Is there a general rule about this? I have a lot of pots to water. Does once a week work?

Yes, the rule is water when water is needed, not before. The other rule is when in doubt, less is better than more.

The easiest way is to put plants with similar watering times together. But, if you learn the needs of your plants, even mixed up, you will know when to water each one. For instance, succulents need more water than cactus. Mammillaria and anything fuzzy and white need less. Some only need water in summer and others mostly in winter. If they are small and in plastic, weight will help you tell.

I know exactly when my cactus need water just looking at them, but if that's not working for you, a moisture meter may help until you get to know them better.

Once a week works for me, but everyone's situation is different, and Daisy has explained why pretty well.

Your situation in San Clemente is not that different from my own (mild coastal temps), so you might start out watering once a week at the start of spring (assuming strong light and fast draining soil) and adjust from there. Some of my plants get water twice a week (mostly small seedlings in 4 inch pots), most once a week (4-16 inch pots), and a few every 2 weeks (either rot prone or slow drinkers, ie. plants that do not dry out the soil very fast). In lower light I might water some plants half as often. Certain plants (eg. Pachypodium) I might water twice as often when in leaf compared to when leafless.

You need to get a handle on when the soil is drying out and then time your watering accordingly. I have used a moisture meter and it can be quite useful but you have to calibrate it against some other reading (like what your finger feels a couple inches down). Only measuring the surface (eg. by eye) is not useful when you are trying to judge soil moisture, because the surface dries out before the soil at depth, which is what matters. I like to time my repotting for when I expect the soil to be dry or mostly dry, so I can get a close inspection and confirm or deny my guess.

As a general rule, these 2 guidelines should help. (1) Watering much before the soil dries out on any sort of regular basis increases the risk of rot. (2) Watering much later than the soil dries out on a regular basis and you are basically water starving your plants. That said, succulents are quite drought tolerant and it's probably easier to kill them by overwatering (ie. watering when the soil is still wet) than by underwatering (allowing the soil to sit bone dry for any extended period of time).

The length of time required for soil to dry out may differ significantly between plastic/ceramic or unglazed clay pots, because the clay allows water to leave through the sides as well as the top of the pot. So a clay pot, especially if it's in the sun, will dry out faster and need water sooner than a plastic pot in the same location, all things equal. Observation and experience will fill in the gaps as you proceed.

Since my senior moments have become senior days (and in some cases senior weeks) I've found visual aids, like putting a marker in the pot helps. Color coding is good and it's subtle, but even better is a sign with simple directions... "1X Month" or "Last Week" or "Don't!!!!"

Just one other thing to remember: When you water, be sure the soil is drenched and that the water drains well. If you give each plant half of the water you think it needs and go back a few minutes later to give them the other half, the soil will absorb the water better, no dry pockets.

Yes, definitely try watering in more than one pass for the maximum hydration. More than twice the hydration, actually, the one time I checked carefully:

The thread "Sunday afternoon experiment: watering in multiple passes" in Gardening Ideas forum

For a while I used small rocks I spray painted orange or green (neon colors I wouldn't miss) to indicate who was getting less or more water than their neighbors. It helped a lot when I was tweaking the details for a bunch of plants. I also mark my watering days on the calendar because I wouldn't remember longer than a couple of days if I didn't.

Baja_Costero said: I also mark my watering days on the calendar because I wouldn't remember longer than a couple of days if I didn't.

So good to know I'm not the only one!

Wow, so much great information!! Thanks all. I think I will also invest in a moisture meter.

That's a good idea, until you get the hang of it.

But, as Baja pointed out, don't rely 100% on the meter. Test with you finger and judge wetness/dryness and then check with the meter. The meters work by measuring the electrical current running through the soil. So salts from fertilizer, minerals in water and temperature can all affect the accuracy of the meter.

But, that's also a benefit because if the soil is dry but measuring wet, its time to repot.

I've been looking at moisture meters and it seems, by reviews, that they don't really work that well on succulent soil. (pumice added). Any suggest with meters and if so which ones?

