The question on every gardener’s mind is what do my garden plants need? Especially how to make fruit trees grow better in Port Edward or South Coast gardens as well as vegetables, because most gardeners are reasonably successful at growing garden plants, yet find it difficult to get the fruit and vegetables they are looking to grow in their gardens.
While we do not fully understand the complex interaction of plants and soil, scientists have proven that plants of all species must access at least 16 primary chemical elements (13 minerals and 3 non-minerals) for growth and reproduction.
If you look at the label on a bag of fertiliser, you will see a listing for NPK content, nitrogen (N), phosphorous (P), and potassium (K), which are considered macronutrients (primary elements) because the plants use a lot of these elements and they are not always present in sufficient quantities in the soil.
Besides macronutrients, plants also need calcium (Ca) magnesium (Mg), and sulphur (S) which collectively are called micronutrients (secondary elements) Sufficient quantities of them are usually present in the soil, so we don’t usually need to add these minerals regularly like other nutrients.
In addition to the above macro and micronutrients, plants need boron (B), copper (Cu), iron (Fe), chloride (Cl), manganese (Mn), molybdenum (Mo) and zinc (Zn). These elements are required at minute levels and therefore are called trace minerals.
Balance the Nutrient Levels
A reasonable question to ask is, “Why not put a lot of everything (all the elements) on the soil and let the plants sort out what’s needed?” (That’s what the fertiliser industry would like you to believe.).
The answer is that in order for nutrients to be available to the plants, plants need their nutrients in relative concentration. Some nutrients don’t get absorbed into the plants and trees unless other essential nutrients are present in the correct quantities. Too little or too much and it will upset the optimal absorption rates.
Law of the Minimum
The Law of the Minimum, states that yield and the level of nutrients in your fruits and vegetables are proportional to the amount of the most limiting nutrient, whichever nutrient it may be. In other words, as Justus von Liebig discovered two centuries ago, “The most growth-limiting nutrient will limit growth, no matter how favourable the nutrient supply of other elements.”. Similar to the old saying that the strength of any chain is based upon the weakest link
A simple analogy is the water-holding capacity of a wooden barrel with a broken stave. The maximum level of liquid that a broken barrel can hold is up to the top of the lowest stave. A dusting of a product like Azomite ensures that the trace minerals, which are difficult to measure in the soil, do not become the limiting nutrients.
Taste is a subjective matter, but in general, we all enjoy fruit that is sweet, with a pleasant aroma and complex flavours. The one factor that we can measure is the level of sugar in fruits and vegetables. It is proven that fruits grown in balanced organic soil contain higher levels of sugar and higher levels of nutrients, than fruits grown in industrial farm soil that is optimised for rapid growth but not nutrients. While higher sugar makes for a sweeter fruit, higher levels of minerals produce a more complex taste. That is why successful Western Cape winemakers monitor many factors, including the mineral content of their soil, carefully.
You may be surprised to see the difference in the nutrient content of an apple grown on an industrial farm in China, versus the same apple grown in a well balanced, KwaZulu-Natal backyard fed by composting kitchen scraps.
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