Starting Dahlia Tubers For Cuttings

Hi, Just want to make sure that I am doing this correctly as it's my first year for taking Dahlia cutting from tubers

I half buried the tubers in normal multi compost and then sprayed (misted quite well) them and the compost with water, put them in a propagator, with the temperature set to 19.C

My main concern is should I keep misting them so as to keep the compost moist
or should I wait until they start to show some grow?

I guess the hope is that being in a propagator that in it-self should create a high humidity and keep them moist.

 

All look snug in there Intel.
Just watch out for fungal activity that will make the new shoots sick. I think you spray them with Bordeaux mixture ? Someone who knows will be along later to give good advice,
Jenny

 

Just tagging this post . I want to try dahlias from tubers this year ,and know absolutely nothing about them. Very nice set up you have there by the way Intel

 

Hi Intel

Very nice set up what make is it ? , I normally do mine closer to March other wise I have too much stock in the greenhouse waiting for all the frost to finish before planting out May in my area , 19c should be ideal as not too warm as you want the cuttings not to be leggy when you take them , have you a grow light ? light levels at this time of year are very low , misting should be fine once a day in the morning so come night time they are a little drier , general fungicide spray comes in handy just in case they get Botrytis especially in a propagator I would keep the vents open a little as the heat will be in the compost just where you want it for now . Keep a eye out for slugs as well.

But all looking really good so easy to take cutting especially of the ones you want to bulk up, the growers normal keep most of the cutting in 4/5 inch pots to sell the tubers the following spring keeps them at a manageable/uniform size.

Spruce

 

First task is OK

Looking at the condensation on the propagator lid suggests that all is well and further watering/misting is unnecessary.

Agreed as I intimated above!

Its when you come to take cuttings that watering becomes more critical!

What you must remember is; the cuttings have NO roots initially so they are not really taking in moisture from the compost.

In fact if the compost is too wet and not open textured enough the base of the cutting is likely to rot! (botrytis)

All they require is keeping the leaves moist so they do not transpire too much!

In fact if the leaves are rather large cut the top half off and this will reduce transpiration!

I use a pump spray containing a fungicide mixture to mist my cuttings,this does two things it keeps the leaves moist and reduces the risk of botrytis forming.

The other thing is during daylight and subject to the ambient temperature I find that removing the propagator lid allows air around the cuttings to dry them off but still maintains bottom heat!

If the ambient temperature is quite low then open the vents fully!

This is quite a large subject so rather than rewrite what I have already written let me link you to how I do it;

http://www.thegardenersalmanac.co.uk/Data/Dahlia/Dahlia.htm

 

As advised and also due to the condensation on the propagator lid I have not misted any further.

Thank you for the link, you have a great site there

Now I can see why Dave Gillam starts his tubers in January as it could be
up to 8 weeks before I can take a cutting and then the cutting has
to develop, which then takes us into April / May, still they are fast growers

Had a trip to Dobbies this afternoon and they were selling Vitax Bordeaux Mixture - but I don't know if this what I should be applying to the cutting?

Hi, I cant remember the make but there is a model number under the propagator and will have a look next time....but it is big about the size of a small coffin
and uses about 100w of power when its on and was only £65 on Ebay

I don't have a Grow light, they are just sitting in a propagator which is in the greenhouse, but the greenhouse does face West and gets as much
light as possible, its only 6 x 6 but one or two of the glass panes
need to be cleaned.

At present the vents on the propagator are about 1/2 way open


The other thing that people should consider is the running costs, I have
3 other small propagators on the go as well (but for other seedlings) and have a watt meter fitted as I was worried about the running costs, the larger propagator uses 100w and the smaller ones use about 65w in total

But the bigger one is more cost effective as it has a temp display and just switches on / off as required whilst the others are a lower wattage, about 20w each but are on all the time........the running costs for the 4 propagators is about 3.5 kw per day

so about 50p per day - so if I have them running for 8 weeks it will cost about £28.00 plus The greenhouse will need to be heated for the seedlings that are not in the propagators :(

Still a great hobby when you see the end results

 

2 weeks, First shoots - Ryecroft Brenda T

 

Lovely sight to see isn't Intel.

I see it as promises of things to come

This is a picture I too earlier this week;

 

Don't know how other people have been getting on but mine have been very slow, the greenhouse was unheated, even through they were sitting in a propagator the temperature struggled to stay at 19.c

Plus also I may have messed up as I read that its best to put on a small bed of sand on the base of the propagator and let the heat filter through the sand onto the trays.

I think this really slowed down the growth but it may have also been the snow / bad weather we were getting for the past few weeks......anyway I removed the sand from the propagator and sat the trays directly onto the base, plus as the greenhouse was getting crowded and the propagator is really big and takes up a lot of space in the greenhouse, so I moved the whole lot to the conservatory last week and since then they have shoot up

So far I have managed to get 6 cuttings (sad I know) and some of the other tubers have not even shown any growth so far

The only other thing that worry's me is that so far I have only managed to get one single cutting from the Winholme Diane Tuber and that had a solid trunk and was not hollow in the middle, if you look at Dave Gillam's Videos on Youtube he says that he finds when a cutting is solid and not hollow in middle, these generally take a long time to root and he tends not to bother with these

Also there is a really good book written by Philip Damp called Dahlias The Complete Guide and in his book he says that when taking a cutting, you should push the cutting right down to of bottom the tray and the depth should be at least a inch, a really good read if you happen to come across this book


I have learnt a lot from this and next year the greenhouse is going to be heated with a gas heater as I don't think a propagator is enough in bad weather in a unheated greenhouse and I guess I never realized how long it take's to get to the stage where you can take cuttings But the bad weather has maybe played a big part in this.

 

Mine have been glacial. They have been in the boiler room for nearly a month now, and only a few have sprouted.

Dunno if you have space, but worth having them in the house until they sprout. Much cheaper to run a propagator (if you even need it) in a centrally heated house than in a greenhouse.

Sand in the bottom helps spread the heat, so you don't get hot-spots, but it needs to be moist.

I have zero so far this year. This time last year I had dozens of rooted cuttings ... you'll fare better in years that are more "normal"

Interesting. I have always thought that hollow cuttings won't root.

Biggest mistake I make is being impatient and taking cuttings that are too small. I take mine just above the bottom leave pair, trim to just under the leaf pair above that, trim off all bar the top couple of leaf pairs, and then insert them up to the lower leaf pair.

The more typical advice is to cut them off the stem with a bit of stem as well. I find mine root almost 100% and the buds from the leaf pair I leave break and give me two more cuttings, whereas having to wait for a bud to break off the main stem takes longer. In a good year I get two "rounds" of cuttings before I need to get the mother tubers planted out. I'll be lucky to get one this year at this rate!

Definitely. Don't make any assumptions, or beat yourself up for any failures, this year. My advice would be to try again in a better year and then you will surprise yourself how well you get on

 

Its amazing how quick these grow, took a cutting from Winholme Diane on Wednesday night and 3 days later, its grown a side shoot which is now just 1 1/2" long......I assume that you can keep going and take cuttings from that side shoot as well?

 

Yes. Probably best to stop around beginning of May, maybe a bit later (e.g. for any variety that has been slow to produce the number of cuttings you want), then the mother plants can recover and put on a bit of growth, be hardened off, and planted out towards end of May. All that can be earlier if you are in a warmer part of the country (but I don't see any point planting out when the nights are still chilly, it just slows them down)