Star apple Nutrient Deficiency: Signs, Causes and the Fertilizer That Fixes It
Star apple nutrient deficiency is one of the first things to check when the leaves of your kaimito (star apple) turn yellow, purple or burnt at the edges. On Philippine farms the usual ones are nitrogen, potassium, phosphorus, magnesium and iron. 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 iron 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 star apple nutrient deficiency you have, and a soil test confirms it. Each one below has its signs, its causes and its fix.
Star apple 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 | The upper side of the leaves turns pale, older leaves yellow and drop, and new shoots stay short. | Ammonium sulfate 21 0 0, Complete 14 14 14 |
| Potassium | old, lower leaves, leaf edges and tips | Edges and tips of older leaves scorch brown. Fruits stay small and poor in quality. | Muriate of potash 0 0 60, Sulfate of potash 0 0 50 |
| Phosphorus | old, lower leaves | Young trees grow slowly and older leaves take on a purplish tint, most on the underside. | Superphosphate 0 20 0, 16 20 0 |
| Magnesium | old, lower leaves, between the veins | Older leaves yellow between the veins while the veins stay green. | Dolomite, Magnesium sulfate (Epsom salt) |
Shows first on the young leaves
| Nutrient | Where it starts | What you see | Fix with |
|---|---|---|---|
| Iron | young leaves and the tip, between the veins | New leaves turn pale yellow with green veins, mostly on limestone or high pH soil. | Ferrous sulfate |
Before you buy fertilizer for a star apple nutrient deficiency
So use the table to pick the likeliest star apple 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 star apple
The signs on kaimito are like those on other fruit trees. The shiny upper side of the leaves loses its deep green, the older leaves turn yellow, then brown, and fall. Growth slows, new shoots are short, and the tree flowers and fruits less. You see it most at this stage: young trees in the first years after planting, and bearing trees during fruit growth.
Why nitrogen deficiency happens in kaimito
Trees that are never fed (most kaimito trees are never fertilized), sandy or limestone soils low in organic matter. Heavy rain that washes nitrogen down.
How to tell it apart
In a long dry season kaimito sheds many leaves and its fruits shrivel, which is drought, not hunger. The underside of a kaimito leaf is normally golden brown, so judge the color on the upper side. To be sure, A leaf test of mature leaves from recent growth shows low nitrogen. New leaves that come out deep green after a nitrogen dose confirm it.
What to apply for nitrogen deficiency
Young trees not yet bearing take 150 to 200 grams of Ammonium sulfate 21 0 0 each, twice a year. At the start of fruiting, 500 grams of complete fertilizer go on twice a year. Full grown trees may need 3 kg or more of complete fertilizer a year. Put it on when the rains begin and again as they end, spread in a ring or dropped into shallow holes under the canopy.
- Ammonium sulfate 21 0 0
- Complete 14 14 14
- Urea 46 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, feed every year and mulch the root zone. On limestone and other poor soils, a complete, balanced fertilizer helps kaimito a great deal. Let a soil test and the crop's color set the season's nitrogen.
Potassium deficiency in star apple
The signs on kaimito are like those on other fruit trees. The edges and tips of older leaves look burnt, and the scorch moves inward. Fruit size and quality drop. You see it most at this stage: bearing trees, most of all while fruits are growing. Raise the potash share of the fertilizer once trees bear.
Why potassium deficiency happens in kaimito
Sandy and leached soils, heavy rain, and years of fruiting with no potash returned.
How to tell it apart
The golden brown underside of kaimito leaves is normal. Phomopsis and Phyllosticta leaf spots make separate spots on the blade rather than a scorch along the edge. To be sure, A soil test for potash and a leaf test.
What to apply for potassium deficiency
For bearing trees, raise potash in the fertilizer to 9 to 15 percent and cut phosphate to 2 to 4 percent. Mixes such as 8 3 9 with magnesium are used. Give Complete 14 14 14 at the usual fruit tree rates and add Muriate of potash 0 0 60 where the soil test shows low potash, in two doses at the start and near the end of the rainy season. 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, give potash every year once the tree bears, and return fallen leaves under the canopy. Keep organic matter up with compost, manure or crop residues.
