Bring your Dahlias back to life.
Set your dahlia tubers up in boxes, if you have not already done so, now is the
time to get those tubers back to life. I started some of the tubers back to life
in January to try and get some early cuttings from my dark leaf seedlings of the
Pathfinder Collection. This is the way to multiply your stock. First you will
need to find a fairly deep seed tray or those blue mushroom boxes; you can
usually pick them up from your local supermarket. Start by making sure that the
boxes you are using have holes in the bottom to let the excess water out. Put
the compost in the boxes about half full (You can use multipurpose compost for
this), place your tubers on top of the compost then lightly sprinkle more
compost around the tuber, just below the crown. Don't forget to place the name
label next to the tuber so you can remember the varieties name. Once you have
put all your tubers in the boxes or trays you can give them a drink of water,
maybe this is the time you have a cup of tea. Then you will need to put them in
a warm place around about 20% centigrade in a fairly light place, then you can
leave them for a week or so, they will start to make root, as they make root
they will becoming back to life you will see that they will making small shoots.
You can start to give them a fine spray this will help the small shoot to grow.
but don't get the compost to wet Some varieties send a thick shoot up first let
this shoot get to about a inch and a half long then cut it of with a sharp knife
just below the first two leaves you can through that cutting away as it will not
root for you. You will see from where you cut the last cutting of there will
start to grow four more cuttings.
The ground where my dahlias are grown is quite heavy, so digging can be delayed
until March, If your ground contains a proportion of clay, then it should be
rough dug from November onwards to allow the winter frosts to work on the soil,
improving the nature of the clay soil. Clay soil needs a large amount of humus
(farmyard muck) to be incorporated or I give my plot 6x, again improving the
soil structure and helping to provide food for the following year's plants.
As the tubers start into growth and the shoot start to appear you must keep your
eyes open for the predators (Green Fly and Slugs) they can soon make a meal of
the tiny shoots. I find for the green fly that any of the systemic insecticides
will do the trick
but for the slugs I use something called Slugit you just spray it all over the
compost and the tuber, this will last a week or two before you have to do it
again. This winter has been a bad winter for keeping tubers I have had a lot of
dahlia growers getting in touch with me to see if I can supply certain varieties
some grower say that the plants never made a tuber, I like to grow pot tubers,
this way you can keep your stock, as they only make a small tuber and they are
easier to store over winter and as you set them up again they don't take up as
much room on the bench. So as your tubers start to come back to life three thing
to keep your eye on are, don't give them to much water as this will rot the
tubers, you can almost let the compost dry out, second keep a look out for the
greenfly and third check for slugs. Slugs will soon make a mess of the tiny
shoots, most people use slug bait, which I think could be detrimental to pets
and wild life, so as I've said I use a liquid deterrent, however there is
another way, and one I thoroughly recommend using it. Photo
Taking cuttings
We talk about taking cuttings So that I can take cuttings early, I grow my
tubers under fluorescent lights. This gives the tuber more light to grow and
produce more cuttings. I leave the lights on from 4pm to midnight each day and
as the evenings get lighter I move the afternoon time later and so on. The Dutch
farmers grow there tubers in the dark at a temperature of about 60 degrees
Fahrenheit the only time they get any light is for watering the tubers and
checking for disease and as they take the cuttings so the cuttings are yellow
when they are taken, but as they are moved into the Polly tunnels as the days go
by with in a week they start to green up. Some dahlia growers take part of the
tuber with the cutting so they root easier. I use a Stanley Knife blade to take
my cuttings I have a number of blades that I use, each time I take cuttings from
a tuber I use only one blade after I have taken all the cuttings from the same
tuber I clean the blade with a sterilizing solution ether methylated spirits or
the tablets that you get from the chemist for sterilizing babies bottles any of
these are ideal for this, I keep a small bottle ready made up next to the
propagating bench. The cuttings I take are about four inches long I cut them
just below a leaf joint, and then I remove the bottom two leaves. The compost
mixture I put them in is about half compost and half sharp grit sand, I get
about half a bucket of each and mix this together until I have made up enough to
fill a 75lt compost bag that will keep me going a day or two. Then I either put
the cuttings in individual cells depending on how many cuttings of the same
variety I take or I put 8 or 10 of the same variety in to one 3 inch pot this
way they all seem to grow the same height. I take cuttings right up to the end
of May as I can use these cuttings to grow on as pot tubers for next year. After
you have taken the cuttings and put them in the compost place them in the
propagator about 20% centigrade give them a good watering and don't water again
until the compost is almost dry, if they start to wilt you can give them a spray
over the top to freshen them up. If the days start to get sunny and very warm in
