Ideal Soil/Substrate Mix

[HaoBao]

I’m looking for people’s opinions on soil/substrate mix and also if there’s been any research into the topic. Ideally I’d like a soil free mix as it can get a bit messy indoors where I keep my plants but if a type of plant prefers it then I’d use whatever is best.

I keep my plants indoors and pretty much all of them are in akadama (Not cat litter, although it could be the same and I got ripped off haha) I use Chempak No.8 at 1ml per litre when I water and the water is just tap water. I have no real idea if this is good or not or if the level of fertiliser is ok. I saw on here Chempak 8 was used but I don’t know how it applies to a soil free mix.

My collection mainly contains:

Agave Victoria Reginae.
Argyroderma.
Aloe Polyphylla and Brevifolia.
Astrophytum.
Conophytum.
Cotyledon Orbiculata.
Crassula.
Dudleya Gnoma.
Echeveria.
Eriosyce (I think).
Haworthia.
Lithops.
Mammillaria.
Myrtillocactus Geometricus.
Pachyveria.
Pachyphytum.
Rebutia.
Sedum.

Do you know if there are there any specific requirements for each one, Eg. Would Astrophytum prefer limestone in the mix? Would Crassula prefer organics too? etc..

And would any substrate benefit certain plants Eg. Pumice would add a beneficial mineral, Limestone would reduce the PH or something like that.

As always any help is greatly appreciated

[habanerocat]

This link was posted up here before. Might be of some help to you.

https://www.oxford.bcss.org.uk/cultivat ... estone.htm

[HaoBao]

Thank you for that, I think I may have stumbled upon that list when I got my first astrophytums and was looking for their soil requirements. The part where they mention ‘turning soil to sludge’ seems familiar. Now I recognise some of the other names on the list that were unknown to me back then.

In my naivety/ignorance/stupidity I thought limestone reduced the PH. (Too many limes in my mojitos I think) This has made me wonder if I should check the PH levels of the soil. And then leads to the question of do different plants prefer a different PH level?

I had heard people using rain water to water their plants was good because it’s more acidic than tap water. And now I’m wondering if it’s the PH that matters or if it’s the minerals in the water/substrate that plants prefer/dislike?

[el48tel]

Lime is used in water treatment to neutralise acids in waste water and to aid precipitation of the solids (you don't need to know more). It is used similarly in the treatment of drinking Water. It raises the pH. If drinking water is harvested downstream of prior waste treatment it receives a double-whammy.
There's much written on the subject of C&S and calcium ion concentration in irrigation water, including misdirected thoughts on some Lithops thought to be imbibing calcium but actually sitting in humus in a hole in a rock.
Yes pure rain water has a pH of 6.3 because of its solution of carbon dioxide from the air. But if you live close to motor vehicle traffic, it will be much lower as it absorbs nitrogen and sulphur oxides and reacts with those. You may be able to boil some of these off. But not all. As for your collection device, who knows what that may add to the water unless it was made of laboratory grade glass. All manner of chemical is added to plastics to make them "plastic" (= scientific term for squidgy) and it leaches out and reacts with the water.
You collects your water from wherever and you takes your chance.

[Terry S.]

!1) Do not bother to play around with different mixes for different genera. Some growers argue that limestone chips help certain plants from the Chihuahua Desert but I disagree. Find a mix that suits you and stick with it. You might want to adjust the relative ratio of components to get a more free-draining substrate for some tricky species.

(2) If you are using purely mineral mixes then feeding will be required all the time, I would suggest fertiliser in perhaps two waterings out of three with the third functioning to wash out any build up of salts. Chempak 8 is a solid so I guess you mean 1g per litre rather than 1ml? I can't make any recommendation based on experience because I use loam-based mixes, but this does seem a rather high concentration for continuous use. The brand of liquid feed that you have chosen is very suitable for your purpose.

(3) I am not aware of any proper research on soil mixes for succulents. The problem is that there are so many possible variables that a very large number of clonally identical individuals would have to be grown and evaluated.

(4) If you want to use baked-clay type products for growing succulents I suspect that Akadama does not offer any advantages over moler but is a lot more expensive.

[Diane]

I agree with everything Terry wrote.

[juster]

I also agree with Terry's advice; just keep it simple. I use Chempak 8 in the growing season, mainly May to August, it comes with a measuring spoon and a recommended dilution, which I cannot recall offhand. I used to feed with the recommended strength at every other watering, but last year I changed to half strength at every watering and I think my plants look better, although the extra time for repotting might also have helped.

[esp]

Birmingham has very soft water. Not much dissolved Ca. Typical pH is around 7.8. You can check it here: https://www.stwater.co.uk/my-supply/wat ... r-quality/

This includes a short table of hardness for a few English cities: https://en.wikipedia.org/wiki/Hard_water#Other_indices

I'd agree with the others, use a mix that works, maybe adjust it a bit for a few tricky species, Ignore fussy recommendations for added limestone / gypsum etc in the absence of "rock" solid, peer reviewed science which proves it helps (I don't think this science exists?)

Ignore fussy recommendations for boiling your water etc (if you live in Birmingham anyway). If you can give your plants a good flush with rainwater once in while, then why not. Collect it in any sensible way you can, or leave plants outside if you can for a period over summer.

I'm another Chempak 8 user. Usually about 1/2 strength, sometimes up to full strength for strong, vigorous growers, sometimes none.

[FredG]

Ignore fussy recommendations for boiling your water etc (if you live in Birmingham anyway).

Why would one boil the tap water anyway? Surely this just concentrates the non-gaseous impurities. I don't think the plants bother a lot with germs.
If you insist on boiling then the bit you want to collect is the steam ie use a still.

[esp]

Why would one boil the tap water anyway? Surely this just concentrates the non-gaseous impurities. I don't think the plants bother a lot with germs.
If you insist on boiling then the bit you want to collect is the steam ie use a still.

Not my idea! It can precipitate out certain salts I believe, but sounds a pointless waste of time / energy for the vast majority of us who don't have water of exceptionally poor quality from, for example, their local borehole in the desert.