Q.stonecrop fertilizer
What should I use for fertilizer for my stonecrop? I have several varieties.

I live in Zone 4 also, and I have stonecrop throughout my garden. I have good luck using a light fish emulsion fertilizer once a month on my plants.

The plants need a low nitrogen fertilizer applied a few times in the growing season.
For more information about stonecrop, please visit the following article:
https://www.gardeningknowhow.com/ornamental/flowers/stonecrop/stonecrop-plant.htm