This is my experience growing it for the first time this year.. They were hung outside from June thru to October, full sunlight, 8hrs a day, hardiness zone 5-6. From late July all thru early September, it rained here every other day. The soil in their pot was so saturated, it was like wet cake. Unbelievably, they did really good, and put on massive growth and sprouted numerous pups. I won't be repeating this next year though. Only did last summer cause I was laid up after surgery and didn't pull in my plants during those rainy months. Lost many Trichocereus species though.
Give it plenty of light when it grows, and water it adequately during summer, but don't overdo it (around once a week is sufficient). It grows best when it recieves lots of light, warm temperatures, and free flowing air.
Not sure, but I have purchased a smaller one that is grown from seed, once they seem to get to the thickness of your finger, they seem to grow quite quickly.
With a tail that long, you can cut it into many pieces and get lots of new plants from it. If you cut it near the base of the plant, you may get it to branch out like my plant.
I think the white bristles get slightly longer each year, but the spines do not. If the spine broke off but the areole is still in tact, it may be able to grow out again. If the entire areole came off, it will not grow back. If you've got a bald section on the plant and it looks really bad, you could probably get away with cutting it off and letting it branch out and grow new stems.
