This section is from the book "The Gardener V1", by William Thomson. Also available from Amazon: The New Organic Grower: A Master's Manual of Tools and Techniques for the Home and Market Gardener.
Under this head may be enumerated a variety of bad practices, as numerous, perhaps, as those which are classed under the general term Neglect. Among these, the system of watering usually adopted takes a prominent position. In hot weather, when the ground is dry, and plants are beginning to droop from the heat of the sun, the uninformed amateur usually sets to work and waters the whole of his flower-garden, the water being carried in many cases direct from the pump. It is consequently several degrees colder than the atmosphere or soil - having much the same effect on the constitution of the plants as would be likely to be produced on a human being by drinking a quantity of cold water when in a state of violent perspiration. I said, "waters the garden," but I mean the surface of it. So that the surface of the soil and the foliage of the plants are wet, presenting a nice cool appearance, the owner is satisfied; he considers he has done a few hours' hard work, and consequently a considerable amount of good. Now, in my humble opinion, he had far better have amused himself in some other way, and have let nature alone, unless he had considered how he could have better imitated her. Watering should never be attempted unless it can be properly carried out.
Few things are more injurious to the well-rooted plants than occasional sprinklings of the soil. Syringing the foliage of plants with tepid water in the evening, in dusty weather, is very beneficial, as it cleans the foliage, and acts in some measure like heavy dews. When water is intended to be given, it should be taken from a pool or brook. If neither is at hand, a sufficient quantity should be pumped in the morning and allowed to stand exposed to the sun for a day at least. Instead of just wetting the surface, the soil should have a complete soaking, so as to reach below the lowest of the fibres; if such is not the case, the small white roots will be turned upwards in search of moisture, and in a couple of days probably will suffer from the burning sun. The roots of plants will always follow after their food, and if left to cater for themselves will generally make the best use of what is within their reach. As a test of this, let the cultivator lav a slight covering of rotten manure on the surface of the soil, in the vicinity of healthy plants, and in the course of a week, on taking the manure away, he will perceive hundreds of small white fibres attached to it, which have found their way there for the purpose of feeding upon the food which is placed near them.
The reader will understand by this that it is better never to attempt watering established plants in the open ground unless the plants are kept well supplied with moisture, which, in such cases, can only be done by constantly soaking the soil whenever it may become dry on the surface. No plan is so beneficial as what is termed "mulching," that is, laying a covering of grass, manure, cocoa-nut fibre, spent hops, or any like material, on the surface of the ground, which should always be done after soaking rains. This practice prevents the evaporation of moisture to a great extent, and keeps the temperature of the ground much more regular than any system of watering could do. The great objection to "mulching" is the slovenly appearance it gives to a garden, so that it cannot be done in flower-gardens generally; still I would rather make use of something of this kind than be compelled to adopt the laborious and uncomfortable practice of watering. Many persons think that much more benefit is derived by the plants from even judicious waterings than I am inclined to suppose is the case. To satisfy myself on this point, a few years ago, on an occasion of dry weather setting in, in the early part of the summer, I made a practice of watering an onion-bed three times a-week with water from a pond.
Another bed by the side of it, growing under similar circumstances and sown at the same time, was left entirely to nature. The bed which received the attention spoken of in about ten days looked much superior to the other, the Onions being greener and growing much quicker; but when the rain came, I was pleased to see the neglected bed was inclined to make up for lost time, which it most certainly did, the crop eventually being quite equal to that of the favoured bed - plainly showing me that I had been working to no purpose. C. J. P.