General questions for Mammillaria spinosissima

Discuss repotting, soil, lighting, fertilizing, watering, etc. in this category.
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Mrs.Deadpool
Posts: 3
Joined: Mon Dec 28, 2015 9:53 pm

General questions for Mammillaria spinosissima

Post by Mrs.Deadpool »

I just got my first cactus as a gift and found out exactly which kind it was. I wanted to do more reasearch on it and figure out somethings since I want to check it for mealy worms and repot it.

1) I've seen some info saying the soil should be mildly alkaline, neutral, or mildly acidic, which is the best? And whats the best recipe you've used/seen used for it? Im hoping for some specific brands since I dont exactly know what peat or grit is. Ive seen 1part John Innes No. 1 compost, 1 part peat, 1 part sharp sand or grit, and 1/2 part broken crock.

2) Its not much of a question, but any other tips and information you can give me would also be very appreciated. I'd hopefully like to get more and start a small garden but like I said I need a lot of help.

My boyfriend bought it for me in LA's floral district so im not entirely sure how well it was taken care of.
iann
Posts: 17184
Joined: Mon Jul 24, 2006 11:10 pm
Location: England

Re: General questions for Mammillaria spinosissima

Post by iann »

Soil type isn't critical. Avoid extremes. You don't want a rich organic soil and you don't want to make it too alkaline. So avoid peat and avoid limestone. No need to add peat to John Innes, it already has (more than) enough organic material. It may not be very noticeable, but that's just the right amount :) JI brands shouldn't matter much but they actually vary a lot. I use Keith Singleton's but it isn't easy to find. Others have their own preferred brands that they can access locally. You may not be able to find it all where you are.

Don't add sand either, just grit. Broken crocks are OK, but preferably broken quite small, say 4mm. Alternatives are crushed brick, certain cat litters such as Tesco Low Dust, or commercial clay granules such as Turface. Less desirable is perlite, which does the same job of maintaining air in the soil.

More tips:
- inspect carefully for pests, repotting is an ideal time to do this;
- don't overpot, just big enough for the roots;
- only water in summer, dry and cool in winter;
- allow the soil to dry before watering again.


M. spinosissima is a fairly vigorous species and will produce flowers easily, but it tends to get tall and then flop over.
--ian
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