Campaign: Diary of a Dhalia Grower Mark Shepherd

Diary of a Dahlia Grower

Week 31-35: July 30 - September 2

4th August

The dahlias are looking good on the allotment. The bed that is filled with CANNA TERRA is on the left of this photo. The CANNA TERRA-grown plants have thicker stems compared to the standard soil-grown dahlias. So far everything is going well. The timing of production of flowers for showing is critical now. As a general rule of thumb for dahlias, it takes around 25 days from the appearance of a flower bud to development of the perfectly formed flower. Since I need perfect flowers for September, I have been removing flower buds right up to the 1st of August. The plants are now starting to bud-up so hopefully I will have some flowers for early September.

Timing of flower production from the dahlia beds in the allotment. Left hand bed are the CANNA TERRA grown dahlias, which have thicker stems than the soil grown counterparts.

6th August

I have set some tubers to one side in a CANNA Coco Professional Plus filled 3-litre airpot. This is a way of forcing the plants to produce small pot-sized tubers that will be reserved as stock for next year. These plants have just started to produce tubers, so I am really happy with them so far.

Dahlia pot tuber grown CANNA Coco Profesional Plus in a 3.5-litre airpot. To be reserved to provide next years stock.

12th August

The growth of my giant onions has really started to slow down. I think that the exceptionally hot season we have had is the cause. I hope that they continue to grow, although I have now reduced their watering/feeding schedule. I am keeping my fingers crossed they can make it another month.

Giant onions grown in CANNA Coco Professional Plus in airpots side by side with my son Harvey to provide an idea of scale.

25th August

Some early dahlia flowers which will be taken home for the vase

Early dahlia blooms (Sues Kilmori)

Early dahlia blooms (Marys Jomanda)

30th August

For the first show of the season, I have decided to lift one of the smaller CANNA Coco Professional Plus-grown onions. I need to keep the larger ones for Harrogate and Malvern. The one I have lifted measured 24 inches around and weighs just shy of 10 lbs.

31st August

A photo of the allotment in full bloom, ready for the coming month of shows.

Week 27-30: July 2 - July 29


I noticed a few spots of thrip damage on the giant onionsand so have now started to spray with CANNACURE to try to stop these pests before they take hold. The onion in the picture looks promising with a very long neck.


The dahlias are looking good, although maybe a little ahead of where I'd like them to be, probably due to this heat wave, which is unavoidable. They have all been trimmed down to the selected number of growing stems. They seem to be liking the CANNA Terra so far and are looking just as good as their counterparts growing in open-ground.


I have some dahlias which are trying to flower now which is not what I want. I want all the flowers to start coming out as the show season starts (September). If I was to let them flower now all of the energy would be drawn from the plant and the flowers that would form later on wouldn’t be of the quality I need for show. So what I do is remove any buds until around 30 days before the first show. It can be a very time consuming job considering I have in excess of 250 plant each having at least 8 growing stems and some having 8 buds on. So potentially I could have 14000 buds which need removed over the course of the next 6-8 weeks.


The giant onions are now starting to slow down in growth as the day length shortens. They are of a pretty good size considering they have been under so much stress from the heat. I am very surprised that none have gone to seed from the hot weather. I have now lowered the watering time due to the slowing in growth. Last year I had an issue with over watering at the latter stage. One thing that isn't so good is spider mite has set in, probably due to the warm dry conditions. Stronger insecticide required.


The chrysanthmums are ticking over nicely. I've reduced the stem number down to 8 on every plant now.

Week 23-26: June 4 - July 1


Today is the day for planting out the dahlia plants. They are all at different stages of growth, but they can be cut back at a later stage so that the flowers can be timed for shows. I have 290 plants to go out into open ground. Twenty four of these will be planted out into a bed filled with CANNA Terra Professional Plus and fed with CANNA Terra Vega and Terra Flores.


I noticed today that some of the giant onions are showing a bit of browning on the flutes just above the necks of the bulbs. Since I have recently increased the EC to 1.8, I am wondering whether this might be the cause and am hoping that it isn't too serious.


Today I planted the giant cucumber and giant tomatoes into CANNA Coco Professional Plus.


I have been very busy at work, having taken on a lot of big projects. My allotment neighbour has been keeping on top of the watering that I should have been doing, while I have been concentrating on the greenhouse at home. It has been a struggle to find the time even to do this.

The recent heatwave has meant that the plants have had to be watered more frequently and keeping everything cool has been a struggle. Having said that the giant onions are looking ok. They are not as big as I would have hoped they’d be at this stage, but they are still growing. I have lost a few of the onions to the flute browning I mentioned previously, which I think is caused by an increase in nitrogen availability related to the increased EC of 1.8.


My first mega-bloom has formed on the giant tomatoes. It’s a little earlier than I had expected, but it’s a good sign that the plants have good genetics. This bloom should form 3 fused tomatoes.


The dahlia plants have now found their feet and are putting on astonishing top growth. The CANNA Terra bed is on the bottom right of the photograph and the plants growing in it are looking superb.


