You may think your shed and all your garden contents are covered while you're away on holiday - but think again, because you may not be sufficiently insured.

The average UK garden is now worth almost £2,000, according to Halifax. Expensive patio furniture, heaters, barbecues, children's play equipment and ornaments left out on display can provide rich pickings for thieves.

In more extreme cases, valuable plants have been dug up, laid turf lifted and even decking has been dismantled and removed.

Thefts from gardens and outbuildings peak in July and August, according to Aviva. Valuables such as patio furniture, barbecues and garden tools are on the most wanted list for opportunist thieves, a survey by Lloyds Bank Home Insurance found.

The report also discovered around a third of homeowners say they spend more money on their gardens than five years ago. But despite their willingness to spend time and money on their outdoor spaces, more than a third (37%) have no secure lock for their garden and a quarter (24%) admit none of their outdoor items are insured.

Tim Downes, senior claims manager at Lloyds Bank Insurance, says: "We know that the majority of thefts from gardens and sheds are opportunistic, so it is worrying to see so many people leaving themselves exposed by investing in gardens without adequate insurance.

"When it comes to protecting our properties, homeowners must remember that what's on the outside also counts, so taking some small easy steps could help prevent having to stump up for lost garden goods should the worst happen."

Lloyds Bank Insurance offers the following tips for keeping your gardens safe:

:: Lock it up: Always ensure garden sheds, gates, garages and outbuildings remain bolted with a secure lock and make sure there are no gaps in fences or bushes for thieves to slip through

:: Put bricks or stones in the bottom of patio tubs to make them more difficult for would-be thieves to carry off

:: Tag it: Mark valuable items, such as patio furniture and ornaments, with your postcode, and keep photos of your garden valuables in case anything is stolen or vandalised

:: If you can't block access to you garden by locking a gate, high walls, spiky fences and prickly bushes can make it more difficult to get in

:: Create a noisy entrance. Filling your driveways or front paths with pebbles or gravel can help you to hear someone approaching your property

:: Avoid leaving tools, lawnmowers and bicycles in plain view in the garden - always lock them away out of sight. Remember tools and ladders can be used to break in too

:: Look into joining your local Neighbourhood Watch scheme to help protect you and your neighbours' properties

Some insurance policies may not provide cover for all your shed contents if you suffer a break-in, Which? Gardening, the Consumers' Association magazine has found.

Belongings kept in sheds and garages are usually covered for theft under your home contents insurance but, depending on the value, they may not actually be protected. Which? Gardening looked at 38 standard policies and found that eight didn't cover thefts worth more than £2,500 from outbuildings, meaning some gardeners may have insufficient cover in the event of a break-in.

Many insurers have a 'single article limit' (the most they will pay to replace one specific item). This could mean that if expensive items like high-end bikes or ride-on lawnmowers are stolen, you may not receive the full value.

Which? Gardening editor Ceri Thomas says: "With thefts from sheds on the rise in summer months, people should check whether their home contents insurance covers outbuildings and whether they need to cover items held outside the home separately.

"In the meantime, our advice is to keep sheds locked at all times, fit a battery-operated alarm, and chain and padlock expensive items."

It's worth checking the cover for 'contents in the open' in your home insurance policy, the consumer website moneysupermarket.com recommends. This includes loss of barbecues, garden furniture, pots and ornaments from theft and malicious damage.

Maximum limits vary enormously, from 'no limit' to £2,000 and down to as little as £250, which is not much if you've just bought a new set of garden furniture or children's outdoor play equipment.

Tot up how much your 'contents in the open' are worth and speak to your insurer to discuss extra cover. If you have particularly valuable garden statues or plants you may have to contact a specialist insurer and have the items individually insured.

BEST OF THE BUNCH - Helenium

These gorgeous burnt orange and yellow flowers, whose domed, daisy-like centres seem to look up at the sun, provide a fantastic addition to the late summer border, paired with crocosmias, salvias and rudbeckias, to give a dazzling show. They are best planted in groups of three or more in a sunny spot in moist but well-drained fertile soil. Established clumps need dividing every couple of years. Good varieties include H. 'Septemberfuchs', a tall variety growing to 1.5m (5ft) which benefits from early staking with canes, H. 'Sahin's Early Flowerer', a more drought-tolerant type with flame-streaked petals, and H. 'Moerheim Beauty', which bears rich orange flowers with a prominent brown centre.

GOOD ENOUGH TO EAT - Peaches

You don't have to live in a Mediterranean climate to enjoy juicy, mouthwatering peaches in summer. However, peaches do need a lot of care because of our climate. They can be grown in warm areas with the protection of a fairly high south-facing wall or fence but the flowers come early and the fruits need a lot of time to ripen. So it's probably best to start them off in a greenhouse and keep them there at flowering time to protect them from frost. The trees need deep, well-drained but moisture-retentive slightly acid soil, with plenty of organic matter added. They should be planted in autumn and respond well to fan training. They are self-pollinating, so you can grow single trees but, as they blossom before many insects appear, it's wise to hand pollinate them as well. The easiest cultivars to grow in pots are compact or 'patio' cultivars, standard trees on high stems with a ball-like head. In late winter, peach trees need to be sheltered to keep off the rain and stop peach leaf curl developing.

WHAT TO DO THIS WEEK

:: Harvest culinary herbs to freeze or dry for winter use.

:: Disbud dahlias, as required.

:: Remove the growing tips from greenhouse tomatoes by the middle of August to encourage the fruit to develop rapidly.

:: Take the last crop of cuttings from pinks.

:: Pick off and destroy any fruits of early apples and plum trees showing signs of rot.

:: Plant new summer varieties of strawberries.

:: Collect and dry seeds of dill, fennel, chives and other herbs as they ripen. They can be resown immediately in seed drills if you want to expand the stock in the herb garden. Alternatively, they are useful for flavouring.

:: Continue to cut sweetpeas to encourage further flowers

:: Feed trees and shrubs that are performing badly with a high-nitrogen liquid fertiliser.

:: Take cuttings of rock plants such as aubrieta, phlox, thyme and helianthemum