Best time to repot a mammillaria?

[stephanelli]

So I have a lovely Mammilaria backebergiana that I've had for a year and a few months now and its big enough to produce lovely flowers at this time of year. Here's a picture of her so you can better understand my description below.



However, it needs repotting into a much better draining mixture. I repotted it when I got it about a year ago into a commercial cactus compost (I didn't know any better at the time) and this takes forever to dry out. It rewarded me with beautiful flowers last year almost straight away and it has rewarded me with beautiful flowers this year (the first stem started flowering in March and finished early April, the second stem started flowering a few weeks later and still has a few flowers and the last stem is still budding and blooming quite happily.

My experience with other non-cacti plants tells me that I should repot it when it isn't flowering and also that Spring is a good time for repotting. Does this hold true for cacti? Given its in flower for most of Spring, should I repot it after it flowers, or wait till very early Spring next year when it is in its growing phase just before it flowers? Or is there another better time to do it?

[ElieEstephane]

I'd say now is a great time to repot. Do so following the advice given here: http://cactiguide.com/forum/viewtopic.php?f=25&t=40641
Cacti do not respond to minor stress like other plants and can even flower without having roots. Either the flowers finish and stop or the repotting stress can induce more flowering.
Btw it looks like it could use more sun if that is possible in the UK

[stephanelli]

Thanks for your reply and the link to the repotting thread (I've used that advice for some of my other cacti recently ) I will do a repot soon then!
Unfortunately it does need more sun (it doesn't live where the photo was taken, but I agree) and its getting as much as possible, we just don't have much sun right now I'll see how whether it improves over the summer otherwise I'll be looking into some growlights.

[7george]

Almost any time is good for repotting of such a cactus, just keep the soil dry some time before and after this manipulation. The plant even may not feel the change if you don't rotate it or move to another spot. I usually change soil in winter months or early in spring when plants do not grow and will have plenty of time to heel damaged toots.

[stephanelli]

Thanks for the advice about keeping the soil dry before/after, 7george. I'll wait for the soil to properly dry out before repotting, I wait for it to dry out before watering again, but as mentioned before, it takes a while to dry out!

[DaveW]

As Ellie says it looks rather lush. Either it could do with being in stronger light or a bit less fertiliser to grow it more slowly? I presume you are giving it a bit of a cooler rest in winter and not trying to keep it growing all year, though that can be difficult these days in overheated central heated rooms in winter?

[greenknight]

I agree with the previous advice posted. Damp soil is okay when transplanting, but it shouldn't be very wet. It does look overly lush to me, too - could be because of spending too much time with wet soil.

[stephanelli]

Thanks for the advice and comment, really appreciated! I'll see what I can do to help my poor plant
DaveW - Yep, it gets a winter rest in a slightly cooler part of my house (my house is slightly strange and has a cooler extension which is perfect for overwintering cacti). I will see what I can do to gradually increase its light levels, although we might have to wait until we're not in cloudy weather...

[DaveW]

Will the 2018 season ever start in the UK Stephanelli? My plants are at least a month behind normal. We had a "two day heat wave here in Nottingham", meaning the sun did come out for a couple of days and now it is back to cold and overcast. The trials of growing cacti in the wrong climate!