Cactus Rot help

[luigonz]

Hello everyone,
I think is more of a confession or a cry for help
I started to grow cacti in 2014. I have collected, bought, or been given about 200 cacti. (slight problem )
Well, mostly this past winter, I have lost about 8% of my cacti collection to rot (too much water or too little). Not bad i guess for a beginner.

Here is a list of a few I lost. most of them were smaller plants, but ouf course I wish I hadn't lost them.
Astrophytum asterias x myriostigma 'Onzuka' hybrid
Astrophytum asterias
Astrophytum asterias 'Super Kabuto'
Astrophytum myriostigma 'Koh Yo'
Astrophytum myriostigma 'Onzuka' forma Quad
Copiapoa laui
Frailea grahliana
Mammillaria bocasana cv fred
Mammillaria hernandezii
Mammillaria perezdelarosa
Notocactus crassigibbus
Rebutia heliosa
Uebelmannia pectinifera 
DISCOCACTUS BUENEKERI
Gymnocalycium baldianum
Gymnocalycium denudatum

Its kind of humbling once you put them in a list. Not sure if everyone is willing to confess to their failings, but I hope to learn from them.

I think some of the mistakes that might contribute to the rots.
--Keeping them in 4 in clay pots..although some have rotted in plastic pots.
--Using too much sand in the potting mix.... I have been progressively been making my potting mixes with less and less organic material.
my typical cactus mix is various amounts of
- decomposed granite
- 1/4" crushed limestone
- red lava rock pebbles
- leaf mold compost mixed w sand

--Winter environment..I brought most of the cacti I lost this winter into the house. the house isnt air conditioned but i would turn a space heater on me (not the cacti) when temps would get down around 32-40 degrees F.
--Perhaps I watered too much or too little (about once a month with watering). i think the biggest thing was winter watering. im still trying to get the hang of it, trying to understand when to water with regard to temperature.


thank you for sharing any info on over wintering cacti ( i shared my "rot list" to give an idea of what didnt work in my environ)
I hope to soon get a Green House to over winter cacti. Perhaps its a matter of limiting my collection to more cold hardy cacti(I over-wintered several cold tolerant species with success outside under the stoop of my house.) Hopefully I will not have to resort to grafting my water sensitive species to keep them alive

[KittieKAT]

I don't water in winter at all, they go dormant in the cold and don't stretch from lack of light or rot or freeze from watering in cold temps. Sorry u had to learn the hard way, but the heater always goes to the cacti not to US! LOL!!!!

[iann]

Even in Texas, a good starting point for winter watering is "none". Then work up from there if some species need it.