Radish Nutrient Deficiency: Signs, Causes and the Fertilizer That Fixes It
Radish nutrient deficiency is one of the first things to check when the leaves of your labanos (radish) turn yellow, purple or burnt at the edges. On Philippine farms the usual ones are nitrogen, boron, potassium, phosphorus, manganese, 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 boron, manganese 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 radish nutrient deficiency you have, and a soil test confirms it. Each one below has its signs, its causes and its fix.
Radish 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 | Small, pale tops that yellow from the oldest leaves, with thin, fibrous roots. | Urea 46 0 0, Complete 14 14 14 |
| Potassium | old, lower leaves, leaf edges and tips | Older leaves scorch at the edges, brown and collapse, and curl backward. | Muriate of potash 0 0 60, Complete 14 14 14 |
| Phosphorus | old, lower leaves, the roots | Older leaves turn strongly purple and die early, and plants stay small. | Single superphosphate 0 20 0, Complete 14 14 14 |
| Magnesium | old, lower leaves, between the veins | Bottom leaves yellow between dark green veins, then redden and get dead spots. | Epsom salt / magnesium sulfate, Dolomite |
Shows first on the young leaves
| Nutrient | Where it starts | What you see | Fix with |
|---|---|---|---|
| Boron | the roots, young leaves and the tip | Roots crack and develop poorly, and the growing point may die. | Borax, Solubor (sodium borate) |
| Manganese | young leaves and the tip, the whole plant | A general yellowing of the leaves about midway through the season, on high pH soil. | Manganese sulfate |
| Calcium | young leaves and the tip, the roots | Growing tips of leaves and roots brown and die, and leaf stalks collapse. | Agricultural lime, Gypsum |
Before you buy fertilizer for a radish nutrient deficiency
So use the table to pick the likeliest radish 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 radish
Leaves turn pale then yellow from the oldest leaves, often with red tints, then die. Leaves are fewer and smaller, plants stunted, and roots thin, stiff and fibrous. You see it most at this stage: from the first true leaves to harvest. Radish grows fast, so any shortage shows quickly.
Why nitrogen deficiency happens in labanos
Sandy soils, heavy rain and too little fertilizer. Repeated crops on the same beds run low.
How to tell it apart
Sulfur deficiency yellows young leaves first. Manganese deficiency gives a general yellowing midway through the season on high pH soils. To be sure, check that the oldest leaves yellowed first. Test the soil. A leaf test confirms it.
What to apply for nitrogen deficiency
Put down about 45 kg of nitrogen per hectare ahead of the season's first planting. For a standing crop give a 1 percent urea spray (10 g per liter, 160 g in a 16 liter sprayer). Too much nitrogen and potash makes radish brittle and prone to cracking.
- Urea 46 0 0
- Complete 14 14 14
- 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, add compost and feed the beds again before the last crop of the year. Let a soil test and the crop's color set the season's nitrogen. Split the nitrogen into two or three doses.
Boron deficiency in radish
Roots develop poorly and crack, and may show brown, broken down flesh inside. The growing point can die and young leaves bunch into a rosette, while older leaves turn orange and pale. You see it most at this stage: root swelling.
Why boron deficiency happens in labanos
Sandy soils low in organic matter, soils at pH 7 or above, over limed beds and dry spells.
How to tell it apart
Cracking also comes from uneven watering and too much nitrogen and potash. Black root disease turns roots black inside and out. To be sure, soil test for boron. Cut roots to look for brown centers. In a soil test, less than 0.5 ppm of boron is low.
What to apply for boron deficiency
Put about 1.1 kg of boron (about 11 kg Borax) per hectare in the broadcast fertilizer, or spray about 0.2 kg of boron per hectare about 15 days after seeding. 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).
- Borax
- Solubor (sodium borate)
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 boron to the basal fertilizer on sandy beds and water evenly. Test the soil every two or three years. Keep organic matter up with compost, manure or crop residues.
Potassium deficiency in radish
The edges of older leaves scorch first, then the whole leaf browns and collapses. Growth stops, leaves curl backward and roots stay small. You see it most at this stage: root swelling.
Why potassium deficiency happens in labanos
Sandy soils and beds cropped many times a year without potash.
