How to Grow Citrus Trees like Lemons, Limes and Oranges Indoors in Cold Climates Like Canada
How to Care for Most Citrus Trees Indoors in Canada
TL/DR: To thrive and produce juicy fruit, citrus trees need full sun (10 hours a day) in a humid environment (50%+), a pot of well-draining soil with regular fertilization, and water every 3-5 days.
Pruning should be done to promote healthy growth and remove dead or diseased branches. One crucial factor for fruiting is the soil’s pH, which should be between 6.0 and 7.0. Finally, pest and disease control measures should be taken to protect the tree from infestation.
About Citrus Trees
Citrus fruits, including Lemons, Limes and Oranges, have a long history and have evolved with a lot of human intervention. They originated in Southeast Asia and were cultivated in China as early as 3000 BC. They spread to India, the Middle East, Europe, and the Americas.
Humans have been hybridizing citrus fruits for centuries. Citrus fruits are made up of hundreds of different varieties, many of which result from cross-breeding. For example, the famous tangerine was created from a cross between a mandarin orange and a pomelo. Other hybrids include the grapefruit, a cross between a pomelo and an orange, and the lime, a cross between a lemon and a citron.
Citrus fruits are hybridized to create new varieties with desirable traits, such as higher yields, disease resistance, improved flavour, and better appearance. Hybridizing citrus fruits also allows growers to select for specific traits, such as higher levels of Vitamin C or improved juiciness.
Today, citrus fruits are an essential part of many diets worldwide. They are an excellent source of vitamin C, fibre, and other essential nutrients. Many citrus fruits are available, from sweet oranges to tart lemons and limes.
About Citrofortunella (The Calamansi Genus)
Citrofortunella is a group of hybrid plants cross between kumquats and other citrus fruits. This plant is known for its cold hardiness, small acidic fruits, and its use as an ornamental plant. In some classification systems, kumquats had their genus, "Fortunella.” This led to Citrofrutnella, a combination of citrus and Fortunella, which has become the standard classification for plants like Calamansi.
Why do people grow citrus trees in a container indoors
Growing citrus trees as indoor plants is a beautiful, aromatic, and delicious way to bring nature into your home. You can grow Citrus trees, including oranges, lemons, limes, and other unique varieties in containers. You can keep them outside in the summer and bring them inside in winter.
Beyond the pop of colour to your home, their sweet-smelling blossoms and sweet fruits will fill the air with a beautiful aroma when they bloom.
Citrus trees help you bring a taste of warmer weather home, whether you are looking for reminders of the Mediterranean landscape, Floridian foliage or want to add a Californian canopy to your home.
*Photo from the Medici Citrus collection in Florence.
The Best Citrus Trees to Grow Indoors in Canada
Growing citrus trees as indoor plants can be a rewarding experience! When selecting a citrus tree to grow indoors, choose a small-fruited variety and enjoy the sweet fruits of your labour. Generally speaking, we recommend choosing small-fruited citrus trees, as they require less energy and are more likely to flower and produce fruit in your home. Our pick for the most accessible citrus tree to grow indoors is the Calamansi lime.
The Easiest Unique Citrus Plant to Grow as Indoors:
- The Calamondin or Calamnsi Lime (Staff Pick)
- Kumquats
The Easiest Lemon Trees to Grow as Indoors:
- Meyer Lemons
- Ponderosa Lemon
- Eureka Lemon
The Easiest Lime Trees to Grow Indoors:
- Bearss Lime
- Kaffir Lime
- Key Lime
The Easiest Orange Trees to Grow Indoors
- Mandarin Orange
- Naval Orange
General Care for Indoor Citrus Trees:
Whether it's a lemon, a lime, or an orange, most citrus trees require the same conditions as a house plant. You need to know how much light they will get, how much water they’ll drink, and how humid the air where they’ll live is.
How Much Direct Sunlight do Citrus Trees Need Indoors: 10+ Hours a Day
Citrus trees need a considerable amount of direct sunlight to grow indoors. Generally, they need at least 8 hours of direct sunlight every day. Without sufficient sunlight, citrus trees can become leggy and weak.
If direct sunlight is unavailable, citrus trees can be supplemented with artificial lighting such as grow lights. They should be placed within 24 inches of the tree and used for 8 to 10 hours daily. Without sufficient sunlight, citrus trees may not produce fruit, and the leaves may become yellow or drop off.
This means that when used as an indoor plant, citrus trees should be placed in a South or west-facing window at the very least.
Why your citrus tree could drop leaves in the winter and what you can do about it:
As the temperature drops and winter begins to take hold, your beloved plant may show signs of stress. Without enough hours of sunlight, you may notice leaf drops and other signs of distress. To help your new plant stay healthy, try using a grow light to supplement its light requirements or prune proactively to ensure that it gets the best possible care.
