Some varieties of lemon naturally exhibit a thicker skin and little juice. However, if the tree in question is a variety that is supposed to produce juicy fruit or has in the past, it is an indicative symptom. Lemon and other citrus fruits may exhibit thick skins and low juice for a few reasons.
Excess nitrogen lowers fruit quality and shortens fruit storage life. The fruit skin thickens and coarsens while the fruit's percentage and quality of juice decline. The fruit also may be puffy and see delayed maturity. The effects of excess nitrogen are amplified when the level of available phosphorus is low.
Fruits of phosphorus-deficient trees are misshapen, with open centers and course, thick rinds. The fruit is pulpy and has a low percentage of juice, which is acidic. Too much phosphorus does not negatively impact citrus trees but may accentuate any effects of a zinc deficiency.
Excess vigor may cause lemon tree fruit to have a thick rind. The fruit may also be puffy or sheep-nosed. This is a characteristic typical of off-bloom fruit and can be controlled by following proper cultural practices.
- NSW Government Agriculture: Citrus Nutrition
- California Master Gardener Handbook; Dennis R. Pittenger; 2002
- Texas A&M System AgriLife Extension: Table 2. Diagnosis of Common Citrus Problems
- Photo Credit Jupiterimages/Photos.com/Getty Images