NOW is the time to fertilise citrus


How’s your citrus tree looking? Didn’t get a good crop of fruit this season? Are the leaves yellowing? Not much new growth?  If these symptoms sound familiar, then your lemon, orange, lime or other citrus tree is trying to tell you “I AM HUNGRY”!

Citrus trees are very hungry feeders and to get good growth and a quality harvest they need regular feeding.

As we approach autumn, now is a great time to feed them with a generous dose of animal manure – this is rich in nitrogen and will of course, also help improve the soil. Citrus trees that are nitrogen hungry will have overall leaf yellowing and stunted growth.

When & how much to fertilise? At the start of autumn apply between 2 – 6 kg per tree of animal manure, depending on the age or size of your tree. A younger tree should only need 2kg, while a larger old lemon tree (more than 10 years old) will need the full 6kg.

I like to use a good quality, pelletised chicken manure that has been composted and steam treated. I can highly recommend Rooster Booster, Rapid Raiser or Bounce Back.

How to fertilise? MAKE SURE – you apply the fertiliser right around the “drip line” of the plant. This is the region from the trunk right out to the tips of the leaves, so the shadow of the plant. Keep the fertiliser clear of the trunk, to prevent rot.

Citrus trees have very shallow roots that spread out from the trunk – so it is important to spread the fertiliser over the whole root system.

A generous application of home made compost, all topped off with a layer of mulch around the drip zone of citrus trees in autumn is also ideal.

Yellow leaves with bright green veins? This is an iron deficiency. Treat with iron chelate – follow application rates on the packet. 

Yellowing older leaves, while the younger leaves are green? This is a magnesium deficiency, treat with a dose of magnesium via epsom salts – around 200-250g for a young tree, up to 1.5kg for an older tree. Sprinkle around and water in well. If the yellowing of older leaves has been a consistent problem over a few years, apply dolomite lime at a rate of 1 handful per sq metre and water in well.

Fertilising potted citrus trees….. citrus trees in pots are even more prone to trace element deficiencies, because nutrients freely wash out the bottom of the pot! To combat this fertilise with an organic based, complete fertiliser that has added trace elements. Apply according to packet instructions.

Watering needs of citrus….. Citrus trees need a well drained soil BUT they also need a regular supply of water. And not just a light sprinkle, they need a good deep watering regularly during the hot summer months. Water right around the drip zone too – so all roots are supplied with water.


4 Responses

  1. Kerri

    Ah! That sounds like you know what you are talking about.
    So many supposed expert forums are “yellow” try everything, perhaps it’s the nursery, water it, fertilise it, iron, magnesium it’s the frost – ummm, hello it’s only winter in the Northern Hemisphere!. Amateur gardeners already think like that; it’s nice to have the problem and actions explained.
    Thanks for your help.
    I love commonsense.

  2. Judy

    This is the most useful information I have found in a web search for my ten year old struggling orange tree. No fruit on it this year and yellow leaves. Thanks Chloe. How do I work out how much water is enough? We live in the Central West and get some long hot summers.

  3. Apun

    I have a lime tree that was planted a year ago it is not blooming. We put in a tube to water it. The leaves are green and it looks very healthy. We feed it when we put it in does it need more feed and should we take out the water tube and water from the top? We live in AZ.
    Thanks for you help

  4. Anjana Mukherji

    I live in Melbourne Australia .I have a blood orange tree in my garden .Every year it gives us plenty of fruits .We look after the tree with pruning ,watering and fertilising timely but the fruits are very sour and loosing it’s red colour inside the fruit .
    I would be very thankful if you (the author) or any other garden enthusiast can help me solve the problem.
    Thanking you


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