Garlic Nutrient Deficiency: Signs, Causes and the Fertilizer That Fixes It
Garlic nutrient deficiency is one of the first things to check when the leaves of your bawang (garlic) turn yellow, purple or burnt at the edges. On Philippine farms the usual ones are nitrogen, sulfur, potassium, phosphorus, boron, zinc, magnesium and calcium. 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, phosphorus and magnesium move inside the plant, so a shortage shows on the old, lower leaves first. But sulfur, boron, zinc and calcium 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 garlic nutrient deficiency you have, and a soil test confirms it. Each one below has its signs, its causes and its fix.
Garlic 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 turn pale to yellow, plants stay thin, and bulbs are small. | Urea 46 0 0, Ammonium sulfate 21 0 0 |
| Potassium | old, lower leaves, leaf edges and tips | Older leaves yellow and die along the edges, and bulbs stay small and store poorly. | Muriate of potash 0 0 60, Sulfate of potash 0 0 50 |
| Phosphorus | old, lower leaves, the roots | Dark green, slow plants, sometimes reddish purple, with small roots and bulbs. | 16 20 0, Single superphosphate 0 20 0 |
| Magnesium | old, lower leaves | Older leaves yellow, with whitish tips, and bulbs grow slowly. | Epsom salt / magnesium sulfate, Dolomite |
Shows first on the young leaves
| Nutrient | Where it starts | What you see | Fix with |
|---|---|---|---|
| Sulfur | young leaves and the tip, the whole plant | Young leaves turn evenly yellow, plants are thin and weak, and bulbs are light with weak flavour. | Ammonium sulfate 21 0 0, Gypsum |
| Boron | young leaves and the tip, fruit, grain or tubers | Young leaves distorted, the growing point dies, and bulbs crack or are misshapen. | Borax |
| Zinc | young leaves and the tip, between the veins | Young leaves pale and stay small, and bulbing is late. | Zinc sulfate, Agricultural lime |
| Calcium | young leaves and the tip, leaf edges and tips | Young leaf tips die, roots are short, and bulbs are soft and store poorly. | Agricultural lime, Gypsum |
Before you buy fertilizer for a garlic nutrient deficiency
So use the table to pick the likeliest garlic 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 garlic
The oldest leaves fade to light green and then yellow, growth slows, and plants stay thin and stunted. Bulbs stay small and yield drops. You see it most at this stage: from emergence to the start of bulbing.
Why nitrogen deficiency happens in bawang
Sandy soils low in organic matter, such as many fields that follow rice, and too little nitrogen.
How to tell it apart
Sulfur deficiency yellows the young leaves first. Viruses give yellow stripes along the leaves, not even yellowing. To be sure, check that older leaves yellowed first. Soil test.
What to apply for nitrogen deficiency
About 112 kg N per hectare lifts garlic yield in nine fields out of ten. More helped in only four. Split the nitrogen through early growth. For quick help a 1 percent urea spray (10 g per liter, 160 g in a 16 liter sprayer) can be used.
- Urea 46 0 0
- Ammonium sulfate 21 0 0
- Complete 14 14 14
Sold here with nitrogen: Atlas Granular Urea (46 0 0) by Atlas Fertilizer, Crown Champion Ammonium Sulfate by Aqua Hydroponic Prime Ventures (21 0 0 with 24 percent sulfur), 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, do not give heavy nitrogen late. It slows maturity and makes the bulbs cure and store poorly. Let a soil test and the crop's color set the season's nitrogen.
Sulfur deficiency in garlic
Young leaves turn evenly yellow first. Plants are thin and weak, and bulbs weigh less and taste less pungent. You see it most at this stage: before and during bulbing.
Why sulfur deficiency happens in bawang
Garlic needs more sulfur than most vegetables. Sandy soils, low organic matter and sulfur free fertilizers bring it on.
