Question: Do blackberry plants need full sun, and what would they like that I can add to the ground to amend the soil?
Answer: Blackberries need full sun for good production. They arent particularly fussy about soil, provided that it is well drained. Manure or compost mixed into the soil may be all the nutrition that they need. Add lime, if needed, to bring soil pH up to 5.57.5. A light layer of organic mulch will keep the soil moisture even.
–Gardening experts George and Becky Lohmiller, Hancock, New Hampshire