Why does my lemon tree have yellow leaves?

It's a red flag to see yellow leaves on lemon trees! They aren't just unsightly; they're also indications that your plant could be sick. In this guide, we'll show you why it happens and how to prevent it with a few easy steps.

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Causes of yellow leaves on citrus trees

Citrus trees are versatile and do well in most climates, but there are lots of things that can give your lemon tree problems! Here are the conditions that can turn your lush greens to sour yellows:

  • Changes in weather
  • Too much or too little water
  • Lack of nutrients
  • Pests or parasites
  • Root rot
  • Sunburn
  • Citrus diseases

How to care for lemon trees with yellow leaves

With preventive measures, you'll get a healthy harvest with tons of yellow lemons instead of yellow leaves. Just follow our top tips for proper lemon tree care!

A branch of lemons on a tree

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Balance temperature

Drastic seasonal changes can give your citrus yellow leaves and stress them out! Lemon trees thrive during summer, but if there's too much heat they can become dehydrated. Also, if it's too cold in the winter the leaves can become brittle and damaged from the frost. So depending on the climate you can try to balance the temperature accordingly by either providing shade or removing it when you see leaves curling.

Just add water

Do you know how often to water your lemon tree? Follow these watering tips and schedules, so they never experience a draught or a drowning:

  • Freshly planted - water every other day during its first week of life. For the next two months, water once or twice a week during dry spells.
  • Planted for two years   - during the first two years of its life, lemon trees need water every five days.
  • Mature plant - water older plants between seven to fourteen days during the dry season.

Diagnose deficiencies

Listen to your lemons ! Just like humans, your plants need a nutritious diet. Using good fertiliser helps provide the essential nutrients for optimum growth. Here's a list of deficiencies, how to identify them, and ways to treat them:

  • Nitrogen deficiency - shows as yellowing of older leaves in the tree's foliage. You can add special nitrogen-boosted fertiliser in your feeding to help resolve it.
  • Zinc or iron deficiency - shows as yellowing of new leaves with green veins. To fix this, use a kelp spray solution or add zinc to the soil bed.
  • Magnesium deficiency -  shows as light green or yellow blotches on leaves. To treat this, dissolve a teaspoon of Epsom salts in half a gallon of water and pour into the soil evenly.

The soil is the foundation where your citrus tree's roots will expand and grow. It's important that it has the right PH levels to maintain great health. If you're concerned, you can get soil test kits to figure out what your plant needs!

Pest control

A pest or parasite infestation is one of the toughest issues to deal with as a gardener. Besides sucking the nutrients from the leaves, the little critters can wreak havoc and give your lemon tree diseases. There are many types of insects, pests and parasites that love lemons, including:

  • Aphids
  • Rust mites
  • Spider mites
  • Leafroller moths
  • Mealybugs
  • Cutworms
  • Scale insects
  • Whiteflies
Pests eating a green leaf

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When giving your plants a layer of protection, always go with the natural route. Using chemicals can negatively affect your fruit and turn your soil toxic, which caused even more problems. Instead, make a homemade spray with organic elements to protect your plant from pesky bugs. You can use Neem and Jojoba oil directly, but you can also make special sprays with these ingredients:

  • Dormant oil - mix a tablespoon of baking soda with two tablespoons of canola oil in a gallon of water.
  • Horticultural oil - mix five tablespoons of hydrogen peroxide, two tablespoons of baking soda, and two tablespoons of olive oil soap in a gallon of water.

Spray your chosen mixture onto all the leaves and branches of your lemon trees. Try to get as much coverage as possible since some bugs won't fall off unless you fully cover them in slippery oil! These will also prevent the spread of sooty mould and powdery mildew.

A senior woman spraying plants

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Proper drainage

Stagnant water trapped inside the soil can cause root rot. If your plants are in pots, make sure there are enough holes for proper water drainage. Rotting can also occur when the roots outgrow the size of their containers. If your lemon tree is getting too big for its pot, give it more room by transferring it to a bigger one!

Prune and trim

Citrus trees enjoy regular pruning to increase airflow, photosynthesis, and growth. Methods like topping and skirting can help prevent bugs from climbing onto the tree. If left unpruned, your tree will be more prone to the spread of diseases from the soil and other contaminated leaves.

Throw shade

Lemon trees love the sun, but there is such a thing as too much of it. Excessive sun exposure can cause the leaves to gradually bleach and fade. Shield your plants from sunburn by giving them shade when it's too hot outside. Some farmers use the whitewashing method to act as a sunscreen by painting white latex on the bark of the tree.

If you see yellow, don't panic!

Stay mellow the next time you see yellow! It may seem concerning at first, but everything should be fine. The lightening of leaves just functions as a warning sign that your lemon tree needs a bit of extra support! Just remember to follow our pro-tips and you'll be back to seeing green in no time!

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