Calamansi Nutrient Deficiency: Signs, Causes and the Fertilizer That Fixes It

Calamansi nutrient deficiency signs, old leaves and young leaves

Shows first on the old leaves

Shows first on the young leaves

Before you buy fertilizer for a calamansi nutrient deficiency

So use the table to pick the likeliest calamansi 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 calamansi

Leaves turn light green, then yellow, evenly over the whole tree with no clear pattern, starting with the older leaves. Old leaves fall early, so the canopy looks thin and hollow, and new leaves come out small, thin and pale. Twigs may die back, the top looks thin and bushy, and the tree flowers sparsely, with fewer and smaller fruit. You see it most at this stage: bearing trees after a heavy crop or heavy rains, and young trees that miss their regular feeding.

Why nitrogen deficiency happens in kalamansi

Sandy soils with little organic matter, heavy rain or watering that leaches nitrogen, drought, very low or very high soil pH. Fresh straw or raw manure that ties nitrogen up as it rots. Waterlogged soil also loses nitrogen.

How to tell it apart

Sulfur deficiency looks alike but starts on the young leaves, with veins that stay green. Late magnesium deficiency also yellows whole leaves, but leaves at an earlier stage show a green V at the base. To be sure, leaf test of 4 to 6 month old leaves from a flush on twigs without fruit, the way citrus is sampled, plus a soil test. A tree whose next flush greens up after fertilizer confirms it.

What to apply for nitrogen deficiency

Give 50 to 100 grams of Ammonium sulfate or Urea per tree a month after planting and every four months after, 200 to 300 grams in the second year. From the fourth year a complete fertilizer with potash at 500 grams per tree, rising to 2 to 3 kg per tree three times a year at 8 to 10 years. For quick greening give a Urea spray at 2 percent (20 grams per liter, 320 grams in a 16 liter sprayer) every 15 days. Use low biuret urea for sprays.

• Ammonium sulfate 21 0 0
• Urea 46 0 0
• 16 20 0
• Complete 14 14 14

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, feed bearing trees three times a year: in the rainy season before flowering, two months after flowering and after harvest. Mulch the ring with dry leaves and keep it weeded. Let a soil test and the crop's color set the season's nitrogen.

Zinc deficiency in calamansi

Young leaves show it first: yellow patches between the veins, with an uneven green band along the midrib and main veins, called mottle leaf. As it gets worse the leaves turn pale yellow to almost white, come out small, narrow and pointed (little leaf), stand upright, and twigs die back. Fruit on these twigs stay small, with a smooth, pale, thin skin and little juice, and the tree flowers and sets less. You see it most at this stage: new flushes, at any age.

Why zinc deficiency happens in kalamansi

High pH and limed soils, soils high in phosphorus or given heavy phosphate, organic soils, and large, frequent doses of poultry manure. Shortage of magnesium or copper can also cut zinc uptake. A soil pH below 6.5 is best.

How to tell it apart

Citrus greening (huanglongbing, HLB) is the big look alike. HLB is common in calamansi. To be sure, do the pen test, then spray zinc on a few branches: if the next flush comes out green and normal sized, it was zinc. If the blotches stay uneven or the tree keeps declining, send leaves for an HLB laboratory test (a PCR test). A leaf test for zinc also helps.

What to apply for zinc deficiency

Spray zinc on the young flush when the leaves are two thirds to almost fully expanded. Repeat on each major flush in bad cases, because zinc does not move on to later flushes. 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 ones. 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 too much poultry manure, and include zinc in regular sprays. Control citrus psyllids and buy certified planting material from trusted nurseries so HLB does not hide behind zinc signs. Test the soil every two or three years.

Potassium deficiency in calamansi

The edges of older leaves turn pale yellow or bronze, and with time the yellowing spreads over the leaf. Growth slows, leaves drop around flowering, and new leaves are small and wrinkled, with scorched tips and small brown resin spots. Twigs may die back. Fruit stay small with a smooth, thin peel and may split from the blossom end or drop. You see it most at this stage: bearing trees during fruit growth, most of all under heavy crops.

