Earthing up in the vegetable garden, how, when and why

There is a simple but highly important operation that is required by many plants: earthing up. It consists in packing new soil around the stem of the plant after it has been planted out and taken root. But why do we need to earth up? It helps the plants grow and produce fruits thanks to a series of advantages.  Let’s see what they are.

1. Mechanical stability. A plant that has been earthed up has a greater mechanical stability against the wind that bends its stem. The seedling offers less resistance to the wind’s action and therefore suffers less stress when the wind blows. It is a good idea to give the plant greater stability by adding extra soil around the base of the stem.
2. Protection for the roots.  In certain cases the soil at the base of the plant can be washed away due to incorrect irrigation; earthing up makes it possible to protect the roots, which otherwise, uncovered, would suffer from excessive evaporation and therefore wither and have a reduced capacity of absorption.
3. Growth of new roots. The soil earthed up to cover new parts of the stem – which would otherwise be exposed to the atmosphere and light – stimulates, in those parts, the growth of new roots.

Earthing up in Summer
Generally speaking all plants gain from earthing up, which in our family vegetable garden is carried out using a hoe. Among the plants to be earthed up during the summer are tomatoes (Lycopersicon lycopersicum L.).
During this season it is useful to earth up after fertilizing the surface of the soil and irrigating. You will need to pack new dry soil around the base of the plant to cover and protect the area that has been watered and fertilized. Essentially the soil acts as a protective summer blanket, because it stops the irrigation water from evaporating; at the same time the tomato plant, in the part of the stem covered, produces new roots.

Stefano Pissi, agronomist, member of the cultural association “gli Ortisti”