A day of very strong winds early in the month battered the chrysanthemums, but the plants are still looking pretty good. I have now stopped them for a second time, and their side branches are about a foot long.

Week 18-22: April 30 - June 3


Today, with the help of mini-me, I filled up the flexitank with nutrient solution for the giant leeks. I am currently using an EC of 1.7 and pH of 5.5 and am adding RHIZOTONIC and CANNAZYM. The leeks growing in Coco seem a little paler than those growing in the raised bed, but this could be because the soil in the raised bed was heavily fertilised before the leeks were planted out. It will be interesting to see whether those leeks growing in CANNA Coco Professional Plus will have a growth spurt later in the season. I am hoping that they will last longer and keep growing until late September for the Malvern show.


In the first batch of giant cucumbers, the plants are now showing their first true leaves. They are a very vigorous plant so grow very fast.


I made a start planting the chrysanthemums into their final pots today. I will be growing them in CANNA Terra in 9-litre Air-pots and fed on a Terra nutrient system. Since the plants will be exhibited in November I will need to move them into the greenhouse in September so that they can flower without the weather damaging them, otherwise, they could be grown in open ground. My son Harvey is, as usual, giving me a hand to tie each plant to a cane to support it and to prevent wind damage.


Just over a week after planting out, the Chrysanthemums have started to grow well. They have now had their second stop (removal of the growing tip). This will force new growth from the leaf joints lower down the stem and allow me to grow the plants '8 up' meaning that 8 axial stems should form on each plant, each of which will generate a single flower head. All additional side shoots and breaks are removed.


After arriving back from Chelsea flower show, all plants are looking great. My allotment neighbour looks after them while I am away and she does a brilliant job. I am now planting out the giant cucumbers. They will be grown in CANNA Coco Professional Plus in the Keder greenhouse that I have at home. They have been growing in CANNA Coco in 1-litre Air-pots up to now and the roots look superb as you can see in the photo. Nice clean white roots and no circling roots. They are now being planted in CANNA Coco in 20-litre Air-pots.


All looking good with the giant onions. I have increased the EC (as of 19th May) as advised by CANNA, it is now at 1.85 and the plants seem to be responding very well to the change. The new growth is very straight and some of the new flutes are almost 4 feet long. Light times are increasing as day length does.

And on a positive note, my CANNA banner has arrived ;-P

Week 14-17: April 2 - May 6


It is still pretty cold outside so the heater in the greenhouse is still on. The dahlia tubers just about have another batch of cuttings ready to take. This will be my 3rd batch of cuttings this year.

I have also now ‘topped’ the chrysanthemums. This basically means that I have removed the growing tips to encourage side shooting.


The giant onions have settled into their final pots and are now starting to bulk up. I am still watering them by hand at the same nutrient dosage (pH of 5.5 and E.C. of 1.4) as previously. I will setup the drip system over the next few weeks. One thing to note is the high neck length.


The giant leeks are ready to be moved into their final growing pots. I will be putting them into 20-litre air-pots filled with CANNA Coco Professional Plus. They are currently in 9-litre pots. In previous years they would already have been in their final growing positions but, since outside night temperatures are dipping below freezing and I don’t have heat in the polytunnels, they are safer in the greenhouse for the moment.


My giant cucumbers have now germinated and will be potted-up as soon as the first true leaf has formed.


It is now time to move the giant leeks and the spare onions into the polytunnel as the overnight temperatures have increased to a minimum of 10°C. They are all being potted-on into air-pots containing CANNA Coco Professional Plus. They will be hand watered with nutrients throughout the season.


I have now taken my final batch of exhibition dahlia cuttings. They will be grown in a raised bed filled with CANNA TERRA and will be side by side with a bed containing normal soil. I have now taken around 400 cuttings. I will only be growing 290 plants in my garden which should give me plenty of choice of quality plants. All of the spare plants will be kept to provide stock plants for next season.

The exhibition chrysanthemums hare now pushing out decent side shoots, these will be stopped again for a final time in June. They have been sprayed with a growth retardant, without which the plants would grow to over 8 feet tall which would make them unmanageable.


The giant onion dripper system is now installed. The drippers are set to come on 4 times per day at intervals and will remain on for 1 minute each time. The amount of water each plant will receive will be approx. 2.5 litres per day. I will flush the plants with water only once per week on a Friday. For comparison, the plants are 2 inches in circumference bigger than last years attempt.

Week 9-13: February 26 - April 1


My CANNA COCO grown giant onions have now been planted into their final pots under lighting that is designed to mimic natural daylight. Over the next month, I will introduce a light sensor to switch the lights on when sunlight levels are low and back off when sunlight increases. This should reduce cost by reducing the amount of electricity being used. I will water the plants at pH 5.5 and EC 1.4 for a few weeks until they have settled in and will then hook up the RTA dripper system to make the watering semi-automated. I now have a regular spray schedule for insecticide and have put yellow sticky insect traps in place to catch anything that is jumping around in the greenhouse.


