NewsJardinTV's editor-in-chief, Patrick Mioulane, invites you today to explore in detail the possibilities offered by an ancestral cultural practice called liming, that is to say the use of lime, a natural product obtained from limestone rocks. Limestones are very common sedimentary rocks, formed by the accumulation over millions of years of shells and skeletons of marine animals. Limestones are mainly composed of calcium carbonate (CaCO3) and magnesium carbonate (MgCO3). By heating limestone to around 900 °C in a calcination kiln, quicklime (calcium oxide Ca0) is obtained. Mixed with water, quicklime becomes slaked lime or calcium hydroxide (Ca(OH)2). Lime has a thousand and one uses in our daily lives: steel industry, glassmaking, paper pulp, water treatment, smoke treatment, soil decontamination, waste transformation, animal feed, disinfection, food additives, construction materials including cellular concrete, etc. In the garden, lime plays a major role as a soil conditioner, moss control in lawns and a barrier against insects and diseases. It is a pH regulator that also provides calcium to plants. We use "TerraCalco Garden" from the Belgian company Carmeuse, which is manufactured in France in Pas-de-Calais. It is a product of natural origin that comes in the form of a ready-to-use dry powder, composed of 94% calcium hydroxide, but which also contains a little magnesium oxide (magnesia). TerraCalco Garden acts on both the soil and the plants, I suggest you understand how and why… Liming improves the chemical properties of the soil: Lime balances the pH of the soil which, for the optimization of a large number of crops, must be constant and neutral (between 6.5 and 7.5). In most of our regions the soils are clayey, compact, asphyxiating and gradually become acidic following too constant use of fertilizers, particularly nitrogenous and too generous use of organic matter. Lime improves the water management of the soil, so the soil's water reserves are more available for plant roots. Lime releases the fertilizing nutrients blocked in heavy and compact soils (especially phosphorus), which reduces the use of fertilizers. Lime limits the ability of plants to absorb toxic elements present in the soil, particularly aluminum which harms the development of plant roots and heavy metals (cadmium, chromium, mercury, nickel, lead, etc.). Liming improves the biological properties of the soil: Lime stimulates biological life in the soil by creating optimal conditions for the development of microflora and microfauna. Lime improves the transformation of organic matter into nutrients by soil microorganisms. Liming limits bioaggressors. Lime prevents the development of moss on lawns and promotes their greening by contributing to deep rooting. Diluted lime brushed on tree trunks and in the crevices of the bark constitutes a barrier against most insects and destroys their larvae. Diluted lime brushed on trees prevents the development of lichens. What is the role of calcium for plants? Calcium is not included in the major nutrients (NPK) or in the trace elements. It is considered a "secondary macronutrient" (with magnesium and sulfur). However, it plays a major role in the constitution of plant tissues and allows plants to develop better. Calcium stiffens the cell walls of plants (the middle lamella of the membrane has calcium pectate as its structural component). It therefore improves the strength of the stems, but it also strengthens the natural resistance of tissues to attacks by bioaggressors (insects and diseases). Calcium activates various enzymes that stimulate seed germination, stem growth and the formation of young roots. Calcium plays an activator role in photosynthesis. Calcium promotes fruit set (transformation of the ovary into fruit) and therefore the quantity and quality of harvests. Calcium makes nitrogen more available to plants. Calcium plays a major role in the adaptation of the plant to environmental changes by acting as a messenger for certain hormones. We hope that this video has interested you and that you have enjoyed it. To improve your knowledge of plants, gardens, botany, nature and gardening, don't miss a new program four times a week: "LE QUOTIDIEN DU JARDIN". It's on NewsJardinTV and nowhere else!