Citrus Nutrient Deficiency: Signs, Causes and the Fertilizer That Fixes It
Citrus nutrient deficiency is one of the first things to check when the leaves of your citrus, dalandan or ponkan (citrus) turn yellow, purple or burnt at the edges. On Philippine farms the usual ones are nitrogen, potassium, zinc, magnesium, boron, manganese, iron, phosphorus and copper. This guide shows where each one starts, how to be sure, and the fertilizer that fixes it.
Start with one question: did the change begin on the old leaves or on the young ones? Nitrogen, potassium, magnesium and phosphorus move inside the plant, so a shortage shows on the old, lower leaves first. But zinc, boron, manganese, iron and copper stay where the plant first put them, so the young leaves and the growing tip show it first. After that, the color and the pattern narrow down which citrus nutrient deficiency you have, and a soil test confirms it. Each one below has its signs, its causes and its fix.
Citrus nutrient deficiency signs, old leaves and young leaves
Shows first on the old leaves
| Nutrient | Where it starts | What you see | Fix with |
|---|---|---|---|
| Nitrogen | old, lower leaves, the whole plant | Older leaves pale green to yellow and falling early, so the inside of the canopy goes bare. | Urea 46 0 0, Ammonium sulfate 21 0 0 |
| Potassium | old, lower leaves, leaf edges and tips | Old leaf edges yellow to bronze. Small fruit that split from the blossom end or show sunken creases in the peel. | Muriate of potash 0 0 60, Sulfate of potash 0 0 50 |
| Magnesium | old, lower leaves, between the veins | Mature leaves next to the fruit yellow on both sides of the midrib, leaving a green V at the leaf base (bronzing). | Dolomite, Magnesium sulfate (Epsom salt) |
| Phosphorus | old, lower leaves, fruit, grain or tubers | Rough fruit with a coarse, thick peel, a hollow core and sour juice. Old leaves dull with bronze freckles. | Superphosphate 0 20 0, 16 20 0 |
Shows first on the young leaves
| Nutrient | Where it starts | What you see | Fix with |
|---|---|---|---|
| Zinc | young leaves and the tip, between the veins | Young leaves mottled yellow between green veins, small, narrow and upright. Small, smooth, pale fruit. | Zinc sulfate, Agricultural lime |
| Boron | fruit, grain or tubers, young leaves and the tip | Small, hard, lumpy fruit with gum pockets in the white peel. Many fruit drop. Shoot tips die and branch out. | Borax, Solubor |
| Manganese | young leaves and the tip, between the veins | Young and medium leaves light green between dark green vein bands. Leaves keep their size. Fruit pale and soft. | Manganese sulfate, Urea 46 0 0 |
| Iron | young leaves and the tip, between the veins | Newest leaves yellow to white with green veins. Tops of trees die back on wet or limey ground. | Iron chelate (Fe EDDHA), Ferrous sulfate |
| Copper | young leaves and the tip, fruit, grain or tubers | Brown gum stains on the fruit peel, fruit that split, and long, soft, S shaped shoots with big dark leaves. | Copper sulfate |
Before you buy fertilizer for a citrus nutrient deficiency
So use the table to pick the likeliest citrus nutrient deficiency, then read its section below. Also keep in mind that dry soil, standing water, cold nights, a pest or a disease can look the same. That is why it pays to check the roots and the whole field first.
Nitrogen deficiency in citrus
Older leaves go pale green to yellow, with pale veins, and fall early. A leaf may last only about 6 months instead of the usual 1 to 3 years. So the inside of the canopy goes hollow. New leaves are small, thin and light green, and the whole tree looks evenly yellowish with no pattern. Trees bloom sparsely and set a light crop. The fruit peel is smooth and pale and the juice is lower in sugar and acid. You see it most at this stage: it shows most after flowering and before the rainy season. Trees often green up again in the rains if the crop is light. Heavy crops on unfed trees show it at any time.
Why nitrogen deficiency happens in citrus, dalandan or ponkan
Low farm inputs, sandy soils low in organic matter, heavy rain or watering that leaches nitrogen, waterlogging, drought. Fresh straw or raw manure. Too little fertilizer is one of the causes of low citrus yields in the Philippines.
