Advice on Planting Dahlia's and Begonia's

Hi,

I wonder if anyone can give me some advice.
I live in Essex & this year I have 12 Dahlia and 18 Begonia bulbs/tubers to plant.
This is the first time at planting bulbs (I am a relatively new gardener) and have read conflicting arguments on various forums.
I would like to get the best and earliest start to my plants. Currently I do not have a greenhouse or a coldframe. I do however have a 5 tier growhouse (It cost me �£30 from the local Garden centre).
I have read that I can start the begonia bulbs indoors about a month before the last frost.
Is this true, and when do I know that the last frost has gone?

I have not found any decent advice when it comes to the dahlia's.
When can I start these tubers indoors?
On the instructions that came with the Dahlia's it say's 'plant from March onwards' , but then further on, under EXPERT ADVICE, it say's 'for early blooms, start the bulbs indoors in April' ???????

Can anyone give me any advice on when's best to start these two plants indoors and any general advice on planting.
I have already planned my garden plants this year and the Begonia and Dahlia's are a big part.
I was hoping to put each tuber/bulb in a pot, keep it indoors and when I start seeing activity, plant it outside in the final position (obvioulsy as long as it isn't too cold).
Am I wrong in thinking that I can get away with doing this?
If I do plant them in pots and keep them indoors, do they need to be on a windowsill, or just is a warmish room?

Sorry about this, but this really is only my second year of gardening, last year I bought all the plants from the Garden centre and it cost me a fortune. This year I'm hoping to save money and also put on a better show of flowers.

Also, I've found some good advice on planting the begonia bulbs (on the surface with the 'hollow' part facing up, but strange advice with the dahlia's.
I've read that they need to be planted horizontally with the eyes facing up. What are the eyes? I don't think mine have them, although they are still in the packets though.

Thanks in advance.

PLEASE HELP.

Regards

 

Hi Bashy welcome to the forum. I'm sure by the time you're back online some kind soul would have answered you request for help as there are a fine bunch of friendly people on here only too willing to help you out. Good luck with your plants. Hel.xxx.

 

Hi Bashy - and welcome to the forum. I have never grown Begonias. I do have some Dahlias, though I am no expert. However last year at the Harrogate flower show I did chat to members of the National Dahlia Society, who had a stall there.

First a Dahlia tuber is a swollen root. If you bury a single tuber - it will never grow. Growth only comes from the crown, which is the woody bit at the top to which the tubers are attached. The eyes are the buds, ie small growing points which will later turn into stems, and these can only arise from the crown.

You could just bury the tuber (ie whole lot) in the garden, when it gets a little bit warmer, and let nature take its course - and it will usually work. But The Dahlia Soc guys told me they start the process off by putting the tuber (ie whole lot) in a pot of damp compost, with the tubers themselves three-quarters covered, but leaving the crown above the level of the compost. This is to prevent the crown getting damp and rotting, whilst it is still in its dormant state. The growth will come from the crown, and when the new stems are three or four inches high its time to plant it out. At this point the crown is active and won't rot, so they said that you can plant it as deep as you like. Even if you totally cover the new growth with soil the Dahlia will still draw its energy from the tubers and is capable of continuing to grow quite happily.

You shouldn't plant the Dahlia in the garden till after the last frosts (which may be about the end of May - but your guess is as good as mine). You could put them in your growhouse perhaps a month earlier, but if there is a frost outside, even a growhouse can get very cold at night. You can start them in a pot indoors as I have described above. But there is probably no rush for a month or more. Once they have started to grow, they will need to be near the light. If they are on a windowsill you will need to turn the pot around every day as they will try to grow towards the light. The reason you don't start them too early is that there could be a long period before it is warm enough to put them outside. If you are able to look after the plants for this period in a greenhouse or indoors, there is no problem, but most of us are not able to do that for long.

