Fixing Nutrient Deficiencies in Cannabis: 5 Steps

Here’s how to spot and fix nutrient issues in your cannabis plants:

Spot the Problem: Look for yellowing leaves, stunted growth, or other signs
Fix the pH: Keep it 6.0-6.5 for soil, 5.5-6.5 for hydroponics
Pick the Right Nutrients: Use quality cannabis-specific fertilizers
Use Nutrients Properly: Follow dosage instructions for each growth stage
Monitor Regularly: Keep an eye on things and adjust as needed

Growth Stage	Nutrient Focus	NPK Ratio
Seedling	Minimal	0-0-0
Early Veg	Nitrogen	2-1-2
Mid Veg	Balanced	10-5-7
Early Flower	P and K	5-7-10
Late Flower	Flush	0-0-0

Start with nutrient-rich soil, test often, and keep a grow journal to track feeding and plant health.

Basic Nutrients for Cannabis

Cannabis needs specific nutrients to thrive. Here’s the breakdown:

Macronutrients: NPK

Nitrogen (N): Fuels leaf and stem growth
Phosphorus (P): Supports roots and flowers
Potassium (K): Helps overall plant health and buds

Secondary Nutrients

Calcium (Ca): Strengthens cell walls
Magnesium (Mg): Key for photosynthesis
Sulfur (S): Helps form plant proteins

Micronutrients

Needed in smaller amounts, but still crucial:

Iron (Fe)
Zinc (Zn)
Manganese (Mn)
Boron (B)
Copper (Cu)
Molybdenum (Mo)

Nutrient Needs Throughout Growth

Growth Stage	Primary Nutrient Focus	NPK Ratio Example
Seedling	Minimal	N/A
Vegetative	High Nitrogen	4:2:3
Early Flower	Balanced NPK	5:5:5
Late Flower	High P and K	6:10:15

Spotting Deficiencies

Nutrient	Deficiency Signs
Nitrogen	Yellowing leaves, starting from bottom
Phosphorus	Dark leaves, stunted growth
Potassium	Brown leaf edges, weak stems
Calcium	Distorted new growth, weak stems
Magnesium	Yellowing between leaf veins
Iron	Yellowing of young leaves

pH Matters

Soil: 6.0 – 7.0 (best at 6.3)
Hydroponic: 5.5 – 6.5

Wrong pH can lock out nutrients, even if they’re present.

Feeding Tips

Start with half the recommended dose
Use "Vegetative" formula during growing phase
Switch to "Bloom" formula when flowers start forming

1. Spot the Problem

Catching nutrient issues early is key. Here’s what to look for:

Nutrient	Symptoms
Nitrogen	Yellowing leaves, starting from bottom
Phosphorus	Dark leaves, stunted growth
Potassium	Yellowing or browning of leaf edges, weak stems
Calcium	Distorted new growth, weak stems
Magnesium	Yellowing between leaf veins
Iron	Yellowing of young leaves

Testing Tools

pH meter: Check growing medium’s pH
EC meter: Measures nutrient solution conductivity
Soil test kits: Breakdown of nutrient levels
Foliar tissue analysis: Lab test of leaf samples

"If the symptoms are visible only on newer or only on older growth, a nutrient deficiency is highly probable." – Ed Rosenthal, Marijuana Garden Saver

2. Fix the pH

pH affects nutrient uptake. Get it right:

Growing Medium	Ideal pH Range
Soil	6.0 – 7.0
Hydroponic	5.5 – 6.5

Fine-tune pH:

Vegetative stage: 6.0 – 6.5
Flowering stage: 6.5 – 7.0

To keep pH in check:

Test regularly
Adjust with pH up/down solutions
Use pH-balanced water for nutrients
Flush plants occasionally

"The pH should be measured whenever you are watering your plants or feeding them nutrients." – Kurt Kinneman, Commercial Cultivator

3. Pick the Right Nutrients

Choose between organic and synthetic nutrients:

Organic Nutrients	Synthetic Nutrients
Improve soil health	Provide quick results
Slow-release	Fast-acting
Less risk of burn	Precise nutrient control
Better for outdoors	Ideal for hydroponics

Choosing Products

For soil: Use organic options like SoHum Living Soil

For hydroponics: Opt for synthetic nutrients like House & Garden

Growth stages:

Seedling: Minimal nutrients
Vegetative: Higher nitrogen (NPK 3-1-2)
Flowering: Higher phosphorus and potassium (NPK 1-3-2)

Start with lower doses and increase gradually.

4. Use Nutrients Properly

Apply the right amounts at the right times:

Growth Stage	Nutrient Focus	NPK Ratio
Seedling	Minimal	0-0-0
Early Veg	Nitrogen	2-1-2
Mid Veg	Balanced	10-5-7
Early Flower	P and K	5-7-10
Late Flower	Flush	0-0-0

Start low, increase slowly. Water more often with smaller nutrient amounts.

Leaf vs. Root Feeding

Root Feeding	Leaf Feeding (Foliar)
Main method	Quick fix for deficiencies
Slower uptake	Fast absorption
Less burn risk	Risk of leaf burn
Use daily	Use 1-2 times a week max

For foliar feeding:

Spray early morning or late evening
Use room temp water
Dilute nutrients more than for roots
Avoid when temps exceed 80°F (26.7°C)

5. Keep an Eye on Things

Regular checks prevent issues:

Leaf tissue analysis: Every two weeks
pH levels: Check bi-weekly
Nutrient levels: Monitor regularly

"When taking samples for sap analysis, anticipate needing a minimum of 80 grams of leaf material from both the top and bottom of the plant."

Adjust your nutrient plan based on growth and test results. Start low, increase gradually.

Wrap-up

Remember the 5 steps:

Spot the Problem
Fix the pH
Pick the Right Nutrients
Use Nutrients Properly
Keep an Eye on Things

Prevention is key. Start with good soil and test often. Keep a garden journal to track progress.

Fixing Common Problems

Nutrient Lockout

To fix:

Check and adjust pH
Flush growing medium
Reintroduce nutrients gradually

Overfeeding

To address:

Reduce nutrient concentration
Flush growing medium
Monitor and adjust

Preventing Future Issues

Action	Benefit
Regular pH testing	Maintains optimal uptake
Consistent feeding	Prevents salt buildup
Using organic nutrients	Reduces overfeeding risk
Periodic flushing	Removes excess minerals

"The best way to avoid nutrient issues is to start with high-quality soil and test it regularly." – Jorge Cervantes, Cannabis Cultivation Expert

Tips to Avoid Nutrient Issues

Choose the right soil mix
Monitor pH levels
Water wisely
Use organic amendments
Maintain good drainage

Add perlite to soil for better drainage. Ensure pots have holes at the bottom.