How Much Water do Citrus Trees Need Indoors: Do not let them dry out
Citrus trees, when grown in containers, are not drought tolerant. While these plants can handle a lot more neglect planted in the ground than then they are grown as container plants, that has more to do with groundwater and maturity than the plant's ability to handle a lack of H2O indoors.
When your tree receives full sun in the summer months, you will want to keep that plant quite moist; it will be thirsty. Check the soil every 2-3 days and if it has dried out by about 20-30%, give it some water.
At least once a week, ensure to saturate the soil thoroughly. The water should drain out of the bottom of the pot, and you may even want to leave a bit of excess moisture for the plant to soak back up. Every week or so, you will want to ensure that you have fully saturated the soil.
When winter comes, you will likely be able to ease off the water slightly. We recommend water about once a week at the very least, but the plant may no longer require a drink multiple times a week. Always use the soil as your guide to whether or not you should put more water in the soil.
How Much Humidity do Citrus Trees Need Indoors
Citrus trees are native to warm, humid, tropical and subtropical climates, so when they're indoors, you need to keep the humidity between 40-60%. To do this, use a humidifier or place a tray of water near the tree.
In their natural environment, the humidity helps keep the leaves and fruit healthy, plus it makes the soil better for the helpful microbes.
Make sure there is good air circulation so the air doesn't get too stuffy and stagnant.
How do you Fertilize a Citrus Tree in a Container
Fertilizing is essential, especially if you want to get these plants to fruit. We need food to grow, and so do your plants.
The most crucial aspect of fertilization is ensuring your plant gets enough Nitrogen, phosphorus, and potassium (NPK). The NPK ratio of most citrus fertilizers is 2:1:2. Which means two parts nitrogen to every 1 part Phosphorous to every two parts Potassium.
You can use a citrus-specific fertilizer with that ratio. Still, there is no harm in using a fertilizer that with an equal NPK Ratio, such as 1:1:1 or 20:20:20. You likely don’t need to get super specific with your ratios if you have multiple house plants. You don’t want a low nitrogen or phosphorous fertilizer that won’t work.
There are a lot of commercially available fertilizers that work well for citrus and are marketed specifically for these plants from brands like Miracle Grow and Jobes.
Any of these should provide your plant with what it wants to grow and fruit. Many of these products are designed to maximize growth and yield and are a great option.
Our team and Promise Supply avoid chemical-based fertilizers and use organic fertilizers to get the right mix for your citrus tree; we recommend a combination of Worm Castings and Bios with a wee bit of your coffee grounds regularly. This would provide the required nutrients while also creating an organic ecosystem of beneficial bacteria and fungi that will help to protect your plant.
If you want to be more scientific, the 3:1:2 NPK ratio of Gaia Green’s Insect Frass would also be an excellent product for citrus.
The nice thing about organic fertilizers is that you can mix them, and there is a lower risk of causing issues due to overfertilization because they break down naturally.
What potting mix should I use to replant my citrus tree in a container?
Healthy roots make for healthy plants. Most commercial potting mixes are a good starting point when creating a citrus mix, but there are a few key characteristics to look for or amend to improve results.
A potting mix for your citrus should be:
- Well draining
- Have a neutral or acidic PH
- Have organic matter to provide nutrients for your plant
Some of our favourite organic soil brands are Gaia Green’s Living Soil and Happy Frog. Both of these mediums would work well for your citrus tree. You can also use almost any other potting mix, but you should prioritize mixes for Tropical Plants and, in some cases, even a Cactus mix.
The soil you select should emphasize that it is fast draining. You want to avoid mixes that offer moisture retention benefits, including many potting mixes designed for vegetables, including Tomatoes. And under no circumstances should you ever purchase “topsoil” for your potted plants. That would be a recipe for disaster.
Generally, our team uses perlite to amend most potting mediums we sell in-store to varying degrees. The benefit of perlite is that it increases the porosity of the soil to help with drainage and can improve root health by improving airflow in the soil because oxygen in the soil will help keep your plant roots healthy.
How to make your soil more acidic
One of the easiest ways to alter the PH of your soil to make it more acidic for your citrus plants is to add coffee grounds to the soil.
Whether you brew at home or ask the barista behind the bar for a small bag of espresso grounds, this is one of the easiest ways to create the right soil environment for your Lemons, Limes, and Oranges to grow.
The top three amendments used by horticulturists to make the soil more acidic are:
- Sulphur or elemental sulphur.
- Composted pine needles or pine bark as mulch.