How to tell it apart
Late magnesium deficiency also yellows whole leaves. It shows during fruit growth and does not green again without magnesium. To be sure, leaf test of 4 to 6 month old leaves from a flush on twigs without fruit, the way citrus is sampled, and a soil test. Even yellowing all over the tree, with no leaf pattern, points to nitrogen.
What to apply for nitrogen deficiency
Give a yearly dose of 200 grams of nitrogen, 100 grams of phosphate and 200 grams of potash per tree for citrus, split over the year. You get 200 grams of nitrogen from about 435 grams of Urea. For quick greening give a Urea spray at 2 percent (20 grams per liter, 320 grams in a 16 liter sprayer) every 15 days. Sprays of low biuret urea, calcium nitrate or potassium nitrate work fast. Weak or old trees do better with small, frequent doses.
- Urea 46 0 0
- Ammonium sulfate 21 0 0
- Complete 14 14 14
- Calcium nitrate
Sold here with nitrogen: Atlas Granular Urea (46 0 0) by Atlas Fertilizer, Amigo Planters Ammonium Chloride by La Filipina (25 0 0), Agripower 46 0 0 (Locally Blended) Coated by Green Acres Agri Tech and Calcipro by Ramgo (15.5 0 0 with 18.8 percent calcium). Check the FPA registration on the bag and follow the label rate. For the how and when, see our guide to urea fertilizer, and the page on nitrogen deficiency in every crop. In anee.io, Anee, the smart farm technician, reads a photo of the leaf and tells you which nutrient is short.
To keep it away, split nitrogen over the year and keep potash in step. Do not overfeed: too much nitrogen gives leafy growth at the cost of fruit and quality. Let a soil test and the crop's color set the season's nitrogen.
Potassium deficiency in citrus
The edges of older leaves turn pale yellow or bronze, and the yellow spreads over the leaf. On mandarins like ponkan, look for yellowing and bronzing with twisted, wrinkled leaves and spindly twigs. The top of the canopy thins. Fruit stay small with a smooth, thin peel, may split lengthwise from the blossom end, or show creasing, narrow sunken furrows in the peel. More fruit drop and the juice is weaker. You see it most at this stage: fruit growth, most of all in heavy crop years.
Why potassium deficiency happens in citrus, dalandan or ponkan
Acid and sandy soils, heavy rain or watering, drought, soils rich in magnesium, limey soils. High nitrogen on heavy crops without enough potash.
How to tell it apart
Creasing can also come from low calcium or boron. Fruit that split around brown gum stains point to copper deficiency. To be sure, leaf test of 4 to 6 month old leaves from twigs without fruit, and a soil test for potash, magnesium and calcium. Count split and creased fruit per tree before and after feeding.
What to apply for potassium deficiency
Give 200 grams of potash (K2O) a year per bearing tree together with 200 grams of nitrogen and 100 grams of phosphate. 200 grams of potash is about 330 grams of Muriate of potash 0 0 60. Split it into two or three doses. For a quick fix give a Potassium nitrate spray at 2 percent (20 grams per liter, 320 grams in a 16 liter sprayer) every two weeks. Give 200 to 500 grams of Muriate of potash 0 0 60 a bearing tree a year in two doses, more while fruits are filling.
- Muriate of potash 0 0 60
- Sulfate of potash 0 0 50
- Potassium nitrate 13 0 46
- Complete 14 14 14
Sold here with potassium: Atlas Muriate of Potash (MOP) by Atlas Fertilizer (0 0 60), Simplot Sulfate 0 0 50 by Nutranta, Potassium Nitrate by Parafield (13 0 46) and Qrop Mix Production 14 0 23 plus 13 Cao by Farmtech Agriland (14 0 23 with 9.3 percent calcium). Check the FPA registration on the bag and follow the label rate. For the how and when, see our guide to potash fertilizer, and the page on potassium deficiency in every crop.
To keep it away, keep potash in step with nitrogen every year, more so on heavy bearing trees. Test the soil every two or three years. Keep organic matter up with compost, manure or crop residues.
