SUMMER CARE OF DAHLIAS
During early summer keep the hoe going between the plants to keep weeds down and to aerate the soil around the plants. Water thoroughly during dry spells. From July onwards it is better not to hoe as you may damage the small roots which grow near to the surface. It is beneficial at this time to apply a mulch — a layer of organic matter such as well rotted farmyard manure, a good quality compost or straw. A mulch conserves moisture, deters weeds and in some cases adds nutrients to the soil.
As the plants continue to grow quickly at this stage you will require to add extra ties to your original stakes. A good method of tying a large bed of dahlias is by use of the ‘tripod’ system which is the method I favour. I insert one strong stake at an angle away from where I place the plant at planting out time and tie loosely. As the plants grow I insert two further stakes or bamboo canes angled in the opposite direction to the first stake. I then use string to enclose the plant in this triangle which is now created. Additional ties are provided at six inch intervals up the canes. As the canes are angled away from the plant, the plant is thus afforded more room as it gets nearer the top of the canes. Ideally your canes should be about six inches shorter than the final height of your plants. I have found this method to be very effective even in high winds and it is very easy and quick to tie in a whole row of plants by just looping the string round each cane from one end of the row to the other.

To increase the bushiness of your plants you will require to pinch out the central growing tip. This is called ‘stopping’ the plant and should be done about the middle of June. As the shoots grow you may wish to restrict the number of shoots or branches on each plant to obtain bigger blooms. For larger (but fewer) flowers it is necessary to remove the side buds leaving only the terminal bud on each branch. Remove all faded blooms to prolong the flowering life of the plant.

PESTS AND DISEASES AFFECTING DAHLIAS
The control of pests and diseases is a never ending chore for the dahlia enthusiast and starts with good hygiene in the greenhouse. Prior to starting any tubers into growth the greenhouse should be thoroughly washed down using a good quality disinfectant.

Greenfly is a constant menace and a regular programme of spraying should be carried out at intervals of not more than two weeks throughout the season using one of the many proprietary insecticides available from garden centres. It is advisable to vary the insecticides used as the greenfly can become immune to them if the same one is used all the time.

When you mention dahlias to some people they immediately think of earwigs as there seems to be a long and close affinity between the two. Good husbandry is important to fight the earwig. Do not leave any hiding places for them. They like old wood, crevices in sheds or garages or to hide under decaying material. Trapping is still a popular method of dealing with them. Place an upturned pot on top of the stakes with a piece of crumpled up newspaper in it and the earwig will use it as a hiding place during the day as they forage for food at night. Some keen growers go out at night armed with a torch to catch the greedy wee blighters devouring their plants.

Mosaic and spotted wilt are due to viruses and there is no cure. You will notice plants are stunted in their growth and not a healthy looking colour.  There is no cure. Lift affected plants and burn them.  Aphids are the virus carriers and that is why the spraying programme I mentioned is so necessary to curb their activities.

LIFTING AND STORING DAHLIA TUBERS
Shortly after the frost has blackened your dahlia plants it is time to lift the tubers to prevent them being destroyed. Cut the stems back to about 6 inches from the tuber. Use a spade and dig all round the tuber taking care not to damage it. Gently ease it up and shake off excess soil. Take the tubers indoors to your greenhouse, shed or garage and try to dry them off naturally. At one time it was recommended to place them upside down on the greenhouse staging but this method is no longer favoured by most growers. Give plenty of fresh air and ventilation during the time they are being dried. There are many schools of thought as to the best method of storing tubers. Some growers like to trim off all the fine roots leaving only the fatter part of the tuber before storing in dry peat or sand or soil. Some like to core the tubers with either a drill or a screwdriver to assist the drying process. Burying the tubers in the ground to a depth of about 12inches has also proved to be effective. Slugs and snails can cause damage to the tubers and if this method is adopted remember to put down some slug bait close to the tubers. Good advice would be ‘not to put all your eggs in one basket’ by employing a variety of methods.

The things to bear in mind about storing tubers is that frost must be kept away from them at all costs. If they are frosted they will be lost for ever. On the other hand if they are kept too hot they will frizzle up and die. If they are kept too wet they will rot. A temperature of around 40 degrees Fahrenheit is reckoned to be most suitable.

The method which I now favour is to lift the tubers and put them straight into boxes of dry peat or soil without removing any soil from them and just let them dry naturally. I do not trim the smaller roots off them at this time. During frosty weather I have a thermostatically controlled heater set at 40 degrees Fahrenheit. In January I trim all the smaller roots off the tubers and place them in boxes of soilless compost, taking care not to cover the crowns. They are then placed on heat in the greenhouse towards the end of February and they are ready for taking the main batch of cuttings during April and May.

This takes us back to where we started so you will see that growing dahlias is an all year hobby.