When is the correct time tocut raspberry stems before spring and when should fertilize them?
Multnomah County Oregon
It depends on the type of raspberry you have. If it fruits heavily on the current year's new growth, such that you harvest in July, it is considered a 'primocane' raspberry. You can cut this type of raspberry to the ground now, or if you want a small crop in June, you can cut the top half off. If you have a variety that fruits heavily on last year's growth, that is considered 'floricane'. If you were to cut that type to the ground now, you wouldn't get any crop this coming year. For this type, you want to cut out the harvested canes in late July or early August.
I have both in my home garden and I cut back the primocane variety in December.
If you don't know what you have, then you are better off not cutting anything back and observing the growth and fruiting.
As for fertilization, I would wait until you see the leaves coming out. At that point the plant can better utilize the fertilizer.