Indoor Lemon Tree Care Guide

Growing indoor lemon trees has become pretty popular over the past few years in colder climates. This comes as no surprise to me as who wouldn’t want to experience that delicious citrus sight, smell, and taste in the comfort of their own home?

As you will probably already know, lemon trees are super popular in the tropical, Mediterranean climates. Not only do they produce succulent fruits, but the smell of the orchards is also just incredible. I seriously can’t get enough of the scent and if you have ever been around the aroma, I bet you can’t either! 

Having said this, it does come with its own struggles but I am going to help you through the process so you can experience all the joy your indoor lemon tree has to offer.

Indoor Lemon Tree Care Summary

Scientific Name	Citrus x Limon
Light	Minimum of 8 hours of direct sunlight. Preferably 12 hours.
Watering	Water as soon as the soil dries out or is only slightly damp.
Soil	Well draining, slightly acidic. Optimal PH = 6.0 to 6.5.
Temperature	Ideally, 85 degrees Fahrenheit (29-30 degrees Celsius)
Fertilizer	Manure and compost is best but the liquid variants are efficient and less-messy for indoor environments
Humidity	50% humidity. See below for how to achieve this.
Harvesting	When they’re firm to touch and almost all yellow.
Pruning	Minimal, light reshaping in February, remove water shoots on mature plants.
Repotting	Standard procedure. See below if it’s your first time.
Toxicity	Yes, to dogs and cats if they eat the leaves.

Indoor Lemon Tree Overview

The good news is that growing a lemon tree indoors is not that difficult. But even if it was, the aroma alone is enough to keep me trucking on with mine! It is absolutely within your houseplant-growing skills to rear a healthy, happy, beautiful potted tree. As I said earlier, the scent it gives off is amazing. Seriously. I should stop saying that but I really can’t stress that enough!

Anyway, aside from this, they look gorgeous — especially if you have a plant-filled house anyway. Lemon trees add a whole new dimension to your space. And, you might get some delicious fruit from it too!

Yes, you do need to think “might” when it comes to the fruit-bearing aspect of your indoor lemon tree. While it is easy to grow the plant, getting it to sprout fruit is another story. But don’t let that put you off! I am going to show you the correct way to do everything so your tree will have the best chance at bearing its yummy fruit.

Right, before I dive into this complete guide to indoor lemon tree care, you can always take a look at the summary below if you don’t have much time. For those that do, I have all the nitty-gritty details on caring for inside lemon trees that you could imagine. Consider me your lemon guru.

Lighting For Your Indoor Lemon Tree

These guys need roughly 8 hours of direct sunlight to live their best life. In all honesty, they generally would prefer 12 hours but this isn’t always possible. If you can give them this then you should celebrate! Trust me, your lemon tree will thank you for it — big time.

This extreme amount of sunlight gives your lemon tree the strength it needs to bloom and bear fruit. While this won’t guarantee your success when it comes to the actual lemon production, it will ensure your plant leads a happy, healthy, and fulfilling life.

Indirect/Filtered Light
There is no way that this little guy will survive in indirect or filtered light. It just won’t work. This might be disappointing to hear if you live somewhere with smaller windows but it’s just the cold hard truth (unfortunately).

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Watering Indoor Lemon Trees

Since your lemon tree is in a pot and not in the ground, you should water it when the soil dries out. Personally, I water mine when the soil is still slightly damp and let me tell you, she is definitely living her best life! 

The point I’m trying to get at here is that you should never let the soil dry out completely. If it’s left arid and dry for 24 hours, the chances are its health will begin to deteriorate pretty quickly. Also, you should be considering what type of water you’re giving your plants.

Oddly, you won’t see any damage until you wet the soil again. At this point, the leaves will start to fall off following the first watering session after they have dried out. The best advice I can give you besides this is to make sure you water it evenly, and that the pot has great drainage. This is vital for the health of your leafy friend.

Why Drainage Is So Important

Your lemon tree’s roots need air to live. Thus, when the soil isn’t draining efficiently, the space that is typically filled by lovely air is clogged with water instead. As you can imagine, the root will start to rot at this point. Remember, healthy roots are pretty solid and white while decaying ones feel slimy and are dark in colour.

If you don’t feel like looking at the roots because slimy things aren’t your thing, I don’t blame you! You can figure out whether your tree is overwatered because the leaves will start to turn a shade of yellow. Eventually, they’ll fall off completely!

Hopefully, I haven’t scared you off as there is a light at the end of the tunnel! Even if your plant loses all its leaves due to watering errors, you can still turn its life around. Just make sure you stick to the watering tips I laid out earlier and they’ll be back to life in no time.

Indoor Lemon Tree Humidity Requirements

Humidity is a struggle in our indoor plant-loving life, isn’t it? You can try your hardest and it still won’t feel like you’ve got everything right (especially since lemon trees need about 50% humidity!). But it honestly doesn’t have to be that hard — yes, I promise! There are a few ways I ramp up the humidity to allow my indoor lemon trees to prosper.

Giving Them Outside Time

Your lemon tree is an indoor plant but to allow it to get its proper humidity levels, you can move it outside sometimes. Whenever you are area is having a warm day, move your plant friend outdoors for a bit. This way, it will soak up all the humidity it needs to thrive.

Using a Humidity Tray

Find a tray that is big enough to house your pot and pebbles. I put little pebbles in and let the water from the pot run into the tray and stay there. It will slowly evaporate and will give your lemon tree a boost in humidity.

Spraying

Since I use the tray, I don’t spray all that often. However, it is really easy to do. Just grab a spray bottle — one with a fine mist — and fill it with water. Then, throughout the day, spray the leaves and the surrounding area. That’s it!

