Hugely helping your plants to get the very most out of the soil they're growing in.
To use in your planting / growing media ?
Say a cupful for every 10 litres.
Doing some potting on ?
Just a dessert spoon' worth in the hole or larger pot.
Planting cuttings ?
Just a teaspoonful around the cut.
As a top dressing ?
Don't waste it, say a dusting just enough to be seen around the base of your crop.