Do you know what kind of fertilizer is best to help my geraniums bloom?
I'm happy to tell you that you can use the best fertilizer, which is one that has a NPK ratio of 10-30-10 or 15-30-15.
When I'm working with my plants, I like to use Miracle-Gro Bloom Boost and Schultz Plant Food.
Geraniums like nutrients like NPK, I totally agree.
I really think your geraniums would benefit from 200 to 250 ppm nitrogen. I've had great success with different types of fertilizers, like 15-15-15 from Geranium Special, 15-16-17 Peat-lite, and 20-10-20 Peat-lite.