Premature corcking, probably due to small watering. Notocactus ottonis origined from southern Brazil, Uruguay and Paraguay in grasslands where year precipitation in high enough that's why in collections plant usually suffer from excessive dryness. I have a Notocactus herteri outside. It gets tons o...

Urea has 46.7% N Ammonium sulphate has 21% N Calcium nitrate has 17% N Potassium nitrate has 13.8% N Ammonium nitrate has 35% N You can work out what you want from there. if you want to acidify or stop alkalization use more Ammonium and/or urea If you want to reduce acidity or stop it from falling, ...

The beige areas around the base indicate premature corking, typical for mixes containing too much soil and organic material. Lean out the mix by adding mineral gravel -- pumice (the best if you can find it), granite gravel, or calcined clay granules. My default recommendation is a 50% soil/50% mine...

Btw - what role does urea nitrogen play and is ammoniacal superior because it removes one more step of conversion through hydrolysis? Urea can be taken up by plants directly and they use the enzyme urease to convert it to ammonium. Nickel is required in this process. Urea is also converted to ammon...

From [url=https://www.reddit.com/r/sanpedrocactus/comments/119f5ju/ However, in containers, it's harder for nitrifying bacteria to survive and it's best to do a little bit of the work for them and just feed directly with nitrate." That is incorrect. Nitrifying bacteria are perfectly able to su...

Conophytum is winter growing - summer dormant. They should look almost dead in summer. No water!
In autumn they shed their skin and become plump and green again. You can water then but not too much.

Steve Johnson wrote: ↑Wed May 08, 2024 5:17 am

Looks good to me. How about you, Mike? Dexter -- if Mike gives us the thumbs-up, go for it.

Looks fine as long as Ca and Mg are coming from somewhere...

A few thoughts.. -50/50 perlite/cactus mix is very lean. These are heavy feeders. I would suggest a gravel, loam, organic mix for them with good drainage. They may be growing too slowly. -The organic part of the potting mix may have broken down too much and hold too much water and not enough air. pe...

C And D wrote: ↑Tue Apr 23, 2024 4:01 pm The Turbinicarpus that no one likes
Turbinicarpus horripilus
IMG_1762.JPG

Gymnocactus horripilus is a beautiful plant.

It need nitrogen. If you cannot afford ferts at this time, use 1 part urine to 10 parts water. No joke. Only suitable for outdoors.

I would sow aztekium, pelecyphora and lots of ariocarpus. As many as I could get. But it's never too late......

Most Mexican and Sth Texas species should be given a late start. Mid to late spring regardless of the temperature. They are not really active until it's regularly quite warm. Astrophyum asterias and Ariocarpus come to mind. They get their first drenching in summer in my area. Rebutias etc should not...

Thanks for the pictures. They are very collectable!

I never spray cacti because they aren't orchids neither bromeliads, no practical use at all. I water them when they are moved to greenhouse and temps are high enough, never give them "some drops" but good amount of water. Better later and much than earlier and little. I spray my cacti alm...

Must have been about 30 to 40 years old as my plants don't grow very quickly. Alas it decided it had lived long enough and with no discernible change in growing conditions died two years ago. A species that does not show much visible signs if rotting since it does not go soft but you find out it is...