Good idea. I have a big pot with soil from a previous plant that is different then the soil my newest one is in... Will that matter? Also i just noticed on one of the leafs that the end seems to be slightly burnt or crusty. Can you give me some advice? And are you sure i shouldnt worry about the little orange spots? They are on all the leafs on the plant except the newest ones sprouting out the top.
Let me backup a bit and ask some questions.
What kind of soil is it in now?
Have you been feeding it nutes yet?
Do you have any more pictures, on the one pic you have I didnt notice it was on all the leaves?
How old is the plant?
Burnt tips usually mean over nuted, at the age it looks in the pictures you shouldnt be feeding it anything but water.
Never use soil that has been used before, all the good stuff has been eaten up by the previous plant, start each plant with fresh soil. As for mixing two different soils, hmmm...never tried that but I dont see a problem.
It looks like the plant is in a cup, am right?
Dont go straight into a 3 gal pot or what ever size you plan to finish them in, go from the cup to a 6 or 8 inch pot or so, so the roots can catch up. If its in too big of a pot for its size you can get root rot.