Many Mammillarias are shallow-rooted - this is obviously one of those, since it was able to grow so large in such a cramped pot. The pictures of them in habitat DaveW linked to show them growing in rock crevices with very little soil. Do give it a bigger pot, but not too much bigger - less chance of...

Much quicker just to bookmark the post you want to come back to.

Bacillus thuringiensis israelensis (Bti) is a bacterium which used to kill the larvae of mosquitoes and fungus gnats. It's available in mosquito dunks, granules, liquid and powder. I would get the powder - mix a little into that cactus mix and seal it up. It will kill the larvae, not the adults - bu...

I like to stick in some larger rocks where there's space, you can easily pick one up and check under it for moisture. Much easier than digging through a layer of pebbles.

The first one looks almost like Echinopsis calochlora, except for the dark central spines.

The problem with identifying these is that not only is E. oxygona highly variable, there are also many related hybrids.

A number of them look like they would have had the seed leaves dried off by now if they hadn't been watered, so I figured you were still watering. Some of the late sprouters may not survive, but you could stand to lose a few. Might not be many lost, anyway, it's amazing how they can survive without ...

I suspect the orange marks are just scars, some species produce that kind of pigment in response to surface damage. Don't know about the blotchyness.

I agree with MrXeric, but don't be too concerned - Opuntias can shrivel quite a lot without harm, as long as it's still green no problem. It really needs that sun, sunburn is the only real hazard to pushing it too fast when it's not used to the hot sun. I see no sign of sunburn. See: https://www.cac...

When they're splitting, you need to withhold water until the old leaves dry up.

The exact origin of the hand-cranked ice cream churn is unclear, but a US patent was issued in 1843. Prior to its invention, ice cream had been beaten by hand in a large bowl set in a tub of ice and rock salt - the ice cream produced this way was much less smooth, containing ice crystals. Really not...

I found this site: https://www.globalseafood.org/advocate/atmospheric-carbon-dioxide-freshwater-aquaculture/ ...Which explains how CO2 forms acid in water, yet it can raise alkalinity in water. The explanation is a little confusing, but if I understand it correctly it's because the CO2 increases the...

Ice lollies can be just flavored ice or ice cream - the former are generally known as Popsicles in the US and Canada (a trademark name that is used generically). or as an ice pop, whille the latter are called ice cream bars. The Posicle concept was patented by a man from San Francisco named Frank Ep...

Carbon dioxide dissolving in water will produce Alkalinity in perfectly pure water very rapidly. Afraid you have that backwards, Jerry - CO2 reacts with water to produce carbonic acid, which makes rainwater weakly acidic. I live in Norway and so far haven’t been able to find pumice locally, even wh...

Great!

Just water, it'll straighten up. Opuntias can be so dehydrated they lay flat, when they get water they stand right up.