Phosphorus deficiency in star apple
The signs on kaimito are like those on other fruit trees. Growth is slow and the tree stays small. Older leaves take on a purple color, most of all on the underside, though on kaimito this can be hard to see against the natural golden brown underside. You see it most at this stage: young trees in the first years, before bearing.
Why phosphorus deficiency happens in kaimito
Acid and eroded soils low in organic matter, limestone soils, and no phosphate at planting.
How to tell it apart
Nitrogen shortage gives an even pale color without the purple tint. Drought stress slows growth and makes leaves drop. To be sure, A soil test for available phosphorus and pH, and a leaf test.
What to apply for phosphorus deficiency
Use 6 to 10 percent phosphate in the fertilizer for young trees. Work Superphosphate 0 20 0, 16 20 0 or Complete 14 14 14 into the soil under the canopy, following the soil test, with manure or compost. 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.
- Superphosphate 0 20 0
- 16 20 0
- Complete 14 14 14
- Ammonium phosphate 18 46 0
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 phosphate and manure in the planting hole and feed young trees with a complete fertilizer every 1 to 2 months in the first year. Kaimito grows best in fertile, slightly acid soil that drains well.
Magnesium deficiency in star apple
The signs on kaimito are like those on other fruit trees. Older leaves turn yellow between the veins while the veins stay green, and growth slows. Include 4 to 6 percent magnesium in the fertilizer for young kaimito trees as part of the regular feeding. You see it most at this stage: bearing trees during fruit growth, and trees fed heavy potash.
Why magnesium deficiency happens in kaimito
Acid, sandy and leached soils, and heavy potash fertilizer, which competes with magnesium.
How to tell it apart
Iron shortage also yellows between the veins, but on the young leaves at the shoot tip. Potassium shortage scorches the leaf edges. To be sure, A soil test for magnesium, potash and calcium together, and a leaf test.
What to apply for magnesium deficiency
On acid soils apply Dolomite, which supplies both lime and magnesium. Take the amount from the soil test. Where the pH is already fine, spread Magnesium sulfate (Epsom salt) or Kieserite under the canopy and follow the label. 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 a fertilizer that carries magnesium, such as the 6 6 6 2 and 8 3 9 mixes with magnesium. Balance potash with magnesium according to the soil test.
Iron deficiency in star apple
Kaimito often runs short of iron on alkaline, high pH soils. The newest leaves turn light green to yellow between the veins while the veins stay green, making a net pattern. In bad cases the new leaves bleach almost white and may burn, while older leaves stay green. You see it most at this stage: new flushes on limestone or high pH soils.
Why iron deficiency happens in kaimito
Alkaline, limestone (calcareous) soils, where iron is locked up. Too much phosphate also brings it on. It is less likely on the slightly acid soils kaimito prefers.
How to tell it apart
Magnesium shortage yellows between the veins of older leaves, not the newest ones. Zinc shortage makes the new leaves small and crowded. To be sure, A soil pH test. Trouble is likely on limestone soils. Leaf tests for iron are not reliable.
What to apply for iron deficiency
On alkaline and high pH soils, use regular soil applications of an iron chelate made for high pH soils. On low pH soils, regular soil doses of Ferrous sulfate can be used. Follow the label for the amount. Spray Ferrous sulfate at 0.5 to 1 percent (80 to 160 grams in a 16 liter sprayer), or an iron chelate at the label rate, two or three times 7 to 10 days apart.
- 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, do not overlime, avoid heavy phosphate, and plant on well drained ground. You can also give 3 to 4 micronutrient sprays a year (copper, zinc, manganese and boron) during the first 4 to 5 years. Test the soil every two or three years.
A soil test is the surest check for any star apple 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 kaimito needs. That saves money, because extra fertilizer is money lost.
Open the Nutrient Deficiency Finder, pick kaimito, 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
Star apple nutrient deficiency questions
Why are my kaimito leaves turning yellow?
What fertilizer fixes nitrogen deficiency in star apple?
What fertilizer fixes potassium deficiency in star apple?
What fertilizer fixes phosphorus deficiency in star apple?
How do I know which nutrient my kaimito 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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