Zinc deficiency in citrus
Young leaves show yellow patches between the veins with an uneven green band along the midrib and main veins (mottle leaf). In severe cases leaves are pointed, narrow, upright and very small (little leaf), twigs thin out and die back. The outer canopy looks dead while the centre stays dense. Fruit on weak twigs are small with a smooth, pale, thin skin and little juice. But water sprouts on the main limbs carry normal leaves and big, coarse fruit. Flowering and fruit set drop. You see it most at this stage: new flushes. Worse on trees with a heavy crop and weak roots.
Why zinc deficiency happens in citrus, dalandan or ponkan
High pH and limed soils, soils high in phosphorus or given heavy phosphate, organic soils, heavy poultry manure, and too much nitrogen. Magnesium or copper shortage can also cut zinc uptake.
How to tell it apart
Citrus greening (huanglongbing, HLB) also gives a yellow mottle between the veins. HLB and tristeza are the main causes of low citrus production in the country. To be sure, do the pen test, then spray zinc on a few branches and watch the next flush. If blotches stay uneven or the tree keeps declining, send leaves for an HLB laboratory test. Nueva Vizcaya mother trees are indexed for HLB by PCR.
What to apply for zinc deficiency
Spray zinc on each new flush when leaves are two thirds to almost fully expanded. Spray Zinc sulfate at 0.5 to 1 percent (5 to 10 grams per liter, 80 to 160 grams in a 16 liter sprayer) with half as much hydrated lime, every two weeks on the new flush. Zinc on the soil rarely pays on acid soils and does not work on limey soils. Give 50 to 100 grams of Zinc sulfate a young tree and 100 to 250 grams a bearing tree a year under the canopy.
- Zinc sulfate
- Agricultural lime
Sold here with zinc: Harvester Zinc Sulphate Heptahydrate by Universal Harvester (22 percent zinc), Tierramino ZN by Unilox Far East Resources (7 0 0 with 10 percent zinc), Liquid Chelate Zinc with Sulfur by Sagrex (10 percent zinc and 5 percent sulfur) and Nemes Foliar by SCL Filipinas (4.8 0 0 with 10 percent zinc, 4.9 percent boron and 4.8 percent magnesium). Check the FPA registration on the bag and follow the label rate. For the how and when, see our guide to fertilizer with zinc, and the page on zinc deficiency in every crop.
To keep it away, keep the pH below 6.5, avoid heavy phosphate and poultry manure, and include zinc in the regular spray program. Plant clean, HLB indexed trees and control psyllids. Test the soil every two or three years.
Magnesium deficiency in citrus
Leaves look normal on the new flush, then mature leaves close to the growing fruit show yellow blotches near the base on each side of the midrib. The blotches join until only the tip and a V shaped area at the base, pointing up the midrib, stay green. In acute cases the whole leaf turns yellow or bronze and drops. Heavily fruited limbs can lose nearly all their leaves while lightly loaded limbs stay green. Fruit are lower in sugar, acid and vitamin C, and seedy kinds swing into alternate bearing. You see it most at this stage: fruit growth and maturing, on heavily bearing limbs.
Why magnesium deficiency happens in citrus, dalandan or ponkan
Sandy and acid soils, soils rich in potash or given heavy potash, and cold, wet periods. On limey soils high calcium holds magnesium back. Seedy kinds need more magnesium than seedless ones.
How to tell it apart
Nitrogen deficiency yellows the whole tree evenly and often greens again in the rains. Magnesium yellowing does not, without magnesium. To be sure, leaf test of 4 to 6 month old leaves from twigs without fruit, and a soil test for magnesium, potash and calcium. Signs worst on the heaviest fruiting limbs point to magnesium.
What to apply for magnesium deficiency
On acid to neutral soils, Dolomite corrects mild cases. Where the soil test shows low magnesium, give magnesium at a rate equal to 20 percent of the nitrogen rate, from Magnesium sulfate (Epsom salt) or Kieserite. On limey soils use magnesium sprays on the leaves. Give 100 to 250 grams of Kieserite or Magnesium sulfate a tree a year, or Dolomite on acid soil. Put the soil dose in before planting or when the rains begin. Sprays show results in 10 to 14 days.
