During the recent spell of fine weather, David Coton has been careful to make sure that none of the container grown plants at the Garden Centre dry out. This is particularly important if you are on holiday and he has these suggestions for other jobs that will keep you busy in the garden during August.
Planters and window boxes are particularly vulnerable at this time of the year, so either ask a neighbour to water them or invest in an automatic system that can be time controlled to release just the right amount of water to keep you plants happy until you return.
If your compost heap is drying out, water it and then cover with carpet to retain moisture. Water hanging baskets until it starts dripping from the bottom, and at the same time continue to deadhead and feed.
It's also a good idea to group containers in the shade, and pick all your sweet peas to avoid finding lots of pods when you arrive back. This will also extend their flowering season into September.
If azeleas, rhododendrons and camelias are dry when forming buds at this time of the year they are likely to fall off in the spring, so make sure they are watered weekly.
If you keep fish you'll need an automatic feeder or feeding block, there are several available to suit all pond sizes and you can set how often and how much food you want to feed the fish.
Lawn And Border Care
Your lawn might look as though it is suffering from the hot weather but you needn't be too concerned as grass has great powers of recovery. When conditions improve, give it a boost by applying an autumn feed to strengthen the roots and prepare the lawn for winter.
Remove annuals that have finished flowering and put them on the compost heap, cut back flowering perennials that are past their best, they don't look good and you'll be opening up space to plant spring bulbs and container grown perennials that provide instant colour.
'Suckers', usually with seven pale green leaves, will literally suck the life out of your roses, so follow them back to the the root stock and pull them out.
To save money, use a paper bag to collect seed from herbaceous perennials on a warm dry day. When they have completely dried, transfer to an envelope and clearly mark what's inside. If the plant has berries, soak in warm water and carefully remove the flesh. Sow immediately to plant out in the spring or store in a cool place.
Perennials that have stopped flowering can be picked up cheaply from garden centres. Buy them, remove foliage and divide. It doesn't matter what the foliage looks like, it is healthy roots that are important. Plants can be divided many times but it is important to plant the roots in poor compost so that the grow slowly and robustly rather than encouraging foliage.
Growing new shrubs from cuttings is easy. Take a piece of non-flowering stem from this season, cut just below a leaf, and remove any lower leaves, dip in hormone rooting powder and place in fresh compost. Cover the pot with clear plastic and leave in a warm spot away from direct sunlight.
The success rate for rose cuttings isn't brilliant but can be worth the effort. Take some new growth about the width of a pencil, divide into 6in lengths by cutting just under a leaf (cut the top with a slant to remind you which end is which) and remove foliage. Place in either an equal mix of compost and grit or directly into a shallow trench in open ground and fill with grit or sharp sand. Bury up to about the top inch and fresh growth in the spring will indicate success.
Wisteria needs pruning twice a year to prevent it growing out of control, perhaps invading and blocking guttering, and to encourage flower buds. So in August cut the year's growth back to five or six buds.
Rambling and climbing roses should also be pruned back when their flowers have faded. With the former, cut out about a third of the older stems or if you have limited space prune out one old stem for each new one. For Climbers, remove any dead or dying stems, support any new shoots. Then for both, prune back any side shoots to one third of their length.
Deadhead perennials to prevent them from self-seeding and to encourage late summer flowering. Remove flower stems from hostas and irises.
Trim lavender but avoid cutting into old wood, regrowth will then harden off before any cold weather arrives. Cut Lady's Mantle (Alchemilla mollis) down to the ground after it begins to fade, fresh leaves will soon appear.
Once cherry and plum trees have finished fruiting, prune them to remove weak, damaged or crossing branches. Prune fruit espaliers to maintain their shape and cut back hard every four years or so.
Night temperatures during August in the greenhouse might drop fairly low but during the day they can soar. Ensure that ventilation is sufficient during any hot weather and that shading is still in place, and automatic vents will save you the trouble of opening in the morning and closing at night.
Support autumn fruiting raspberries with stakes and string to keep them tidy.
Protect ripe fruit from birds and make sure brassicas are netted securely against cabbage white butterflies.
Pinch out the tips of runner beans to encourage side shoots, and keep thinning vegetables such as beetroot and turnips.
Cut old growth from blackcurrants when they finish fruiting, the best fruit comes from two year old stems, Prune summer fruiting raspberries down to the ground as new growth will carry berries next year.
