STUDIES show that expenditure on gardening-related products is set to soar by a third over the next five years. But, while spending continues to rise, the space available for gardening looks set to decline with the trend towards single-person households and apartment dwelling.

However, living in a property with no outside space doesn't mean you can't be a gardener as a little forethought, patience and ingenuity can help you create your own little piece of Eden.

If you're keen to add an instant touch of colour to the outside of your property, it's worth looking into buying a window box or two. They have been around, in various guises, since Roman times and are still immensely popular on the continent.

Window boxes come ready made in a variety of materials, so it's a question of deciding which is best for you.

Plastic containers keep water well and come in a number of styles and although wooden boxes are an equally versatile and popular alternative, they need treating every two years with preservative to prevent them rotting.

Once you've decided which type of box suits your style of home, the next step is to get it properly installed.

It's important to remember that the box will become quite heavy once filled with plants and soil, so it needs to be held securely in place - especially if the window is directly above a street!

Make sure that the height of the box doesn't prevent you from opening the window properly, as there is little point in having a box that you can't gain access to!

If you have particularly narrow ledges there may be no option but to buy a box that overhangs slightly but you can support it with strong metal brackets fixed firmly to the wall.

Don't forget that most window ledges slope slightly to allow rainwater to run off, so you may have to put wedges under your box to get it on an even keel. Finally, ensure that the box has holes in the base to allow excess water to drain. Once the box is in place it is time to prepare for planting.

It's wise to put an inch thick layer of stones or pebbles in the bottom of the box to aid drainage. Then cover the stones with a thin layer of partially rotted leaves.

This will help to prevent the stones being clogged with the potting soil you will use.

Planting window boxes is very much an art in itself so, as with anything to do with the garden, a little bit of planning goes a long way.

When deciding which species to plant it is important to take into account the backdrop to the display.

If you have a complex window frame, fussy curtains or a glut of ornaments, then it is probably best to go for one main colour that complements or stands out against the background.

You also have to think about whether the box will get lots of direct sunlight, or whether it will be in shade for much of the day.

Sun-loving plants like pelargoniums, particularly the ivy-leaf varieties, are an ideal choice for south-facing boxes.

Trailing petunias are also suitable, especially if you have a plain box or one set on an upstairs window ledge.

Marguerites such as argyranthemum frutescens give an excellent display and combine well with African marigolds (tagetus erecta).

In shady areas, spring-flowering polyanthus or bulbs, like miniature daffodils, and grape hyacinths can be used in the early part of the year, but for the summer months opt for something like pendular begonias, which can be used as trailing plants, while yellow-variegated abutilon give height.

Another idea for window boxes is to consider placing one outside your kitchen window and planting common herbs, as not only do they look interesting, but they also make grabbing a handful of herbs for cooking so much easier too!

If you do go down the route of window boxes it's good to remember that half the fun in designing them is experimenting with various plants to get the most pleasing display.

However, whatever you decide to plant, the golden rule is don't be too regimented about the whole thing. Planting in straight lines will take the fun out of your display.

Hanging baskets are also a great way of creating a huge impact on a small scale.

To ensure success, there are some basic steps to follow but, once you've got them sussed, you have virtually unlimited design creativity at your finger tips.

Because plants all have differing needs it is wise to group together those for which have similar water, fertilizer and light requirements.

The next step is to think about colour, as a successful range of hues is the key to creating a high-impact basket.

When choosing colours, decide whether you want to create contrast or harmony in your basket. A good way to create a striking contrast is to mix yellow and violet or orange and blue.

For contrasting combinations, mix the primary colours: red, blue, and yellow.

To create an equally stunning effect with cooler colours, why not go for white and silver combined with dark purples and blues?

However, if harmony is the feel you want, it is better to mix flowers which have different shades and tones of a single colour.

When you've finally decided on the flowers, think about adding some foliage plants as this will give visual texture to the basket. A good rule of thumb is to include one leafy plant for every four flowering ones.

However, a mistake many people make is to use too few plants.

Although the plants will fill in with time, the idea behind hanging baskets is to create instant sensation, so design them to look beautiful right from the start.

Design your hanging basket so that it offers eye appeal at every level. To do this, add height with upright plants and use low growers for balance.

Finally, remember that hanging baskets can dry out quickly, so feed them once a week and water them every day. Tweet