How to Plant, Grow, and Care for Dwarf Lime Trees

During the dark days of winter, few things are as refreshing as savoring a piece of lime meringue pie or sipping on a tangy lime cocktail. While there’s nothing wrong with purchasing limes from the supermarket, growing your own limes at home brings a whole new level of appreciation for this tangy citrus fruit!

The tricky part of growing lime trees is their cold sensitivity. If you try to grow them outdoors in places like Pennsylvania or Colorado, you’ll watch them quickly succumb to winter temperatures. However, before you write off growing one of these trees at home, consider growing them in a pot indoors!

Dwarf lime trees remain less than ten feet tall, so they’re perfect for container growing and sunny indoor areas. Not only do they produce tasty fruit, but they also act as a conversation-starting houseplant! Stick with me to learn how to plant and care for these tiny citrus trees.

What Is It?

Unless you live in the warmest areas of the United States, you’ll have difficulty growing lime trees outdoors. However, if you live in zone 7 and colder, you can still grow these trees at home if you bring them indoors during the winter. Since smaller trees are easier to move and keep indoors, dwarf limes are a great option for northern growers.

The dwarf lime tree isn’t a specific species or variety. Instead, it’s any type of lime grown onto a dwarfing rootstock. The rootstock keeps the tree small and provides some disease resistance, while the scion determines fruit flavor, size, and production. That means you can find dwarf key limes, dwarf makrut limes, and dwarf Persian limes.

Characteristics

As I mentioned above, not all dwarf lime trees share the same characteristics. However, they do have many commonalities!

All max out between six and eight feet tall when grown in the ground. Container-grown trees remain smaller and typically grow four to six feet tall. Therefore, they’re a great option if you want to grow a lime tree indoors.

They are evergreen, so they keep their leaves year-round and never enter true dormancy. The leaves are oblong and may have a pointed or rounded end. Most of these citrus trees produce the majority of their small, white flowers in the spring, but flowers continue to pop up throughout the year.

The flowers eventually turn into small fruits that grow until they reach the size of a golf ball or a little larger. Most limes will mature and ripen sometime between early fall and winter.

Native Area

Lime trees are native to Southeast Asia. The exact native area depends on the type of dwarf lime tree scion. Regardless, all of these trees prefer warm tropical climates but tolerate indoor growing conditions.

Planting

Depending on where you live, you can either plant these trees outdoors in the ground or in a movable container. Planting these trees in pots allows you to keep them outside in the summer and move them indoors when colder weather arrives, but you can also keep them indoors year-round. Regardless of where you plant them, it’s best to start the planting process with a seedling.

Transplanting Outdoors

If you live in zone 8b or above, you’re lucky enough to be able to grow this short-statured citrus tree outdoors year-round! You may need to protect the trees from irregular cold snaps, but they can live for multiple decades if they remain safe from hard frosts.

The best time to plant any type of citrus tree outdoors is the late winter or early spring, after cool weather has passed but before the heat of summer arrives. Choose a location with full sun and well-draining soil. If you notice your soil is heavy in clay or compacted, loosen the soil with a digging fork or broad fork.

Although dwarf trees remain smaller than full-size trees, they can still grow up to ten feet tall. So, make sure to provide them room so they can grow without coming into contact with buildings, powerlines, or surrounding plants.

Once you’ve found the ideal spot:

1. Dig a hole one and a half times as deep and twice as wide as the tree’s root ball.
2. Fill the bottom of the hole with finished compost until it’s as deep as the rootball.
3. Place the tree in the hole.
4. The graft union, the line that indicates the fusion between the scion and rootstock, should be at least two inches above the soil line.
5. Return the soil to the hole, gently compact it around your tree, and water well.

Although mulching is optional, I recommend adding a few inches of wood chips or straw to the top of your tree. The mulch will help trap moisture and keep weeds down. Just make sure to a few inches around the base of your tree’s trunk mulch free.

Growing In a Container

While lime trees can’t tolerate low temperatures, you can still grow these tangy citrus fruits if you live in an area with cold winters. The trick is to plant the trees in containers that allow you to grow them indoors or at least move them inside during the winter. Early to mid-spring is the best time to repot a dwarf lime seedling into a larger pot.

When selecting a container, the first step is ensuring the bottom of the pot contains drainage holes that allow excess water to escape. These trees hate sitting in moisture, so drainage holes and a well-draining potting mix are crucial! Choose a pot that’s at least as large as the container you bought your plant in. Most varieties are happy in a foot-wide container for their first few years of growth, but they benefit from an 18-inch wide pot as they grow larger.

