Guava Nutrient Deficiency: Signs, Causes and the Fertilizer That Fixes It
Guava nutrient deficiency is one of the first things to check when the leaves of your bayabas (guava) turn yellow, purple or burnt at the edges. On Philippine farms the usual ones are nitrogen, phosphorus, potassium, zinc, magnesium and boron. 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, phosphorus, potassium and magnesium move inside the plant, so a shortage shows on the old, lower leaves first. But zinc and boron 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 guava nutrient deficiency you have, and a soil test confirms it. Each one below has its signs, its causes and its fix.
Guava 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 | Old leaves pale green to light yellow from the tip. Slow, thin tree with few fruits. | Complete 14 14 14, Urea 46 0 0 |
| Phosphorus | old, lower leaves, the whole plant | Older leaves dark blue green or bronzed with purple to red specks. Weak, slow tree and poor fruit. | Ammonium phosphate 18 46 0, 16 20 0 |
| Potassium | old, lower leaves, leaf edges and tips | Older leaves yellow and scorch at the edges. Weak stems, small and few fruits. | Muriate of potash 0 0 60, Sulfate of potash 0 0 50 |
| Magnesium | old, lower leaves, between the veins | Old leaves get yellow, bronze or reddish patches between the veins while the veins stay green. | Magnesium sulfate (Epsom salt), Dolomite |
Shows first on the young leaves
| Nutrient | Where it starts | What you see | Fix with |
|---|---|---|---|
| Zinc | young leaves and the tip, between the veins | Newest leaves small, narrow and pointed, strongly yellow between bright green veins, with tiny brown dots. | Zinc sulfate, Ammonium phosphate 18 46 0 |
| Boron | young leaves and the tip | Newest leaves narrow, thick and brittle, bent down as if the stalk were broken. Shoot tips die back. | Borax, Solubor |
Before you buy fertilizer for a guava nutrient deficiency
So use the table to pick the likeliest guava 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 guava
Older leaves turn pale green to light yellow, usually starting at the tip, and in bad cases they die and drop. The tree grows slowly and stays small, with few new shoots, so it flowers and fruits less. You see it most at this stage: young trees, and bearing trees after heavy crops.
Why nitrogen deficiency happens in bayabas
Trees that get little fertilizer, sandy soils low in organic matter, and heavy rain that washes nitrogen away.
How to tell it apart
Root knot and other nematodes can also stunt the tree and bring yellowing, wilting and dieback. So check the roots for galls. To be sure, soil test and a leaf test of the third pair of leaves from the shoot tip. New growth that greens up after urea confirms it.
What to apply for nitrogen deficiency
Use Complete 14 14 14 at 100 to 150 grams at planting and 200 to 300 grams per young tree. For bearing trees 300 grams to 1 kg of complete fertilizer plus 300 grams each of Muriate of potash 0 0 60 and 16 20 0, in a shallow furrow around the canopy edge, together with compost. A bearing tree needs about 300 to 400 grams of nitrogen a year. For a quick lift, give a Urea spray at 1 to 2 percent (10 to 20 grams per liter, 160 to 320 grams in a 16 liter sprayer) every two weeks. Give about 100 grams of Urea 46 0 0 a tree for each year of age, up to 1 to 2 kg for a bearing tree, split between the first rains and the last, under the canopy edge.
- Complete 14 14 14
- Urea 46 0 0
- Ammonium sulfate 21 0 0
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, fertilize every year in splits during the rains and add compost or manure under the canopy. Let a soil test and the crop's color set the season's nitrogen.
Phosphorus deficiency in guava
Growth is slow, weak and stunted. Older leaves turn dark or blue green, and in bad cases leaves and stems take a purple color. Fruit matures late and develops poorly. It can show as bronzing, with purple to red specks across the leaves and older leaves turning bronze or copper. In bad cases many leaves fall. Brown patterns on the fruit skin. You see it most at this stage: young trees, and bearing trees once fruiting begins, when the tree pulls nutrients from old leaves into the fruit.
Why phosphorus deficiency happens in bayabas
Poor, acid soils. Bronzing is common where the soil is poor and the pH is low. The leaves were low in nitrogen, phosphorus and zinc.
How to tell it apart
Magnesium deficiency also gives bronze or reddish patches between the veins of old leaves, but the veins stay clearly green. Potassium deficiency scorches the leaf edges. To be sure, soil test for available phosphorus and pH. A leaf test of the third pair of leaves from the shoot tip for nitrogen, phosphorus, potash and zinc together.
What to apply for phosphorus deficiency
Spray 0.5 percent DAP (Ammonium phosphate 18 46 0, 5 grams per liter, 80 grams in a 16 liter sprayer) with Zinc sulfate every week for two months. This clears most bronzing. Give DAP at 2 percent every two weeks. For the soil, give bearing trees 300 grams of 16 20 0 plus complete fertilizer and potash. Lime very acid soils, following the soil test. 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.
- Ammonium phosphate 18 46 0
- 16 20 0
- Complete 14 14 14
- Superphosphate 0 20 0
- Zinc sulfate
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, use a complete fertilizer with phosphorus and potash every year from the time trees start to bear, plus compost, and correct acid soils.
Potassium deficiency in guava
The edges of older leaves turn yellow and then scorch brown. Growth is slow, stems are weak, and fruits stay smaller and fewer. Shortage of potash, with phosphorus, is also linked to leaf bronzing once trees start to fruit. You see it most at this stage: bearing trees, during fruit growth.
