signal wrote:I would like to know how often to water it.
I need to know how often to water it, and any other care instructions that can keep the last piece alive. And is it possible to save the broken off part?
In the care instructions, it says to water 1 tablespoon/per month/per plant (if soil is dry). Is that a good amount?
The instructions say to set it in a saucer of 1/4-1/2" water for 10-15 minutes every month.
How much should you water? The basic answer is to water as much as the cactus will take without bursting or rotting. But how do you know when that is? You should water again when the upper-third to half of soil feels dry. But, really, this is a difficult question to answer, as there are several other factors you need to look at.
1) How well-drained is the soil you are using? It looks too me like it is either too well drained or poorly draining. What do I mean by that? If that is a peat-based soil, then water will probably bead right off, and you will really not be watering your cactus at all. If it is non-peaty soil, then the water will be standing in the pot, and that is a real cactus killer. Cacti require a well-drained soil to thrive. You will see a lot of threads on this forum about amending potting soil or mulch with perlite, pumice, and calcined clay bits. These all add porosity to the soil, encourage root growth, help distribute water rapidly throughout the pot, and retain just enough moisture for the roots to take in what they need. Check out the Cultivation Forum for tips on cactus soil.
2) Kept indoors, cactus soil will not dry out as fast as those in the outdoors or a greenhouse.
3) Also, cacti don't require much water--and some none at all--during the fall and winter when they are not growing. So, from about early September through early March, you should water very sporadically, and just enough to give the roots a quick drink.
4) Don't worry too much about watering instructions. Cacti are famous for their ability to withstand drought, and if it is well-drained soil, the plant can handle occasional overwatering. You need to find a happy medium (no pun intended
). By the way, the instructions for your glued down cactus are for bottom-watering (as there is no way to water it the normal way from the top). I highly recommend you remove the glued top portion and see what type of soil is there. Then begin a normal top-watering regimen.
5) Don't forget to use plant food, either mixed in with the water, or sprinkled on the top of the soil.
RE your Mammillaria, you should be able to root the fallen-off part, if it is healthy. Hard to say from the pictures, though.
RE the moon cactus, the top (the scion) can't survive without the bottom green plant (the stock). And, in my experience, they just wither up and die after a time. It is what it is.
signal wrote:I also have cactus seed, how should I go about planting it?
For this, I recommend you check out the Grown From Seed forum. There are several ways to go about it. I find the baggie technique to work great most of the time.
Good Luck! And if others have tips or corrections to what I wrote, please feel free to reply