Cactus collection looking sickly... any advice?

[squidgygoanna]

Hey fam, been a while since I've posted here.

 

I moved all my cacti collection into a shade cloth covered greenhouse probably 18 months ago

 

All were doing really well and looking super healthy, flowering etc. However over the past few months they've started looking a bit unwell

 

Most have new blueish growth on top and the older, green growth below it looks and feels really "sunken" and flimsy, instead of firm and plump like they were a few months ago

 

Any idea what the issue could be? too much water? not enough? nutrient deficiency? pests?

 

 

EDIT: no idea why pics are uploading sideways. Apologies

 

 

Edited March 27, 2020 by squidgygoanna

[Evil Genius]

Extreme dehydration due to unsuitable soil. The minerals you have there would probably be fine, but it lacks finer ingredients so water runs straight through it. Get some finer Pumice, Lava, Coir and stuff like that and mix it evenly. Roots can't properly form around these huge particles. They are just too loose, and it just makes it very hard for the plants to get a good root system. And ditch the quartz topping layer too. It makes it even harder to judge about the humidity of the soil because you can't check it easily. And yeah, more water and fertilizer in the future. Bye Eg

[etherealdrifter]

you could easily just do an emitocon but its better to speak

[squidgygoanna]

The Scoria/pebbles are only scattered on top, mostly for aesthetics. Would never try to use them as the growing medium.

The soil mix underneath is fine as I've been using the same mix for close to 10 years.

Weird that they're dehydrated, I was watering once a week and started seeing signs of rot so I cut it back a bit.

I thought it looked like dehydration but didn't want to water again and do more damage.

 

Good call on removing the top layer though, will make it easier to judge moisture levels

Edited March 27, 2020 by squidgygoanna