If you want to feel a bit safer about not rotting the unrooted cut trunk, you can let it air dry for a longer period of time by setting it within a 15 gallon sized black plastic nursery can and allow the leaves to support the plant's trunk within the pot. I've done this with mature cut Agave attenuata, and left it in a bright shaded spot for a couple of months to form roots before replanting. This extra step may not be necessary for you in southern California, especially if you have good draining soil and not pure clay. Now is as good a time as any if you don't get frost in your garden, as this species is pretty much in active growth mode year round. I find that chopping the mother plant is often a necessity when it has been forced into a space too small to accommodate its natural tendency to lean out towards the light as it grows. They do reroot pretty easily, although you may lose some of the older leaves from moisture stress until it forms new roots. I usually cut the trunk so that there is at least a foot of clear trunk below the lowest leaves, and also remove several circles of older leaves after cutting, as they are likely to wither and yellow in any case.

Adding sand to a potting soil mix is not usually a good idea. Sand is not coarse enough to improve drainage with typical potting soil ingredients such as peat, bark, or coir, it will just weigh down the soil and clog up the spaces which already exist. In these soils you need a very coarse, and preferably light, aggregate such as pumice or perlite. Grit is sufficiently coarse but can collapse "fluffy" soils such as peat. Sand can improve the drainage of loams, that is soils which are based on clay. In circumstances when high levels of clay particles cause a drainage problem, the drainage can be improved by adding enough sand that the clay particles are kept apart and air pockets are maintained. Cacti and succulents are often grown in loam soils, but in a pot even a sandy loam generally has insufficient drainage and a more coarse material such as grit is also required. In summary, sand will rarely help drainage in a pot, use a material with larger particles like pumice, grit, perlite, etc.

Welcome to this fabulous hobby - as you're finding out, these plants grow well in temperate zones (at least in the summer). Once you get these down, you'll want to expand your collection to include cold-hardy stuff, too, but what you have is a good start. 1) Because they worship at the altar of Mammon and don't really care about the plants. 2) Warmth, some air movement and bright light (most of the day), along with a daily spritz, will get these cacti pieces rooted - then you can pot them up. 3) Pictures would be great, but that sounds all too true - they're called glufers and I hates 'em forever (said in a Gollum voice). It sounds like you're doing things right - you might look at some of the posts here which have lots of responses, as it offers you a greater chance to turn your sponge into a Shamwow and get a lot of exposure to these plants of ours.

Due to time constraints, I was only able to visit one nursery during my weekend visit. We went to Grigsbys. This was a typical place where their main emphasis is mail order or wholesale, not retail. That means it is not very well kept, plants are not very organized and parking is very limited. You wander up and down the place, walking through several greenhouses, then if you find an interesting plant; it is not for sale, because it doesn't have a price tag on it. Anyway, I purchased three plants from them. First an Euphorbia Aeruginosa, minor an Euphorbia Genoudiana and finally, a Pachypodium Namaquanum Thank you to you all who gave me the info. in finding this place. I will go back if I happen to be driving thru the area or visiting nearby.