleece, cloches and polythene can be used to protect early outdoor sowings if the weather turns chilly. Many vegetables can bolt (go to seed prematurely) if sown outside too early when it’s cold without protection – beetroot being a good example.

Tomatoes, sweet and chilli peppers, cucumbers and aubergines can be sown indoors now with warmth – either in a warm room in the house or, better still, in a heated propagator. Check the germination temperature needed as shown on the seed packets. A seed sowing compost, such as Levington Original Multi Purpose Compost or Levington John Innes Seed Compost, will produce excellent results and strong young plants.

Topical tip
If you want a really early crop, you can plant out seed potato tubers at the end of the month, although it’s better to wait until April in colder regions or where frosts are still forecast. Protect the young growth from cold and frosts with cloches or fleece.


Mulch the soil around fruit trees and bushes with a 5-7.5cm (2-3in) thick layer of Miracle-Gro Moisture Control Decorative Pine Bark or Levington Water Saving Decorative Bark. This will prevent weeds growing and maintain soil moisture levels during summer, and so help ensure bumper crops.

If you didn’t do it last month, give all fruit a good feed. This should be applied over the main rooting area – roughly equivalent to the spread of the branches. Good choices include Miracle-Gro Rose & Shrub Continuous Release Plant Food, Miracle-Gro Growmore Garden Plant Food, Miracle-Gro Fish, Blood & Bone All Purpose Plant Food, while Miracle-Gro Sulphate of Potash Natural Fruit & Flower Enhancer is high in potash and will help encourage better fruiting.

Place cloches or fleece over outdoor strawberry plants for an early summer crop. Make sure to lift the cover during warm days to allow pollinating insects to enter. A liquid, high potash feed, such as Levington Tomorite, will help encourage flowers and fruit.

Topical tip
This is an excellent time to plant new fruit trees and bushes, so if you’re thinking of growing your own fruit – now’s the time to get planting.


Although deciduous plants are moved when they’re dormant from autumn to late winter, it is better to move evergreens that are growing in the wrong place or have outgrown their space now.
Wherever possible, prune back up to half of the top growth first – to reduce the stress on the roots and so ensure more successful re-establishment. This may not be possible with conifers, for example, without ruining the shape.

Water the soil around the plant thoroughly the day before moving. Dig up as big a rootball as possible that you can manage to lift. Replant in well-prepared soil improved with lots of added organic material, such as Levington Organic Blend Soil Conditioner or Levington Organic Blend Farmyard Manure, and add Miracle-Gro Bone Meal Natural Root Builder to help improve root growth and re-establishment.
Firm the soil around the rootball, water in well and keep well watered during dry periods for the first year.

side-Time-to-prune---Clem#CB1B86Tall plants may need staking to help keep the roots secure while they’re establishing, and the foliage protected from cold winds with fleece or windbreak material.

Early March is the time to prune summer- and autumn-flowering clematis; leave spring-flowering clematis until after they’ve finished flowering.

Large-flowered clematis that start flowering in May and June (Group 2 varieties) should be cut back by around half to two-thirds, just above a bud or pair of buds. Those that start flowering in July or later (Group 3) need harder pruning. Cut them back to a bud 30-45cm (12-18in) above ground level. Or you could cut back half the stems in this way and prune the remaining half less severely; this helps produce a longer flowering time.

Other plants to prune this month include many summer-flowering deciduous shrubs, such as Buddleja, Caryopteris, Ceratostigma, hardy fuchsias, Hydrangea paniculata (not mophead and lacecap hydrangeas), lavender, Lavatera and Perovskia.

After pruning, give the plants a feed with Miracle-Gro Rose & Shrub Continuous Release Plant Food to help them recover and produce good, flowering growth.

Topical tip
Plants that are grafted onto a rootstock can produce suckers from the rootstock, which can soon take over the plant. These should be removed as soon as they are seen. But don’t cut them off, carefully pull them off, otherwise you’ll leave behind buds that can produce lots more suckers!


Making your own garden compost is a great way of recycling and producing your own humus-rich material for use as a soil improver and mulch. Any plant material can be used, as long as it isn’t diseased, apart from the roots of perennial weeds.

You’ll need a compost bin to keep all the material together and provide the correct conditions for speedy rotting. Make sure there’s a good mix of plant material, and that any stems have been cut into smaller pieces, otherwise they’ll take a long time to rot down. You can speed up the composting process by adding Miracle-Gro Compost Maker.

Weeds will start growing in earnest this month. The best way to deal with annual weeds growing in beds is to hoe them regularly to keep them in check. Always make sure the blade of the hoe is sharp to cut through the weed stems.

To prevent annual weed growth in the first place, you could apply a thick mulch (5-7.5cm/2-3in deep) of Miracle-Gro Moisture Control Decorative Pine Bark or Levington Water Saving Decorative Bark. When planting new borders, use Botanico Weed Control planting membrane to keep them weed free.

Perennial weeds should be dug up with a hand fork, ensuring you completely remove the roots. An easier option is to spray with a systemic weedkiller, such as Fast Action Roundup Ready to Use Weedkiller, which will kill the roots as well as the top growth. Roundup Gel can be used on weeds growing around wanted plants, where the weedkiller spray may drift onto their foliage.

Weeds on paths and drives should be treated with Weedol Pathclear Weedkiller or ready-to-use Weedol PS Pathclear Weedkiller, which will also prevent new weeds for up to three months. The NEW battery-operated Power Sprayer makes applying weedkillers quicker and easier and provides lots of weedkilling power.

As we move into the warmer spring weather, don’t forget the garden birds. Many people believe that birds only need supplementary food to be put out in winter, but they will benefit from feeding all year round – and reward you with regular visits to your garden. Putting out a good selection of different foods will encourage a wider range of birds. The ChapelWood range contains all the categories of food types, plus a fabulous selection of feeders. Research shows that encouraging more birds into your garden helps reduce plant insect pest problems,

Topical tip
When gardening on wet clay soils, work from a plank of wood or board, rather than treading on the bed, to avoid compacting the soil and damaging its structure.


After their winter dormancy, your houseplants will now be coming back into growth. This means you’ll need to increase the amount of water you give them to help keep the compost just moist. Always use tepid water, not cold water straight from the tap, and make sure you don’t overwater – more houseplants are killed by ‘kindness’ by giving them too much water than any other reason.

And, as they’re starting to grow, you should also start regular feeding with Miracle-Gro Pour & Feed.

Topical tip
Potbound plants may need repotting into bigger pots to give their roots room to grow in. Only repot plants that need it and only into the next size pot. Most flowering houseplants perform better when kept slightly potbound.


Use plant protection products & biocides safely. Always read the label and product information before use. Pay attention to the risk indications and follow the safety precautions on the label.

Fast Action Roundup® Ready to Use Weedkiller and Roundup® Gel contain glyphosate.
Weedol® Pathclear™ Weedkiller and Weedol® PS Pathclear™ Weedkiller contain glyphosate and diflufenican.

Products marked ® and ™, Botanico, ChapelWood, Joseph Bentley, Levington, Miracle-Gro and Yeoman are trademarks of The Scotts Company LLC or its subsidiaries.
Roundup® is the registered trademark of Monsanto Technology LLC.

For further information on your garden log onto: