Do you fertilize your dahlias?

Only with the water soluble Miracle Grow. Is there a better kind?

My "Arabian Night" suddenly did this too, bloomed well for a couple weeks and then all the new flowers in various stages of opening up seemed to dry up. I cut all those off and now the newest flowers are OK but nowhere near as black as the first ones, but more of a purple color. Any ideas?

Are any other parts of the plant visibly hurting?
It sounds like it might be botrytis. Cut off and dispose of or destroy affected parts and perhaps you can control it. I have one little dahlia in a planter box that is doing this: browning dry petals on not-even-open bud. I cut it off.

There are also tips for other common pests that plague the dahlia. I've already squished a couple crops of black aphids.
See the link below for anything of help.

Here is a link that might be useful: Scroll down for Cultural problems/tips

I am very new to planting dahlias. I just planted 8-12 inch plants with one or two blooms in a place that gets full sunlight. i used good organic soil and fertilizer. the plant seems to have taken and the leaves look green and healthy. the blooms are all turning dry and brown though! can you please help!!

thanks

sangita