Leaving the odd weed in a few pots helps to indicate the water content of a mix. Even after years of growing I find myself wondering if I should give water. This is particularly helpful at the end of the growing season when you are starting to harden plants off. (my growing season has ended) You may think they are dry but cacti are adapted to extract water from seemingly dry mixes. Here are a few pictures of weeds in pots in various stages drying out. If the weeds are green there is still water to be had!
Watered a few days ago...
20240513_145534.jpg (140.05 KiB) Viewed 289 times
#1 Plenty of moisture....
No water for 3 weeks
20240513_144328.jpg (154.3 KiB) Viewed 289 times
#2 You can see the grass in the middle of the pot starting to lose colour....
Yes! A great way of indicating moisture I've learnt from various sources on the interwebs. I used to pluck most of weeds growing as I know they'll compete with my cacti and that could be detrimental for my cacti's growth, but as years go by, I became too lazy to weed my collections and realize letting those weeds grow bring more benefits, though I need to be more wary during rainy season when they grow like crazy.
I mean, knowing how durable cacti can be, I think cacti won't mind a bit of competition with alien weeds
Tropical region, summer all year long
12 hours of sunlight (shaded by 1 p.m.)
Rains often from September to February
24°C at night, 32°-34°C at evening
Mix: scoria, pumice, zeolite, bamboo humus, and kanuma
Fertilizing may vary
I agree that this is a good indicator but you have to be carful with this
From my experience perennial grasses growing right next to the body of large spiny cacti (like Ferocactus) are the worst.
If you let them establish it is very hard to get rid of them without repotting the cactus.
Another place where it causes problems is next to very young cacti. If you pull the weeds out you can uproot the cacti.
