Growing dahlias from seed.

andygb

About three weeks ago, I bought two packets of Thomson and Morgan dahlia seeds, and planted them in the long window containers with clear lids. The are 60 plants in all, and 56 of them have developed into healthy looking seedlings between 1 and 2 inches high.
When I looked on the net for advice, it says to transplant them to pots when the "proper" pair of leaves has appeared.
So can anyone else give me some advice on this, because some of the seedlings look as though they now have to be potted on from their little plug tray.
Cheers.

suisidevw

Have you got any pictures? I normally move them into 3 inch pots when they are a couple of inches tall so sounds like you can go for it now

Davesnave

Yes, 3" pots if you're old school, but 9cm square pots if you are a trendy young thing like me.....:D Dahlias grow fast, so they will soon get their feet into pots of that size.

I like the square pots because plants can go one in each corner for a short while if space is really tight. That's where my tomatoes are at present. They'll get their own pots in a week or so, when there's less danger of them being frosted.

Some will say that's moving them twice, but mine have never complained.....and they'll move again, and probably again after that.

andygb

suisidevw wrote: »

Have you got any pictures? I normally move them into 3 inch pots when they are a couple of inches tall so sounds like you can go for it now

Thanks, I may well do that this weekend. Is it also a good idea to take the clear lid off during the day. They are North facing and the windows are shut, so I suppose the temperature is around 18C.

andygb

Davesnave wrote: »

Yes, 3" pots if you're old school, but 9cm square pots if you are a trendy young thing like me.....:D Dahlias grow fast, so they will soon get their feet into pots of that size.

I like the square pots because plants can go one in each corner for a short while if space is really tight. That's where my tomatoes are at present. They'll get their own pots in a week or so, when there's less danger of them being frosted.

Some will say that's moving them twice, but mine have never complained.....and they'll move again, and probably again after that.

For the second stage in the 9cm pots, would you use seed compost or a mixture? I have seed compost in these trays plus a thin layer of vermiculite on top, and I am pleased with the results at the moment.:)

A._Badger

andygb wrote: »

For the second stage in the 9cm pots, would you use seed compost or a mixture? I have seed compost in these trays plus a thin layer of vermiculite on top, and I am pleased with the results at the moment.:)

Don't pot on into seed compost. A good seed and cutting compost is deliberately low in major nutrients, which isn't what your germinated seedlings will need.

You can either take the modern, easy, route of using a good multipurpose compost or, if you prefer to use soil based John Innes types, move them into JI No 1, using No 2 for the potting on after that.

Davesnave

I agree with the above, though in my imperfect world, something unfussy, like dahlias, would probably get last year's tomato compost mixed with some slow release fertilizer granules.

Dahlias are great fun from seed, especially from one's own favourite plants, as they won't breed anything like true. Many surprises, if you have the space.

andygb

Thanks for all the replies folks.
I have some compost left over from the growbags which I used for the courgettes last year, and it looks quite healthy and not too claggy, so I suppose that would be OK.
I suppose that these dahlias are different to the ones which I grew from tubers last year aren't they? By that I mean that these are probably a one off plant and that they will not appear year after year.

suisidevw

Yes.... from the seed that you sow today, this will grow into a dahlia and when you take them out of hte ground in November/Decemeber, there will be a healthy tuber underneath! You can then use these to replant next year. I do this year after year and always successful

Davesnave

If you take seed from varieties with attributes you like, there's more chance of getting something 'good.'

For example I have had some super smaller plants from Dahlia 'Plum Pudding'.....but I've also had tall ones too and others with the 'wrong' foliage. So, it pays to be ruthless and start destroying anything you don't think is up to the mark, otherwise you'll soon be drowning under mediocre dahlias!

Keeping seed is beneficial, because if you have a winter disaster with the tubers, there's always something to fall back on.

andygb

This is all sounding quite good, and I know what you mean Davesnave about weeding out the runts of the bunch, because I am already wondering what I will do with nearly sixty dahlias.