Rebutia flavistyla problem

[habanerocat]

Do Rebutia flavistyla like a high calcium and alkaline environment?

No

Is calcium basically the same as limestone as far as cacti are concerned?

[el48tel]

Do Rebutia flavistyla like a high calcium and alkaline environment?

No

Therefore not a good idea to use raw bone meal.

[SimonT]

I've recently tried a few different conditions for growing R. flavistyla. In the end I liked best using pure John Innes seed compost for seeds and very young plants, similar to the method Paul D described recently on this forum. Bigger plants seem OK in a simple compost of 2/3 John Innes no2, 1/3 extra drainage (I use an even mixture of perlite, grit and/or Tesco's low dust cat litter).

[ralphrmartin]

You'll do best with your Rebutias and many other South American cacti if you grow them in ericaceous compost, as there is not much limestone in the Andes. I use a mix
JI Ericaceous compost / Coir / Granite grit
in equal parts. I also feed withe Ericaceous miracle grow.

[SimonT]

I guess there is a difference between compost that is sufficient to support the growth of these plants and compost that might be closer to providing the optimal growth conditions. But still, I'll certainly try this mix against what I normally use.

[habanerocat]

Said I'd just add to this thread as my problems continue on most of my Rebutias. Common signs are the browning and the missing ring of spines. But the latest manifestation is this weird growth on some heads, new or old.

I've re-potted most of them this spring but it's like something has gotten into the plants, like a poison.

[SimonT]

It is hard to tell from the photos but the problems that you had previously might be growing out? Mites for example can cause damage near the shoot growth tips. After the infection you get a ring of damage that slowly moves down the plant. If there is a lot of damage the growth tip does not continue to grow but instead you can get an offsets replacing it. This might be happening for you here?