help!! my cactus is falling over
I have a 35 year old cactus, approximately 18 inches tall. I put it outside during summer so it blooms. anyway, I have noticed it is leaning pretty drastically, and keep turning it towards the sun to straighten up. but I also noticed that the base of the cactus is narrower than the top and that is where it seems to be bending over. how can I remedy this problem? plant deeper, plant in a larger pot? please help!!