 

Hi Bashy I leave my Dahlias in the ground after they have finished flowering and just mulch around them them as Peter says in the coldhouse might be to cold for them yet have you got a garage or some other dark spare room you could put them in put them in some boxes and cover with straw or newspapers give them a spray and you should see some growth in the tuber as it gets warmer
My begonias are in my conservatory all in wine boxes after taking them out of containers etc. I clean them and dry them and put them in the boxes cover them up I use straw and I spray them just like the Dahlias only lightl spray do no not soak them they may rot on my tubers now the eyes are showing and with the warmer weather they will soon grow have patience you will succeed

 

i am the last person to ask about dahlias i can grow em fine but i cant store them. a man told me to store mine in a box with paper shredding, and i did and checked them last week ooooh they was rotted to hell and wet through.so im still learning so any info i will be taking on board myself but heres what i grew last year

 

Hi Intermiplants - nice picture. I think the key is to make sure they are thoroughly dry before you put them away for the winter. This involves placing them upside down to ensure that the water drains out of the hollow stems. Or you could push a skewer through the bottom of the hollow stems and allow the water to drain that way. They also suggest you wash the soil off to remove any possible bugs and infections. Once they have dried for two or three weeks in the warm you can then put them in compost or shredded paper or whatever in a cool but frost free place. They mustn't be allowed to totally dry out and get shrivelled and dessicated as they will die, so you need to keep them just fractionally damp.

Its also suggested that you inspect them at intervals and remove anything that has rotted. But I have to admit that I don't do that.

Some people, as Nathan said, leave them in the ground overwinter in warmer parts of the country. This can work OK, but I think it is a bit risky as the threat in winter comes just as much from excessive wet as from cold. In fact that is true of many borderline hardy plants such as Penstemon. Its as often the wet that kills them as the cold.

 

Once you`ve washed the soil off, let the tuber dry and then treat with sulphur dust, this will help prevent them rotting. Bashy, if your Dahlias are in polythene packaging you need to take them out. Also, if you want to start them off indoors, then I would suggest you do it the end of this month.

 

Thanks Daitheplant,but they are all diifferent Dahlias. What's the best way to store them when they've been removed from the packaging?
Can I just lay them out on the floor and leave them there till planting.
Also, is it best to store in a cold room?

T|hanks to veryone who has helped so far.

 

I have grown dahlias for the past couple of years. If you are going to dig them up at the end of the season when the first frosts strike.Make sure they are dry before storing away. Also dust some sulphur powder over them to stop them from rotting.

 

Hi Bashy,
I have been growing begonias, the non-stop variety, for going on 5 years now, and still have my original stock,(around 40). At the end of each season, which in my area is late September, I take them from the ground and let the tubers dry off in the greenhouse for about 2 weeks. I then brush and clean them, picking off the dying stalks and ensure there are no pockets of soil remaining, and leave them for a couple more weeks beside my central heating boiler. When sure that they are really dry, they are then placed in polystyrene boxes, covered in a few layers of newspaper, and placed in the loft. In mid March I take them down from the loft and uncover and leave them at room temperature for 2 days. They are then placed in shallow trays (about 2" deep) indoors,in multi-purpose compost, and with the compost covering tops and any buds, by about half an inch and well watered initially, to get them going. After that only enough watering to keep the compost moist. I move them to the greenhouse around mid April and by early June they are ready to plant out in beds. I have had really good results. Hope this of some help.
Happy planting.

 

I wouldn't leave the dahlia tubers out in the open air. They will probably dry out too much and shrivel up. They might be best left in the packaging, there is usually some peat in there to keep them moist, without there being any free water which will make the tubers rot.

We've had dahlias in our garden, in Yorkshire, for at least 5 years. They were planted quite deep. (tops 6 to 8 inches down). They have never been lifted, and are thriving. I cut the stems down to stubs in the autumn when they have died back.

 

Beechleaf - that interesting that you've left yours in the ground in Yorkshire. But I am on heavy clay, and I wouldn't trust them to not rot.

 

Maybe, when you plant them, you could put a layer of gravel in the planting hole. That might prevent the "rotting" problem.

 

Good ides, I am always hearing them talk about that on television, Cajary - but I have never done it.

 

Yes, we are on sandy loam, and the soil in n never waterlogged

Leaving the dahlia tubers in the ground avoids all the problems of lifting the tubers, and storing them. They easily rot if damaged. I knew someone who lifted the tubers and sprinkled them with flowers of sulphur to inhibit rotting.