Get Your Greenhouse Winter-Ready

Provide a little heat and insulation to protect plants

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The days are getting shorter now and the nights are cooler, so if you have a greenhouse that you use to overwinter plants, it’s time to make sure it’s winter ready.

Although an unheated greenhouse can drop below freezing in cold weather, it still offers protection, especially to plants in containers that dislike being too wet over winter. Pots of cordyline, agapanthus and other borderline hardy plants will often get through winter better in a greenhouse than when left outside in the wind and rain.

If you’re able to give a little heat to protect from the frost, the sky' s your limit as you’ll be able to overwinter a wide range of plants without too many problems. Plants such as pelargoniums, fuchsias, streptocarpus, cacti, succulents, citrus and many other tender perennials will tick over nicely if you can maintain a temperature of 5C (40F).

The most economical way to do this is to use an electric heater that is thermostatically controlled and will cut in when the temperature drops below the set temperature. Keeping the greenhouse well insulated also helps a great deal by cutting out cold draughts and by retaining warmth on days when the sun does shine. With a small heater and good insulation you’ll find the heating costs over winter are not that expensive.

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Plant herbs in winter containers

Get some growing now in pots sited close to your kitchen!

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Herbs are very popular in the garden for a variety of reasons. Many are grown for their culinary uses to add flavour to all types of savoury and sweet dishes through the year. Others are grown for their medicinal use and lots of people grow a selection of herbs to make teas and infusions to help sooth sore throats, headaches, indigestions and other ailments. And we mustn’t forget that many herbs plants are also very decorative and when in flower attract bees and beneficial insects into our gardens.

Through the winter months it’s possible to grow a good selection of perennial herbs in pots and containers so that you can gather fresh leaves and sprigs as and when you need them. To grow outside choose hardy varieties and although many of our popular herbs originate from the Mediterranean region, they are very tough. They don’t seem to mind the cold, but don’t like very wet soils, so always grow in well-drained compost.

At this time of the year you can find young perennial herbs such as rosemary, sage, thyme, winter savoury, curry plant and others for sale that are perfect for planting into larger pots or hanging baskets. Or grow larger plants as specimens in pots to create a winter display close to the kitchen.

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Set bulbs for colour in spring

Pop them in the ground now for early razzle-dazzle!

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Early autumn is the time to start planting spring-flowering bulbs for a colourful display next year. You’ll find them now in nurseries, garden centres, at flower shows and by mail order. There’s a good range of bulbs available such as daffodils that come in all shapes and sizes, tulips, crocus, iris, hyacinths, alliums, snowdrops and many more.

The secret to success is to buy quality bulbs of a good size. The larger the bulb for its type, the better it will flower. If you’re able to select your own bulbs, choose substantial ones that are firm and free from any mould or soft areas. If buying pre-packed, still have a feel and when ordering mail order buy the larger bulbs.

Most spring bulbs can be planted now, either into the garden or into pots where they’ll very quickly start to produce roots. Tulips on the other hand should be kept in a dark, cool place until November before planting. This is because they need much cooler soil conditions to avoid fungal diseases.

The other thing to consider when planting bulbs (‘nose’ up) is the depth you plant them. As a guide, always plant three times the depth of the bulb, so if the bulb is 5cm (2in) from top to bottom, plant in a hole 15cm (6in) deep.

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Get strawberries in for next summer

Plant runners in containers now for an early crop of fruits

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Next summer’s strawberries seem a long way off, but September is the time to plant rooted runners so they establish a good root system over the autumn. Alternatively, cold-stored runners - as used by commercial growers - are available in spring, but if you want to start now, you’ll need some new plants.

A recent method of propagating strawberry plants is known as ‘misted tips’. These are runners rooted under cover using mist propagation to produce strong plants early in the autumn. The advantage is you get new, healthy strawberry plants faster than the traditional method of rooting bare-root runners.

