Base of cactus turning brown.

[Aramidesaxi]

I recently purchased this cactus and it is now starting to turn into a weird color. I only water once a month and it receives 3 to 5 hours of direct sunlight every day. For the rest of the day it receives great light but no direct sunlight. I live in the tropics and it’s been dry and around 90° lately. The colored area is not soft.

Thank you for your input!

[Steve Johnson]

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% mineral gravel mix, although you could go a bit leaner (maybe 40% soil/60% mineral).

[MikeInOz]

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% mineral gravel mix, although you could go a bit leaner (maybe 40% soil/60% mineral).

Steve, I would suggest this plant has been starved of N mainly. ottonis will happily grow in 100% organic mix if enough N is supplied. What must be remembered about the organic component is that decomposing bacteria always win the battle for N so enough for them and the plant needs to be present.

[anttisepp]

Premature corking, 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.

[MikeInOz]

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 of water all year. It is corking badly because it's potting mix is exhausted and it's starving for N P K (no food for 3 years) although this corking is not reversible now of course....

[Aramidesaxi]

Thank you Al for your help!!! Very much appreciated!!!