Soil for a crevice garden

[John85]

As Tim pointed out that some of the best rock garden where on a slope with some water percolating I wonder if some gardeners have included an irrigating system while constructing their rock garden so that they can water their plants from below encouraging a deep root system.

[penstemon]

Bob - have you never seen an alpine cushion plant growing out of the narrowest crevice amongst rocks? This is their métier

Alpine plants grow in crevices because they can, not because they have to. Less competition, oxygenated soil, a means to trap water, and plenty of warmth.
Ideas like "shedding excess water" and "drainage" come from a horticultural perspective, not an ecological one.
Gentiana verna grows very well here in a couple of troughs.

[Lawrence]

I am in the process of constructing my first crevice garden in a small trough but am a little perplexed by the advice on the compost to use. My first reaction was to use the standard mix I use for the alpine house, an Eric Jarrett formula of equal parts grit, course sand and vermiculite, three parts of this to one part JI2. Then I see pictures of Ian Y using pure sand and getting very good results. Will my mixture be to "rich" ? Does the pure sand approach drain to quickly and hence supplementary watering required and what about the lack of organic matter and nutrients, isn't the sand just to sparse a medium to sustain healthy plants

[ian mcdonald]

Hello Lawrence, this has been discussed recently. I would not go for bare sand as it would drain too much and need watering every day in summer. Try experimenting, bearing in mind the species you are growing. I used a few handfuls of compost and an addition of fine grit, no need to be exact measurements, and placed thin pieces of sandstone at an angle to place the plants in-between as seen in Ian Christies garden.

[Maggi Young]

Ian McDonald mentions a recent thread on this subject - I was going to give the link but I think it is more sensible to merge the threads.



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