Temperature

Your indoor lemon tree is a tropical child so it prefers warmer climates. Temperatures between 70 and 100°F (21 to 38°C) should be acceptable for your lemon tree. However, if you have greater control over the temperature, I’d say 85°F (29 to 30°C) is perfect.

Never let temperatures creep above 105°F (40°C) as your poor baby will just simply stop growing! Equally, you shouldn’t let it get too cold either — i.e. below 50°F (10°C) — as it will move into dormancy. Not to mention that temperatures under 30 degrees Fahrenheit (-1 degrees Celsius) will cause the leaves to fall off and your tree to die completely!

Soil For Your Indoor Lemon Tree

Okay, thankfully your indoor lemon tree’s soil needs are much simpler. Your leafy-green pal isn’t picky in this department and can withstand loads of soil mixes. But of course, there is an optimal mix that will allow your tree to proud fruit and be as happy as possible. In internet terms — live its best life.

A soil pH between 5.5 and 7 is generally acceptable, however, I would suggest you stick to a pH of 6 or 6.5 for best results. Allowing the soil mix to creep above these values will strip your gorgeous tree of iron, manganese, zinc, and other essential minerals. If this happens, you will need to acidify the soil. I tend to add compost or humus to do this. In extreme cases, you will need to add some sulfur compound.

On the other hand, allowing the soil mix to sink below these values will prevent new leaves, flowers, and fruits from growing. To get out of this sticky situation, you need to add alkaline to the soil to ramp the pH level back up. I have found that limestone works well here and you should only need a few tablespoons.

Air Requirements

Your lemon tree needs natural air movement — just like any tree. Unfortunately, this is near on impossible when you keep it indoors since buildings are pretty much airtight. Like I said earlier when I was discussing humidity, moving your lemon tree outside can combat the effects of stagnant, indoor air. Outdoors, the air is always moving, which is exactly what your plant wants!

Just be mindful of doing this after it has been inside all winter. I try to move mine into sunnier spots gradually so the leaves don’t get sunburned (yes, that’s a thing).

Limited Outdoor Space
If you don’t have an outside space, don’t fret! Keep opening doors and windows as much as possible to promote air circulation for your indoor lemon trees.

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Fertilization

Just like you and me, micro and macro-nutrients are needed by lemon trees too. Obviously, these come in different forms to what you and I would eat but the concept is the same.
Usually, you would add aged manure, compost, or dried manure into the soil twice a year to keep it high in nutrients.

However, since your plant is inside, I would suggest you use liquid fertilisers. I tend to add it into the water but they can be used just before you water them if you prefer. Alternatively, you can use NPK fertilisers but these will still need to be dug in like the manure. Not to mention you will have to use them more frequently, which is likely to cause a lot of mess inside!

How To Prune & Train Your Indoor Lemon Tree

I’m pleased to tell you that they don’t need much when it comes to pruning! When February rolls around, you will want to reshape your tree pal. It’s super simple and you have probably done it before.

Just thin out any branches that are overcrowding the rest. Not only will it look tidier but I promise your leafy friend will thank you for it (yes, even though it feels scary at the time). During the hot, summer months you might need to pinch the tips of hardcore growth. This is a no-tools procedure! Use your thumb and index finger to literally pinch it.

Finally, if you have a mature plant, you’ll want to look out for water shoots. These are just those unnecessary, fast-growing things on the branches. Take them off as soon as possible if you see them on the bottom and middle branches. But, if you see them near the tips, simply shorten them and do not remove.

Repotting

Honestly, repotting your lemon tree isn’t much different from any other plant. Regardless, I will break it down anyway:

1. Buy a pot that is ¼ bigger than its current one.
2. Fill your new pot to the ¼ mark with potting soil.
3. Water until moist.
4. Use a trowel to loosen the soil around your tree’s root ball and current pot.
5. Hold your tree near the base and lift.
6. Examine the root system. Here, you are looking for roots that appear to engulf the circumference of the ball.
7. Slice these with a clean knife.
8. Place your tree on top of the soil in the new pot.
9. Fill around the roots with soil. Make sure it is sitting pretty like it was in the old pot.
10. Water thoroughly.
11. You might need to add more soil if it has sunk further than you imagined.

Harvesting Your Indoor Grown Lemons

You can harvest them as soon as they are yellow and are firm when you touch them. They should be roughly 2 or 3 inches long. I wait until they are the optimum size, rather than the optimum colour but it’s really up to you!

Although, I will say that waiting too long is a lot worse than picking them early. Lemons are likely to ripen fully after they’ve been picked. But, if they’re already squishy, you’ve missed out.

So, how should you actually pick them? No different to apples! Grasp the fruit firmly but gently, and carefully twist it until it breaks from the tree.

Indoor Lemon Tree: Pests and Diseases

I mentioned briefly there that the old-world Meyer Lemon was susceptible to diseases. While this has been massively reduced thanks to the continued inter-breeding, lemon trees may still contract diseases and attract pests.

There are three main pests in particular that love to infest lemon trees:

Glasshouse Red Spiders

If these guys have infested your tree, you will notice that the leaves will be mottled. Webbing may also be seen covering the leaves where the spiders are living.
Unfortunately, they will make your plant’s leaves fall off far too early.

Scale Insects

You’ll notice little yellow scales on the underside of the leaf if scale insects have been there. They tend to secrete honeydew which can encourage mould so you’ll need to deal with them ASAP.

Mealybugs

Mealybugs congregate in the leaf joints and under any loose bits of bark, sucking sap and emitting honeydew. Again, these can cause black soot-like mould.

Toxicity

The lemon tree has been deemed toxic to cats and dogs. But, they are usually repelled by the smell. Plus, the damage can only be done if they actually ingest the leaves which, since the aroma is too much for them, rarely happens.