Why potassium deficiency happens in kalamansi

Acid and sandy soils, heavy rain or watering that leaches potash, drought, soils rich in magnesium. High nitrogen rates on heavy crops without enough potash.

How to tell it apart

Magnesium deficiency also starts on older leaves, but it leaves a green V at the base of the leaf. Salt or fertilizer burn scorches leaf edges on leaves of all ages after a heavy dose or salty water. To be sure, leaf test of 4 to 6 month old leaves from twigs without fruit. A soil test for potash, magnesium and calcium together.

What to apply for potassium deficiency

Apply Muriate of potash 0 0 60 or a complete fertilizer in the ring in split doses, following the soil test. From the fourth year give a complete fertilizer with potash at 500 grams per tree, rising to 2 to 3 kg per tree three times a year at 8 to 10 years. 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.

• 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, match potash to nitrogen, especially on heavy bearing trees, and never feed nitrogen alone for long. Keep organic matter up with compost, manure or crop residues.

Magnesium deficiency in calamansi

It shows on mature leaves close to the fruit. A yellowish green blotch starts near the base of the leaf on each side of the midrib and grows until only the tip and a V shaped area at the base, pointing up the midrib, stay green. In bad cases the whole leaf turns yellow to bronze and drops, heavily fruiting branches lose most of their leaves, and those twigs may die. Seedy fruit like calamansi draw more magnesium than seedless kinds. You see it most at this stage: during fruit growth, on heavily bearing branches. The new flush may look normal while older leaves near the fruit yellow.

Why magnesium deficiency happens in kalamansi

Sandy and acid soils, soils rich in potash or given heavy potash, and cold, wet periods. On limey soils, the high calcium also holds magnesium back.

How to tell it apart

Nitrogen deficiency yellows the whole tree evenly with no pattern. Potassium deficiency bronzes the leaf edges. To be sure, leaf test and a soil test for magnesium, potash and calcium together.

What to apply for magnesium deficiency

On acid to neutral soils, Dolomite corrects mild cases and gives lime too. Where the soil test shows low magnesium, give magnesium at a rate equal to 20 percent of the nitrogen rate. Magnesium sulfate (Epsom salt) or Kieserite can supply it. 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, use dolomite when liming and keep potash and magnesium in balance.

Boron deficiency in calamansi

Fruit stay small, hard and misshapen with a lumpy surface, many drop. Dark gum spots form in the white inner peel and sometimes in the core. Young leaves wilt early, show water soaked spots, curl, and the veins can split and turn corky. The growing tip dies, so the shoot sends out many side shoots and the tree looks bushy. You see it most at this stage: flowering, fruit set and fruit growth, often after a long dry spell.

Why boron deficiency happens in kalamansi

Sandy and alkaline soils low in organic matter, high nitrogen or calcium, cold wet weather and drought. It also shows where growers use only high analysis fertilizers with no micronutrients.

How to tell it apart

Citrus greening also gives corky veins and small, lopsided fruit that color unevenly. Use the pen test on the leaves. To be sure, leaf test and soil test for boron. Cut a few fruit: brown or gummy spots in the white peel point to boron. 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 every year where it is needed, either on the soil or as a spray but never both, because citrus is easily burned by too much. 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, not straight high analysis grades only, keep organic matter up and water during long dry spells. Test the soil every two or three years.

Manganese deficiency in calamansi

On young leaves a fine mesh of green veins shows against paler green, softer than the zinc or iron pattern. Once the leaf is full size the pattern is plain: the midrib and main veins carry dark green bands. The tissue between them is light green. In bad cases white spots form between the veins, leaves drop early and the tree looks weak. Leaves keep their normal size and shape. You see it most at this stage: on young and newly matured flushes. Mild signs on new shoots may fade as the flush hardens.

Why manganese deficiency happens in kalamansi

It happens on both acid soils, where manganese leaches, and on limey or overlimed soils, where it is locked up. Sandy and organic soils and cold, wet periods add to it. It often comes together with zinc shortage.

