Cactus frailea and avocado pear problems

Question

The cactus frailea is becoming sunken. Also, every time I plant the pith from the avocado, it dies even with a big root.

• 

Answer 1

Your cactus has likely suffered from root rot.
Make sure you are growing the cactus in a cactus planting medium and not over watering.
Here are some articles that will help you with growing Avocado.
https://www.gardeningknowhow.com/edible/fruits/avocado/indoor-avocado-plant-care.htm
https://www.gardeningknowhow.com/edible/fruits/avocado/avocado-houseplant-care.htm

Here is a link with more information.
https://www.gardeningknowhow.com/ornamental/cacti-succulents/scgen/cactus-going-soft.htm
https://www.gardeningknowhow.com/ornamental/cacti-succulents/scgen/