Succulent Soil Composition

[WayneByerly]

I've been growing succulents, mostly cactus, for several years now ... I started in 2009 ... that makes me a newbie I guess. In this time, the information I've collected tells me that the following formulation might be a good one for growing Cacti, Caudiciforms and other succulents in General.

Members: If you have the time, please examine this "formula" and give me your opinion/thoughts/ideas/criticisms. I will appreciate any and everything that anyone MIGHT be able to inform me on/correct me with.

My Soilless Mixture Succulent Growing Medium

-- (1 part) Miracle Gro Moisture Control Potting Mix [sphagnum peat moss, (one or more of the following: processed forest products, peat and/or compost), coir, perlite, fertilizer and a wetting agent]
..... to provide SOME organic material but in big enough pieces as to assist drainage.

-- (1 part) equal amounts of 1/4" black lava rock and 1/4" red lava rock ... two kinds ... just for decorative reasons.
..... the stuff that grows in Hawaii is verdant beyond belief. My firm opinion is that this is because they are growing in a lava rock enriched environment with all the mineral supplements that ANY growing thing could want. It's rough texture should also assist in drainage, aeration and water retention.

-- (1 part) coir
..... what i have read about this is that I could use it by itself, and grow ... things ... successfully. It drains well, retains moisture to some extent, and inhibits the growth of many fungi from what I read. I have also read this coir lasts up to 4 times as long as peat.

-- (1 part) coarse sand
..... to help promote drainage & aeration ... should I perhaps substitute pumice here (I despise the use of perlite due to it's "float to the top" nature ... ugly stuff).

-- (2 parts) 1/4" bark fines
..... to help promote draining, water retention, aeration and light so that roots may easily grow,

If anyone can think of any objections to any of the above materials, I would appreciate an explanation as to the reason.

Thanks, in advance, if any of you have the time and/or inclination to respond to this.

[iann]

The only real objection will be if plants don't grow well in it. Personally I can find all sorts of things to complain about, but then I grow Lithops

[DaveW]

I agree with Ian. If your plants grow well in it and don't look overblown it's OK. The Dutch nurserymen can grow their plants wonderfully well in peat potting mixes. But once allowed to dry out by the retailers we have trouble wetting them again. It's always a case of "if it ain't broke, don't fix it". Peoples growing conditions vary and what may work for them may not work for you.

The basic requirement is a potting soil that provides all the nutrients the plants need (or you need to provide these by regular fertilisation) and drains and dry's out quickly in your conditions. You will get away with a more water retaining potting soil in a hot country, since it will dry quicker in the heat, than in our colder climates where it needs to be even quicker draining.

A friend of mine claims you can grow cacti in virtually any soil provided you get the watering right, since it's all really down to how long the plants stay wet around the neck and roots. We all keep trying the next "wonder mix" hoping it will increase the plants growth rate, but seldom if ever find it.