POTTING SOIL

Wairarapa Times-Age, 23 July 1941, Page 3

POTTING SOIL

SHOULD BE STERILISED. Soil used for the first time, or which is to be used for the second time for growing greenhouse crops such as tomatoes, French beans and others, should be sterilised. Apart from killing spores of fungus pests and eggs of insects, sterilising also has a beneficial effect on the soil, because it ensures that harmful bacteria (denitrifying) are destroyed and the beneficial bacteria (nitrifying) or nitrate makers are induced to multiply more rapidly. For a small quantity of compost it is only necessary to suspend it in a piece of sacking over boiling water for 30 to 40 minutes. Another method for a small quantity of soil is to place it in a deep pan or bucket and stand it over a fire or gas jet until it becomes steaming hot right through. It must of course, be kept constantly stirred to ensure the best results. Sterilisation can also bo effected by the use of chemicals. Mix 3oz of formaldehyde in 1 gallon of water and water the soil, stirring it with a stick all the time. Half a gallon of the solution should be sufficient for one barrowful of compost. Cover the heap with sacks and leave for a week or two, then uncover and stir the soil to allow the remaining fumes to escape.