Your tree can happily grow in a terracotta, plastic, or metal pot. However, if you plan to move your pot between indoors and outdoors, consider the planter’s weight. A simple terra cotta pot is much easier to move than a glazed ceramic planter! Some planters have rolling stands to make transport even easier.

How to Grow

When I first thought about growing a dwarf lime tree at home, I’ll admit I was intimidated. I wondered if it was even possible to grow a citrus tree outside of a tropical climate. While growing one of these lime trees is harder than maintaining a pothos or lettuce plant, these plants are relatively easy to keep healthy as long as you provide them with the right environment.

Light

Like all citrus trees, dwarf lime trees require a lot of light. Not supplying enough bright light is one of the most common reasons the trees become stressed and unhealthy.

If you’re growing the trees outdoors, choose a location with full sun. Aim to provide the plants with at least twelve hours of bright light in the summer. Indoor plants still need a lot of light, but the plants can tolerate eight to ten hours of bright light in the winter. If you don’t have a room with a bright south-facing or west-facing window, use a grow light to provide supplemental lighting.

Water

Provide a moderate amount of moisture to keep your tree healthy. Since they thrive in well-draining soil, plan to water your plants deeply anywhere from a few times a week to once every two weeks. Rather than watering a little bit every few days, wait until the top few inches of the soil dry, then thoroughly water your tree until water pours out of the bottom drainage hole, then stop.

Although these trees are evergreen, they still use less water in the winter than they do in the summer. Therefore, expect to water less often in the winter than in the summer.

Soil

If you’re growing your dwarf lime tree in a container, using the proper soil mix is crucial! These plants prefer a potting mix that’s rich in organic matter, slightly acidic, and well-draining. Mixes designed for citrus plants work well for dwarf limes.

Another option is to create your own potting mix by combining organic matter and drainage materials. A good recipe includes:

• Five parts pine bark fines
• One part perlite
• One part finished compost

Since the pink bark will break down over time, make sure to repot your trees every few years.

Outdoor trees planted in the ground also prefer well-draining soil. Ideally, you’d plant them in sandy or loamy soil, but you can also amend your native soil until it suits these trees. Since they require excellent drainage, aerating compacted soils with a digging fork or broad fork is a good first step. Once the soil is well-aerated, add a few shovelfuls of finished compost to improve aeration and overall soil texture. 

Temperature and Humidity

Dwarf lime trees prefer warm temperatures between 60-80°F. They can tolerate brief periods below 60°F, but they’ll begin to struggle if they regularly experience temperatures below 50°F. If the plants are exposed to below-freezing temperatures, they will face major damage or die.

Since these plants like moderate humidity, average household humidity typically works fine. However, if the air moisture drops during the winter, the plants always appreciate a boost of humidity from a humidifier or spray bottle.

Fertilizing

Regularly fertilizing is essential for growing healthy plants covered with blooms. But before you grab any old fertilizer and add it to your plants, know that applying the wrong type or quantity of fertilizer can cause more harm than good. 

When your plant is still young and not producing flowers, you want to apply a fertilizer that encourages strong vegetative growth and a robust root system. Look for a fertilizer, with a balanced NPK ratio, like 8-8-8 or 10-10-10. 

Once your tree is old enough to begin producing flowers, you should switch over to a citrus fertilizer designed to support fruit production and overall plant health. These fertilizers contain a near-equal amount of nitrogen and potassium but less phosphorus.

Along with looking at the NPK ratio of your fertilizer, you should also examine the different types. You can find slow-release granular fertilizers, liquid fertilizers, and fertilizer spikes. All of these can work well as long as you follow product instructions to ensure you’re applying the correct amount of nutrients.

If you’re using a granular or liquid fertilizer, aim for three applications: the first in January, the second in March, and the last in May. Avoid fertilizing in the late summer or fall since this can encourage new growth that is susceptible to cold damage.

Maintenance

Like most fruit trees, dwarf lime trees benefit from annual pruning. The trees can still grow well and produce fruit without pruning, but spending an hour removing unnecessary branches will help keep the plant healthy.

The late winter is the best time to prune. Pruning may seem complicated, but keeping your overall goals in mind can help simplify the process. Aim to remove any crossing or rubbing branches, prune off suckers, and eliminate any dead or diseased wood. Since lime trees can handle heavy fruit loads and produce fruit in shady areas, there’s no need to prune the tree to open up the canopy.

