Ash is a touchy subject. I recommend it only if you grow outdoors directly on the ground. For pots it is preferable to use another method.
Starting to sprinkle ash on the soil during the first weeks of flowering will provide your plants with excellent levels of potassium.
But you must be careful, the ash when wet will generate lime and salts that in large quantities can burn the roots at most, or modify your pH levels generating deficiencies.
Start the plant slowly, using little ash and seeing how it reacts, and then increase the dose.
- If you have a stove or grill, collect the finest ash you can find in a plastic bag, leaving aside the pieces of coal.
- Take a handful with your hand and sprinkle around the plants above the ground, without touching leaves or flowers.
- Take care not to cover the entire land. Take a look at the example photo.
- Water normally with calm water from now on.
This will give you a good hit of nutrients, especially for flowering potassium, and it will stay in the ground for a while.
Be very careful not to sprinkle too much. And if you are applying this type of fertilizers, it would be better to start regulating the pH.