Guide for watering

Hi all,

Like most cacti collectors, I've had big problems in the past with over-watering my plants. So I've come up with something that might help. Basically I've filled a see-through bottle with my soil mix in the same way that I would fill a pot for a cacti. Then I water the bottle the same way I would water my plants. As the bottle is see-through it allows you to see where the water in the bottle is and how dry/wet the soil is. The below image shows this. At about the middle (where the indentation in the bottle goes around) there is a change in soil colour that shows where the moisture line is. Just put this out where the cacti are so it gets the same amount of sun and rain, and it should give a good indication of how dry/wet the soil in your pots is, and it can give a guide as to when water is needed (and more importantly, when its not needed). Also, remember to drill some holes in the bottom of the bottle so that it drains like a pot.



The white tape around the top is just there to try and stop the bottle from cracking.

Any thoughts/comments about this?

Noddy.

Hey! I used to do this until I knocked it over and it went everywhere
I think its a good idea.

noddy wrote:

Like most cacti collectors, I've had big problems in the past with over-watering my plants.

i don't see why so many growers have problems with 'over-watering'. i have found the solution to be simple..
. use as fast a draining mix as possible... incorporating plenty of coarse inorganic material.
. use small pots (where practical)
. use shallow pots (where practical)
. use clay pots (for maximum porosity)
. only use pots with adequate drainage holes.. the more the better
. include some porous media in the soil.. eg. scoria
. use pure scoria if you want (its great!)
. don't overpot
. water when dry - follow the basic principle of flood then allow to dry
. water well in the appropriate season (ie a particular plants' growing season)
. ensure your plants are getting enough light - to maximise evapouration (if necessary)
. get a greenhouse- to increase heat (if necessary)
. use wire mesh benches
. grow some gymnocalyciums
*this is biased to my personal experience in melbourne growing mainly miniature cacti. in warmer climates the aim may be to retain as much water as possible between waterings.

Noddy,
I can't see the image but get the principle behind it. I have peronally never used this but it could be of some use.

Lewis,
I see where your coming from in regards to inorganic material and I too belive this is one of the keys to growing cacti sucessfully (I'm also moving away from sand ! I will make a post regarding this a litte later). However, I think saying the solution is simple is a bit of a squeeze on anyone's imagination especially when considering rot prone minitures.

I like that you have mentioned over potting. I think many of us are guilty of over potting and this does contribute to rot.

Im only on here for a min so, overpotting? You mean placeing a small cactus in a lot bigger pot?

^yep. the bigger the pot the longer the soil stays moist and doesn't dry out.

I knew the pot shouldnt be much bigger then the plant, but alot of my plants are in "bigger" pots, as for the plant to grow into them (this only being my say "show" pots) not the black plastic ones.
Ohwell.

Thing is, not only does this increase the chance of the roots rotting but seems to vastly slow down growth rates. It's far better to plant the cactus into the right size pot for the plant and then repot, generally, when the cactus hits the edges of the pot.

I like the jist of this thread and I think it's sticky worthy, keep the info rolling in.

Also, am really looking foward to reading more from HN on the subject of inorganic potting mixes.

Great thread!!!

Quote :

Thing is, not only does this increase the chance
of the roots rotting but seems to vastly slow down growth rates. It's
far better to plant the cactus into the right size pot for the plant
and then repot, generally, when the cactus hits the edges of the pot.

that's how its done around these parts as well.

but it should be pointed out that any rule will only be good in certain climates. you Aussies in hot dry areas may be able to get away with peat/coco/soil mixes, in wetter areas this means instant rot....just form the humidity, doesnt even have to rain.


i think the only universal "rule" that is safe for all nations is, dont water until its dry....at least underwatering a bit is safe

perhaps its good to say what climate we are in and what we use...pros and cons, advantages etc for our given climate?
i used to have various columnars (trichocereus, cereus, myrtle etc) outside in 100% grit/rock/pumice (what i use for all cacti here)....and even they all showed rot, the trichocereus ALL rotted and i made cuttings and keep them in now. i know my mix in canada when i lived there is about 95% different than my mix here in taiwan lol. and they both worked equally as well, but wont work well at all in the other location.

For my Mexicans, mainly Astros and Arios I am now pretty much using just inorganic mixes, sometimes with a small amount of seived cactus mix added (still trying out different mixes, looking for that perfect mix), the main reason for the high inorganic content for me is that it is very humid where I am (though I suspect your climate is far more humid Kada?), as for my Trichos and other more forgiving cacti, they mainly go in a standard commercial cacti mix (Debco) and sometimes with some course sand added if I have any spare, occasionally perlite, but I find it annoying and only really add it to my Mexicans and other rot prone cacti these days. The ones in the commercial mix, especially the Trichos seem to thrive if put in full sun and sometimes (quite often) these never quite dry out completely and as I said seem to thrive. Never really had any problems with rot in this department. As for the Mexicans etc; these only get watered when fully dry to the root. I check by poking carefully with a length of wire if necessary to see if they need a watering, usually you can tell though. I still find this organic mix seems to take awhile to dry and am pretty sure this is to do with my climate, so therefore I am very careful with watering. It must be remembered that when using these low organic mixes that it is imperative to provide the nutrients and trace elements for healthy growth.

Best way is to follow pretty much what lewis offered, also know your plants and the genus & species requirements and a little info on the native climate can go a long way

I should mention I am am in the Northern Sydney region and coastal location, so my techniques will vary from other peoples' techs be it that they hail from western Sydney, VIC etc; etc; Be interesting to hear what others think.

Oh yeah, I try to avoid peat/coco for my cacti mixes too. Except for when propagating seeds.

Interesting thread.

I don't like recipees that suit everyone, because they don't exist.

Fast growers love to be transplanted to big pots, the bigger the better, but you were referring to slow growers and spherical cacti in general.

I am in greece, mediterranean climate. Very hot and dry summer, and generally mild winter

I am leaving the majority of my collection on the roof to be freely watered by rain in automn and winter. I am teaching them to swim, as I joke about it. Many columnars including trichocereus and myrtillocactus have been literally wet for months in a row. Even some spherical ones are left like that.

Mexican slow growers are usually protected during these rainy seasons, but I have left slow growers like astro myrio and feros exposed to the rain as well so short periods of time - oh I have my feros in clay pots.

Despite my risky attitude, I have lost only a couple of plants , if any, due to that, f.e. a stenocactus, after months exposed to rain...

I eventually started to introduce other material in my cactus mixes, especially with the very slow/senbsitive gorwers I bought this summer, so I am adding perlite and gravel. I am even adding it to other more hard cacti, I even put some in my columnars. I also started to use clay pots more with slow growers. I live clay pots and I think the slow growers like it too.

I have also a number of freshly bought lithops in clay trays, also bought some argyroderma now. Now these are some challenge.