We're doing a science project. What will happen if I add these things to my soil? Will it harden or stay the same? talc aluminum halite/sea salt iron sand/silt carbon ashes
Certified GKH Gardening Expert
All of those amendments will change the soil in some way. The questions is though, what kind of soil are you starting out with? For example, if you have clay soil and you add sand, it will harden the soil. But, if you have loamy soil and you add sand, it will loosen the soil.
It would be best to test each amendment with your local soil type to determine how it will affect your soil.