Allium cepa Brown Leaf Tips - Causes & Fixes

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Water Stress (Drought or Fluctuating Moisture)

Onions have shallow root systems and are highly sensitive to moisture fluctuations. When soil dries out too quickly, the leaf tips lose turgor pressure and undergo necrosis.

Very Common

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How to confirm: Check if the soil surface is cracked or significantly dry several inches below the surface.

build How to fix it

shopping_cart Recommended Products

1 Ensure consistent soil moisture by checking the soil depth with a moisture meter to prevent the rapid drying cycles that cause tip necrosis.

GROWIT Soil Moisture Meter - Blue

Water Meters

$12

In Stock

2 Apply a layer of organic mulch or vermiculite to the soil surface to help retain moisture and stabilize the root zone temperature.

Back to the Roots Organic Vermiculite 24qt

22.7 L • Vermiculite

$42

In Stock

3 Mulch the base of the onion plants with organic matter to reduce evaporation and protect the shallow root system from drought stress.

Back to the Roots Organic Worm Castings 5lb

Worm Castings

$17

In Stock

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Nutrient Deficiency (Potassium)

Potassium deficiency in Allium cepa often manifests as chlorosis followed by browning at the leaf tips and margins. This nutrient is critical for osmotic regulation and water use efficiency in bulbs.

Very Common

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How to confirm: Observe if the browning starts specifically at the edges of the leaves moving inward toward the center.

build How to fix it

shopping_cart Recommended Products

1 Apply a potassium-rich organic fertilizer to the soil to restore essential nutrient levels for osmotic regulation.

FoxFarm Bush Doctor Kelp Me Kelp You Liquid Seaweed Fertilizer 1 Quart

0.9 L • 1 pcs

$32

In Stock

2 Supplement the soil with organic worm castings to improve nutrient availability and overall soil health.

Back to the Roots Organic Worm Castings 5lb

Worm Castings

$17

In Stock

3 Monitor soil moisture levels using an analog meter to ensure consistent hydration, preventing further tip burn.

GROWIT Soil Moisture Meter - Blue

Water Meters

$12

In Stock

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Salt Accumulation (Soil Salinity)

Onions are sensitive to high salt concentrations in the soil, which causes osmotic stress. Excessive fertilizer use or saline irrigation water pulls moisture out of the leaf tips, causing 'tip burn.'

Common

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How to confirm: Check for a white, crusty residue on the soil surface near the base of the onion plants.

build How to fix it

shopping_cart Recommended Products

1 Flush the soil thoroughly with large amounts of fresh, low-salinity water to leach accumulated mineral salts away from the root zone.

2 Reduce the frequency of fertilization and avoid high-salt fertilizers to prevent further osmotic stress.

FoxFarm Bush Doctor Kelp Me Kelp You Liquid Seaweed Fertilizer 1 Quart

0.9 L • 1 pcs

$32

In Stock

3 Monitor soil moisture levels closely to ensure consistent hydration without overwatering, which can exacerbate salt concentration.

GROWIT Soil Moisture Meter - Blue

Water Meters

$12

In Stock

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Ascochyta Leaf Blight

This fungal pathogen causes necrotic lesions that often begin at the tips or edges of the leaves. It thrives in humid conditions and can rapidly spread through the onion foliage.

Common

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How to confirm: Inspect the brown areas for small, dark fungal fruiting bodies (pycnidia) embedded in the lesion.

build How to fix it

shopping_cart Recommended Products

1 Remove and destroy all infected foliage immediately to prevent the fungal spores from spreading to healthy plants.

2 Apply an organic fungicide to protect remaining healthy tissue and manage the spread of the blight.