Yes, just be sure that you are using it for alkaline or ph neutral plants, not acid loving plants. Calcium raises the ph in soil slowly and wood ash is alkaline. It should not be used in compost too heavily because it can disrupt the microbial activity. Also, avoid using with nitrogen fertilizers like urea because it creates ammonia gas. 😉 Biochar is great for many plants in the garden and you will find many companies using it in bagged soil. Thanks for sharing @rakkasan84 and great tip:

You can spray some water on the coals after your wood has burnt down and it will stay like a charcoal.

Just be sure to use hardwoods - they contain as much as 5x more nutrients than soft woods. Oak & maple work great, but I recommend readers avoid using chemically treated wood like pallets and construction​ debris.