IN AND ABOUT THE FARM.

Waipa Post, Volume VI, Issue 266, 21 November 1913, Page 4

IN AND ABOUT THE FARM.

WATER SUPPLY FOR GROWING PLANTS. ITS IMPORTANCE IN TOMATOCULTURE UNDER GLASS. The question of moisture_ in plant-production is of vital importance. It is well known that to keep a plant in health there must be a continuous and regular supply of moisture to the roots. This is drawn up and evaporated or perspired, through the leaves. It is this process of transpiration that keeps a plant cool in the hottest weather. It is so rapid that, according to J. D. Hooker, "a sunflower-plant has been found to give off a quart of fluid in twenty-four hours." In a tomato plant, every part of which is green and soft, this transpiration takes place from every part of the stem as well as through the leaves. To prove that this is the case one has only to notice those plants which have had their leaves almost entirely taken away to ripen their fruit (wrongfully, of course) to understand that in their case the transpiration must be very great, even through the green stems.

It has to be realised by the grower of any plant, particularly plants being raised "nder glass, that where the conditions depend to a great extent on their being maintained artificially, the soil medium must be such that the supply of moisture, air, and temperature to the roots can be regulated. To state that good drainage is one of the chief means to attain this condition of moisture in the soil may appear, to any one unacquainted'with the principals of plant-growth, contradictory. It is, however, really the case that the providing of a means of taking away surplus water regulates a better supply of moisture to the roots of plants. By affording good drainage and cultivation the soil is then in much the same condition as a sponge, which draws up to itself from below just that supply of moisture necessary, admits air from the surface, and maintains a temperature suitable to plantgrowth. In representing the soil as a sponge it can also be understood more readily how the roothairs, with their spongioles, can push their way through the interstices in every direction, and draw the moisture and air required for their growth.

Let it be noted now how necessary it is to prepare the soil beforehand by trenching and draining in order, to obtain these conditions. When the surface is regularly cultivated —just lightly hoed —the moisture is maintained about the roots, and much watering of the surface is thus avoided. When watering is done it should be by moving the rose over the surface several times rather than giving one heavy application, so as to avoid consolidating the ground. It is obvious that where a stream of water out of a hose is left running for hours very considerable consolidation of the soil must occur. This method ofapplying water is too often practised, with a frequently disastrous result to the plants, because the insterstices or minute cavities become closed. This prevents the entrance qf air and the free growth of roots, and lowers the temperature of the soil. A short time ago the writer met with a case that will serve as an illustration of bad and good culture. A tomato house (go ft. by 27 ft.) was situated on a gentle slope. The soil was a good loam of some 6in. to Bin. deep, with a retentive clay subsoil. It was drained around the outside, but, owing to the cold, impervious nature of the subsoil, this proved insufficient to get good results. After growing tomatoes in it for a few years the owner gave it up, the yield of fruit scarcely paying expenses. The house passed into the hands of another man, who on obtaining possession at once proceeded to trench the whole house. In the bottom of the trench he placed a layer of broken bricks, grading the trench with a slight fall to the side drains. On the top of the bricks he replaced the soil, well mixed together and with other good soil added, to a depth of lßin to 20in. The result was that he cleared £BS from his first year's crop. The second crop is now well advanced, and is an object lesson of good work, even growth and healthy condition. He says that the yield for this year will more than double the yield of last season. It may be added that he used very little water.