The best spot to plant?And a few other bed prep questions...

I've learned a lot about dahlias this year. Well, more like, things NOT to do next year! The most important thing I learned is where the sun hits in March (my planting time) is different from month to month, sometimes even week to week. I don't have much to my back yard, which is where I have to plant-too many trees up front. I have one side that receives full sun, 8-10 hours, which is where I planted the majority of my dahlias this year.
Well, this was wonderful in March, April and the beginning of May-they grew quick and bloomed prolifically. However, end of May, June, July, August it was just too hot and the sun too strong for them. Every other spot seems to get too much shade (I think?) at some point or another-whether it be spring, early/late summer,etc. But, those spots do get a few hours of early a.m. sun and late p.m. sun-is this enough?
Do I just plant where it's shadier and hope for the best, since I definitely know they don't too well in the full sun spot?

Also, when should I dig in my compost to prep the beds? In the past (like I said-still learning), I have just half-heartedly mixed it and amended it here and there, never fully prepped ahead of time.
Thanks for any help!

Carrie

I'd prepare planting holes a month in advance of planting new dahlias next year.

You might be able to containerize some dahlias if they don't get too tall so you could move them to the appropriate area when they're at risk of getting too much sun. Otherwise I see no alternative but to give them partial sun and hope for the best.

I have quite a few of the lower dahlias (about 2' tall) in partial shade and I still get lots of blooms. They only get early morning and very late afternoon sunshine.

Thank you-I will prep beds accordingly.

I tried a lot of them in containers this year and they all rotted-dang it. I used very large containers so, if they grew big quickly, I could just leave them in their pot. Yeah, then the monsoon rains came and the pots were too big to move-lol! All that rain plus the potting mixture I made held too much water.
I guess I could rig some kind of covering...I tried it in another area of the garden and it worked. I think my growing season is just too long here (don't hate me for saying that) and maybe they weren't meant to keep going for 9-10 months???
Thanks for your help, pirl.

They are perennials in Mexico so I guess they can keep growing all year. Those monsoon rains are awful for dahlias, great for cucumbers.

Oh...I didn't know they were perennials there. I think that's where I went wrong. I thought, since they were native to Mexico, they would do great in FL sun, not accounting for the cooler nights there, but not so much here! Doh!

Any chance of doing something like this?

http://www.dahlias.net/dahwebpg/Soil/Soil_04.htm

LOL-I WISH!!! I do, however, have a better chance of doing the pvc house in dnut's pvc link. I may do that, or the "dahlia dorm" I did earlier this year. But, I have to tweak a few things to make it more effective.

TY, guys-

Carrie