Water spinach Nutrient Deficiency: Signs, Causes and the Fertilizer That Fixes It
Water spinach nutrient deficiency is one of the first things to check when the leaves of your kangkong (water spinach) turn yellow, purple or burnt at the edges. On Philippine farms the usual ones are nitrogen, phosphorus, potassium, 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, phosphorus, potassium 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 water spinach nutrient deficiency you have, and a soil test confirms it. Each one below has its signs, its causes and its fix.
Water spinach 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 | Lower leaves turn pale yellow and shoots stay thin and short. | Urea 46 0 0, Ammonium sulfate 21 0 0 |
| Phosphorus | the whole plant, old, lower leaves | Plants stay short with dark green leaves and thin, woody stems. | Complete 14 14 14, Ammonium phosphate 16 20 0 |
| Potassium | old, lower leaves, leaf edges and tips | Older leaves look greyish, then bronze, with brown edges. | Complete 14 14 14, Muriate of potash 0 0 60 |
| 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 | The newest shoot tips turn pale yellow between green veins, then fully yellow. | Ferrous sulfate, Iron chelate |
Before you buy fertilizer for a water spinach nutrient deficiency
So use the table to pick the likeliest water spinach 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 water spinach
Older, lower leaves fade to yellowish green and then yellow, and in bad cases the whole plant turns pale. Shoots are thin and hard and grow slowly, so bundles are light at harvest. Kangkong without nitrogen grows to less than half its usual height, with paler leaves. You see it most at this stage: from planting to harvest, which comes only three to four weeks after planting, and again after each cutting.
Why nitrogen deficiency happens in kangkong
Sandy soils, daily watering or heavy rain that washes nitrogen away, low organic matter, and missed weekly feeding. Each harvest removes a lot of nitrogen with the shoots.
How to tell it apart
Iron shortage yellows the youngest tips with green veins instead. Too much water or root rot also makes plants pale. To be sure, lower leaves yellow first. A soil test for organic matter and a test drench on a few plants.
What to apply for nitrogen deficiency
The drench urea dissolved in 16 liters of water at 150 ml per hill, using 75 grams of urea in the first week, 150 in the second, 225 in the third and 300 in the fourth. Repeat a light feeding after each cutting. Side dress 1 to 2 bags of Urea 46 0 0 per hectare, about 5 grams a plant, two and four weeks after transplanting, and water it in.
- Urea 46 0 0
- Ammonium sulfate 21 0 0
- Complete 14 14 14
- Chicken manure
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, mix chicken manure or compost into the beds before planting and keep up the weekly drench. Let a soil test and the crop's color set the season's nitrogen. Split the nitrogen into two or three doses.
Phosphorus deficiency in water spinach
Growth is held back without yellowing. Stems are slender and woody, leaves are small and darker green, and some leaves show a reddish purple tint underneath. Without phosphorus, the leaves also hold less chlorophyll. You see it most at this stage: early growth after sowing or planting cuttings.
Why phosphorus deficiency happens in kangkong
Acid soils (pH 5.5 to 6.5 is best), iron rich soils, low organic matter, and feeding urea only.
How to tell it apart
Purple stem varieties are naturally colored. Root knot nematodes also stunt upland kangkong. To be sure, soil test for available phosphorus and pH.
What to apply for phosphorus deficiency
Use complete 14 14 14 in the beds, adjusted to the soil test, and lime very acid soil. Follow the soil test for the rate. A usual basal dose is 4 to 6 bags of Complete 14 14 14 per hectare, about 10 grams a hill, mixed into the soil at transplanting.
- Complete 14 14 14
- Ammonium phosphate 16 20 0
- 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, apply complete fertilizer and manure at bed preparation.
Potassium deficiency in water spinach
Older leaves turn ashy grey green, then bronze or yellowish brown, and the edges brown and cup down. Stems are slender and weak and roots are poor. Lack of potassium lowers the chlorophyll in the leaves. You see it most at this stage: later growth and regrowth after repeated cuttings.
Why potassium deficiency happens in kangkong
Sandy soils, heavy watering, and repeated harvests fed with urea only.
How to tell it apart
Leaf spot diseases make round spots across the leaf rather than edge burn. To be sure, soil test for potassium.
What to apply for potassium deficiency
Use complete 14 14 14 or muriate of potash based on the soil test. Follow the soil test for the rate. A usual dose is 1 to 2 bags of Muriate of potash 0 0 60 per hectare, split between transplanting and the first side dress.
- Complete 14 14 14
- Muriate of potash 0 0 60
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, use complete fertilizer at planting and after every few cuttings. Keep organic matter up with compost, manure or crop residues.
Magnesium deficiency in water spinach
Older leaves turn yellow between the veins while the veins stay green, and the leaves become brittle with edges curling. Without magnesium, kangkong leaves hold clearly less chlorophyll than those of well fed plants. You see it most at this stage: mid growth.
Why magnesium deficiency happens in kangkong
Acid soils, heavy potash fertilizer, and heavy liming with plain lime only.
How to tell it apart
Nitrogen shortage yellows the whole leaf, veins included. To be sure, soil test for magnesium, potassium and pH.
What to apply for magnesium deficiency
Spray magnesium sulfate on the leaves for quick relief and correct acid soil with dolomite. Follow the soil test for rates. A usual dose is 100 to 150 kg of Kieserite or 150 to 200 kg of Magnesium sulfate per hectare at planting. On acid soil, 1 to 2 tons of Dolomite mixed in before planting both limes and feeds. For quick help, spray Magnesium sulfate at 1 to 2 percent (160 to 320 grams in a 16 liter sprayer) two or three times, 10 to 14 days apart.
- Dolomite
- Magnesium sulfate (Epsom salt)
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 instead of plain lime on acid beds. Keep potash in balance with magnesium and calcium.
Iron deficiency in water spinach
New leaves at the shoot tips turn light yellow, first between the veins, then over the whole leaf, usually without dead spots. Kangkong short of iron has clearly less chlorophyll in its leaves than well fed plants. You see it most at this stage: any stage, mostly on limed or alkaline soil and in nutrient mixes without iron.
Why iron deficiency happens in kangkong
Alkaline or overlimed soils, and soilless or hydroponic setups with too little iron. On ordinary acid Philippine soils iron shortage is uncommon.
How to tell it apart
Nitrogen shortage yellows the older leaves first. To be sure, soil pH test, and a check of the nutrient recipe in hydroponic setups. A soil pH test and a leaf test of the young leaves confirm it. In a soil test, less than 4.5 ppm of iron is low.
What to apply for iron deficiency
Stop liming, and spray ferrous sulfate or iron chelate on the leaves, or add iron chelate to the nutrient mix. Follow the product label. 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
- Iron chelate
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 beds, and include iron in hydroponic mixes. Test the soil every two or three years. Keep organic matter up with compost, manure or crop residues.
A soil test is the surest check for any water spinach 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 kangkong needs. That saves money, because extra fertilizer is money lost.
Open the Nutrient Deficiency Finder, pick kangkong, 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
Water spinach nutrient deficiency questions
Why are my kangkong leaves turning yellow?
What fertilizer fixes nitrogen deficiency in water spinach?
What fertilizer fixes phosphorus deficiency in water spinach?
What fertilizer fixes potassium deficiency in water spinach?
How do I know which nutrient my kangkong 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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