How to tell it apart
Nitrogen deficiency yellows old leaves without scorch. To be sure, soil test for potassium.
What to apply for potassium deficiency
Ahead of the season's first planting, put down about 85 to 140 kg K2O per hectare, the amount the soil test sets. Give a 1 percent potassium chloride spray (10 g per liter, 160 g in a 16 liter sprayer). Do not overdo potash, which can make roots crack.
- Muriate of potash 0 0 60
- 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, feed potash once for the season and add wood ash or compost. Split the potash on sandy soil.
Phosphorus deficiency in radish
Root growth is poor, so plants stay stunted. The older leaves turn strongly purple and die early. You see it most at this stage: early growth.
Why phosphorus deficiency happens in labanos
Acid and volcanic soils, and cold, wet soil.
How to tell it apart
Cool weather can tint leaves for a short time. True phosphorus shortage also stunts the plant. To be sure, soil test for available phosphorus.
What to apply for phosphorus deficiency
Give about 55 to 110 kg P2O5 per hectare before the first crop, depending on the soil test. Use single superphosphate for a quick fix.
- Single superphosphate 0 20 0
- Complete 14 14 14
- 16 20 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, mix phosphorus into the beds before sowing.
Manganese deficiency in radish
Leaves yellow in general, usually about midway through the season, with young leaves turning pale yellow first. Unlike nitrogen deficiency, it does not start on the oldest leaves. You see it most at this stage: midway through the season.
Why manganese deficiency happens in labanos
Soils above pH 6.5, over limed sands and soils high in organic matter. Radish needs a lot of manganese.
How to tell it apart
Nitrogen deficiency starts on the old leaves. Iron deficiency keeps the veins green on young leaves. To be sure, leaf test for manganese and a soil pH test. In a soil test, less than 1 ppm of manganese is low.
What to apply for manganese deficiency
Spray about 4.5 kg of manganese sulfate per hectare twice, 7 to 10 days apart. Give a 0.5 percent manganese sulfate spray (5 g per liter, 80 g in a 16 liter sprayer).
- Manganese sulfate
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, do not lime beyond pH 6.5. Test the soil every two or three years.
Magnesium deficiency in radish
Bottom leaves yellow between dark green veins first, and the yellowing moves up. The yellow leaves turn red, develop dead spots and drop. Roots are small, stiff and pale. You see it most at this stage: mid season.
Why magnesium deficiency happens in labanos
Acid sandy soils and heavy potash.
How to tell it apart
Potassium deficiency scorches leaf edges first. To be sure, soil test for magnesium.
What to apply for magnesium deficiency
Give a 0.5 to 1 percent magnesium sulfate spray (5 to 10 g Epsom salt per liter). Give about 80 kg magnesium sulfate per hectare in bands near the plants. Apply it apart from potash. 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, use dolomite on acid beds. Test the soil every two or three years. Lime acid soil with Dolomite rather than plain lime.
Calcium deficiency in radish
Root tips and leaf tips, where the plant grows, turn brown and die back. Internodes shorten into a rosette, leaf edges turn ragged and brittle, and leaf stalks collapse so the leaves wither. You see it most at this stage: early growth.
Why calcium deficiency happens in labanos
Very acid soils, high phosphorus and boron shortage. 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 kills the growing point, with cracked roots and orange old leaves. 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. About 840 kg per hectare in two splits where it is 3.5 to 4.5. On alkaline soils use Gypsum.
- Agricultural lime
- Gypsum
- Dolomite
Sold here with calcium: Planters Products Lifelime (36.2 percent calcium), Dolomite by A6 Agrisource (24 percent calcium and 11 percent magnesium), Calcipro by Ramgo (15.5 0 0 with 18.8 percent calcium) and Philphos Gypsum (22.2 percent calcium and 17.4 percent sulfur). 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 beds at pH 6.0 to 6.5. 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 radish 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 labanos needs. That saves money, because extra fertilizer is money lost.
Open the Nutrient Deficiency Finder, pick labanos, 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
Radish nutrient deficiency questions
Why are my labanos leaves turning yellow?
What fertilizer fixes nitrogen deficiency in radish?
What fertilizer fixes boron deficiency in radish?
What fertilizer fixes potassium deficiency in radish?
How do I know which nutrient my labanos 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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