Lophophora dormancy? How to water?

[MBM7]

I purchased a small 1-2 year old Lophophora williamsii in early September. During September I watered it every two weeks or so, and the temperatures were still ranging from 15-25C. A few weeks ago it started getting soft (i.e. flacid, as opposed to turgid), and I started watering it more to get it to fill out. However, even though I was watering it more often, it refused to fill out. I also suspected that its roots might have been rotting so I pulled it out of its pot and let the roots dry out thoroughly, and I did also discovered a few root tips beginning to rot. Right now I'm just leaving it dry until I know what is going on.

The temperatures the last few weeks have fluctuated in the 10-20C range. Can anyone help me understand what is going on and why the Lophophora refused to fill out? My only theory is that it got shocked into early winter dormancy. However I've read several online sources that say to give the Lophophora a little water during winter to keep it turgid. So I guess the question becomes

1) Did the Lophophora go dormant?
2) Can Lophophora or cacti in general still absorb water when they go dormant?
3) If it didn't go dormancy, why would it refuse to absorb water?

In terms of other relevant conditions, I have it growing in 1-3mm gravel with no organic matter. Right now it is out on my balcony which probably gets 2-3 hours of direct afternoon sun, which is becoming progressively less as the sun is lower in the horizon every day and the tall buildings here block out progressively more sunlight as we get closer to winter solstice. I live in Barcelona.

Thank you for any help!

[MikeInOz]

Every 2 weeks in Barcelona? I don't think that is enough water. If you don't give enough water when they are growing, Root tips can die. When root tips die they become a potential seat for infection and there is a downward spiral. Cacti should be growing quite strongly in autumn in a Mediterranean country. They are slightly dormant over summer when it is very hot. 10-20C range they should be growing still. I recommend cutting the roots tips off and replanting in very dry mix. After a week, give water by the teaspoon when it is dry for a couple of weeks and then perhaps one good drink before the cold weather starts.
BTW, 1-3 mm gravel without organic matter is a very bony mix which may dry out too quickly. Loph do very well in a mix which contains 15% or even more very old organic matter. If you use a layer of course perlite on the bottom for root aeration (nothing to do with drainage) you will be able to water with more confidence.

[DaveW]

If kept cool in winter Lophophora's dehydrate and thicken their sap as a form of antifreeze. They are the only cacti that feel squishy in winter but are not usually rotten. Mine will not get watered in my cold greenhouse from now until the end of March. You may need to water slightly if kept in warm conditions, but being tuberous rooted slightly dehydrated top growth is the normal way they cope with cold. They will also split if overwatered in summer.

I find Lophophora's tough as old boots and mine in the UK often just dip below freezing at night in cold winters provided the greenhouse warms up in the sun during the day. If very cold I just cover them with a layer of newspapers. Whether it is daylength or temperature that triggers flaccidity I do not know, but it is their normal winter resting state.

https://lophophora.blogspot.com/2013/02 ... -cold.html

As Mike says they like water in the growing season and some are flooded in habitat for a time, just as with some Ariocarpus. But few cacti like water when they are dormant.

[7george]

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In terms of other relevant conditions, I have it growing in 1-3mm gravel with no organic matter. Right now it is out on my balcony which probably gets 2-3 hours of direct afternoon sun, which is becoming progressively less as the sun is lower in the horizon every day and the tall buildings here block out progressively more sunlight as we get closer to winter solstice. I live in Barcelona.

Thank you for any help!

I think Lophs can go dormant just from the short days this time. So better be careful with water. Bring that pot indoors if you want to water them but be sure they are in active growth before. How big these seedlings are? My small Lophs stopped growing already but is colder here and days are shorter.