How to tell it apart

Zinc deficiency makes the leaves small, narrow and pointed. Iron deficiency is paler, with a finer net, on the newest leaves. To be sure, look at the leaves more than once over several weeks before acting, 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 the new flush when the leaves are two thirds to fully expanded. A little low biuret urea in the spray helps uptake. On acid soils manganese sulfate can also go on the soil. On limey soils use sprays only.

• 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 spray program. Test the soil every two or three years.

Iron deficiency in calamansi

It always starts on the youngest leaves: yellow green, then pale yellow between veins that stay green, sometimes with even the fine veins green like a net. In bad cases the whole leaf turns ivory, new leaves are small, thin and fragile and drop early. Twigs die back at the top and edge of the canopy while older leaves stay green. You see it most at this stage: new flushes, especially in the rainy season on wet soils.

Why iron deficiency happens in kalamansi

High pH and limey soils, too much water, poor drainage, cool soils, salty soils, high phosphorus. Copper built up in old orchard soil. Calamansi does not tolerate waterlogged ground.

How to tell it apart

Manganese and zinc shortages often come with it, since all three get worse at high pH. Flood damage to roots and copper toxicity both first show as iron chlorosis, so check the roots and the spray history. To be sure, soil test for pH, and for copper on old orchard land, and check drainage and the roots. In a soil test, less than 4.5 ppm of iron is low.

What to apply for iron deficiency

Fix drainage first. Trees helped or cured just by better irrigation and drainage. On high pH soils apply an iron chelate (Fe EDDHA) to the soil. Iron sprays on citrus are not advised, because they green the leaf only in specks and can burn. A Ferrous sulfate spray at 0.5 percent (5 grams per liter, 80 grams in a 16 liter sprayer), twice, two weeks apart, is a quick try.

• 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 or raised beds, avoid overliming, and keep the pH near neutral. Test the soil every two or three years. Keep organic matter up with compost, manure or crop residues.

Phosphorus deficiency in calamansi

Older leaves lose their deep green and turn dull, small and narrow, with a purplish or bronze cast. In bad cases small brown to bronze freckles join up along the main veins. Leaves and fruit drop early, flowering and fruit set are poor, and roots stay short. Fruit are rough, with a coarse, thick peel, a hollow core and more acid. You see it most at this stage: young trees and new plantings on land never fertilized. Rare in trees fed regularly for years.

Why phosphorus deficiency happens in kalamansi

Strongly acid soils where iron and aluminium lock phosphorus up, very alkaline soils, 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. Use ammophos (16 20 0) with potash once trees bear. Superphosphate suits soils of any pH and adds sulfur. Do not use DAP 18 46 0 on alkaline soils. Lime very acid soils so the phosphorus stays available. Give 200 to 500 grams of Complete 14 14 14 a young tree, up to 1 to 2 kg a bearing tree, when the rains begin.

• 16 20 0
• Superphosphate 0 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, and add compost.

Copper deficiency in calamansi

The first sign is unusually large, dark green leaves with the midrib bowed up, on long, soft, angular shoots that droop in an S shape. Small blisters of clear gum form at the nodes, and reddish brown gum breaks out on older twigs. Twigs then die back from the tip and push out a bunch of weak buds. Fruit can show brown gum stains and split. You see it most at this stage: young trees in new plantings, and trees pushed with heavy nitrogen.

Why copper deficiency happens in kalamansi

New plantings on sandy or organic soils never farmed before, limey soils, and heavy nitrogen feeding. It is rare where copper fungicides are sprayed.

How to tell it apart

Gummosis, dark, sticky gum oozing from branches and trunk, is a bark disease. Copper deficiency gum sits in small blisters on young twigs and as stains on the fruit. To be sure, check the spray record: if copper fungicides are used, copper deficiency is unlikely. A soil test on new land helps. In a soil test, less than 0.2 ppm of copper is low.

What to apply for copper deficiency

Near immediate recovery 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 it on a few branches first, since plain copper sulfate can burn soft leaves. Cut back excess nitrogen. Do not overdo copper: it builds up in the soil and below pH 5.5 it can kill roots. 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. Where copper fungicides are already sprayed, no extra copper is needed. Keep the soil pH near neutral.

Calamansi nutrient deficiency questions