Why potassium deficiency happens in bayabas
Sandy and leached soils, heavy crops, and programs that give nitrogen only. Soil that runs low in both phosphorus and potash brings on bronzing too.
How to tell it apart
Phosphorus shortage and bronzing give purple to red specks over the leaf rather than a scorched edge. Salt damage can brown leaf tips and edges too, and then leaves drop and branches die back. To be sure, soil test for potash and a leaf test of the third pair of leaves from the shoot tip.
What to apply for potassium deficiency
Give bearing trees 300 grams of Muriate of potash 0 0 60 with complete fertilizer and 16 20 0. A bearing tree needs about 250 to 350 grams of potash (K2O) a year. A Sulfate of potash spray at 1 to 2 percent gives more fruit of better quality. Give a 2 percent spray (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
- 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, raise the potash share once trees bear. For bearing trees, pick a fertilizer mix with 9 to 15 percent potash. Test the soil every two or three years.
Zinc deficiency in guava
The youngest leaves come out small, narrow and pointed, with raised veins. The blade cups up or down along the midrib, with the edges turned in. Leaves yellow strongly between the veins while the veins stay bright green, and small brown dots spread over the blade. Shoots stay thin and the tree stays dwarfed. You see it most at this stage: new flushes, and orchards on poor soils where bronzing also shows.
Why zinc deficiency happens in bayabas
High pH soils, heavy phosphate fertilizer, and poor, acid soils low in zinc and organic matter. Bronzed trees on such soils often show low leaf zinc.
How to tell it apart
Iron deficiency also keeps green veins on yellow young leaves. But the leaves keep a normal shape, turn fully yellow and then whitish, and lower leaves stay normal. To be sure, leaf test of the third pair of leaves from the shoot tip. A seedling whose leaves test about 9 ppm zinc is short. A healthy one holds about 14 ppm.
What to apply for zinc deficiency
Spray Zinc sulfate with DAP at 0.5 percent every week for two months to clear bronzing. Before flowering, also spray 0.3 percent Zinc sulfate (3 grams per liter, 48 grams in a 16 liter sprayer) with 0.4 percent boric acid. It lifts yield and fruit size. On bronzed trees, also put 100 grams of Zinc sulfate per tree on the soil.
- Zinc sulfate
- Ammonium phosphate 18 46 0
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, avoid heavy phosphate and overliming, add compost, and include zinc in a pre flowering spray where leaf tests run low. Test the soil every two or three years.
Magnesium deficiency in guava
Older leaves develop yellow, bronze or reddish patches between the veins while the veins stay green. In bad cases younger leaves show it too and leaves fall early. You see it most at this stage: bearing trees, mostly on acid soils.
Why magnesium deficiency happens in bayabas
Acid soils, and heavy potash or calcium fertilizer, which compete with magnesium.
How to tell it apart
Bronzing from low phosphorus and zinc also gives purple to red specks on the leaves. A leaf test tells them apart. To be sure, leaf test of the third pair of leaves from the shoot tip, and a soil test for magnesium, potash and calcium together.
What to apply for magnesium deficiency
Give a foliar spray of Magnesium sulfate at 2 percent (20 grams per liter, 320 grams in a 16 liter sprayer) every two weeks. On acid soils use Dolomite, following the soil test. For young trees, use a fertilizer mix with 4 to 6 percent magnesium. Give 100 to 250 grams of Kieserite or Magnesium sulfate a tree a year, or Dolomite on acid soil.
- Magnesium sulfate (Epsom salt)
- Dolomite
- 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 acid soils with Dolomite and keep potash and magnesium in balance.
Boron deficiency in guava
The youngest leaves come out narrower than normal, pale, with a dark net of veins on a light background. They thicken, turn brittle and curl or twist downward as if the leaf stalk were broken. The top pairs drop while older leaves stay. Later the growing points die and branches dry from the tip down. You see it most at this stage: new flushes and before flowering.
Why boron deficiency happens in bayabas
Sandy, leached soils low in organic matter and long dry spells bring it on. Boron acts together with calcium and phosphorus in the leaf, so keep those in balance too.
How to tell it apart
Aphids feeding on young growth also curl the leaves. But you can see the insects and the leaves are not thick and brittle. To be sure, leaf test of the third pair of leaves from the shoot tip. Short seedlings test about 7 ppm boron in the leaf, while healthy ones hold about 43 ppm. A soil test for boron helps.
What to apply for boron deficiency
Give a foliar spray of Borax at 0.5 percent every two weeks. Before flowering, a spray of boric acid at 0.4 percent with Zinc sulfate also helps. Boron is toxic in excess, so do not repeat high doses without a test. 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, add organic matter and include a small boron dose in a pre flowering spray where tests run low. Test the soil every two or three years.
A soil test is the surest check for any guava 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 bayabas needs. That saves money, because extra fertilizer is money lost.
Open the Nutrient Deficiency Finder, pick bayabas, 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
Guava nutrient deficiency questions
Why are my bayabas leaves turning yellow?
What fertilizer fixes nitrogen deficiency in guava?
What fertilizer fixes phosphorus deficiency in guava?
What fertilizer fixes potassium deficiency in guava?
How do I know which nutrient my bayabas 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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