Guide: How to Grow Lemon Trees Indoors That Actually Produce Lemons
By Steven Biggs
Can You Grow a Lemon Tree Indoors? Sure!
If you’ve seen lemon trees growing outdoors in warm climates, you might be wondering how you can grow a potted lemon tree indoors, without it getting too big.
Many lemon varieties grow into small trees when grown in the ground outdoors in warm climates.
(Keep this in mind if you plant a lemon tree in the ground in a greenhouse – it can get big!)
If you know a few simple things about how lemon trees grow and how to care for them indoors, you can enjoy the fragrance of lemon flowers and harvest your own lemon fruit indoors.
This guide to growing a lemon tree indoors explains what you need to know.
Lemon Tree Size
You can keep a lemon plant small. When it comes to the ultimate size of your lemon tree, remember that as the gardener, you’re the boss. You’re the one with the pruning shears!
Here are things (besides pruning shears!) that can affect the size of your lemon tree indoors:
Most commercially produced lemon trees are grafted. That just means that a piece of a lemon variety with nice fruit is attached (“grafted”) onto another variety that has roots with desirable traits (a.k.a. the rootstock). Some rootstock varieties have a dwarfing effect, keeping the lemon tree smaller. (A common dwarfing rootstock is called ‘Flying Dragon’).
If you have grown a lemon tree from seed, or your lemon tree is a rooted cutting, it will be growing on its own roots. There’s a good chance it will get bigger than lemon trees grafted onto a dwarfing rootstock.
Pot Size
This potted lemon tree is over 50 years old. Pruning and pot size keep it compact.
The smaller the pot, the smaller the lemon tree.
Think of how bonsai trees that are hundreds of years old can grow in very small pots.
It’s a combination of a small pot, along with root and stem pruning that will keep your citrus trees small.
Lemon Variety
There are many lemon varieties—just like there are many apple varieties. As well as differences in the fruit, there can be differences in the way the plant grows. Some are more compact than others.
A good example is the Meyer lemon tree, which is naturally dwarf and more bush-like than many other lemon varieties. (Meyer lemon trees are actually a hybrid that has some tangerine genes in its bloodline!)
(I think a potted Meyer lemon tree is a great starting place for first-time gardeners. They're compact, and very fruitful. I've harvest 50 lemons from a knee-high potted Meyer lemon tree.)
Indoor Lemon Tree Leaf Drop
A lemon tree that’s been growing in cool, humid fall conditions outdoors will often drop leaves when brought indoors for the winter. It’s ugly…but common. They grow back.
Lemon plants are evergreen, meaning that they have leaves on them year-round.
It is common for some leaves to drop off as the temperature and light levels change with the season.
(Especially if you have a potted lemon growing in cool, humid autumn conditions outdoors and then you bring it into the dry air of a centrally heated home. It might just drop its leaves in protest!)
What Kind of Light do Indoor Lemon Trees Need?
Bright light is best. Look for a location that has at least 8 hours of bright light per day. That usually means a south-facing window.
When the lemon tree is growing in full sunlight, the growth is more compact, and there will be better fruiting and flowering.
If you don't have bright natural light, try a grow light. (I've seen pictures of an indoor lemon tree doing very well under a grow light...in the Yukon!)
Indoor Lemon Tree Harvest
Lemon trees have flowers and fruit at the same time. Pictured are fruit at different stages of maturity.
Lemon is one of my favourite citrus trees because lemon trees can have fruit and flowers at the same time. That means that while you’re enjoying the smell of lemon blossoms, there might also be small immature fruit on your lemon tree—and some larger ones.
Ripe lemons can remain on the plant for many weeks. There’s no rush to harvest them.
The size of the lemon harvest you can expect depends on a few things:
Variety
Plant size
Growing conditions
Season length
Indoor Lemon Tree Pollination
Pollinate flowers on lemon trees growing indoors using a small paintbrush.
Do you need 2 lemon trees to get lemons? No!
Every lemon bloom has male and female parts. They are also “self-fertile,” meaning you don’t need pollen from a different lemon tree to get pollination.
Outdoors, wherever there is a breeze, or a bee, pollen from the male part naturally drops or is transferred onto the female part of the flower and a small fruit starts to form.
Indoors, use a small paintbrush to transfer pollen between flowers.
Partially or imperfectly pollinated blooms can form fruit that drops off early. Not enough water can also cause small fruit to abort.
Tip: Lemons can make a lot of flowers in a cluster. Sometimes up to 12-15 booms. If they all become lemons, it’s a lot of work for the plant. Thin out the little lemons to 3-6 fruit per cluster.
