As a general rule, the less soap the better. ;) For what it is worth, my recipe has ALWAYS been 1 tablespoon (or less) per gallon and that is the standard recipe that often comes up for discussion here. There is no standard recipe for making it in quarts and that is where much of the confusion comes from - that and the fact that many confuse the abbreviations for teaspoon and tablespoon. Personally, I would never use anything stronger than the 1 tablespoon per gallon as even that mixture, if applied too heavily, can easily kill plants. As to the soap - plain old Ivory, when you can get it, is good, plain blue Dawn dishwashing liquid (the original) also works with no problems. But the best, IMO is Murphy's Oil Soap simply because it also contains some oil and so sticks better. So, I have often used as little as 1/4 tablespoon of Murphy's Oil Soap in 1 gallon of water effectively. If the infestation got severe for some reason I would up it to 1/2 tablespoon but never more than 1 tablespoon per gallon of water. Then just pour it into a quart sprayer if you wish but don't mix it in the quart sprayer. As with all such sprays - never in the heat of the day, never in the direct sun, lightly mist don't drench, and aim for the bugs not the plant as a whole. ;) And, if in doubt go with a commercially prepared spray. Hope this helps. Dave

Here I am to keep the thread alive! First, thank you to all who've posted because while I did know the pencil cactus was poisonous, I didn't realize just how dangerous it could be if the sap got into my eyes. That said, I just purchased a large pencil cactus today that needs to be repotted. I don't have any pets or kids, so no concerns there, and I've already warned my husband. I'll definitely be wearing disposable gloves and protective eyewear just in case. @ Kevin Dondrea Also, peanut butter has been banned in plenty of schools... I don't know if you were being sarcastic? @ Larry WestCoast, You really had me going with that astroturf bit :D All in all, a good reminder to be vigilant with the plants around us. I'm a plant enthusiast, and even I sometimes forget to pay attention to the potential threats and dangers of different species. I'm obviously not eating any unidentified plants, but from now on I'll be more vigilant about wearing gloves and immediately washing my hands after yard work too.

I'm the one that has been spreading that news. Several years ago I had heard of this approach. I presented it here and on other forums but nobody ever tried it. Finally Cactus tried it and took a lot of pictures. I'd link you to the forum where he presented it but that's not really polite and I'm pretty sure GW blocks links to that forum. Here's a link to the youtube video that really shows how to do it. How much soap and molasses has been figured out by Cactus. Suffice it to day baking soda will kill crabgrass in a day or two; HOWEVER, it might also kill your grass. The results are not in for all grasses but for St Augustine, it works GREAT! St Aug is only slightly affected by the baking soda. Subsequent photos posted by Cactus show the St Augustine recovering nicely after 30 days. After Cactus' report hit the forum, Andy tried it on his grass in MA. He reported that the baking soda test killed about 75% of his northern mix grasses. So there is good news here for northern gardeners. If you are not worried about the surrounding grass, like in a flower bed, baking soda will kill crabgrass every time. The reason for the soap and molasses is to pretreat the hydrophobic blades of crabgrass so the baking soda will stick.

Yes. Most people put their cacti in soil instead 100% orchid bark. I would get cuttings, 100% orchid bark, and start new.