How to Grow and Care for a Clementine Plant

The clementine plant (Citrus clementina) is a rewarding plant to cultivate indoors. It is prized for its sweet, easy-to-peel fruit and its attractive appearance as a houseplant. With glossy, dark green leaves and fragrant white blossoms, a clementine tree adds warmth to any bright room. Its manageable size, especially as a dwarf variety, makes it a popular choice for growing citrus without a large outdoor space.

Growing Clementines Indoors

When growing a clementine indoors, you can start from a seed or a young, grafted tree. Starting from seed requires significant patience, as it can take years for the tree to produce fruit, if it ever does. Because clementines are hybrids, a seed-grown tree may also produce fruit with different characteristics than the parent.

Most gardeners opt for a grafted dwarf tree, which ensures the desired type of fruit and yields a harvest within two to three years. Grafting involves joining a branch from a mature, fruit-bearing clementine (the scion) onto a different root system (the rootstock) chosen to keep the tree a manageable size. Many growers move their container-grown clementines outdoors during summer to benefit from natural sunlight, bringing them inside before the first frost.

Choosing the right pot is important for the plant’s health. A container about 16 to 20 inches in diameter provides adequate space for a young tree’s root system. Porous materials like terra cotta are recommended as they allow soil to dry evenly, reducing the risk of root disease. As the tree grows, it will need repotting into a larger container, though citrus plants thrive when their roots are slightly confined.

Clementine Plant Care

Light

A clementine plant requires a substantial amount of direct sunlight to thrive and produce fruit. Place it in the sunniest location available, such as a south-facing window, where it can receive at least six to eight hours of direct light daily. If this level of natural light is unavailable, especially in winter, supplement with a full-spectrum grow light. Insufficient light is a common reason for a plant to fail to produce flowers or fruit.

Soil

Clementine trees prefer a well-draining, slightly acidic potting medium with a pH between 5.5 and 6.5. You can use a commercial potting mix formulated for citrus trees or create your own. A homemade mix can combine standard potting soil, perlite or sand, and organic matter like peat moss to ensure good aeration and drainage.

Water

Proper watering prevents common issues like root rot, as clementine trees do not tolerate soggy soil. Use the “soak and dry” method by watering thoroughly until water runs from the drainage holes. Allow the top two to three inches of soil to dry out completely before watering again. Always empty the saucer beneath the pot after watering to prevent the plant from sitting in excess water.

Fertilizer

Clementine trees are heavy feeders and require regular fertilization during the spring and summer growing season. Use a fertilizer designed for citrus, which is high in nitrogen to support foliage growth. These formulas also contain micronutrients like iron and magnesium to prevent issues like leaf yellowing. Reduce feeding in the fall and winter when the plant’s growth slows.

Temperature and Humidity

Clementine trees prefer daytime temperatures between 60 and 90 degrees Fahrenheit (16-32 C) and must be protected from frost. These plants also appreciate a humid environment, which can be a challenge in dry homes. You can increase humidity by misting the leaves daily, placing the pot on a tray of pebbles and water, or using a room humidifier.

Encouraging Fruit Production

Even grafted trees need a few years to mature before they can support a harvest. Providing the consistent light, water, and nutrients mentioned previously is the foundation for encouraging fruit. Without sufficient energy from sunlight, a plant may produce lush foliage but few, if any, blossoms.

Clementine flowers are self-fertile, but indoor pollination is less efficient without wind or insects. To improve fruit set, you can assist with pollination manually once the flowers open. Use a small, soft paintbrush or a cotton swab to lightly transfer pollen from the anthers of one flower to the stigma of another. This simple action mimics the work of a bee and can significantly increase your yield.

Common Problems and Solutions

Indoor clementine trees can encounter pests like spider mites and scale insects. Spider mites are tiny and create fine webbing on the undersides of leaves, causing a yellow, stippled look. Scale insects appear as small, immobile brown or white bumps on stems and leaves. Both pests can be managed by thoroughly spraying the plant with insecticidal soap or neem oil.

Yellowing leaves, or chlorosis, often signals a nutrient deficiency. A lack of nitrogen, iron, or magnesium is a common cause. If yellowing appears on older leaves first, it may be a nitrogen shortfall, while yellowing between the veins of new leaves suggests an iron or magnesium deficiency. Applying a balanced citrus fertilizer as directed should correct this.

Improper watering can also cause yellowing leaves. Overwatering leads to root rot, which prevents nutrient absorption and causes leaves to yellow and drop. Allowing the soil to become too dry can also stress the plant and cause similar symptoms. Adhering to a proper watering schedule is the best prevention.

Harvesting Clementines

The main indicator of ripeness is color; the fruit should be a uniform, deep orange with no green patches. A ripe clementine will also feel heavy for its size and have a slight give when gently squeezed. Citrus does not ripen after being picked, so wait until the fruit is fully mature on the tree before harvesting.

The harvest period runs from late fall into early winter. While a visual check is a good start, the most reliable method is a taste test. If one fruit is sweet, others that look similar are likely ready. The fruit can remain on the tree for several weeks after ripening, allowing you to harvest them as needed.

When ready to pick, use pruning shears or clippers to snip the stem, leaving a small piece attached to the clementine. This method is better than pulling the fruit off, which can tear the peel and lead to faster spoilage. Careful harvesting protects both the fruit and the plant from damage.