Is there anything wrong with these L williamsii?

[Grimm]

My housemate is concerned about the growth of one of her Lophophora williamsii, she thinks I may have overwatered or something (even though they only get a couple of waters a year) as it has lost its round appearance and looks over-stuffed. I've put photos from 2009, earlier this year (2016) and today.


As arrived in the post in 2009, re-potted straight after this!


Earlier in 2016


Earlier in 2016


Today

Also, one bought in 2012 that had a blemish/rot mark and doesn't seem to have grown since, any ideas about what to do? She bought a couple of others at the same time and they have grown (albeit slowly!) I think it just needs new soil!


Rotten/blemished williamsii in 2012


Rotten/blemished williamsii in 2012, potted (yes, I know I can't spell peyote on the tag :p )


Rotten/blemished williamsii in 2016


Rotten/blemished williamsii in 2016


Rotten/blemished williamsii in 2016

Cheers

[toadstar]

They look pretty good. They might be a bit over potted though.

[adetheproducer]

They look great but as toadstar said very over potted. I would put them in much smaller pots just bigger than the plant it self. Over potted cacti can take too long to dry between watering and may lead to problems such as rot.

[Grimm]

Thanks

Yes, I know the pots are big for them (especially the younger one). It's mostly to make sure there is space for the taproot, whilst sticking to the terracotta she wants rather than plastic. They do taper down a lot though. It's why I have to be so careful with watering! These past two years have been the worst, because we've had very high humidity. I'll have another search around for smaller un-glazed ceramic pots that can take the taproot.

[adetheproducer]

I would stick to plastic pits and our mineral mix. I guess you are using terracotta pot to dry quickly but a smaller pot and loose mineral mix is fine. I use 7cm and 9cm square pots and for mine and they dry really quickly also plenty of room for the tap roots.here take a look.

[greenknight]

If you can't find small pots that are deep enough, you can take up some space with a few large rocks - leave a well in the center for the tap root, with rocks around the sides.

Non-porous pots are better for the plants, I agree.

[Grimm]

It was for evaporation at first, especially as they live on a windowsill (therefore low air flow) but now it's more of a "if it's not broke, don't fix it" kind of thing. She has, however, agreed that I can repot the little one in spring in a non-porous pot and mineral mix and see how it goes.

Her soil mix is

1 part seived and baked/sterilised peat-free compost (very fine)
1 part washed sharp sand
2 parts fine non-porous aquarium gravel - the same stuff that used as a topping in the photos.
Edit: I forgot, also 2 teaspoons of powdered shell

I personally think it drains slower than my mix (1 part seived John Innes #2 and 1 part fine non-porous aquarium gravel), I suspect the sharp sand is too fine, but I've not done any proper tests to make sure. I also don't have any taproot cacti myself, so can't really compare.

Edit 2: We also live next to the sea, so humidity can be a problem (especially these last two years for no apparent reason), it can mean that neither the pot nor the cacti evaporate/transpire much water.

[adetheproducer]

I would forgo the soil and sand completely they are not really needed. I use a mix of mainly limestone chippings, granite chippings, cat litter(the backed clay type from tesco the cheeper one there), lime free potting grit and sandstone chippings and various other rocks including lava rocks and pumice etc. Most can be found in your local garden centre or go out into nature and do a bit of collecting. I crush larger rocks by hand with a lump hammer so the average size chippings are about 8mm then stick a couple of larger lumps in the mix as well, the different size rocks and chippings is good for root growth. You may want to sieve out the fine dust or any bits smaller than about 1mm, I use my kids toy sand sieve you know plastic ones for the beach. The end result is a very free draining, mineral rich mix which should supply the plants nutritional requirements and no worries about the soil being damp too long. I just water with rain water from my barrel catching the run off from the roof which should supply the nitrogen requirements the plant will need so no need for fertilisers either.

[Grimm]

Here's the little one de-potted, earlier than planned:



So, very little growth in 4 years and obviously in need of a drink - the old soil literally poured out of the pot, bone dry. We're going to try a mineral mix.

[adetheproducer]

It looks healthy but you can tell it's been in a rich mix so the stem grew more than the roots. Give it a go in a mineral mix in pot just bigger the the roots. It will most likely need to be left un-wartered until sprong for it winter rest but you will see the benefits in the growth season next year. When I pot mine I keep them pretty flush with the surface of the 'soil' so only the very top is visible. Once that root gets established you will see the pot bulge out at the sides if you use a plastic pot, they can even split ceramic pots.