Gill can you point me to the alpine grit product you are buying?

Gill, you are master on this subject.

"frequent watering, rather than the mix retaining more water, there is a subtle difference there." very good point.

Marie

Westes, yes, I'll certainly point you to it...it's just inside my greenhouse many miles away in the UK..... Sorry, bad 'joke' there! Thanks for adding your locale btw.

Here's a couple of pics, it's sold as alpine or horticultural grit over here available at garden centres or what you refer to as the big box stores, DIY stores over here though :-)Aquarium gravel sold in pet stores as fish tank substrate also works equally well as the pieces are of a similar size I find. Gravel also adds stability to top heavy pots, I dislike plain perlite and c/s mixes as they are too lightweight, plus the darned perlite floats to the top.

@Marie, ha-ha, thanks, but certainly no 'master' as my poor plants have been to hell and back in the years I've been growing them....never been a 'mistress' either come to think of it :-)

Gill

@Gill, that alpine grit is what we call "river rock" in the Western US. Yours has nice brown tones. So basically your soil is a standard gritty mix, but you added about 1/4 of the volume as commercial cactus/succulent mix. My usual problem with that is the sand, small dust particles, and especially the peat moss will tend to retain moisture as free standing water, thus partly undoing the main value of the gritty mix, which is good drainage.

Do the roots of Adenium Arabicum want exposure to localized high moisture areas within the soil? They will get that with sand and peat in a mix.

What about the idea of replacing all of the alpine grit with perlite or equivalent? (I also hate perlite for all the reasons you gave and I hate the aesthetics too.) In other words, every part of the gritty mix will contribute to water retention, while keeping particle sizes large enough to prevent free standing water around the roots.

Westes don't use peat its not good for D/R be careful with what type of sand .Use builder's sand beach sand is to rounded and tends to glog up the substrate .if the substrate drains instantly you are on a good thing.

Do you have access to pumice?

@Liz I have Dry Stall, which is a pumice. I understand that pumice is lava rock that is exploded by the volcano, whereas perlite is a similar rock that has been exploded by mechanical heat applied during production, so they are really similar? Supposedly perlite has a closed cell structure and does not retain as much water as the open cell of pumice?

So what about the idea of doing a gritty mix that is equal parts of pumice, turface, and fir bark, all filtered for size? This will be a moister soil than gritty mix with gravel, but it should still drain well and should not allow pooled water.

We are in the same zone, but I believe them to be much different. I use a mixture of bark and miracle gro potting soil. It's very warm and humid here, but plants dry daily in summer.

I guess one question I did not ask was do Adeniums like high humidity in the soil? If yes, that strongly argues in favor of something like Turface, which has multiple layers of water retention that it is able to slowly release as greater humidity in the soil.

Hi Westes. Another deciding factor on my particular choice of mix may well be that all my adeniums are housebound, with an occasional holiday in the greenhouse so all water they receive is strictly controlled as opposed to them being subject to our copious UK rain....which by the way, a has fell almost every day, and most nights, during August. :-/ The plants live on my sunniest south facing windowsills and can dry out in a couple of days max. I've not had a case of root rot to date...crosses fingers tightly. I've never tried a completely inorganic mix though, so can't advise.

I've yet to see pumice for sale over here, and no one would know what I'm on about if I asked them for Turface. No doubt hydroponic websites sell the expanded clay pebbles that I read about on here, but again, I've never ever come across a hydroponic store in the UK. The only expanded clay we get is a food grade type for use in 'blind baking' pastry! They're about 1 cm in diameter, so far too large. Bonsai shops are also non existent, but I faintly recall seeing tiny tubs of small clay pellets for bonsai mixes in a distant garden centre years ago. Coir products are rare and rice husk is not available. Kitty litter is available, obviously, but I've never tried it. The bags of perlite are a complete nightmare, well over half their contents are wasted due to them being too small or they've disintegrated even further into just plain old dust. I honestly detest the stuff. However, we have to use what we have available.

Interesting that my UK horticultural gravel/alpine grit is referred to as 'river rock' over in the U.S......more proof that the great divide of the Atlantic Ocean influences lots of differences between our cultures/languages in many ways. All fascinating stuff :-)

Gill

I personally don't think that Arabicums need any different culture to obesums or any of the other adenium varieties....just my opinion though:-)

Gill

@Gill, the alpine grit has very smooth edges on it. The way that rocks become polished like that is under the force of water washing them every day for tens of thousands of years. So they are - quite literally - rocks found at the bottoms of rivers.

You can also use No. 2 cherrystone, or chicken grit, available at ag supply stores (Ten dollars or less for a 50 lb. bag). Do NOT get the crushed oyster shells.

Add some floor dry (Napa part No. 8822) and you are good to go.

Or, to create the 'gritty mix' discussed ad nauseum on the container soils forum, add pine bark (pet stores sell it as Reptibark) if you wish. Drains like a champ. Ratio 1:1:1

fertigate with half strength MG or foliage pro through August here in the states.

The Arabicums should be planted up into the same mix. They do not require different cultural needs. Arabicum will require more space in pots in width more than depth to grow wider. Arabicums are known to be more tolerant of cooler temps as opposed to obesum's.

Depending on where you live and conditions they are receiving (outside in elements or greenhouse situation) much will depend on if they can dry back sufficiently prior to being watered again. If they go into dormancy, then they require a different water schedule.

Rick

The problem I see with this Alpine grit is that it is gravel for decoration and the pebbles are smooth. Instead use bonsai soil mix which contains akadama, volcanic rock, pumice, clay and some fine bark. these rocks are porous which are ideal for holding moisture as well as aeration for the roots. This type of soil or substrate is the best draining with some organic material. You could also add some compost. Trust me when I tell you you will not go back to using regular soil.

I live in Kentucky my plant will be indoor more then outdoors is miracle grow cactus soil ok for my adenium desert rose?

@gina gina Miracle-Gro soil mixes tend to have too much peat moss, even the cactus mix.