For those of you who have grown cycads for at least a few years, you probably have heard repeatedly that the most important rule to observe for the successful growth of cycads is to be certain that they are grown in a well draining soil. This is in reality a very general and somewhat relative concept. I know that many growers have different ideas as to how to formulate a good well-draining mix for cycads. I think that there is no one perfect soil mix. More realistically I believe that cycads in general are quite adaptable, and that there is a fairly broad range of well-draining mixes that are well suited to cycad growth.
I basically classify my soil mixes into two general component groups. Group number one includes a variety of mostly inert components that enable the final mix to permit good water drainage. Specifically some of the primary components that allow drainage are: decomposed granite, small size gravel, coarse sand, and pumice. These are crucial, although these components deliver very little in the way of nutrition to nourish the plant.
Number two is a group of materials that are broadly described as naturally occurring organics. These components provide nutrition to the plant by way of microorganisms in the soil which feed on the decomposing organics and help to provide nutrition that the plant can absorb. These components can be a combination of well-decomposed compost, made up of and leaf mulch, small twigs, and tree bark. There are additionally quite a few organic materials that are processed for sale from local nurseries and big box stores. Some of these components are chicken manure, peat moss, oak leaf mold, steer manure, worm casting, etc.
When varying combinations of each of the aforementioned two groups are combined into a final mix that drains well, then you have produced a soil mix that will be suitable for growing cycads.
I have not given an exact proportion of group number one and group number two materials. This is primarily due to the fact that cycad growers don’t agree on any one formula. This tells me that there is a general range of materials that will work well. Combined elements from groups one and two should be tried and proven, and gradually refined for your geographical location and seasonal conditions. The average range for combining groups one and two would be at 50% of group number one to 50% of group number two. This would be a good place to start a mix if you have never made your own mix before. In time you may learn that certain plants may respond if your mix is altered as much as 5% to 25% for either of the two groups. You may alter either of these two groups to gain more drainage in wetter climates or to gain a little more water retention in dryer climates.
If you try this approach I think you can develop a soil mix that will benefit your plants and promote optimal growth.
Grow and prosper.