When i water woth the grotty mix, i water deeply until it runs out the bottom. The gritty mix if made properly wont hold the water long enough to hurt the plant.

Thats good to know! I'll do that then. Thank you!

While watering most cacti too often is flirting with fungal root infection of any of several genera of fungi covered under the umbrella of damping off diseases, more often it's the water held in the pores between soil particles that proves to be most limiting and sets the table for root diseases. Screening gritty mix components so almost all particles are larger than 1/10" ensures a minimal amount of water in these inter-particular spaces and a much greater volume of air space than media based on large fractions of fine materials like peat, coir, compost, composted forest products, sand.

Every container gardener should know about the trick I'll describe. It puts some simple science to work and can be used no matter what medium you use, including the gritty mix, & very effectively removes all excess (perched) water from pots of manageable size. It can allow you to grow reasonably well in media most growers would find too water retentive.

Newton's First Law

For conventional container culture, it's a given that saturated/partially saturated media rob roots of the oxygen they need to function normally and efficiently. At best, soil saturation robs your plants of immense measure of potential in areas like growth, appearance, yields, ….. At worst, plants unable to cope with the strain of drought stress caused by saturated media will succumb to it. This isn't a 'scare tactic, it's a very simple and straightforward observation that will be difficult to disagree with a straight face.

Newton's First Law of Motion states that an object will remain either at rest, or in motion at a uniform rate and in a straight line unless acted upon by an external offsetting force. In this case, we will designate the 'object' as excess water in your potting medium. At risk of my being redundant, the 'law' can be seen as a simple statement about inertia, that objects will remain in motion and in a straight line unless a force acts to change the motion. To put the law to work for you/your plantings, you should water to beyond the point of total soil saturation - so the medium has been completely saturated and at least 15-20% of the water you have applied has exited the pot. Unless your soil is purposefully constructed to eliminate all/nearly all excess water, it's extremely probable, when the pot has stopped draining, there will be too much water in the potting medium, from the plants' perspective.

To eliminate this excess water: immediately after a thorough watering, hold the pot in one hand over the sink, lawn, or over-sleeping significant other and move it downward, then sharply reverse the direction to upward. You'll immediately note that a good measure of 'excess' water will “continue downward in a straight line” and exit the drain hole. The sharper the reversal of direction, the more water exits the drain hole. When you have repeated the exercise until water no longer exits the drain hole on the reversal of direction, you will have eliminated all excess water and your plants will regard you with a newfound sense of awe.

Al

LOL!! ^^ That may prove tricky to do with a 5' tall cactus!!

Lora, I don't use that specific recipe for gritty mix that is known as Al's Gritty Mix.. But I have numerous succulents in variations -- all of which lack potting or succulent soil. For example, 1 part each sifted pumice, Turface, and Manna Pro chicken grit. Or 100% sifted and washed pumice. Or a 2:2:1 (sifted pumice, Manna Pro and Turface). But for every and any mix I use that doesn't have soil, I do what Whip1 suggested above -- I water until it runs out the drainage holes at the bottom.

One factor I recommend considering is the TYPE of pot your cactus is in. Most of my plants are small and are in 4" or 6" pots, occasionally an 8" pot but not often. Terra cotta (clay) pots dry out significantly faster than plastic or ceramic pots, because the moisture evaluates THROUGH the walls of the pot with terra cotta. I have small plants in 4" terra cotta pots, in a gritty mix, and they can be dry within 3-4 days....whereas with a plastic pot, it can easily take a week for the mix to dry out. With your 14" pot -- I'm guessing it could easily take 10-12-14 days to need watering again.

al .... i dont know if you stated such in your answer ...

but do you start by pre moistening all your ingredients.. and then mix them together ???

i dont understand how one would create a high draining mix.. and when they pour water on it.. none runs out.. unless the ingredients are so bone dry.. they are sucking up all available water ... which means.. until its moistened.. the roots have potentially no water available..

and depending how it runs thru the pot.. .. e.g. runs down the sides ... you may never get the center .. where the roots are.. properly moistened ...'

ergo.. pre moisten it before you use it ...

if properly moistened .. and you put a cup of water in the top .... shouldnt nearly a cup run out the bottom.. isnt hat the point of a high draining media ... basically allowing a sip of water .... and then draining away excess ... [of course there are other variables like evaporation.. pot heat in the sun.. etc .... which would cause more to be retained .... but im trying to simplify it ... ]

ken