Saturday, May 30, 2020

Dave's soil mix for growing succulent and desert plants

My seed raising mix, essentially identical to Mesa Garden's recipe
My seed raising mix, similar to Mesa Garden's recipe
Here is my soil mix for succulent and desert plants. The mix should be mostly mineral materials with minimal organic matter so that it mimics the low oragnic content of desert soils. This doesn't mean the soil is necessarily poor in nutrients. Mineral materials contain the inorganic salts that plants combine with water and carbon dioxide to create organic molecules using photosynthesis. A mineral soil is suitable for most plants. Think about a hydroponic system, there are no organic components in the system other than the plants. Most plants do not require an organic component in their soil.

Main mix. This is what I use for almost all my succulents and desert plants.

1 part decomposed granite (DG)
1 part coconut coir
1 part perlite
1 part red scoria

You can substitute different items depending on what's available in your area.  If you live in an arid or semi-arid area and have good desert soil, e.g. "sandy loam", you can substitute it for decomposed granite (DG).  Pool filter sand can also be used to replace the DG component, but it doesn't have the fine particles and soluble nutrients of DG and I personally don't like it. Coconut coir can be substituted with peat or commerically available "cactus potting soil". Coconut coir is best obtained as dehydrated compressed bricks for easy storage and transportation, and it's fairly sterile. Perlite can be substituted with pumice. Do not use vermiculite as it holds too much water. Red scoria can be substituted with black scoria. Some components can also be left out and the mix made from only two or three of the components.  The aim is to create a well draining soil with little organic matter.  You can also vary the ratio of the components for different ypes of tplants.

Seedling mix
Use Mesa Garden's germination tips and follow them to the letter.

2 parts coir (replaces Coconut blend potting mix)
2 part decomposed granite (replaces sandy loam)
1 part perlite (for aeration and drainage)
1 part vermiculite. (to hold water, young seedlings require constant moisture for the first year or so)

- Dave Bad Person

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