Lemons can make a lot of flowers, sometimes 12-15 booms in a cluster. Thin out the little lemons to 1-6 fruits per cluster.
Indoor Lemon Tree Care
Watering Lemon Trees Indoors
When lemon trees are watered too often, the roots rot. Healthy roots are bright, like the ones pictured.
Top tip for indoor lemon tree care: Watering is the #1 key to success for indoor lemon trees.
Lemon trees don’t like to be in continuously wet soil. They hate having “wet feet”. Too much water can rot the roots.
After watering, the soil at the bottom of the pot remains quite wet until your lemon tree draws on that water – so don’t just water when the soil at the top of the pot looks dry.
When watering your potted lemon tree, touch the surface of the soil, and put your finger into the soil to see if it’s moist below. A good rule of thumb is to keep the soil on the dry side of moist.
In doubt? Pick up the pot to feel how heavy it is.
Frequency of watering will depend on:
Soil
Pot type
Plant size
How fast the plant is growing
How dry the air is
Temperature (and, yes, heated floors will definitely cause the soil to dry out more quickly!)
Keep Your Lemon Tree Through the Winter
And enjoy fresh homegrown lemons!
Pruning an Indoor Lemon Tree
Prune lemon trees so branches are well spaced.
Here are some general pruning tips for lemon plants:
Remove crossing branches
Prune so branches are well-spaced
Cut back to a bud or a branch
Remove fast-growing, upright branches (water shoots)
Remove suckers coming from below the graft union on grafted plants
Indoor Lemon Tree Pests
An indoor lemon tree can get the same pests as an outdoor one...but indoor conditions are often better for the pest!
The two most common pests of indoor lemon trees are:
Scale on an Indoor Lemon Tree
The adult stage of scale insects are immobile and have a shell. Scrape them away with your fingernails, or use a cotton swab soaked with rubbing alcohol.
Scale insects can be dabbed away individually with a cotton swap dipped in rubbing alcohol. If the outbreak of scale is larger, try rubbing them off with your fingers, spraying the tree with a high-pressure water source, or using a biological control such as a predatory mite.
Before noticing scale, you might first notice sticky spots on the floor below, or a dark, sooty coloured film (mould) on leaves. Scale insects give off sticky liquid, and that’s the cause of the sticky spots below, and the mould, which feeds on the liquid. Wash leaves with a soft cloth to remove sooty mould.
Spider Mites on an Indoor Lemon Tree
Watch for spider mites when growing lemon trees indoors. They’re hard to see without a magnifying glass…you might only see little spots moving on a leaf. If leaves begin to look stippled, check for spider mites.
Spider mites do well in the dry air in centrally heated homes. Higher humidity helps minimize leaf drop and make conditions less suited to spider mites
Seasonal Moves for a Potted Lemon Tree
Moving Your Indoor Lemon Tree Outdoor for Summer?
Gradually harden off plants in the spring over a period of a couple of weeks. Don’t go cold turkey and put them in full sun without hardening them off or there can be sun scald and wind burn.
Moving Lemon Trees from Outdoors to Indoors
If you’re bringing a potted lemon tree indoors for the winter, consider moving it indoors earlier rather than later, so there is less of a drastic change in temperature and humidity. This helps to minimize leaf drop.
While the fragrance of the flowers makes it nice to have lemon trees in a bright kitchen or living room window, your lemon tree does not need to be at room temperature. It will do better in cooler temperatures.
Here are examples of protected spaces that have cooler temperatures:
A bright attic window
A sun room (it does not need to be fully heated, keep the temperature just above freezing)
Find Out How to Grow Your Own Lemons
Harvest more lemons this year. Grow Lemons in Cold Climates Masterclass shows you how to grow a lemon tree in a pot or outside with protection. And get lemons!
Pots for Indoor Lemon Trees
Do not us pots with reservoirs (“self-watering” or “SIP”). This is because this sort of pot keeps the soil constantly moist…and lemon tree roots can rot in wet soil.
A decorative pot with no drainage holes is a recipe for soggy soil and root disease. Make sure to select a pot with drainage holes so that the roots don’t rot!
Lemon Tree Pot Size
When deciding on pot size, consider:
The size of pot you can move
Young plants that have not attained the final desired size can be moved to a bigger pot annually, early in spring or early summer once the roots fill the current pot.
Whether the roots are likely to quickly fill the pot. “Overpotted” lemon plants (plants in pots that are too big) won’t use up soil moisture as quickly—so there is more chance of root rot.
