POTTING SOILS

Wairarapa Times-Age, 19 May 1939, Page 3

POTTING SOILS

SOME USEFUL HINTS. , Those who grow plants in pots or who raise plants from seed are interested in potting soils and the best of these consist of the top four inches of an old pasture which has been grazed by cattle or sheep for years. The nature of the grass is important, and a good mixture of ryegrass and clover with some fescues and browntop are a good indication, but a turf of either pure browntop or fescue is not so desirable, for these are usually found on' comparatively poor soil, or one which is inclined to be sour. Turf from a swamp should also be avoided for good drainage is necessary to get the right amount of fibre, and accompanying soil. Good potting turf can often be obtained from the roadsides, but it is advisable to obtain the consent of the local authority before removing it. When cut, it should be stacked with the grassy side downwards, and if the soil is poor it is an advantage to put in a layer of cow manure between each layer of sods. A dusting of wood ashes is also an advantage. When building up the heap finish off with a sloping roof like a haystack, or cover with a few sheets of iron to keep out excessive wet. Sterilising potting and seed sowing soils is now considered almost essential and as there are several simple methods of carrying out this. work there is no need to use soil which has not been treated. Partial sterilisation not only destroys the weeds and w r eed seeds and all harmful insect pests, but it has a very important influence on the micro-organisma.v destroying those which are harmful and thereby increasing the soils fertility. It is true that the good organisms are destroyed as well as the bad. but the good recover more quickly, and are able to do much useful work before their parasites become numerous again. Sterilisation by means of steam is the most satisfactory method when large quantities have to be treated, and after removal from the container it should be spread out to allow the moisture to evaporate, otherwise when it cools it becomes soggy. Sterilisation by means of electricity is both simple and effective. A simple and inexpensive method, when only a small quantity of soil has to be treated is to make a fire in an oil drum, to damp the soil and put it on a sheet of iron; put a wet sack over it and place over the fire in the drum. In about 20 minutes it will be heated sufficiently to kill weed seeds and destructive insects. Sterilisation by means of chemicals can also be carried out, and the simplest is with apterite. This is a reddish powder which is mixed with the damp soil as it is turned over, mixing about a pound to a barrowload of soil. It is then covered over with damp sacks, which keep in the fumes, and left for a few days.