Maybe a little confusing the title of the topic, but I would like you to share with me the experience of using different types of stones for the purpose of gardening and planting. I am interested in more information about:
1. gravel
2. pumice
3. lapilli
4. perlite
5. silica sand
I am well acquainted with perlite and silica sand and these are the only two things I use occasionally. Silica sand helps me keep the soil loose, and perlite helps me to ventilate the soil and retain water. I am more interested in the first 3 things. If anyone uses or has knowledge of what the first 3 things are best let me know.
The reason I am interested in this is the recent loss of L. sulphureum. I would like to improve the soil composition to have better drainage. My biggest problem is the summer heat that lasts for months and rain is really rare. That is why my main ingredient in the soil is peat with the addition of coconut fiber, and that helps me retain water better when I need it most. However such a mix is disastrous in winter if there is too much rain. So far I have had no problems with other trumpets and lilies, but obviously this is not the case for Sino-Himalayan species such as L. sulphureum.
Do you use gravel, pumice and lapilli and if so in what percentage? Can the use of these stones change the pH of the soil and are they harmful to some species? Is it best to leave the composition of the soil as it is, but to pay more attention to the protection of bulbs from winter moisture and water?
Edit: I forgot to write granite. Is it used in gardening and soil improvement?

No replies. So no one uses any stones.
Is this crushed gravel good?

I use pea gravel in my gardens, lilys, hostas and others. Like it for vole prevention and for aeration, does not seem to affect the Lillies adversely.

I've used turkey grit which is essentially some rough small rock chips/pieces. I've heard as RJ mentioned above, that it could deter voles, mice and underground critters. I'm early in the trials as far as it working or not. We'll see....