We have a raspberry patch in a sunny south side location. It is made up of everbearing plants from Starks. It is on automatic drip system and gets periodic fertilization. It does produce raspberries, but they tend to be quite small, like a quarter to a half inch at most. Some small ones become very hard and unusable. They are staked up. I'm trying to figure out what we are doing wrong, and why the berries tend to be so small. Only a very few are of the size you see in the supermarket. Any ideas will be appreciated.