Organic mix to add to Pumice/Grit mix?

[bartab]

Trying to find a good over the counter mix that I could add to the plants that I want a little organic matter in with my usual inorganic blend. I'm trying to avoid a heavy amount of peat, and also don't want huge chunks of bark like so many have. I seem to recall some nice looking blends that are coir based, but can't recall the names. What do others find to be a good addition to their mix? Thank you.

[DaveW]

Usually best to mix your own if you can obtain the ingredients. Coir is usually available in blocks. Neither peat nor coir has any great amount of nutrients they are merely soil conditioners, though peat will increase the acidity of the potting soil.

It is the soil element that adds nutrients, or if you are using purely mineral mixes regularly using half strength fertiliser.

Therefore if you are trying to improve the texture of your potting soil use peat or coir, but not for providing nutrients.

https://homeguides.sfgate.com/peat-moss ... 69786.html

Remember the remarks in the following video are intended for normal plants and not Cacti & Succulents. I would not use actively rotting compost for Cacti & Succulents since plants do not rot in arid environments where our plants (apart from epiphytes) grow, but simply dry and turn to dust when they die. Therefore our plants are not used to the bacteria in actively rotting material.

https://www.youtube.com/watch?v=MvYZdxVipAo

I am giving Coir I try by mixing a little in my potting soil as I tend to forget to water my plants therefore it retains moisture a little longer. Again modify your potting soils to suit your conditions and climate. "One size does not fit all" around the world for potting soils.

Anyway how to convert Coir from the "brick" form it often comes in:-

https://www.youtube.com/watch?v=46Zk01blD2Y

[keith]

I use supersoil I posted a picture of it somewhere on this site . Miracle grow another popular bagged brand is not so good IMO.

[greenknight]

Have to disagree with DaveW a bit, not all cacti grow in extremely arid environments, those that want a more organic mix especially. However, "actively rotting compost" is not good in any potting mix, it should be finished compost - the manufacturers are cutting corners when they use incompletely composted material.

Anyway, I use Four Corners Organics potting soil. It's produced here, so the local stores carry it (not to be confused with Four Corners Organics & Hydroponics, that's a different company that's in Colorado). They don't sell it directly, only wholesale "to the West Coast and beyond", don't know if you can find a source for it. What it contains is earthworm compost, peat and perlite (used to be pumice, but they cheaped out). Earthworm compost (worm castings) are widely available, and is an excellent source of organic nutrients. There are definitely no chunks of undigested organic material, it went through a worm's digestive tract! That's what I recommend - it can be fairly expensive, but you don't use much for cactus mix.

A little bit of worm castings, a little bit of peat or coir, and a lot of grit, makes an excellent cactus mix.

[DaveW]

I should have said "where most cacti grow are arid areas" though I did exclude epiphytes. Most cacti do get some form of organic material in habitat even if it has taken hundreds of years to accumulate in cracks in rocks or open ground as dust from dried up dead plants in the past.

Note the dead plant turning to organic grey dust around it in habitat. Apart from the wet epiphytic cactus type climates you do not get the same type of actively rotting of dead plant material as you get in compost heaps.

dust.jpg (184.69 KiB) Viewed 1046 times

It is also true that cacti often inhabit the soils they do because other plants can't. Therefore they will grow in many soil mixes just as well or even better than in habitat. You don't slavishly have to mimic habitat soils to grow them apart from providing excellent drainage and maybe a PH that suits them.

[7george]

I use supersoil I posted a picture of it somewhere on this site . Miracle grow another popular bagged brand is not so good IMO.

"Miracle Grow" and organic mixes containing worm castings are not good for cacti soil mix. These contain too much nitrogen from witch cacti lose their natural shape, spines get weaker, blooming fails. Maybe just in moderate amount for fast growing plants growing in outdoor beds.

Well degraded sheep manure or leaf mold, also coco bark would better for standard cactus mix.