Misted tips are produced in cells, meaning no root disturbance, and when planted out they establish quickly, resulting in a larger first year crop of fruits. Many commercial growers in the UK now use this system to maximize an early crop of strawberries, but we can also use this new growing method in our own garden. Although the plants can be planted into the garden, they can be grown in pots and containers under cover to get fruit a couple of weeks earlier.

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Care for Crops in Containers

With a little care you can grow a wide range of edibles in pots

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You can grow a surprisingly wide range of crops in pots, troughs or growing bags – pretty much anything goes, except for perhaps cauliflowers, Brussels or broccoli! And most plants are happy in a good-quality multi-purpose compost.

If you’ve grown fruit and veg in pots smaller than around 45cm (1½ft) diameter, you might have found they haven’t thrived as you’d hoped, or have needed more watering and feeding than usual; in future just pick bigger pots so crops have plenty of room and good capacity to hold water and nutrients. Yellowing leaves and sickly plants are often a symptom of being tightly constricted in small containers.

Drying out is common, so evenly water your plants. Diseases such as blossom end rot can be caused by environmental problems like where they’re situated and how they’re fed and watered. Make sure pots aren’t crowded out, stuffed by a wall or hedge, in a rain shadow or not getting as much sun.

Grow hanging baskets of fruit and veg!

They need a little extra TLC but these dangling displays of crops are worth it

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Perhaps you’re running out of space on the patio for any more potted crops, or you’re looking for something unusual for your baskets this year. Well, a surprising number of crops work really well in hanging baskets. They’re such fun for growing crops in – dangling displays of tempting fruit and veg just outside the door are great for picking when you’re pottering about the garden on a summer’s day.

Choose as large a basket as possible, and the ones with holes in mean you can plant at the top and at the sides for a fuller look – and you get to harvest more crops too. There are lots of plants specially bred these days for cascading in a basket, but ordinary lettuce, cucumbers, peas and beans or beetroot all work just as well.

Make sure your baskets aren’t too exposed and don’t get too sun-scorched – or vice versa; ensure they don’t languish in a shady rain shadow either.

What’s vital is to feed and water your basket edibles frequently, particularly in dry spells – despite this, basket crops are worth all their diva demands! Below are some excellent examples of basket crops, all available to buy as plug plants now.

Plant easy oca tubers

Add to your root veg options with this easy-grow exotic

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If you love cooking comforting potatoes and root vegetables, I can recommend adding oca (New Zealand yams) to your repertoire. And the good news is, you can get hold of tubers easily from most garden centres or mail order suppliers, and they’re super easy to grow.

It’s a south American native of the oxalis (wood sorrel) family, is an attractive plant in itself with lovely clover-like leaves, and the tasty tubers have a nice citrussy, sharp taste to start with. If left, tubers have a more mellow flavour. You can dig up plants and harvest them from late autumn.

You could plant them outside in pots now, but to be on the safe side with regard to frosts, start them off in pots indoors and then plant them out at the end of May. You can eat them raw but, as for cooking, you can roast them or mash them as you would potatoes, or use them instead of carrots or other root veg. A wonderful upside of growing these easy veg is not only their ornamental appeal, but they don’t get blight and slugs don’t seem to like them!

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Try new streptocarpus plants

With the right growing conditions they’ll last for many years

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Streptocarpus are one of the most rewarding houseplants

Streptocarpus are one of the most rewarding houseplants

Streptocarpus make excellent flowering pot-plants for the house, conservatory, greenhouse, or even outside during the summer in a shaded spot. The range of colours increases every year with the introduction of exciting new varieties.

I’ve been growing streptocarpus since I was an apprentice gardener on a parks nursery and the choice was limited back then, but nowadays there’s a much better selection and I’m looking forward to growing three new ones from Dibleys called ‘Leah’, with velvety plum-red flowers, ‘Zoe’ that has violet-blue flowers and ‘Lemon Sorbet’ which is pale yellow and mauve.

