How to grow a kumquat tree outdoors – fruit tree experts reveal the secrets to happy trees and top harvests

How does the idea of a compact, aromatic, and fun-to-grow citrus tree strike you? It does sound good, doesn’t it, so let's look at how to grow a kumquat tree outdoors to fill any space with beauty and fragrance.

Kumquats are great fruit trees for small spaces as they are compact and self-fertile. Once established, they are low-maintenance and will produce large harvests of small sweet-tart fruits that can be eaten whole, cooked, or used in baking.

To showcase how to grow a kumquat tree outdoors, I spoke to two fruit tree experts to get tips on where to plant and how to maintain these lovable fruit trees. So you can enjoy glossy foliage, sweet-scented blooms, and quirky fruits in any space.

How to grow a kumquat tree outdoors - an expert guide

Kumquats are a citrus tree with dark green, glossy leaves and fragrant flowers and fruit. The compact evergreen trees are suitable for small backyards as they grow to eight feet tall and are self-pollinating, so you only need one tree to get fruit. The fruits come in various shapes, depending on the species, and can be eaten whole.

Popular types of kumquat include ‘Nagami’, ‘Meiwa’, and ‘Marumi’. Whatever type you choose, they are easy fruit trees to grow. We reveal planting and maintenance tips to help you confidently grow a kumquat tree outdoors.

How to grow a kumquat tree outdoors - planting tips

Kumquat trees are suitable for growing outdoors in US hardiness zones 9 and 10. However, Tatiana Anderson from Top Tropicals claims they are ‘among the hardier citrus trees’ as they can withstand temperatures as low as 18°F (-7°C).

‘In cooler regions, they can be grown in containers and moved indoors during colder months,’ adds the tropical plant expert.

Plant kumquat trees in a sunny spot where they can enjoy 6-8 hours of direct sunlight daily and in a well-draining, loamy soil type. Though best planted in the ground, you can grow the fruit trees in pots outdoors, or you can grow a kumquat tree indoors.

Kumquat trees can be bought from fruit tree specialists, nurseries, or online to add to your backyard ideas. You can grow a kumquat from seed, but it requires dedication and patience, as it may take many years to get fruit.

The best time to plant fruit trees is in spring. Make a large hole and plant the kumquat at the same level it was in the pot. Press the soil down to remove any air pockets and give the tree a deep water.

Tatiana Anderson

Tatiana Anderson is the co-owner and co-founder of Top Tropicals, based in Fort Myers, Florida. Top Tropicals grows and sell a whole range of flowering and fruiting tropical plants.

How to grow a kumquat tree outdoors - care tips

• Watering - Newly-planted kumquats need regular watering to keep the soil consistently moist. Keep a close eye on watering plants as they will need at least weekly watering for the first year. Once the tree is established, Tatiana Anderson recommends: ‘Maintain consistently moist soil, especially during dry periods, but avoid waterlogging. Water deeply every 10 days during dry weather.’ Using a soil moisture meter can help determine when to water plants and avoid overwatering, which can lead to root rot. Mulching around trees helps to retain moisture in the soil and suppress weeds.
• Fertilizing - Bethany Lakatos, plant expert at Fast Growing Trees, advises fertilizing the fruit trees twice a year, in spring and summer, when they grow in the ground. She adds: ‘Fertilizing should be done with a citrus-specific fertilizer, including iron and zinc, or a 10-10-10. For potted kumquats, fertilize regularly with a citrus-specific fertilizer from spring to fall, stopping in winter.'
• Pruning - Kumquats do not need lots of pruning annually, and you tend not to need to prune citrus trees as much as other fruits, such as apples or peaches. Bethany Lakatos advises to ‘prune in spring’ and highlights three primary reasons to prune the fruit trees. ‘You prune to remove dead, crossing, or diseased wood, and to open up the center for better light penetration and air flow,’ she says. 'Also prune out any suckers or growth below the base or graft line, as well as any weak wood.'
• Harvesting - Kumquats are harvested from late fall onwards and, depending on your climate and the variety, can continue to produce fruit into spring. The color and feel are the best indicators of a ripe fruit. ‘Kumquats turn bright orange when mature,’ explains Tatiana Anderson. 'Ripe fruits are firm and can remain on the tree for weeks, allowing for a staggered harvest. To harvest, gently twist or cut the fruit from the branch to avoid damaging the tree.’ Using a pair of clean and sharp pruning shears, garden snips, or scissors is a safe way to harvest kumquats. Never pull too hard; it can be a harvesting mistake that damages the fruit tree.

Bethany Lakatos

Bethany Lakatos is a Plant Expert at Fast Growing Trees. She graduated with honors from Oregon State University with a BS in Horticulture with a focus on sustainability and a certificate in Permaculture Design. She loves to talk about soil and edible landscaping, and lives just outside Fort Mill, SC, where she has the opportunity to delight and geek out over all the plants in the Fast Growing Trees nursery

FAQs

Can you grow a kumquat tree in a pot?

Kumquat trees are well-suited to growing in containers, which makes them ideal for cooler regions where you need to overwinter plants indoors. Tatiana Anderson from Top Tropicals recommends a pot at least five gallons in size, but adds that ‘15 gallons is ideal’. Any pot must have drainage holes in the base and be filled with a well-draining potting mix.

‘Place the container in a location that receives full sun and water regularly, allowing the top inch of soil to dry between waterings,’ adds Tatiana. ‘In colder climates, bring the potted kumquat indoors before temperatures drop below 45°F (7°C). Repot the tree every 2-3 years to refresh the soil and accommodate root growth.’

If you are looking for more citrus tree inspiration, our guide on how to grow an orange tree covers all you need to know for happy and healthy trees. It includes planting and care tips for all the different types of oranges so you can enjoy the fragrant flowers and juicy fruits.