The Wonderful Kumquat: A Unique Citrus Gem

What’s a Kumquat?

The kumquat is a distinctive, nutritious citrus fruit that stands out for its delightful blend of sweet and tart flavors, easy cultivation, and impressive health benefits. Unlike most citrus fruits, it offers the rare advantage of an edible peel, making it a versatile addition to both diets and gardens. Packed with essential nutrients and boasting a compact, manageable growth habit, this small oval fruit has earned its reputation as a beloved citrus superfood, cherished for its unique taste and nutritional density.

Origins & Nomenclature: From “Gam Gwat” to Kumquat

Known as “cumquats” in Europe, these tiny orange fruits are native to the mountainous regions of southeast China and Japan, where they were originally called “gam gwat” (Cantonese for “Golden Fruit”). In 1846, Robert Fortune— a collector for the London Horticultural Society and namesake of the kumquat’s genus Fortunella—introduced the plant to the Western world. Today, kumquats are widely available in the United States, found in farmers markets, grocery stores, and used in salads, as a snack, or preserved as candied treats or marmalade. While their seeds are bitter, they are harmless and can be swallowed or spat out, leaving the sweet peel and juicy pulp to be enjoyed in full.

A Delicious Citrus Super Fruit

Renowned for its vitamin C content— a key nutrient for fighting colds— the kumquat holds its own against larger citrus fruits like oranges: 100 grams of kumquats deliver 43.9 mg of vitamin C (73% of the Recommended Daily Allowance), nearly matching oranges’ 53.2 mg per 100 grams. What truly sets kumquats apart, however, is that they are eaten whole—peel and all—ensuring no loss of the concentrated nutrients found in the outer layers of most fruits and vegetables. The peel is a nutritional powerhouse: it contains 6.7g of fiber per 100 grams (17% of RDA, nearly three times that of oranges), 14 times more carotenes than oranges, and abundant antioxidants like tannins. It also houses essential oils such as limonene, which has natural antimicrobial properties. Beyond vitamin C, kumquats offer 25% more vitamin A, double the niacin (a B-vitamin), and vitamin E compared to oranges, all working to neutralize harmful free radicals. The peel is also rich in minerals: 50% more calcium, over twice the copper, nearly 10 times the magnesium, six times the manganese, double the zinc, and a remarkable 11 times the iron of oranges.

Kumquat Care

Kumquat trees require similar care to lemons and other citrus varieties, thriving as potted plants or outdoor specimens in suitable climates. The most common varieties in the U.S. are Nagami and Meiwa kumquats, with breeders also developing crosses like mandarinquats (kumquat × mandarin orange) and limequats (kumquat × lime). Among the hardiest citrus fruits, kumquats can withstand temperatures as low as 24°F, growing year-round outdoors in USDA zones 9 and 10, or as attractive container plants in greenhouses across all zones. These thornless trees grow slowly, reaching a maximum height of 15 feet (typically 8–12 feet) but easily pruned to maintain a dwarf size. They prefer hot summers, which encourage abundant white flowering, and their bright orange fruits ripen in winter—perfect for boosting immunity during cold and flu season.

Fertilizing & Nutrition Needs

To support healthy growth and fruit production, kumquats require a balanced diet of nitrogen, phosphorus, potassium (N-P-K), and micronutrients like magnesium, iron, and manganese to keep their foliage dark green. A slow-release organic citrus fertilizer with an N-P-K ratio of around 5-3-3 or 6-4-6 works well, applied 3–4 times annually from early spring to late summer. Container-grown kumquats may need more frequent feeding with liquid fertilizer every 4–6 weeks. Adding compost or aged manure to the soil improves nutrient retention and promotes robust root development, while regular watering—especially during fruiting—prevents drought stress and fruit drop. For those looking to grow their own, a range of kumquat and other citrus trees are available for purchase through Grow Organic.

FAQs About Kumquats

Kumquats are small, oval citrus fruits with edible peels, offering a sweet-tart flavor and rich in vitamin C, antioxidants, and fiber. Their peel is uniquely nutrient-dense, packed with fiber, carotenes, essential oils like limonene, and more vitamins (A, C, E) and minerals (calcium, iron, copper) than oranges. Care for kumquat plants mirrors that of other citrus trees: they thrive in hot summers, require well-draining soil, benefit from regular pruning, and need balanced fertilization to maintain healthy foliage. The Nagami kumquat is a popular variety known for its tart taste and compact size, suitable for containers or outdoor growth in mild climates. Notably cold-hardy, kumquats can tolerate temperatures as low as 24°F, making them ideal for regions with mild winters.