What Is Limewater: Uses and Precautions in Agricultural Planting

Limewater is the calcium hydroxide solution obtained by adding water to quicklime. People commonly call the clear upper layer limewater, while the undissolved cloudy slurry is called milk of lime. Quicklime releases heat when it meets water and gradually turns into slaked lime, so it needs to be stirred while water is added during preparation. Limewater is colorless and transparent in appearance, with a distinctly alkaline nature.

It is fairly strongly alkaline, and on contact with carbon dioxide in the air it forms calcium carbonate, which turns the liquid cloudy. This property can be used to test for carbon dioxide, and it also reminds users that limewater should be prepared and used fresh; leaving it too long will reduce its effectiveness.

In agricultural production, limewater has a fairly wide range of uses. It is often used to adjust acidic soil and improve the growing environment for crop roots, and it can also be used to disinfect seedbeds, livestock sheds and farm tools. The whitewash applied to tree trunks also has lime as its main ingredient. In flower care, a small amount of limewater can neutralize overly acidic growing media, but acid-loving plants such as orchids (Cymbidium) and rhododendrons should be used with caution, so as to avoid alkalinization of the medium affecting growth.

When using limewater, take protective precautions, as it is somewhat irritating to the skin and eyes, so it is best to wear gloves during handling. Quicklime generates heat when it meets water, so water should be added slowly and stirred thoroughly during preparation, and the concentration should not be increased at will. When used in the field or in containers, avoid the plant's tender buds and young leaves and choose fine weather, which will make the results more reliable.