- Dolomite
- Magnesium sulfate (Epsom salt)
- Kieserite
Sold here with magnesium: Dolomite by A6 Agrisource (24 percent calcium and 11 percent magnesium), Agsmart Kieserite Granule (20 percent sulfur and 16.3 percent magnesium), DDDD Planter's Choice Magnesium Sulphate Monohydrate by Modern Time (15.1 percent magnesium) and Zetryl MAG 9 by Zetryl Chem (9 percent magnesium). Check the FPA registration on the bag and follow the label rate. For the how and when, see our guide to complete fertilizer, and the page on magnesium deficiency in every crop.
To keep it away, lime with dolomite, keep potash and magnesium in balance, and avoid very heavy crops on weak trees.
Boron deficiency in citrus
Fruit show it most: small, hard and misshapen with a lumpy surface, with gum pockets and dark spots in the white inner peel (albedo) near the rind and sometimes in the core, and gum on the skin. Many fruit drop, peel can crease, and fruit rot more after harvest. The growing tip dies and the shoot sends out many side shoots. Young leaves wilt early, show water soaked spots, curl, and the veins split and turn corky. You see it most at this stage: flowering to fruit growth, often after a long dry spell.
Why boron deficiency happens in citrus, dalandan or ponkan
Sandy and alkaline soils low in organic matter, high nitrogen or calcium, cold wet weather and drought. Feeding with only high analysis fertilizers that carry no micronutrients. Poor boron also cuts calcium uptake in the peel.
How to tell it apart
Citrus greening also gives corky veins and small, lopsided fruit that color unevenly. Check leaves with the pen test. To be sure, leaf test and soil test for boron. Cut open a few fruit to look for gum and dark spots in the albedo. In a soil test, less than 0.5 ppm of boron is low.
What to apply for boron deficiency
Give a Borax spray at 0.5 percent (5 grams per liter, 80 grams in a 16 liter sprayer). Use boron each year where needed, on the soil or as a spray but never both, since citrus is easily burned by excess boron. Give 25 to 50 grams of Borax a young tree and 50 to 100 grams a bearing tree a year, spread evenly under the canopy.
- Borax
- Solubor
Sold here with boron: Etifert 11 (Borax Decahydrate) by Zetryl Chem (11 percent boron), Fertibagra 15G by Unilox Far East Resources (14.6 percent boron), B17 (Boric Acid) by Newman Chemicals (17 percent boron) and Better Yield by Bacphil Planters Fertilizer (0 0 0.9 with 10 percent boron). Check the FPA registration on the bag and follow the label rate. For the how and when, see our guide to foliar fertilizer, and the page on boron deficiency in every crop.
To keep it away, use fertilizers that carry micronutrients, keep organic matter up, and water in long dry spells. Test the soil every two or three years.
Manganese deficiency in citrus
On young leaves a fine mesh of green veins shows against paler green. Once the leaf is full size, dark green bands follow the midrib and main veins, with light green to yellow tissue between them. In bad cases white or grey spots form between the veins and leaves drop early, but leaf size and shape stay normal. The crop is smaller, and fruit are smaller, softer and paler in color. With zinc shortage it forms marl chlorosis: dark veins with dull white and green between. You see it most at this stage: young and newly matured flushes. Mild signs can fade as leaves harden.
Why manganese deficiency happens in citrus, dalandan or ponkan
Acid soils, where manganese leaches, and limey or overlimed soils, where it is locked up. Sandy and organic soils and cold, wet periods add to it.
How to tell it apart
Zinc deficiency makes leaves small, narrow and pointed. Iron deficiency is paler, with a finer net, on the newest leaves. To be sure, watch the leaves over a few weeks, since mild signs can pass. Then do a leaf test and a soil test for pH and manganese. In a soil test, less than 1 ppm of manganese is low.
What to apply for manganese deficiency
Give a Manganese sulfate spray at 0.5 percent (5 grams per liter, 80 grams in a 16 liter sprayer) every two weeks. Spray when the new flush is two thirds to fully expanded. A little low biuret urea in the tank helps uptake. On acid soils manganese sulfate can also go on the soil, but not on limey soils.
