Of the ash types, only wood ash is suitable for improving the soil

Of the ash types, only wood ash is suitable for improving the soil.

Although ash is rarely used to improve soil, be said here, that ash of lignite (briquettes) can do more harm than good. It smears the soil and worsens the soil condition. Only pure wood ash or wood ash slightly mixed with brown coal ash should be brought into the ground when digging. Soot is safe to put in the ground, although the nature of its effect is not yet fully understood.