Streptocarpus originate from rainforests, so when we grow them at home we need to provide them with shade from direct sunlight, moisture and a humus rich compost. Given the correct growing conditions the plants will thrive and last for many years. Now’s a great time to get started with them and you’ll find young plants at flower shows or direct from Dibleys, who specialise in breeding and growing streptocarpus. When you get your new plug plants it’s important that you pot them as soon as possible into a 10cm (4in) pots using a good quality peat or fibre-based compost. The plants will flower this summer for you and next spring they can be re-potted into a 13cm (5in pot) to continue growing. Only start feeding when plants are established and roots fill the pot, up until autumn.

STEP BY STEP

Sow easy flower fillers now

They’ll take just weeks to flower and bring summer colour

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Gardening’s a satisfying hobby; seeing all your graft and painstaking sowing, planting and feeding pay off and a beautiful, thriving garden emerges.

Yet sometimes it’s just as satisfying to chuck a few seeds about and, with as little work as possible, your border gaps quickly fill up and froth with blooms all summer! If you’re in a hurry, have large spaces to fill, or you simply like the carefree natural look and a bit of effortless gardening, get hold of some seed now. Sometimes you just need a few easy garden jobs where Mother Nature can help you out by doing all the work!

Now we’re cruising along in spring and there are plenty of packets of seeds you can simply open now and sprinkle thinly among your other plants or sown as low-growers at the front of borders, which will take a matter of weeks to sprout and flower. They’re fantastic filler plants that you’ll be grateful to all summer for their colour and abundance.

Plant a summer salad bowl

Sow seeds every few weeks for a continuous supply

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Lovely warm weather usually means we eat more salads with our meals and if you are a fan of fresh salads, it’s very easy to grow your own. Lettuce and all the many different mixes of salad leaves grow very well in shallow pots or bowls of compost and by planting little and often from now onwards, you’ll be able to enjoy your own freshly picked salad leaves when you want them.

Seed germinates quickly and as the weather warms up the plants grow quickly. The easiest method is to simply sow the seeds thinly in bowls of compost and keep them watered in a light, frost-free place.

Alternatively, you can buy young lettuce plants in cell trays to plant into the containers, or you can grow your own by sowing seed into plug trays to produce your own plants for the containers. Although seedlings need a little protection at this time of the year, once we get into May, the seeds will germinate without any protection.

The secret of making sure you have a continuous supply of lettuce and salad leaves through the summer is to have several pots at various stages of growth. Sow every two or three weeks and as you finish a pot, empty it onto the compost heap, ref-fill with fresh compost and sow more seeds.

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Check for pests and disease on plants

Keep an eye on plants to make sure they’re healthy

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Now that the season has got into full swing, all manner of creatures and pathogens are taking advantage of the warm weather and emerging or multiplying. Therefore it pays to keep a constant check on plants for outbreaks of diseases and pests. April is the month many pests are on the march, some laying eggs or coming out from overwintering, so there’s a long list of things you should be looking out for.

Gooseberry sawfly, allium leaf miner and leek moth will cause noticeable foliage discolouration and notches eaten out of leaves, while cabbage caterpillars and slugs and snails are on a mission to munch as many of our plants as possible too. Once many pests or diseases become established on a plant they can be difficult to eradicate. Plants you know are particularly susceptible should be routinely dealt with: prevention is better than cure!

The easiest method of control, particularly in the greenhouse, is to check the plants every day, especially on the undersides of leaves and at growing points, squash any pests that you find and remove diseased leaves.

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Click the images to find out how to deal with these pests and diseases…

Create a spring display on shelves

It’ll show off your prized plants better and you can change it regularly

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A simple and easy way to display a selection of seasonal plants is to stand them on a shelf unit to create a plant theatre.

It’s a great way to brighten up a dull fence or wall and when plants are displayed this way you can see and appreciate them much better. Another advantage is you can change the display several times over the year by using different plants to provide a lovely feature 12 months of the year.