- Manganese sulfate
- Urea 46 0 0
Sold here with manganese: Manganese Sulfate by Zetryl Chem (31 percent manganese), Tierramino MN by Unilox Far East Resources (7 0 0 with 12 percent manganese), Multimate by Agway (4 0 0 with 4.5 percent sulfur, 2.8 percent zinc and 1.8 percent manganese) and Nutri Tabble Meta Foliar by NS Northern Organic Fertilizer (12 percent zinc, 9 percent sulfur, 2 percent magnesium and 1.2 percent manganese). Check the FPA registration on the bag and follow the label rate. For the how and when, see our guide to foliar fertilizer, and the page on manganese deficiency in every crop.
To keep it away, avoid overliming and include manganese with zinc in the regular sprays. Test the soil every two or three years.
Iron deficiency in citrus
It starts on the youngest leaves: yellow green, then pale yellow between veins that stay green, sometimes like a fine net. In acute cases leaves are small, very thin and fragile and shed early. The tree dies back hard at the top and outer edge, sometimes with a dead top over normal lower limbs. It may hit only one branch or a few trees. Fruit are small, hard, coarse and light colored, with weaker juice. You see it most at this stage: new flushes, mainly on wet or limey ground.
Why iron deficiency happens in citrus, dalandan or ponkan
High pH and limey soils (lime induced chlorosis), over watering, prolonged wet soil, poor drainage, cool soil, excess salts, high phosphorus. Copper built up in old orchard soils.
How to tell it apart
Manganese and zinc shortage often come with it. Flood damage to roots and copper toxicity both show first as iron chlorosis. To be sure, soil test for pH, and for copper on old orchard land. Check drainage and look at the roots. In a soil test, less than 4.5 ppm of iron is low.
What to apply for iron deficiency
Improve drainage and watering first. Trees helped or cured by that alone. On high pH soils apply an iron chelate (Fe EDDHA) to the soil. Iron sprays on citrus green the leaves only in specks and can burn leaves and fruit. So if you try one, keep it to a Ferrous sulfate spray at 0.5 percent (5 grams per liter, 80 grams in a 16 liter sprayer), twice, two weeks apart.
- Iron chelate (Fe EDDHA)
- Ferrous sulfate
Sold here with iron: DDDD Planter's Choice Ferrous Sulphate Heptahydrate by Modern Time (19 percent iron), Ferrous Sulfate Monohydrate by Zetryl Chem (30 percent iron), Ferrous Sulphate Monohydrate by Newman Chemicals (30 percent iron) and Liquid Chelate Iron with Sulfur by Sagrex (5 percent iron and 3 percent sulfur). Check the FPA registration on the bag and follow the label rate. For the how and when, see our guide to foliar fertilizer, and the page on iron deficiency in every crop.
To keep it away, plant on well drained ground, avoid overliming, and keep pH near neutral. Test the soil every two or three years. Keep organic matter up with compost, manure or crop residues.
Phosphorus deficiency in citrus
Leaf signs are weak. Older leaves lose their deep green, partly yellow. May show a dull purplish or bronze cast or small bronze freckles along the main veins. Leaves and fruit drop early and flowering is poor. The clearest sign is the fruit: rough, with a coarse, thick peel, a hollow core and high acid, ripening late. You see it most at this stage: young trees and new plantings on land never fertilized. Rare where trees have been fed phosphorus for years.
Why phosphorus deficiency happens in citrus, dalandan or ponkan
Strongly acid soils where iron and aluminium lock phosphorus up, limey soils where calcium does, low organic matter, cold wet soil and weak roots.
How to tell it apart
Potassium deficiency gives the opposite fruit: small, with a smooth, thin peel. Nitrogen deficiency gives evenly pale leaves without bronze freckles. To be sure, soil test for available phosphorus and pH, and a leaf test.
What to apply for phosphorus deficiency
Apply a phosphorus fertilizer, following the soil test. The usual yearly citrus dose includes 100 grams of phosphate per tree. Superphosphate suits soils of any pH and adds sulfur. Avoid DAP (18 46 0) on alkaline soils. Lime very acid soils so phosphorus stays available.
- Superphosphate 0 20 0
- 16 20 0
- Complete 14 14 14
- Agricultural lime
Sold here with phosphorus: Philphos 18 46 0 (Di Ammonium Phosphate), Atlas Super Gro (16 20 0) by Atlas Fertilizer, Amigo Planters Granular Single Super Phosphate by La Filipina (0 18 0 with 11 percent sulfur) and Triple Super Phosphate by Newman Chemicals (0 46 0). Check the FPA registration on the bag and follow the label rate. For the how and when, see our guide to 16 20 0 fertilizer, and the page on phosphorus deficiency in every crop.