the greenhouse but it is still to cold to open the windows or door, you can
place some newspaper over the cuttings to shade them from the bright sunlight
and give the newspaper a spray this will help to keep the cuttings fresh. If all
the conditions are correct then the cuttings should start to root in about 14
days, the first cuttings you take from the tuber always seem to take the longest
to root. Don’t forget to keep your eye open for those pests; they will soon make
a mess of your cuttings. This year I was amazed at the outcome of an experiment,
I was trying to find out how soon cuttings would make root using various
methods. The one that stopped me in my tracks was a batch I rooted in
washed grit. When I tapped them out of the pot
they were all rooted, but as well as roots there was an added bonus of small
tubers, which are illustrated below, has anyone ever uncounted the same
amazing results? All this after four short weeks. (It's
the way he grows `em KES)
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| Cuttings rooted in 50/50 washed grit and Peat based compost | Cuttings rooted in washed grit only, had made tubers. |
Getting your plot ready
Now that the nights are starting to draw out, and after a day in the office or
factory it is nice to get out on to the plot and start to get the ground sorted
out. First if it’s full of weeds like dandelions and dockings you have to dig
them out and put them in the dustbin, it's no good putting them on the compost heap
as they will only start to grow again. Once they are all removed then you can
put the rest of the weeds on the compost heap. One of the best fertilizers you
can put on your plot is farmyard manure, or as the late president of the
National Dahlia Society (Derek Hewlett) did, go to your nearest zoo and get
some elephant manure I think they would be pleased to get rid of some. I put 6x
on my plot or a similar type, Rooster or any concentrated mix that you can get
from your garden centre. You can ether spread the manure all over your plot and
dig it in, or trench each row and put the manure in the bottom of the trench. I rotavate my plot twice, the first time opposite to the way that I am
going to plant my dahlias as my ground is very heavy, this way it helps to break my
soil up, the second time, as I rotavate I spread super phosphate on the ground.
25kg bag spread over 12 meters by 45 meters that's the size of my plot. Super
phosphate is used for making root at the start of the plants growth, so they get
established fairly quickly. As we are doing all this the tubers are making more
cuttings for us to take and the early cuttings we took may need potting up in to
a bigger pot so that they don't get pot bound. We must also keep spraying with a
systemic insecticide for all the predators that like the lush fresh plants. Some
of the plants will need to be moved from the greenhouse in to the cold frame to
start to harden them of, but don't forget the cool nights if there are signs of
frost you will have to cover the cold frame over at night with an old blanket or
carpet, and don't forget to take it off again in the morning. If, the day start
to warm up, open the frame a little to stop them from getting to hot.
Potting Your Dahlia Cuttings Up
Now that some of the cuttings have started to make root you will have to start
to think about potting them up in to individual pots. The best type of pot I
find as I grow a lot of cuttings is the 4 inch square pots as they take up less
room in the greenhouses. The first cuttings always take the longest to root as
the days are short. When the cuttings have rooted they are knocked out of the
pot. I pot them up in a compost mixture of half multipurpose compost and half
horticultural grit sand the grit sand helps to keep the compost open and allow
some weight to the pot so the pot will not dry out to quickly, and the roots
should be stronger If you do the mix this way when you finally plant out in to
the open ground the plant will get away more quickly than if you just plant them
in multipurpose compost with no grit in this way you will find that the plants
root are soft and fibrous and will be slow to get away in the open ground.
Separate the rooted cuttings from each other trying not to knock to much compost
of them then half fill the pot, take the cutting by holding the main two pair of
leaves try and hold it in the centre of the pot place the compost around the
cutting trying not to break any of the roots as this will knock the plant back
until it makes more root. Gently firm around the cutting then give it a good
drink. At this stage don’t forget to put the label in the pot, if you don’t you
will get mixed up with all the different types and you will have to wait until
it flowers before you can name it. Then place the pot in a cool shady part of
the greenhouse for a day or two until the plant gets established. Do not water
the pot until it starts to dry out, if you give them too much water at this
stage you will find that the small roots will start to rot. If the weather is
fairly sunny it will be advisable to put some newspaper over them just to take
the bite out of the sun. Continue to take cuttings until you have the amount you
require. As time goes on keep potting the cuttings up to build up a stock. As
the greenhouse starts to fill up you can move the first lot of plants to a
cooler place, the ideal spot is a cold frame to harden them of before they are
planted out in the garden. Through the day you can leave the frame tops open
slightly to let some air in If we get some cold nights they may have to be
covered with an old blanket or carpet to keep the frost off them.
Don’t forget to spray for greenfly and the dreaded slugs as they love the lush
growth of the dahlia plants tender green leaves.