Using Wood Ash as a Fertilizer.

"Using Wood Ash as a Fertilizer Wood ash is an excellent source of lime and potassium for your garden. Not only that, using ashes in the garden also provides many of the trace elements that plants need to thrive."

"But wood ash fertilizer is best used either lightly scattered or by first being composted along with the rest of your compost. This is because wood ash will produce lye and salts if it gets wet. In small quantities, the lye and salt will not cause problems, but in larger amounts, the lye and salt may burn your plants. Composting fireplace ashes allows the lye and salt to be leached away."

https://www.gardeningknowhow.com/garden-how-to/soil-fertilizers/using-wood-ashes.htm

Placing rotting food into a composter indoors seems strange at first. You get used to it though because it makes such great soil.Mold really isn't an issue. In fact; cheap soil from the store is more likely to go moldy than rich, broken down homemade soil. I recommend "vegan" soil free of dairy & meat. It makes the mold more manageable.

The most basic Wood ash compost recipe is: Ash, soil & composting food.
You can also add:
manure
worms
worm castings
epsom salt
calcuim
magnesium
kelp

Don't forget to water! Compost can't break down if it's dry. Also make sure you don't over water. Let the soil dry out almost all the way between waterings for maximum potential & to avoid mold. Advanced growers should measure PH of soil/run-off

I use plastic bins just like this. Make sure you poke holes in the bottom just like you would for a plant. Make sure that the water is running out of the holes and they don't get clogged. Keep the lid on. If the soil appears moldy or smells bad: place outside for a few days. If the mold doesn't go away keep it ouside permanently. Keep the room with the compost clean. Add a fan if the air is stale.

This "recipe" also works well outdoors. Enjoy.