Feed sweetcorn, squash and tomatoes with a high potash feed such as liquid seaweed, when you have five or six squashes remove excess flowers and fruits. Feed tomatoes
Clear any mulch away from strawberries as well as weeds, then cut off this year's growth so that new foliage can emerge before winter.
Start cutting back woody herbs such as thyme, in stages to help maintain their appearance, also remove any dead material to let in light and air.
On a dry day harvest dill and fennel seeds. Store in a cool dark place ready for planting next spring. Cut back half of your mint to encourage new growth but only the flowering heads of the other half so that you can continue harvesting. It's simple to take rosemary cuttings, prune leading growth, strip off the lower leaves and plant in gritty compost.
Trim evergreens so they remain in shape over winter. If plain leaves have started to appear on variegated shrubs, this is known as reversion, remove them or they will soon take over the whole plant.
Remove long stems from shrub roses to avoid wind damage.
Still Time To Sow
Sow fast growing salad vegetables such as rocket for a quick and tasty harvest, these can be used as a 'catch crop' between later maturing vegetables like kale.
Sow turnips, sprinkle thinly, cover lightly and water. In warm ground they will grow quickly, if cold weather arrives either cover with a cloche or fleece. Eat young before the end of November.
Sow swedes, these can be left in the ground until February / March. Beetroot already grown in plugs can also be planted out and will overwinter.
Spring cabbages raised from seed (or bought as young plants) can be planted out.
When onion foliage turns brown and withers it's time to lift them and lay out in the sun. When thoroughly dried, either cut the dead foliage off and store in netting or use the leaves to tie the onions together. Hang in a well ventilated frost free environment. Garlic can be dried, then trim the roots, remove any earth and store in a basket in a cool dry place.
Keep runner and French beans well watered and continue picking when they are young to encourage further pods, don't leave them to grow too large, they'll become tougher and stringier. Harvest ripe chillies to encourage other fruits to ripen.
If you use a normal fork to harvest potatoes be careful not to spear the tubers, leave them to dry, then clean and store in hessian potato sacks in a dark, cool, frost free place. As with apples, only keep perfect tubers. Don't put any foliage that is showing signs of disease onto the compost heap, burn it.
After harvesting crops, sow green manure to improve soil structure and fertility. Growing throughout the winter, Alfalfa or Red Clover will be dug in next spring, releasing nutrients into the soil. Faster growing manures such as mustard and buckwheat can be used that are dug in during the autumn.
If you want lovely new potatoes to go with your sprouts at Christmas, buy early varieties such as 'Charlotte' or 'Maris Peer' and use a pot or potato bag. Place three tubers on a 4ins layer of free draining compost / organic matter then cover with about 6 ins of compost. Keep well watered in a frost free environment and keep covering the foliage until the top of the pot or bag is reached.
During August you must keep checking the health of your pond and aquatic plants. It's a good month to tidy any marginal plants by cutting back summer growth. As leaves start yellowing, remove them together with any fading flowers. This will prevent the dying foliage falling into the pond, rotting and causing water quality problems.
Blanket Weed And Algae
To break down any blanket weed, you can choose one of a number of water treatments that will solve a range of problems or add barley straw either in the form of pellets, a bale (best located near a fountain or at the base of a waterfall) or as an extract. Barley straw does take longer than alternative chemical treatments to start working but will last for around six months and doesn't remove oxygen from the water.
Aerating The Pond
Oxygen levels are critically important and in August they may be very low, if you see your fish gasping for air then this is a tell-tale sign that the water needs oxygenating. You can do this in several ways, a waterfall or fountain, either solar or mains powered, can be added to the pond, introducing oxygen to the pond when the water's surface is disturbed. A pond air pump can also be installed that sits outside the pond with a pipe and air stone(s) going into the pond and this simply pumps oxygen directly into the water.
Testing The Water
Finally, it's always a good idea at regular intervals to check the health of your pond with a test kit. This will tell you whether for example there is an excess of ammonia or nitrite, high levels of which will kill fish; nitrates that will result in algae problems; and the water's acidity / alkalinity. Once these levels are discovered, appropriate action can be taken to rectify any problems.
Don't be tempted to bring any plants back from your foreign holidays, there's always the chance that you'll bring pests and diseases back with them. And, to save you the trouble and protect our native species, many will be available at your local garden centre anyway.