After a long period of rain, the soil becomes very wet and even saturated. This can lead to unexpected delays in plant growth. Prepare your plants now so that they can use this water during summer dry spells.
By Jean-Marie Laporterie, agricultural engineer. After very heavy rain, the soil is damp, even saturated. This leads to exceptional delays in vegetation. It may prove wise to leave the carpet of grass in place (and weed later) and/or to perform the next plantations on piles of earth.
Starting now, let´s prepare our plants so that they can make the most of this water during the summer drought.
Encourage deep roots If your soil has good biological activity and is broken up on the surface, the roots will go down deep (see the feature ""Think of your soil as a living organism""). The young plant develops its root system in deep, damp soil. When summer approaches, the soil will dry at the level of the surface, especially if there is wind, but the plant will resist the drought and will not become stressed (1).
Before the summer, delay and/or moderate watering to ""force"" the plant to take deep roots and to acquire resistance to water stress.
Deep roots=
Savings in irrigation water and watering time. Limited evaporation
During the day, when it is hot, plants develop a strategy of avoidance that allows them to limit their water consumption. The leaves fold and curl up on themselves. At night or in the morning, they are back to their usual appearance. Gardeners call this ""letting them suffer"". This plant is restored, because there is no significant hydric stress, no lack of water.
To effectively limit the evaporation of water in soil, you can resort to mulching (2). Without mulching, the water in the deep layers of the soil comes back up to the surface and evaporates. Mulching acts as a barrier and the water remains available to the plants. When summer comes, mulching allows you to delay watering or to water less frequently.
Mulching = Savings in water irrigation and watering time.
Irrigate according to ""maximum dose"" During the summer, we reduce the frequency at which we water by using the ""maximum dose"". This is the amount of water required to moisten all of the volume of soil used by the roots without loss through deep percolation. Water the base of the plant at the end of the day, and not the upper part (less loss due to evaporation and good sanitary conditions for foliage).
Irrigation by ""Maximum dose"" = Savings in water irrigation and watering time. Do your tomatoes look sad because you have been neglecting them? It is quite possible that you will water them generously. Too generously! Too dry most of the time and drowned all of a sudden, your tomatoes may develop ""black bottom"" and they will not grow properly. If the roots are deep, they will escape the brutal nature of these cycles and their growth will be more harmonious and they will produce more.
(1)HYDRIC STRESS: A plant that lacks water becomes stressed and develops biological responses that allow it to survive. The greater and longer lasting the lack of water, the more the plant suffers. It´s logical. However, the stress is multiplied by alternating periods of drought and periods of overwatering and this is even worse. The plants, in particular tomato plants, are unable to cope! Deep roots, moderate watering and good soil cover will solve the problem. (2)MULCHING: At least 5 cm thick, this is made from plant debris that will also enrich the soil (straw, bark, grass clippings…), or mineral components (gravel, slate, pozzolane…).
Jean-Marie Laporterie, doctor in soil science, engineer and pedologist has devoted his life to studying soils. Now that he has retired, he continues to fight to improve food producing methods, in particular in Ethiopia, where, at his initiative, thousands of olive trees have been planted.
