Helen

I understand why you want some water retention...but if you want 100%, just use regular soil. Not good for succulents, but will stay wet for some time. I would think that using inorganic substrates and yet wanting complete water retention is kind of waste of more expensive and hard to get materials - from what you said, most of them seem to be unavailable and/or you didn't hear about and/or even looked for.

Have you considered using just Cactus & Succulent soil? That would give you some water retention. Maybe you should test it in your climate to see how fast it dries up?

Is it only a week at the time you are away? I would imagine that at least few days out of the week plants are OK without watering. How hot does it get?

Shade cloth will help a great deal. Vermiculite turns into a glittery mess. Turface/similar substitute would be a very good idea. Charcoal would be a waste of money and space as it is just filler.

If possible, some sort of compromise between mixes would be best for summer vs winter. Repotting every winter would be a pain and set your plants back in growth.

Perhaps you could just try changing a few plants that are not so sensitive to being on the dry side first. Even though I tend to water most of my succulents at the same time, there are many that will still look good even if I stretch the watering period by a lot. Others of mine are very picky and missing watering by a couple days really sets them back.

Mesembs thanks for the Vermiculite tip. I went to 2 places that had it, but couldn't see inside the bag and shop didn't know what size the bits were. Glad to leave that one.

Rina, I think temps only got up to low 30°s so far, thats the worry. Summer is lots of mid to hi 30s & heat waves of week/s of up to 44ish.

My understanding of the inorganic substrates that are water retaining, is that when we water the plants the water can flow through the mix, provide oxygen to roots and fill up the porous substrates. Then the plant has some water available without sitting in soggy stuff. If I've got some of this wrong please tell me. Thats why I did this thread.

Basically, though, I don't want soil at all. I don't like it in my room and I'm still getting bugs I think. Planning to use 100% only with plants that need it.

Really I'm away from home 8/9 days including traveling days. Always water night before, then morning I leave, Monday. Then again night I get back, Tuesday week, sometimes Wednesday. I finally found 2 places to get regular small stones cheap.

ewwmayo thanks for the tips on Vermiculite, Turface substitute and charcoal. Finally found the wording I'd saved to search for a turface substitute yay.

Helen I don't use 100% gritty mix because for 5-6 months outta the year I would have to water constantly. If I used gritty mix for my succulents in pots they would fry. I hate watering. I've said this a hundred times, but I live in a very Mediterranean climate. So it only rains from Oct-April. Sometimes we don't get rain till the end of Nov., but by May the rains just disappear. So the humidity drops way low usually ranges from 27%-35% in the summers. With temps rising above 100F consistently. My area had the hottest day in September this year, it was between 110F-115F. That day in San Francisco it was 95F. That is crazy hot for SF.

I use cactus soil in my mix for two reasons as filler and to hold onto moisture. So I use pumice, perlite, and cactus soil. So maybe for succulents adding 30% cactus soil to your mix would help to hold onto moisture a bit. The other 70% be gritty. Cactus I use about 20% cactus soil. Also as stated above using a shade cloth would really help. Moving plants where they will be protected like under trees. I use other plants that are acclimated to the sun to protect other sensitive plants.

Kara hi. I was hoping you would pop in ;-) as I was pretty sure you had pretty hot summers too. But we both have Mediterranean Climate!

Anyway, for plants that are really struggling even behind a heavy shade cloth, do you think a mix without any soil, but made with ALL WATER RETAINING inorganic products would not hold enough moisture? I was planning to check the charts (that I think you did) for the water holding capacity info on different products.

Just in case you missed some of what I'd written, or more likely I wasn't clear on some things, please reaffirm for me. Again, thanks.

Helen

Turface has about 52% water holding capacity. That may be highest of substrates mentioned. So getting 100% could be difficult. You are correct that many substrates hold water internally and release it slowly, but you are looking for 100% water holding capacity - I am not sure what would you have to use...maybe ewwmayo can calculate it (SORRY Kevin!). He did sample of WHC of different substrates and even few different mixesin this thread but nothing is 100% water retaining - we are trying to get much less than that. Here is sample chart:

Bugs are not exclusive to use of soil. Many ppl get mealy bugs and others even if using gritty mix. OTH, many ppl use mix of 50/50 C&S soil and perlite and I don't think they have more bugs on average.

I use very gritty mix, but do not live in such hot climate. So it would be wise to listen to ppl that do, like Kara. Al's water retaining mix is still not 100% water retaining. His suggestions are for ppl that are in hot climate, but plants still need watering except not daily. I am not sure if Kara mentioned somewhere how often she waters succulents in her mix.

Shade cloth is definitely big help, just tie it so that there is still good air circulation - but I am sure you know that. There are also timers you maybe can set up (?) that would water your plants whenever you set them to: daily or 1x/week and anything in-between.

Sorry rina and others. I have given wrong impression. I meant 100% inorganic gritty mix, all of which have some water retaing capacity.

And thanks rina for the heads up on not being total protection against bugs :-(

I would still prefer inorganic gritty mix though. The potting soil is difficult to manage and I especially don't like living with it in my room lol.

Just a thought, I did see charcoal 4-6mm, in a list of garden and building supples. Is it like the dirty leftover bits of a wood fire, or something else?

Thanks for all the info and help guys.

Helen - You can try akadama, that is very popular in California. It holds a lot of water and is quite expensive.

Thanks ewwmayo. I've only heard of it on this forum, but I'll check it out online. Expensive sounds scary lol.

Hi guys, I was looking for an old thread and came across this one. Thanks to you guys help and encouragement I am now potting into a mix of small pebbles, perlite and small amount of Attapulgite clay (depending on plant). Plants are happier, so I am happier :-D

Haven't finished repotting but getting there.

My plants and I say a big thank you to mesembs, rina, ewwmayo and Kara :-)

Use charcoal and bark for nutrition in an inorganic mix.

I add a bit of wormcast to my gritty mix to give some organic nutrition. And a small midgin of kelp meal (but it is pricey).

huh, wonder if caterpillar poop would work... spent a part of the morning sweeping little caterpillar pellets off our patio. Gypsy moth caterpillars do love our oak tree. Very annoying.

I plan to use a very watered down Seasol occasionally. Lol to caterpillar poop :-D Thanks though. I really appreciate the help and advice in this forum.