I'm a beginner to this stuff also, so take my word with a grain of salt... but I think I can address a couple of your questions. First off, if the pot has good drainage, I don't see the harm in continuing to use it. I'd assume peak growing season is spring to early summer, when it is throwing new shoots left and right. I believe regular potting soil is a bit too dense for bonsai... perhaps mixing in some clean sand or peat would help. And... to remove tight plants, I loosen the soil from the edges of the pot with a dinner knife (gently, careful of the roots) then pull the tree up from the base of its trunk. I don't know much about root rot yet (yikes!) ... Best of luck! Tortoise

Definitely a euphorb. Probably Euphorbia trigona. cd

Hi dharini, first your cactus is going to like it on the dry side. You could water it every two weeks or so and see how it does from there and adjust your wartering. As for your cactus tipping over, sounds like your soil my be too wet or the cactus is top heavy.How tall is your cactus? Can you post pics for a better idea? Rigo

I think it should be "Mammillaria matudae". It depends more on the size of the root ball than the size of the plant, but it sounds as if it is time to repot it. The pot should not be too big, perhaps an inch wider than the root ball. A clay pot could be wider as it dries out quicker, I believe.