I've been using the water soluble Miracle Grow (the bloom enhancing kind). Not sure if this is the best way to feed them.
I've seen a couple of posters say they use Tomatoe food. I dont really know what to use because my dad is a fertilizer salesman, he comes home and says "Put this on them" and I do and they grow. :O)
I'm using a 10-10-10 granular 2 month fertilizer. Used to use Osmocote and would again if I hadn't bought a huge bagful with too high of a Nitrogen concentration. In mid to late July, I'll use MorBloom liquid to improve bloom production- that's the theory anyway. I used it last year and couldn't really tell if it made a difference, but I had plenty of flowers.
I have used the Miracle Gro too. The bad thing is I've noticed ALOT of grennery. That can be bad for air circulation for the plants. Also I woukd suggest being careful about how much nitrogen is applied. It can burn the plants. Been there, done that.
The Michigan Dahlia Assoc. literature says DO NOT use Miracle grow types fertilizers. Avoid Compost,Fish fertilizers and high nitrogen water soluables as they promote weak stems,small blooms or no blooms at all. Use high percentage potassium and phospherous such as 5-10-10 or 10-20-20
Hi, I use a variety of foods...ALL organic...NO MIRACLE GRO on anything...Try Whitney Farms all purpose, Dr. Earth, E.B. Stone, MaxSea...I pick at least 2 bucket fulls of blooms every day, and only 1/3 are in bloom at present! I also use a fertilizer called "Oragnic Advantage" which has humic acid in it...OOHHH and I also use compost tea.