I have one bristle brush cactus and a red-headed irishman. I got them about 4 or 5 months ago and it's starting to get cold so I'm just trying to figure out how to take care of them. My room gets pretty cold in the winter, so I was curious if maybe it was best to move them to a room where they'll stay warmer? Also, when I first got these cactuses I did research a little bit...I know that for different seasons you water them different amounts (or not at all) and I also read about a fertilization spray. Would it be smart to invest in this spray for my cactuses over the winter?
I had never heard these names before, but as I understand it they refer to Mammillaria pilcayensis and Mammillaria spinosissima. How, cold is your room in winter? I let the temperature drop to about 2°C where I keep my cacti, a little lower for the most cold-tolerant (I do not grow species that require higher temperatures, like Melocactus). I do not water them in winter, and I have just given them what I think was the last watering this year. All Mammillaria I know about (ok, they are not too many, I specialize in other genera) can be kept at temperatures close to freezing. Fertilization spray? I have not heard of this either. Sounds dangerous to spray the plants with fertilizer, as it may promote fungal attacks on the skin (of the plants). I add fertilizer to the watering can.
I do apologize, I should've included their scientific names. My room gets cold, but not that cold, I usually put the blinds down and a blanket over the window to try and keep some warmth (I have three windows on a corner of a house unfortunately) so they wouldn't have much opportunity for sun (when it's there) is that a bad thing? (that they wouldn't get too much sun) I was considering moving them into my bathroom but after thoroughly thinking about it I fear that heat from the shower may ruin them :( If I were to give fertilizer in the water, what kind of fertilizer would I use? At what dilution?
If they are dry and the temperature is low enough, around 10°C/50°F, they will not need much light. Some collectors even put their plants in a dark cellar or a refrigerator in winter. If it is too warm they will try to grow, and then there will not be enough light and the plants will become etioliated (thin, light green growth). They often contain enough water to be able to grow a little even if you don't water them. Storing them in a bathroom is usually a bad idea, both temperature and humidity are typically too high. I only fertilize in summer, at every watering and at about 1/4-1/2 the dose recommended for common house plants. The dose depends on how much heat and light they get. There is plenty of discussions on the Internet about NPK values in relation to the type of soil they grow in in habitat etc., but what I think is more important is to use a well-balanced fertilizer that contains the necessary trace elements. Works well for my cacti. The brand I use is not available in the US, AFAIK. I should mention that I never add any solid fertilizer to the soil itself, I believe that frequent feeding with a low-strength fertilizer is better than shock treatment.
Alright so my window treatments sound like they won't harm my cactuses. I watered them about two days ago, should that be their last watering?
Probably (it depends on the climate). At least they will not be harmed if you stop watering them now. I watered mine for the last time (this year) just a few days ago.
I can't tell you the exact climate but I live in Pennsylvania, US. Temperature outside is in the low 60's. Not sure about humidity, but it sounds like it should be their last watering. Thank you so much for helping me! Taking care of cacti is new to me, I hope to make it a new hobby of mine and I'm trying to learn as much as possible.
