Brassica rapa Yellow Leaves - Causes & Fixes

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Nitrogen Deficiency

Nitrogen is a mobile nutrient in Brassica rapa; when lacking, the plant moves nitrogen from older leaves to new growth, causing older leaves to turn pale yellow first.

Very Common

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How to confirm: Observe if the yellowing started on the bottom-most leaves and if the overall growth of the plant seems stunted.

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1 Apply a nitrogen-rich liquid fertilizer to provide immediate nutrient uptake for the developing leaves.

Back to the Roots Blood Meal & Gypsum (4 Pack)

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2 Supplement the soil with a balanced organic fertilizer to ensure long-term nitrogen availability.

FoxFarm Grow Big Liquid Plant Food 1 Quart

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3 Monitor soil moisture levels to ensure the roots can effectively absorb the newly applied nutrients.

GROWIT Soil Moisture Meter - Blue

Water Meters

$12

In Stock

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Overwatering and Soil Compaction

Excessive moisture in the soil displaces oxygen, leading to root hypoxia which prevents the turnip or pak choi from absorbing essential minerals.

Very Common

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How to confirm: Stick your finger two inches into the soil to see if it feels waterlogged or if the soil has a sour odor.

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1 Immediately reduce watering frequency and allow the top inch of soil to dry out completely before watering again to prevent further root hypoxia.

GROWIT Soil Moisture Meter SMM-V3

Water Meters

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2 Gently aerate the soil surface with a hand tool to alleviate compaction and improve oxygen flow to the root zone.

Fiskars Ergo Cultivator

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3 Repot the plant into a well-draining medium enriched with perlite to ensure better aeration and prevent future waterlogging.

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Clubroot (Plasmodiophora brassicae)

This soil-borne pathogen causes galls on the roots of Brassicas, which disrupts water and nutrient transport, manifesting as chlorosis (yellowing) above ground.

Common

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How to confirm: Carefully uproot a plant to check for large, swollen, irregular growths or 'clubs' on the root system.

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1 Remove and destroy infected plants immediately to prevent the soil-borne pathogen from spreading to healthy Brassicas.

2 Improve soil drainage and aeration by incorporating horticultural perlite to reduce the moist, heavy conditions that clubroot thrives in.

3 Apply a balanced organic fertilizer to help the plant recover from nutrient transport disruption caused by root galls.

FoxFarm Grow Big Liquid Plant Food 1 Quart

0.9 L • 1 pcs

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Iron Chlorosis

High soil pH (alkaline conditions) can lock iron away from the plant, resulting in yellow leaves with distinctly green veins (interveinal chlorosis).

Common

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How to confirm: Check if the new, emerging leaves are turning yellow while the veins remain dark green.

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shopping_cart Recommended Products

1 Lower the soil pH by applying an acidifying amendment to make iron more bioavailable to the plant.

FoxFarm Happy Frog Acid Loving Plant Fertilizer

Organic

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2 Monitor soil moisture levels closely using a moisture meter to ensure the plant is not experiencing water stress, which can exacerbate nutrient lockout.

GROWIT Soil Moisture Meter - Blue

Water Meters

$12

In Stock

3 Apply a balanced liquid fertilizer to provide immediate micronutrient support while the soil pH stabilizes.

FoxFarm Grow Big Liquid Plant Food 1 Quart

0.9 L • 1 pcs

$30

In Stock