How to tell it apart
Nitrogen deficiency starts on older leaves. To be sure, soil and leaf test for sulfur. In a soil test, less than 10 ppm of sulfate sulfur is low.
What to apply for sulfur deficiency
Use Ammonium sulfate 21 0 0 for part of the nitrogen, or add Gypsum or single superphosphate, following the soil test. Give about 25 kg sulfur dust per hectare on sulfur poor soils. Give it at planting or with the first side dress.
- Ammonium sulfate 21 0 0
- Gypsum
- Single superphosphate 0 20 0
Sold here with sulfur: Crown Champion Ammonium Sulfate by Aqua Hydroponic Prime Ventures (21 0 0 with 24 percent sulfur), Philphos Gypsum (22.2 percent calcium and 17.4 percent sulfur), Harvester Sulphate of Potash by Universal Harvester (0 0 50 with 17.5 percent sulfur) and Agsmart Kieserite Granule (20 percent sulfur and 16.3 percent magnesium). Check the FPA registration on the bag and follow the label rate. For the how and when, see our guide to ammonium sulfate fertilizer, and the page on sulfur deficiency in every crop.
To keep it away, keep a sulfur source in every crop. Keep organic matter up with compost, manure or crop residues.
Potassium deficiency in garlic
Older leaves yellow and then die along the edges. Bulbs are smaller with less dry matter and store poorly. You see it most at this stage: bulb enlargement, when potassium demand rises sharply.
Why potassium deficiency happens in bawang
Sandy soils and fields cropped for years without potash. Soils already above 100 ppm potassium give no response, so test first.
How to tell it apart
Leaf blight and purple blotch give spots, not even edge burn. To be sure, soil test for exchangeable potassium.
What to apply for potassium deficiency
Apply Muriate of potash 0 0 60 before planting and, where needed, again during bulbing, following the soil test. Give a potassium sulfate spray of 10 g per liter (160 g in a 16 liter sprayer) for quick help. A usual dose is 1 to 2 bags of Muriate of potash 0 0 60 per hectare, half before transplanting and half when bulbs start to form.
- Muriate of potash 0 0 60
- Sulfate of potash 0 0 50
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, base potash on a soil test every season. Keep organic matter up with compost, manure or crop residues. Split the potash on sandy soil.
Phosphorus deficiency in garlic
Growth is stunted and slow, and leaves are dark green, sometimes with a reddish purple tint. Roots and bulbs develop poorly. You see it most at this stage: establishment.
Why phosphorus deficiency happens in bawang
Acid and volcanic soils. Garlic's small roots need phosphorus close by at planting.
How to tell it apart
Nitrogen deficiency makes leaves pale, not dark. To be sure, soil test for phosphorus. Garlic seldom responds to phosphorus, so add it only when the soil test is low.
What to apply for phosphorus deficiency
Place phosphorus in the root zone at planting, such as 16 20 0 or single superphosphate, following the soil test. A usual basal dose is 4 to 6 bags of Complete 14 14 14 or 2 to 3 bags of Diammonium phosphate 18 46 0 per hectare before transplanting.
- 16 20 0
- Single superphosphate 0 20 0
- Complete 14 14 14
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, band phosphorus near the cloves at planting.
Boron deficiency in garlic
Young leaves grow twisted, and a bad case kills the growing tip. Bulbs crack or grow misshapen. You see it most at this stage: bulbing.
Why boron deficiency happens in bawang
Sandy soils low in organic matter, alkaline soils and dry spells.
How to tell it apart
Calcium deficiency kills young leaf tips and softens bulbs. To be sure, soil test for boron. In a soil test, less than 0.5 ppm of boron is low.
What to apply for boron deficiency
Give about 10 kg Borax per hectare to the soil, or a borax spray of 1 g per liter (16 g in a 16 liter sprayer). Do not exceed it. Boron is toxic in excess. Give boron before flowering: flowers and fruit set need it most.