I saw the same reviews of moisture meters and then purchased one with the best reviews. It worked for a month or so and then was completely unreliable. It would read when obviously wet but would read dry when the pot was damp (not soaking wet)
So I gave up on it. A waste of money.
Lifting the pot and judging by weight is the quickest and easiest method.
It becomes natural after doing it for a while.
I tell others to use a freshly sharpened wood pencil.
If the dirt is moist it will darken in color.
If the wood stays the same color then the soil is dry.
A new wood chopstick or a new wood skewer will also work.
Once the wood has darkened you need to sharpen the pencil again.

succulentlife said:I've been looking at moisture meters and it seems, by reviews, that they don't really work that well on succulent soil. (pumice added). Any suggest with meters and if so which ones?

I got the cheapest one I could find (in the range of $5-10), just a metal probe with an analog readout on top and no other functions. I don't think there's any particular benefit to a more expensive meter with a fancy head unit as the basic underlying technology is not rocket science, it's based on conductivity.

There are limitations, you have to calibrate with some other measurement (like your finger) to know what "moist" means, and so forth. My meter tends to read "moist" (middle of the scale) when things are drying out, but not all the way there, so that line was the one I used to determine when it would be time to water.

A moisture meter works best comparing the same type of soil (vastly different soil mixes will give different readings for the same subjective moistness) but it worked reliably for me in a mix of half pumice, to the point where I don't need or use it any more.

As a general rule of thumb,watering succulents once a week works ONLY and only IF the soil is completely dry. For most succulents, and of course this depends on your climate and the type of succulent you have, you have to wait for the soil to be 100% dry. Once try, you should completely SOAK the soil and let any excess water drain. This means you should have well draining soil, or succulent soil, and of course, a pot with drainage holes.

I absolutely LOVE my moisture meter .. BEST money I ever spent because no matter how well I plan, I am not any more reliable than the rest of life!

Just because I was supposed to water it on Tuesday, or that I am sure on Tuesday I watered all of it's neighbors, does not mean that it actually happened, lol. Maybe I ran out of water and skipped a pot in refill, or got distracted by a phone call. A lot of my plants are so old there's NO WAY you could get a finger in the pot. the roots are so dense I can barely force the meter's probe in. The problem is the harder they are to test with a finger the more likely they are older and emotionally significant.

I feel confused every time I approach a pot. I have swamp plants and desert plants. I really have no concrete idea of the last day they were watered.. EVER. Having a moisture meter really reduces the cognitive load.
It's not an authoritative result... in my fast draining media it reads near dry all the time, and in other pots a low-medium is where the leaves start to wilt, but you get to know what your babies want and once you get that hang of it the moisture meter is invaluable- using it as a tool by a knowledgeable gardener, informed about their plants, well informed about their substrate and the way a meter works, it's the best thing ever. Now if I could only remember where I put it....

I know that's not a great answer, but it is the right one. I have a beautiful huge jade my mother gave me in a 9" pot that could probably go the entire winter with no water. I have babies from that plant in pots that are only 2" square that would never tolerate that. Same plant- literally! Genetically identical! Entirely different care needs.
It's the plant, species and size, size relative to pot, overall pot size, the substrate, sunlight, household humidity. Every single plant is gonna have different demands because they are going to be in a different pot with different light and different temperature.

If all your succulents are outdoors, once a week is okay. But in winter, be very mindful of your overnight temps. Our areas here in Cali vary greatly. On my side we really get very cold at night in the 32F range, so I much prefer to delay watering a bit longer than usual, or just wait for Mother Nature to rain on them. Right now I have not watered for over a week already, our overnight temps has been hitting the 32F level overnight and online the feel is like 26F..so a big no no to water. I am just glad our temps gradually goes warmer to 60F during daytime.

If your overnight temps are more stable like always in the 45F to 50F range, then once a week watering should be okay, for sure your daytime highs is getting much warmer too.

Also, this suggestion is for succulents that continues active growing in winter. Some succulents do have winter dormancy too..and those ones are overwintering indoors and staying dry all throughout winter.