Propagation

In the horticultural industry, professionals propagate by bud grafting the scion onto an appropriate rootstock. If you’d like to try to replicate this process at home, you need to start with an actively growing rootstock and a cutting from your dwarf lime tree.

Bud Grafting

Budding involves taking the bud from a plant with desirable fruit and adding it to a dwarfing rootstock. Once this union heals, you can trim the portion of the rootstock above the union so all of the vegetative growth resembles the scion rather than the rootstock.

The best time to propagate a tree by budding is during the late spring through early fall. During this time, the tree is actively growing and quick to heal. Look for new growth that has just started to harden, and use a sanitized and sharp pair of pruning shears to cut the shoot off the tree.

Once you have your shoots, it’s time to remove the vegetative buds.

1. Start by removing the leaves to give you a better view of the buds.
2. Insert a sharp knife about half an inch below a bud until it’s a quarter of an inch deep.
3. Next, insert the knife about a half inch above the bud.
4. Cut down until it meets the first bud.
5. The final bud should be about an inch long and a quarter of an inch deep.

Now, it’s time to add the bud to the rootstock. The two major types of bud grafting are chip-budding and t-budding, and both are suitable for lime trees.

Chip-budding involves making similar cuts to the rootstock, so you end up with a hole the size of the bud. Insert the bud snuggly into the rootstock, then wrap the graft with grafting tape until it heals.

T-budding involves making a T-shaped cut into the rootstock about a foot above the ground. Gently peel the bark outward, then slip the bud behind the rootstock’s bark. Wrap the union with grafting tape until it heals.

Harvesting and Storage

Since flowers sometimes appear throughout the year, you may be able to harvest limes throughout the year. However, the largest harvest period occurs from the early fall to winter.

When you think of limes, you probably imagine a green fruit. But as lime fruits mature on the tree, you’ll notice the green fruits developing hints of yellow. This is when they’re ready to harvest.

If you plan to use your limes within a week, you can store them on the counter. However, pop them in a dry spot in your refrigerator to increase their storage life.

Common Problems

As I mentioned above, one of the most challenging parts of growing a dwarf lime tree is providing lots of light and warm temperatures. However, these plants also face numerous pest and disease challenges. Keep an eye out for the following issues.

Pests

These citrus trees are susceptible to attack from a few common pests as well as some unique to citrus crops.

Sap-Sucking Pests

Both indoor and outdoor lime trees are susceptible to attack from sap-sucking pests, including aphids, spider mites, mealy bugs, and scale. While these pests are tiny, they can quickly multiply and cause serious damage. Regularly examining your tree for pests can help you deal with these pesky critters before they become problematic.

If you notice any of these sap-sucking pests, try wiping them off with a soapy rag. This method may not work for large infestations, so you can spray the pests with neem oil or insecticidal soap.

Citrus Leafminer

The citrus leafminer is a small brown moth that lays its eggs on citrus leaves. When the eggs hatch, the larvae eat the leaves and leave notable “tunnels.” Although these pests can become a serious problem in commercial operations, they rarely become a major threat to backyard lime trees.

Even if you notice the telltale tunnels, you don’t have to treat the pest. A few naturally-occurring wasp species lay their eggs near the tunnels, and the resulting wasp larvae feed on the leafminers.

Diseases

Look out for a range of fungal, bacterial, and viral pathogens, but not all of them will be major threats to home-grown citrus. I’ve listed some of the most common and problematic diseases below.

Phytophthora Root Rot

Remember how I said lime trees need well-draining soil? If you disregard this advice, you may end up fighting phytophthora root rot. This soil-borne fungus causes roots to rot and can lead to symptoms including yellow leaves, leaf drop, and slowed growth. If it’s not remedied, it can lead to plant death.

The best way to prevent this disease is:

• Use well-draining soil
• Choose resistant rootstocks
• Only water your tree when the top few inches of the soil is dry.

If you suspect a potted plant is infected, repot it with fresh potting soil and decrease the amount of water you use. 

Sooty Mold

If you’ve never encountered sooty mold, it can be alarming to watch it coat a tree in black. The good news is the actual sooty mold fungus doesn’t harm the plant, but too much fungus can limit photosynthesis and harm plant health.

Sooty mold can only grow on the sticky honeydew secreted by sap-sucking pests like aphids and thrips. Therefore, the best way to control sooty mold is to control these pests. Neem oil and insecticidal soap are appropriate control options, but you can also rely on predatory insects like ladybugs and green lacewings.

Frequently Asked Questions