Repotting Lemon Trees
Covering everything from lemon varieties, to location and watering, to pruning and shaping, to overwintering, dealing with pests, and more—and including insights from fellow citrus enthusiasts—this book will give you the confidence you need to grow and harvest fresh lemons in cold climates.
Mature plants don’t need to be repotted annually. Remove and replace the top few centimetres of soil every couple of years.
Soils break down over time and air pores collapse, so you will eventually want to repot the plant in new potting soil.
Lemon Tree Potting Soil
If you’re moving your lemon tree outdoors for the summer, a heavier soil can prevent the pot from tipping over in the wind.
Here’s what I do for potting soil:
For young plants that are growing quickly and that I’m moving to bigger pots regularly, I use a lightweight soilless potting soil. It’s great for fast-growing plants.
For lemon plants that have reached a size I want to keep them at, I add some garden loam to my potting soil for added weight (so they don’t tip over when I put them outside for the summer.)
The potting soil products available to you will depend where you are. The key thing is to tailor your watering to the mix you’re using—and don’t over-water. (I spoke to a grower who make a very well-drained mix because he found he was always heavy-handed on the watering!)
Indoor Lemon Tree Fertilizers
Potted lemon plants must be fed! You’re getting a small amount of soil to support all that plant and fruit development.
Start feeding in the spring, as plants begin to grow. Cut back on feeding in late summer as cooler temperatures and less light cause plant growth to slow.
There are many fertilizing products on the market, both organic and conventional. And each lemon grower has a favourite formula.
Not sure where to start?
Look for “all-purpose” or “general-purpose” product. Make sure it has micronutrients
Decide what suits your style of gardening (do you want to mix solutions regularly – or apply slow-release fertilizer granules just once in the spring)
More on Micronutrients and Potted Lemon Trees
“Interveinal chlorosis” (yellowing between leaf veins) on a lemon tree.
Micronutrient deficiencies are common with lemons. So make sure the fertilizer contains micronutrients.
“Interveinal chlorosis” is a fancy way of saying yellowing between the leaf veins. And it's a common thing to see on lemon tree leaves.
It's often iron, zinc, or manganese deficiencies. These deficiencies can even occur when the micronutrients are present in the soil, but the soil is too alkaline. That alkalinity prevents the lemon plant from taking up the micronutrients.
What to do for Micronutrient Deficiencies in Potted Lemon Trees
Forget lab analyses. Here are some other things you can do:
Use elemental sulphur to lower the soil pH. Available for home gardeners at garden centres.
Occasionally use a water-soluble fertilizer for acid-loving plants.
Some areas have a lot of lime in the water, and it builds up in the potting soil with repeated watering. So just repot your lemon more often.
Flying Dragon rootstock is intolerant of lime – so you might find lemons on their own roots are less troubled by high pH than grafted lemons on Flying Dragon.
Growing a Lemon Tree FAQ
What should I do if I don’t have full sunlight?
Ripe lemons last a long time when left on the the tree.
If you’re growing your lemon tree inside year-round, this can be a problem. You might want to add supplemental light, or grow your lemon under artificial lights.
But…if, like me, you put your lemon tree outdoors for the summer, think of indoor overwintering as simply a way to get your tree to survive the winter.
What about other citrus plants?
Another favourite citrus tree of mine is yuzu, a very cold-tolerant citrus with a very fragrant rind. It grows very well in a pot—and the fruit are very useful in the kitchen. Another very cold-tolerant fruit tree is mandarin orange.
How long can I leave homegrown lemons on the tree?
They last weeks, often months, on the tree. Don't pick what you're not ready to use.
What can I do with my Meyer lemons?
Lemons lined up to process into lemon curd. Meyer lemon curd is my favourite!
Lots of Meyer lemons is a good problem to have. My favourite uses are Meyer lemon curd, or sorbet.
How long before my indoor lemon trees will produce fruit?
Seed-grown fruit trees go through a juvenile stage where they don't bear fruit.
But a rooted cutting or a graft from a mature fruit tree can bear fruit right away. I've seen a six-inch tall lemon tree flower and form fruit. (My recommendation is to pick it off, so that energy is used to grow the plant bigger.)
Can I grow Meyer lemon trees from seed?
If you grow a lemon tree from seed it will likely grow up to be like the parent plant. (This doesn't happen with many fruit trees, apples are a good example of fruit trees that have offspring different from the parent plant.)
Keep Your Lemon Tree Through the Winter
And enjoy fresh homegrown lemons!