The effect of culture on the nuts is quite marked. All varieties will
vary in size from season to season and in different orchards during the
same season, depending on the plant food and moisture supply available
during the time the nuts are maturing. Some varieties, notably the
Nonpareil, will vary more in size than in plumpness, while other
varieties, like the Ne Plus Ultra, are more inclined to produce somewhat
shriveled kernels and imperfectly developed shells and the variation
in size will not be as great. As the trees bear larger crops the nuts
produced are inclined to be smaller. Young, vigorous trees with a light
crop will often produce unusually large nuts with comparatively thin
shells. The value of a variety, therefore, will depend largely upon its
behavior after the trees reach full maturity and bearing.