- Add Aluminum sulphate or Iron sulphate into the soil.
How to Move your Citrus Tree Outdoor for the Summer
Plants love going outside for the summer; they get more sun, higher humidity, and natural fluctuations in temperature that can help them regulate their growth.
When you move your plant outside, you change the conditions in which it grows significantly. It will receive more sun, and temperatures will fluctuate significantly.
Once there are no more signs that your region will continue to experience a spring frost, you can bring your citrus plant outside.
Start by gradually introducing the tree to outdoor temperatures. Hardening off your citrus tree will be essential to ensure it doesn’t experience stress and leaf drop. You don’t have to harden off your tree, but the little bit of extra work is usually worth it.
How to harden off your citrus to go outside for the summer:
- Start by gradually introducing the tree to outdoor temperatures. On the first day, move the tree outside to a sheltered spot and leave it there for two hours. Bring the tree back inside at night.
- On the second day, leave the tree outside for four hours and bring it back inside again at night.
- On the third day, leave the tree outside for six hours.
- On the fourth day, leave the tree outside for eight hours.
- On the fifth day, leave the tree outside for ten hours and bring it back inside at night.
- On the sixth day, leave the tree outside for 12 hours.
- On the seventh day, you can transplant the tree into its permanent spot in the garden.
How to Move Your Citrus Tree Indoor for the Winter
When bringing plants inside, you will want to examine them for potential pests and proactively treat the plant with insecticidal soap. Once you’ve brought it in, keep it isolated from other houseplants for the first few weeks to see if you spot any potential pests you want to take care of.
How do you harden off a citrus tree to bring it inside for the winter:
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Begin the hardening-off process a few weeks before bringing the citrus tree inside. Start by gradually reducing the amount of water you give the tree and the amount of sunlight it receives.
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Move the citrus tree to a well-ventilated but sheltered outdoor spot, such as a porch or patio. After a few days, move the tree to a more exposed spot.
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Continue to reduce the amount of water and sunlight the tree receives over several weeks.
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When you’re ready to bring the citrus tree inside for the winter, choose a spot with bright light and plenty of air circulation with high humidity.
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Monitor the tree closely and adjust the amount of water and light it receives accordingly.
Keeping Citrus Trees In Your Sunroom
A sunroom that may not be entirely insulated is an excellent place for a citrus tree as long as you monitor the temperature. In many ways, the plant will enjoy the seasonal temperature change, but most importantly, it will appreciate your increase in direct sunlight.
Additional Care Details for Indoor Lemon Trees
Lemon trees need more water, a lower PH and more pruning than other citrus trees.
- Lemons want More Water Lemon trees do require slightly more water than other citrus trees, so it is essential to water them more frequently.
- Lemons benefit from Lower PH The soil should also be slightly more acidic than other citrus trees, so it is essential to use a soil amendment like peat moss or sulphur when planting.
- Lemons like more Pruning Finally, lemons require more pruning than other citrus trees, so it is essential to prune the tree regularly to keep it healthy and promote fruit production.
Additional Care Details for Indoor Lime Trees
Lime trees need more water, more humidity, and more fertilizer. They are also more sensitive to cold temperatures.
- Limes want more water Lime trees require more frequent watering than other citrus trees, as they are more sensitive to dry conditions.
- Limes like more humidity Limes typically prefer more humid climates than other citrus fruits. They need a climate with a minimum of 50% humidity to thrive.
- Limes benefit from more nitrogen They should also be fertilized more often than other citrus trees, as they require more Nitrogen.
- Limes can’t handle the cold Finally, lime trees should be protected from cold temperatures more than other citrus trees, as they are more susceptible to cold damage.
Additional Care Details for Indoor Orange Trees
Sweet citruses – such as oranges and tangerines – need a lot of heat to ripen, whereas the acid citrus – These types ripen their fruit much faster and tend to be nearly ever-blooming.
Additional care for Calamansi
Calamansi, also known as Calamondin, is often called the Philipino lime. They are a cross between a lemon and a tangerine in terms of flavour. These hybrids are easier to care for as they require more sun, less water, and less fertilizer and prefer warmer climates.
- Calamansi need less water Calamansi plants need less water than most fruit-bearing plants, making them an ideal choice for areas with limited water resources.
- Calamansi need less fertilizer Calamansi is an incredibly resilient and low-maintenance crop that requires minimal fertilization for optimal growth.
- Calamansi require more warmth Calamansi thrive in warm climates because the heat helps the fruit to ripen and sweeten,
- Calamansi prefer more sun Calamansi trees need more sun than other citrus trees to produce the sweet-tart, juicy fruit that makes them so popular
