Gardeners are noticing that some leaves on vegetables are turning yellow.
There are several reasons for the yellowing of leaves:
* *senescence* – the natural process of deterioration which follows
the period of development of a plant.
* *shading *- as the plant grows, the leaf canopy expands, thus
reducing the light available to the lower leaves, which then turn
yellow.
* *water logging* – causes yellowing and wilting – the plant will
not be happy.
* *nutritional problems* – usually a deficiency. The essential
element for green leaf production is nitrogen. Lack of nitrogen
is the most common cause of yellowing. This is easily rectified
by an application of a nitrogenous plant food or fertiliser.
Deficiency of certain trace elements also causes yellowing of
leaves, for example manganese.
