I am not the Dahlia expert that some of the people on this forum, but ..........dont worry about which direction the old "stem" is pointed, its the new ones that count. I have read that pinching the new growth back to about an inch is best, then either point the new growth up or to the side (and they will find there way up anyway). I pretty much always lay the tubers on their "sides". The eyes (where the sprout is forming on the tuber) need to be 4-6" deep. If you tried to plant them vertically in a pot you would need a pot that is 12-16" deep just to get them planted.

As far as growing them in 8 in pots goes, that seems small to me, but it really depends on the type of Dahlia. The smaller varieties may be fine, crowded but fine. I wouldn't plant anything in a pot that has the potential to grow more than twice the height of the container. So they sure wouldn't work for Dahlias that get 4-5 feet tall, or even 2 feet tall.

The size of the tuber has almost nothing to do with the size of the mature plant. I have had Dahlias that shoot multiple stems, growing 5 feet tall from 3" tubers. Make sure you know what you are growing before you plant them up.

Yes, Mandolls is correct. The new shoots will find their way to the light, you should plant the tuber in the correct, horizontal or angled position. They are not too fussy. I would also pinch them back as mandoll suggested, back to the first leave node (you will have to splay them open to not pinch them all off because the leaves are not open yet). So in other words- I would plant them as shown in your pictures 3-6 inches (from the collar where the sprouts are coming out) deep.

As far as containers, she is right again. 12" pot for 3-4' dahlia would be crazy in that it would topple over. It is not so much the dahlia not blooming or looking sad, but containers need extra attention when it comes to watering, fertilizing and staking.

I have some small bedding dahlias (8" max height) in 20" pots and they do great, but you can see my ration of height to pot. The larger the pot, the more stable and less frequently I have to water.

How fun! Look at all your dahlias! They could be divided into many more for sure!

I hope that helps.

Keri~

I'm glad to see these photos as I received some that looked similar to these from Costco and didn't know whether to plant them in clumps or separate them. Did I do harm since I didn't separate them?

No, no harm from not separating them because they are so young.

We divide them to get more plants, share with others, keep their tuber mass managable to handle and to keep them blooming. When they get big (5-10+eyes) they tend to fizzle out on blooming and become sad because they have no room to grow.

Congrats on your new dahlias!

Keriann~

PS: dont forget to stake them, or mark were you can stake them, so you do not pierce a tuber later.