The answer of Maryse Friot, President of the Société d’Horticuture de Touraine.
Indoor plants live in more or less large pots. The roots are locked in the substrate and develop as best they can. They consume the mineral elements present in the substrate but, gradually, these are running out. The soil is depleted and food reserves are no longer sufficient.
What happens then?
– The plant withers and the internodes lengthen
– Foliage becomes dull
– The flower buds abort (they dry up and detach from the plant)
– Very quickly after watering, the plant wilts. In fact, the water can no longer block itself in the pores of the soil because there are not enough of them.
– When watering, the water flows in large quantities outside the pot without moistening the root ball.
– The roots come out through the hole in the center of the bottom of the pot (we say that the head plant).
– There is no longer enough room for the roots that are overflowing from the pot.
– When the substrate is lacking, the soil decreases in thickness. it seems to melt on the surface of the pot.
In all these cases, it is important to repot.
– Bring a suitable soil mixture, airy and rich in mineral salts.
– Choose a pot with a larger diameter of a few centimeters.
– Preferably repot in spring or autumn, but if there is an emergency, do it whatever the season!