On the shelves in our garden I tend to use a selection of old terracotta pots and galvanised bowls and cans for a rustic look, but of course you can use anything that fits in with the style of your garden. I also have a few evergreen ferns and variegated ivies that live permanently on the shelves to add additional structure to the planting. I can then fill the gaps with whatever plants are looking good at the time.

For my spring show I’m using a selection of primulas, violas, saxifrage, sempervivum and aubrieta, but basically you can use anything that’s available in your garden or from garden centres, as long as it can be grown outside. If watered on a regular basis the plants will continue to flower, especially the violas that will carry on flowering for several more weeks.

STEP BY STEP

Sow herbs in pots

Plant now to add aromatic flavour to home-cooked dishes

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It’s time to start getting your herb garden flourishing for the year! Herbs are nice easy plants to grow, with the added benefit of being wonderfully aromatic and edible, transforming your cooking from humdrum into heavenly. Anyone who’s added rosemary or bay to a stew or roast potatoes will know the richness and depth of flavour that herbs can bring. And they bring lovely flowers and attractive form to veg gardens and patios, too.

Most herbs can be grown in containers, in fact some need to be grown like this as they’re either more tender (basil) or too invasive in the open ground (mint).

Annual herbs that aren’t as hardy as others such as sweet basil and marjoram can be sown now under glass for planting out in the garden during May or June. Perennials such as chives, rosemary, hyssop and thyme can be sown direct outdoors. The compost shouldn’t be too rich or dense, and should be kept nice and light and gritty, with a light watering to keep it just moist. Use a general balanced fertiliser if need be, to encourage leafy growth and not flowers. Liquid seaweed helps herbs grow nice and lush and flavoursome.

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Transplant large evergreen shrubs

Moving them can be stress-free and easy with the right approach

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No matter how well you think you’ve planned your garden, shrubs often grow faster or larger than you anticipated! When this happens one way to deal with the potential problem is to lift and move the shrub to a different part of the garden where it has more room to grow.

You can move shrubs that are up to 10 years old or even older if you do it at the right time of the year and carry out the lifting and re-planting with care, but the older and bigger the shrub, the greater the risk!

Evergreens are best moved in autumn or spring but given the choice I prefer to do it in April, just before the plant starts into growth. The combination of mild days, cool nights, moist soil and April showers all help the evergreen to settle into its new home.

The secret when transplanting an evergreen is to lift the plant with a good ball of fibrous roots and to replant straight away into moist, well prepared soil. Through the spring and summer, the soil around the roots needs keeping moist to encourage new root growth. Watering over the foliage on a regular basis also reduces transpiration and helps to prevent the leaves from drying out, while the roots are re-establishing in the ground.  

Plant dahlias in pots

Bring on the summer flower power with these beauties

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Dahlias make beautiful specimen plants in pots; let them shine in the container on their own for some excellent patio flower power in summer. However, to thrive they need more care than when they’re planted in open ground.

Set one tuber around 10 to 12cm deep in a pot of good multipurpose, sprinkled with a little blood, fish and bone or Growmore in the planting hole to set it off. Cover over your tuber with compost and put the pot in the greenhouse until May if you live in Scotland or northern England, or in a sheltered, sunny spot outside in southern counties.

Now, dahlias are extremely hungry and thirsty feeders in pots, which is easy to tell by their demeanour; big, blowsy flowers and thick fleshy stems and leaves mean they need food and drink regularly! Water them really well, ensuring it drains well too. Once plants are established and start to bud up, give them a regular high potash feed (such as a tomato food) every week or so until early autumn.

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See below for compact varieties to grow in pots.

Plant asparagus crowns

This tasty, tender treat is so easy and satisfying to grow

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Asparagus is a very tasty vegetable, but when you grow your own and eat it fresh from the garden, the taste is truly amazing! That’s what makes it so special for the six to eight weeks that it’s harvested from late spring to mid-summer.

