Why are Fertilizers Necessary?

Te Ao Hou, March 1962, Page 59

Why are Fertilizers Necessary? by R. G. Falconer Most home gardens are quite small, and these small areas have to be used year after year for growing different sorts of vegetables. Plants use up a lot of the goodness in the soil, and this is particularly so in a small area such as a home garden. You must put this goodness back into the soil again if you want to keep on growing vegetables successfully. You can do this in two ways. Firstly, you should build up the fertility of the soil by putting in lots of organic matter; that is, either compost or else household vegetable matter such as dead cabbage tree leaves, lettuce leaves, and so on. Seaweed is very good too. When there are parts of the garden which you do not need in winter time, you should sow them with lupins, or some other suitable cover crop, according to your locality. Lupins are a valuable way of putting goodness back into the soil, and now is the time to be thinking about planting some for the winter. When the lupins die at the end of winter, you should dig them into the soil to enrich it. So the first way of making your soil better, is to dig in humus, that is, decayed plants of all kinds. This is most important of all. Artificial Fertilizers As well as this, you can help your soil by using artificial fertilizers. These are accepted today as a simple and practical way of keeping soil healthy, but remember that it is important always to dig in natural fertilizers, (that is, decayed plants and vegetables) as well as the artificial ones. There are three main fertilizing elements which are needed for the healthy, well-balanced growth of vegetables. Nitrogen is obtained from organic sources such as dry blood, blood and bone, and fish manure, and from inorganic sources such as sulphate of ammonia, nitrate of soda and so on. Nitrogen helps to make plants grow rapidly and become leafy. Phosphates, which are obtained from organic sources such as bone dust, and inorganic sources such as super phosphates and basic slag, help roots to grow, and plants to become sturdy and fruitful. Potash, sulphate and potash or muriate of potash, is also important. This is possibly not used in home gardens as much as nitrogen and phosphates, but it is also very necessary, as it helps plants to resist disease, and gives colour to fruit and foliage. Fertilizer manufacturers today are producing what is called a complete fertilizer, which has the proper proportions of nitrogen, phosphate and potash mixed up together. These complete fertilizers come under various trade names. If you use one, your soil will get the right amount of these three main elements that it needs to keep it healthy. Complete fertilizer is good for crops such as potatoes, tomatoes, cabbages, lettuces, pumpkins, melons, etc., and on the whole it can be used with advantage for strawberries, raspberries, blackcurrents, gooseberries, and fruit trees. But do not forget that whether or not you use these artificial fertilizers, it is very important to use decaying plant matter as well. You can use this as a mulch on top of the soil, or else you can dig it in. Either way, your plants will grow much better because of this. Horse and cow manure are very good as fertilizer also, and if you live in the country you should use this. Trenching Another good plan, at this time of the year, is to trench any part of your garden which you won't be wanting for the next few months. Trenching is a way of digging and turning over the soil very thoroughly. You dig a complete trench, and shift the top soil from this trench to the opposite end of the area you will be digging. Then you use your garden fork to loosen up the sub-soil by turning it and breaking the top crust. After this you dig the next row, shift the top-soil over into the part you have just finished, and loosen the sub-soil in the same way. You keep digging one row after another like this, until you have finished the whole area. It is a good idea to dig in decaying vegetation or compost while you are on the job. Root vegetables, such as carrots and parsnips, do well when the soil has been treated in this way. Trenching takes a fair bit of time and energy, but you will really see results if you do it. The idea should be to trench one small part of the garden at a time, so that in the end you will have dug over the whole garden.