If you asked 20 dahlia growers their methods of growing dahlias they would all differ in some way. There would be differences in soil preparation, propagation and cultivation. The system they use is the one that works for them. My system works for me. It took me many years of trial and error to get the system I use today. It may not work for everyone and I must say that I only grow medium and small semi-cactus on this system. I am fortunate that I live near to Tim Dale and I will always be grateful for the help and guidance I received from Tim and the late Vivien Dale, both National Champions in their own right. I know that it is their advice that has taken me to National Champion level. Even today if I have a problem I telephone Tim and the advice I receive is always sound and genuine.
This area of Wales receives an above average rainfall, infact in early May my garden received 170mm (seven inches) of rain in 24 hours. The soil in my garden is a silty loam but has good drainage. So, by the first week in June I was able to plant out even after all that rain.
My soil preparation starts around Christmas time. By then all the tubers will have been lifted. I rotovate all the dahlia remains and the straw mulch back into the soil. The garden is then left until March when the soil is analysed and I get the Ph and nutrient levels. The Ph level is very important to me because this determines the type of organic material I will use to improve the soil structure.
Ideally I am looking for a Ph of 6.75. If for example the soil sample gives me a reading of 6.5 I would then add mushroom compost a layer of 3 inches being sufficient to raise the Ph by 0.25. If on the other hand the reading was say 7.0, I would add sedge peat to a depth of 3 to 4 inches, this would drop the Ph back to my ideal level of 6.75. Supposing the Ph was 6.75 to start with I would then use a combination of mushroom compost and peat to improve the soil while maintaining the correct Ph level. I do not use farmyard manure, it can vary so much from load to load and does produce in small and medium cactus varieties a coarseness in the blooms with swirling petals and in some cases flat decorative type petals around the bloom centres.
The soil analysis also gives me the nutrient level. My ground will be short of nitrogen as this is absorbed by the decaying straw. I replace the nitrogen with hoof and horn and nitrate of chalk, these are applied mid May. The hoof and horn is slow acting and the nitrate of chalk will release nitrogen by planting out time. The phosphates I use would be bonemeal and superphosphate again applied in mid May. The bonemeal would be slow acting but the superphosphate would release phosphates at planting out time. I use sulphate of potash which lasts two to three months in the soil. This would take me up to bud stage on the plant, then I would start to feed Chempak No 4. I also use horticultural gypsum to improve the soil, this binds the soil particles and improves drainage and aeration.
I plant out my dahlias the first week in June, Planting at 2.5 feet apart and 3.0 feet between the rows. I only need 2.5 feet spacing because of my method of soil preparation, I grow less blooms per dahlia plant than my competitors.
The list of dahliass I grow is shown below together with the
number of breaks per plant.
Grenidor Pastelle grown
7 up
Pink Pastelle grown
7 up
Symbols grown
6 up
Sunray Glints grown
6 up
Eastwood Moonlight grown 5 up
White Moonlight grown
4 up
Wootton Impact grown
5 up
Nancy Margaret grown
5 up
Scottish Rhapsody grown
5 up
Hillcrest Albino grown
7 up
I only grow seven out of the ten above varieties each season, I grow the four banker dahlia varieties plus three others. Last season the other three varieties were Golden Symbol, Nancy Margaret and Sunray Glints.
The four banker varieties, the two Pastelles and the two Moonlights I find produce their best blooms in opposite seasons. If the season is hot and sunny the two Moonlights do well but if on the other hand it is a cold wet season the Pastelles do best. Of the others Nancy Margaret and Scottish Rhapsody like the same season as the Moonlights whereas Wootton Impact and Hillcrest Albino like the same sort of season as do the Pastelles. I find I can get a vase of the Symbols and Sunray Glints never mind what the weather does.
Feeding and watering the dahlias is carried out as and when required by the growth on the plant and the weather conditions. If I did feed it would be Chempak No 3 a balanced feed up until the bud stage. From then on I would use Chempak No 4, a high potash feed.
Once I start cutting blooms, normally at the end of August I only water and feed if required. If for instance I intended to show on a Saturday I would cut the blooms early on Friday morning. If the garden then required watering or feeding I would do so on Friday evening. I transport my dahlia blooms in a Leyland Sherpa van with a side door and an up and over rear door. In this van I can transport 52 blooms, this ensures that no blooms get damaged in transit and that they arrive at the show in the best possible condition. It is then up to the judge.