- Borax
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, test before applying boron. Test the soil every two or three years. Keep organic matter up with compost, manure or crop residues.
Zinc deficiency in garlic
Young leaves turn pale between the veins and fail to expand fully. Growth is stunted and bulbs form late. You see it most at this stage: early growth.
Why zinc deficiency happens in bawang
Alkaline soils, low organic matter and heavy phosphorus.
How to tell it apart
Iron deficiency also yellows young leaves but bleaches them more. To be sure, soil and leaf test for zinc. In a soil test, less than 0.8 ppm of zinc is low.
What to apply for zinc deficiency
Give about 20 kg Zinc sulfate per hectare, or a morning spray of 2 g zinc sulfate with 2.5 g lime per liter in severe cases. Keep zinc and phosphate apart. Give the soil dose at planting or when the rains begin, and sprays on young growth.
- 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), Semia by SCL Filipinas (20 percent zinc) and Omex Zynergy by Jardine Distribution (3.8 percent zinc and 2.1 percent copper). 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 soil pH between 5 and 7.5. Test the soil every two or three years.
Magnesium deficiency in garlic
Older leaves turn yellow between the veins, sometimes with white tips and oval pale patches. Bulb growth slows. You see it most at this stage: mid season.
Why magnesium deficiency happens in bawang
Acid sandy soils and heavy potash.
How to tell it apart
Nitrogen deficiency yellows leaves from the tips and keeps them upright. To be sure, soil test for magnesium.
What to apply for magnesium deficiency
Give about 80 kg magnesium sulfate per hectare in bands near the plants. Use Dolomite on acid soils. Put the soil dose in before planting or when the rains begin. Sprays show results in 10 to 14 days.
- Epsom salt / magnesium sulfate
- Dolomite
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 acid fields with dolomite. Test the soil every two or three years. Keep potash in balance with magnesium and calcium.
Calcium deficiency in garlic
The tips of young leaves die and turn brown, and roots grow less. Bulbing is late, and bulbs are soft and store poorly. You see it most at this stage: bulbing.
Why calcium deficiency happens in bawang
Very acid soils and dry spells that stop calcium moving into the plant. Heavy potash or ammonium fertilizer, salty soil and dry spells keep calcium from reaching fruit and young leaves.
How to tell it apart
Boron deficiency also damages young leaves but cracks the bulbs. To be sure, soil pH and calcium test. A soil test for calcium and pH, and a leaf test, confirm it.
What to apply for calcium deficiency
On acid soils, lime about 250 kg per hectare where the pH is 5.5 to 6. On alkaline soils use Gypsum. Lime 2 to 4 weeks before planting. Calcium sprays go on young fruit from fruit set.
- Agricultural lime
- Gypsum
- Calcium nitrate
Sold here with calcium: Micronized Activated Calcite by CMCS Agricultural Products (37.6 percent calcium), Dolomite by A6 Agrisource (24 percent calcium and 11 percent magnesium), Titon Pro by Vast Agro (27.2 percent calcium, 6.1 percent silicon and 3.6 percent magnesium) 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 fertilizer for tomatoes, and the page on calcium deficiency in every crop.
To keep it away, keep the soil evenly moist so calcium keeps moving into the bulbs. Test the soil every two or three years. Keep potash in balance with magnesium and calcium.
A soil test is the surest check for any garlic 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 bawang needs. That saves money, because extra fertilizer is money lost.
Open the Nutrient Deficiency Finder, pick bawang, 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
Garlic nutrient deficiency questions
Why are my bawang leaves turning yellow?
What fertilizer fixes nitrogen deficiency in garlic?
What fertilizer fixes sulfur deficiency in garlic?
What fertilizer fixes potassium deficiency in garlic?
How do I know which nutrient my bawang lacks?
Find the missing nutrient and fix it
With Libre + Anee, read the whole guide: how to tell the deficiency from look alikes, how to be sure, what to apply, and the fertilizers sold here that supply it.
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