We use good old farm fertilizer 10-20-20. It works on just about anything- flowers, fruit, berries & veggies. We get it at the local farm Co-op.

10-20-20 works for me in Maryland. You should have seen the Farmer John I just cut. Steve in Baltimore County.

Well, Steve, we could see it if you'd take a picture & post it :)

Yea Oscar where are the pictures.

I don't know how to post pictures. Steve in Baltimore County.

Soil test should be done and then set up fertilizer program based on the results. Without a soil test, there are two choices: (1) if you are growing dahlias in an area that has not been fertilized in several years, use the 10-20-20 that the others recommend. (2) if the area has had lots of fertilizer applied in previous years, use only a high nitrogen product. A typical lawn formulation (without weed killer) would do well. Urea 46-0-0 is the farmers best source for nitrogen and is used by many dahlia experts.