QuestionsHow to growFlowersBorder Perennial Flowersgrow on ashes 0 Vote Up Vote Down kathleen furlong asked 16 years ago I have what s called a ash pit if i put soil in it, can I sow there? 1 Answers 0 Vote Up Vote Down Gerry Daly Staff answered 6 years ago An ash pit can be very alkaline and cause problems for plant roots. Much depends on the ash and how aged it is. If it is old the ash will have been leached out by rain. If the layer of soil is deep enough, say 30cm, most flowers will grow on it.