The term “baby lemon” refers to the young, immature fruit that has successfully transitioned from a pollinated flower into a developing citrus ovary. This stage, known horticulturally as “fruit set,” is when the lemon tree commits resources to growing the fruit. Its appearance is notably different from the familiar yellow lemon found in stores.
The Initial Appearance of the Tiny Fruit
Immediately after the white flower petals drop away, the initial lemon fruit is an extremely small, smooth green sphere. This fruitlet is often described as being about the size of a pea, quickly expanding to the size of a marble. The young fruit is uniformly deep, dark green, resulting from high chlorophyll concentration in its rind.
The texture of this tiny citrus fruit is glossy and smooth, lacking the pitted, oily surface that characterizes a mature lemon. A persistent green structure called the calyx, the remnant of the flower’s sepals, is visible at the base where the fruit attaches to the stem. The tree produces far more fruitlets than it can sustain, and most of these tiny green spheres will naturally drop from the tree in a process of self-thinning.
Development and Defining Characteristics
Once the fruit has successfully set and survived the initial drop, it begins a steady period of growth lasting between four to nine months, depending on the variety and climate. The fruit continues its rapid expansion, progressing from marble-sized to the size of a golf ball and beyond. It remains a dense, deep green color throughout this growth phase.
As the lemon expands, it develops its unique, recognizable shape. The fruit begins to elongate, and a small projection forms at the end opposite the stem, known as the stylar end. This characteristic protuberance is a defining feature that helps distinguish the developing lemon from other young citrus varieties, such as limes or oranges, which remain more spherical.
The smooth rind gradually develops its mature texture, with the oil glands becoming more pronounced as the surface area increases. The final change in appearance is the color transition from deep green to a lighter shade and then to the familiar bright yellow. This change is often triggered by a drop in temperature, which breaks down the green chlorophyll pigments and allows the yellow carotenoids to become visible, signaling that the fruit has reached full maturity.