Lemons Not Turning Yellow: Why Do My Lemons Stay Green

Lemon trees make attractive, ornamental specimens in containers or in the garden landscape. Like all citrus fruit trees, they require a bit of maintenance to produce ripe, flavorful fruit and without care can develop unsightly, bitter, juiceless fruit. So what happens if the lemon tree fruit does not turn yellow, and is there a “cure” for lemons that stay green?

Why Do My Lemons Stay Green?

Lemon trees need plenty of sunlight in a protected area with adequate moisture. The tree, like all citrus, should be pruned to allow the sunlight to penetrate and allow for adequate air circulation as well as to maintain the shape and make it easier to harvest lemons. 

A regular feeding schedule of an all-purpose soluble food (18-18-18) should be applied to the tree. If you are doing all of this and still wonder, “Why do my lemons stay green?”, read on. 

Citrus trees do not ripen the way rock fruits or apples and pears do. They gradually mature and gain sweetness; in fact, the fruit may take as long as nine months to ripen. Once the fruit is mature, it can be left on the tree for a few weeks, but it does not ripen more. 

So first off, the lemons may not be turning yellow because they have not been ripening on the tree long enough. If this is the case, then patience is in order. If, however, you have knocked this factor off your list, cultural conditions such as inadequate light or adverse weather conditions could be the reason that lemons stay green.

In fact, the most common cause for citrus fruit, in general, to fail to ripen is lack of sunlight. The tree may be too shaded, or trees may be planted too close together. Weather conditions affect the fruiting of lemon trees and contribute to slow ripening. Irregular amounts of irrigation will affect how the lemon tree fruits and matures.

Drought conditions stress the tree, producing juiceless fruit or that which splits or fails to ripen. All citrus trees need consistent, even watering. This may depend on how hot the weather gets, the season, the soil, and whether the tree is container-grown or in the garden.

In very hot, dry weather conditions, citrus trees (depending upon the size) may need as much as 37 gallons (140 L.) of water per day! Lastly, diseases may be a factor in lemons that refuse to yellow.

However, if a disease is afflicting the tree, there will be other more obvious signs of distress than just a lack of yellow fruit. Stressed trees are vulnerable to disease, so a regular watering schedule is paramount.

Finally, commercial citrus growers will sometimes use dyes to enhance the color of the fruit. In the home garden, the yellow color is not a prediction for ripeness; in fact, the fruit may be ripe even if it appears green. The best bet is to taste the fruit for sweetness and juiciness to ascertain its ripeness.