Now and over the next few weeks is the perfect time to plant crowns. These are young plants grown from seed that can be brought from mail order catalogues or nurseries.

To grow well, asparagus needs a sunny position and good soil, that is well-drained, but moisture retentive. A sandy loam is ideal, but where soil is heavier or very sandy, you can improve it by working in plenty of well-rotted manure or garden compost. On clay soils you can also plant on a mound to aid drainage. The site needs to be free from perennial weeds such as couch grass, ground elder, docks and bindweed, otherwise weed control will become a problem.

Once planted the asparagus needs two growing seasons to establish properly to allow it to build up a strong root system. If planting now, it will be spring 2021 before you can start cutting, but then you’ll be able to enjoy your own fresh asparagus for the next 20 years or more!  

Plant up path edges

Bargain rockery plants will clump up prettily

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The ideal border when it’s all planted up is usually a sort of tapering shape, right from the larger shrubs and perennials poking out at the back, cascading down to the front where smaller pathside plants reside.

Sometimes we just plant where we can, trying to find something we like for the right place. But with good planning and consideration of compact height and habit you can create a lovely low-growing display that doesn’t bury the plants behind it, makes your garden seem bigger, softens the hard edges of your path and will creep and clump prettily at ankle level as you walk past. 

Some of the best plants for the job are rockery or alpine plants, so make your way to the alpine section of your garden centre now and you can get some good deals. Planted now they’ll establish well. You could even make these path-edge areas a little more authentic and add pebbles, stones or smallish rocks to complete the look.

Rockery plants usually like good sunshine and really well-drained soil so fork over the soil and add a little grit to each planting hole. Spring’s a great time to enjoy making your little alpine pathside patchwork!

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Plant some companion flowers

They’ll bring in pollinators as well as look pretty

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There really is a place for flowers among your crops for a few reasons. Firstly, they look beautiful and make the whole area a much more attractive place to be, particularly if your plot is adjacent to your house. If you’re spending time sat among leeks and cabbages on a summer’s day, it makes sense to look at some pretty flowers too! As I’m growing a patio of potted veg again this year, I’m making sure I sow seed in the borders that will sit next to all my fruit and veg containers.

Secondly, plenty of the right flowers bring in pollinators galore, which are needed to set fruit on many of your crops such as strawberries, beans, courgettes, apples, raspberries and peas. If they’re attracted to your lovely selection of flowers, they’ll also visit your crops to pollinate them, making for bigger, better harvests.  

Thirdly, loads of flowers attract beneficial insect predators, like lacewings and ladybirds, which devour all the insects you don’t want near your crops, like aphids. It’s a lovely natural cycle, which ultimately means you get to grow more flowers so it’s a win-win! Here are four excellent companion flowers to sow now to bring in the minibeasts this year.

Take cuttings of perennials

They should root easily, giving you lots of new plants for free

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Many perennials are increased by division or by seed but another easy method to propagate a range of perennials is to take basal cuttings in spring. Unlike stem cuttings where you tend to use the tips of the shoots, with basal cuttings you remove the first flush of growth as it emerges from ground level, hence the name basal! Herbaceous perennials such as lupins and delphiniums are traditionally taken this way and because you cut the new shoots close to the root, they usually root very easily. Other herbaceous perennials that can be taken this way include phlox, physostegia and lysimachia.

With some plants, when you cut the new shoot pushing through the soil, very often roots are already developing at the base of the stem, which guarantees success. Not all plants are ready at the same time, so keep an eye open and when the new shoots are just a few inches long you can take cuttings.

Other perennials that can be propagated now include evergreen types such as heuchera and some hardy geraniums. Shoots growing from ground level can be detached, trimmed with a knife and the lower leaves removed. These cuttings also root very easily, especially when placed in a propagator. Plants grown from cuttings will always be identical to the parent plant and of course, they’re for free!

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