They seem to do better in pots for me. My guess is the soil get heated by the sun better than the ground. Difficult to keep the soil moist though but not really an issue for Dahlia. Does not stop slugs eating them!

Hi pdb,
two questions here
(1) ref remembering the names of your Dahlias,
Why not do as kids do and give them names of people you know,
ie lets say you have a friend who's tall and her name is Sally!! then tag that Dahlia "Sally" and so on,
something thats in your mind and helps you remember size, etc.
"Even if your friend "Sally" should ever see she's a Dahlia "named after her! she'll feel good you think of her.
(2) ref Using pots and not direct into the ground,
If you use a pot thats wider than the tublers you'll not restrict the root growth, clay pot's are good for this method,
and ref keeping them moist, use a mulch around the growing Dahlia and this will help the ground above the pot from drying out and keep the soil moist (but still water & feed as normal).

Many thanks for your answers. Thanks Dungy for your funny suggestion re names. Good idea. Also another question - do I bury the pots in the ground or just simply place them on top and let surrounding plants camouflage the pot?

Any heat advantage of planting in pots will be lost if you bury the pots in the border, Pdb, so you might as well put them straight in the ground instead. What's critical is the blasted weather - the warmer and sunnier it is, the better dahlias respond, and I don't think anyone can be unaware that our weather for the past 19 months has not consisted of much of either. I'd have started them in pots in March, indoors, ready to plant out (after hardening off) at the end of this week - an early start means bigger plants and earlier flowers, but if you've not done that, I'd still pot them and start them into growth, get them going before planting out.

I'd leave in pots and simply pot the pot in the ground so the rim of the pot is just a little above 1/4 inch, you'll be able to see the pot when your going to take it out of the ground later on.

Bamboo yes totally agree re the weather. it is so disappointing considering the summer last year. I did start them off earlier in the year and they all have new growth on them. To be honest I've not had problems with the quality of the flowers think I've just not planted them in the right place due to me not knowing what colour or size I was planting . Think I will plant some but still hold some back for filling in when the border is looking tired. Many thanks

I just heard on the tv that this has been the coldest spring for 50 years. I'm relieved actually, I was beginning to wonder if it was me being older that I keep needing the heating on...

If it's any help,
Ive a well in the middle of our court yard and ive a bucket i use every year with Dahlia's in it hanging from the chain and roller,
and except for changing the compost i just leave the plant in the bucket and it grows.
It's about 8 inch high so far.

I always have mine in pots and place them where I need them to flower. I do the same with lilies. I half bury the pot then the watering doesn't become too much of an issue.

as for naming whilst it s good for your memory it causes genuine problems when plants are offered for sale. The latest magazine from the Plantsman talks of how misnaming is a major problem now. Plant heritage is important for future breeding programmes.

Rooted dahlia plants will grow fine in pots planted directly into the ground.
What happens is that feeding and watering roots grow through the holes in the bottom of the pot, so you don't need to water the pot itself.
If your dahlias are in 4 or 5 " pots that is the ideal size.
This is one of the methods used by exhibitors to produce pot tubers.
However, if you are planting tubers I'd plant in pots until you see growth, then plant the tuber in the soil directly.
I wouldn't leave it in it's pot.