I received my chrysanthemums from John Peace (National Champion) which consists of 48 late flowering singles and 16 anemones. I intend to grow these in CANNA Terra, in 9 L Air-pots and if all goes well I will enter the best flowers into the National Championship in early October


My leeks are now all in 3 L pots or bigger and are so far looking really healthy. They are all now in the allotment greenhouse. The temperature in the greenhouse never goes below 10ºC. One thing that I have noticed with the leeks grown in CANNA COCO is that their roots are bright white and very clean. The combination of growing in Air-pots and CANNA COCO means that the roots grow and establish themselves very fast each time they are moved into a new pot. The result of this is that they are growing faster than they would in soil.


I have taken my first batch of dahlia cuttings later than usual but, to be honest, there is still plenty of time left. My aim is to grow 250 dahlias this year, in open ground. One of the beds will be filled with CANNA TERRA.


SNOW! Very late in the year but we have had 4 inches of snow on the ground. The roads are too dangerous to drive on, so no work for me. My greenhouse has maintained a steady 10ºC. Here's a shot of my son who took a break making his snowman to come to help me in the greenhouse.

Week 1-8: January 1 - February 25


Giant Onion seeds were sown in CANNA Coco Professional Plus in an Air-pot seed tray.

The strains I'm growing this year are from Peter Glazebrook, Paul Rochester and Joe McKenzie. Germination rate has been very good in CANNA COCO.


Potted up the giant onions into a cell tray in CANNA COCO and now feeding with a Coco A & B (EC 1.1 and pH of 5.7). Growth is pretty slow. I have the T5 grow lights on 24 hours a day. No bottom heat as the heater has burned out (new one on way).


Potted up the giant onions into 1 litre pots. EC and pH of nutrient solution are continued at previous rate, I have now started using CANNAZYM and RHIZOTONIC and the plants are looking well.


Plants are now potted into 3 litre Air-pot in CANNA COCO. EC has been increased to 1.2 (ph remains the same), I have also continued using CANNAZYM and RHIZOTONIC. The light times have now been reduced to 11 hours per day. I have now switched to a CFL grow light as a supplement only to natural day light. Really happy with the growth of the plants so far.


Giant pot leeks are now in the grow cabinet. This will be the first year I am attempting to grow giant leeks in coco and I'm feeling ambitious. I am going to grow 12 plants full term in coco. The EC and pH will mimic that of the giant onions.


All of the plants have been moved to the allotment greenhouse which is heated by propane. They have been moved to make the most of the natural day light. All of the giant onions will be potted up into their final pots (45 litre Air-pot) over the coming week.

Mark Shepherd was born and grew up in Newcastle. His interest in growing was ignited by his grandfather at the age of 6. By the age of 13, he had his own allotment where he realised his passion for growing perfect vegetables and later progressed to growing “big, ugly, giant vegetables”.

At 30 years old, Mark remains one of the younger growers making an impression at national shows. He uses social media to encourage a new generation of enthusiasts to 'get their hands dirty' and grow for fun or for competitions.

In 2016 Mark won the 'biggest 3 leeks' category at the Moorhouse Leek show and in 2017 was awarded fourth place in the heaviest onion category at the Harrogate show.

Mark's eye was turned to dahlias in 2013 and he won first prize in the novice section at the Harrogate show in his third season of growing them.

A year later, in 2017, Mark was awarded first prize in the main dahlia classes at the Malvern show.

In the 2018 season, as exhibition dahlias, giant onions and giant leeks, Mark will be growing Chrysanthemums for the first time. His objectives for the 2018 season are to be amongst the top three placings for heaviest onion and heaviest leek at the 'CANNA UK Giant Vegetable Championship' at Malvern or better still to get first place and a world record.

His plan is to grow 20 giant onions and 12 gaint leeks in CANNA Coco Professional Plus and 20 dahlias in CANNA Terra Professional Plus (in raised and lined beds). For his Chrysanthemums, Mark will break with the tradition of using heavy clay pots and soil, and will instead grow 40 Chrysanthemums in 9 litre Air Pots using CANNA Terra Professional Plus. This experimental approach is being undertaken with the support of one of his competitors, John Peace, who will grow the same strains of Chrysanthemums using traditional methods. Between them, Mark and John are interested to find out whether it is possible to use lighter weight materials without compromising flower quality. If it works, it would make transport to shows much easier for future growers. Later in the year, Mark's journey from Newcastle to the Malvern Autumn Show will be covered by the BBC series “A1: Britains Longest Road”.

Growing medium: CANNA Coco Professional Plus CANNA Terra Professional Plus
Plant: Giant Onion x20 Giant Leek x12 Exhibition Dahlia x20 Exhibition Chrysanthemum x40
CANNA Nutrient: Coco A & B (5-4-3) Terra Vega (3-1-4) and Terra Flores (2-2-4)

Mark will also be using CANNA additives (RHIZOTONIC, CANNABOOST Accelerator, CANNAZYM and PK 13/14).