After a tree or piece of wood burns, it produces wood ash. According to "Biomass and Bioenergy," up to 1.8 per cent of the mass of burnt wood turns into ash. Wood ash can benefit the soil and act as a fertiliser to low-acid plants. It is important that you test your soil's pH before spreading wood ash as a fertiliser, which works best in soils that have a pH of 7.0 or lower.
Asparagus is a flowering plant and vegetable. According to "Interactive Flora of NW Europe," asparagus is in the lily family and is related to onions and garlic. The asparagus plant can grow up to two meters tall and thrives in salty, sandy soil. The Cornell Cooperative Extension Office states you should apply no more than five pounds of wood ash to every 100 square feet of soil on an annual basis, preferably in the winter. This rule applies to asparagus and other plants that benefit from wood ash.
The juniper is a coniferous tree or shrub in the cypress family and grows throughout the northern hemisphere. Young juniper plants have pointy needle-like leaves while mature plants have scaly needles. The berries juniper produce are a main ingredient in gin and a spice.
Grass is an herbaceous plant that supports many animals. The Oregon State University Cooperative Extension states that if your lawn needs lime or potassium, it may benefit from a sprinkling of wood ash every year. They recommend spreading 4.54 to 6.8 Kilogram over 1,000-square-feet of grass every year if the soil is alkaline and potassium levels are low.
Roses are perennial, fragrant flowers that grow on a shrub or vine. The pruning of roses is a form of art, as is their care. The University of Oregon Cooperative Extension recommends spreading one-half to one pound of wood ash every year around the soil under a rose bush. After spreading the ash, carefully rake it into the soil to spread the ash evenly.
Broccoli is a vegetable closely related to cabbage. The flowering heads of broccoli and their thick stalks cause the vegetable to look liked a small tree. Clemson University Cooperative Extension states broccoli does not do well in highly acidic soils and thrives in cooler temperatures. The ideal soil for broccoli offers good drainage, such as sandy or clay loam.