To keep it away, put phosphorus in the planting hole and in the first years on new land, and add compost.
Copper deficiency in citrus
On oranges the fruit often show it first: brown stained areas of hard gum on the peel that darken to almost black by half size, fruit splitting across or around the stains, and heavy fruit drop. Leaves come out unusually large and dark green with the midrib bowed up, on long, soft, angular, drooping S shaped shoots. Clear gum blisters form at the nodes, reddish brown gum breaks out on twigs. Twigs die back and sprout bunches of weak buds. You see it most at this stage: young trees and new plantings, and trees pushed with heavy nitrogen.
Why copper deficiency happens in citrus, dalandan or ponkan
New plantings on sandy or organic soils never farmed, limey soils, and heavy nitrogen (it is also called ammoniation). It is rare where copper fungicides are used.
How to tell it apart
Normal splitting starts only at the blossom end. Copper splits also run across the fruit and around gum stains. To be sure, check the spray record. Copper deficiency is unlikely where copper fungicides are sprayed. Fruit signs are the most reliable field indicator.
What to apply for copper deficiency
Near immediate recovery and normal fruit set from a copper spray at flowering. Give Copper sulfate at 0.5 percent (5 grams per liter, 80 grams in a 16 liter sprayer) every two weeks. Try a few branches first, since plain copper sulfate can burn soft leaves. Cut back excess nitrogen. Below pH 5.5 built up soil copper can kill roots, so do not overdo it. In the soil, 5 to 10 kg of Copper sulfate per hectare lasts several years: never repeat it without a test.
- Copper sulfate
Sold here with copper: Grower's Choice Copper Sulphate Pentahydrate by Zetryl Chem (25 percent copper and 12 percent sulfur), Liquid Chelate Copper with Sulfur by Sagrex (5 percent copper and 2 percent sulfur), Indra by Farmtech Agriland (2 percent zinc, 2 percent manganese and 2 percent copper) and Biozome by Manchem Industries (12 percent sulfur, 12 percent zinc, 3 percent manganese, 1 percent magnesium and traces of iron, copper, boron, molybdenum). Check the FPA registration on the bag and follow the label rate. For the how and when, see our guide to foliar fertilizer, and the page on copper deficiency in every crop.
To keep it away, on new sandy land add copper to the fertilizer at 2.5 percent of the nitrogen rate. Keep pH near neutral and nitrogen moderate. Test the soil every two or three years.
A soil test is the surest check for any citrus nutrient deficiency. Before you buy, ask your Municipal Agriculture Office where to send a soil sample. The DA regional soil laboratories test soil, and the result says how much of each fertilizer your citrus, dalandan or ponkan needs. That saves money, because extra fertilizer is money lost.
Open the Nutrient Deficiency Finder, pick citrus, dalandan or ponkan, say where the leaves changed first and what you see, and get the fertilizers sold here that fix it.
- Anee, the smart farm technician, reads a photo of the leaf
- The cropping calendar dates every fertilizer application of your season
Citrus nutrient deficiency questions
Why are my citrus, dalandan or ponkan leaves turning yellow?
What fertilizer fixes nitrogen deficiency in citrus?
What fertilizer fixes potassium deficiency in citrus?
What fertilizer fixes zinc deficiency in citrus?
How do I know which nutrient my citrus, dalandan or ponkan lacks?
- Yara Philippines: Nitrogen deficiency in citrus
- Yara Philippines: Potassium deficiency in citrus (mandarin and orange)
- Yara Philippines: Zinc deficiency in citrus (orange)
- Yara Philippines: Magnesium deficiency in citrus (lemon, orange, satsuma)
- Yara Philippines: Boron deficiency in citrus
- Yara Philippines: Manganese deficiency in citrus
- Yara Philippines: Iron deficiency in citrus
- Yara Philippines: Phosphorus deficiency in citrus
- Yara Philippines: Copper deficiency in citrus
Find the missing nutrient and fix it
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