Potassium deficiency

Edges and tips of older leaves go yellow, then brown and crispy, with weak stems. Check pH and EC before reaching for more feed.

Symptoms

• Edges and tips of older leaves turn yellow, then brown and crispy.
• Weak stems.
• Can look like nutrient burn, but starts on the leaf edges of older leaves.

Quick checks

• Check feed and run-off pH and EC.
• Compare run-off EC to feed EC: much higher suggests salt build-up or burn instead.
• Which week are you in?

How to fix it

1. 1
   Check

   Rule out pH and EC problems

   Check the basics first: feed and run-off pH (5.5–6.5), EC for this week, watering, climate and light.

2. 2
   Feed

   Follow the chart's flowering programme

   In flower, follow the Bloom chart plus either the PK 9/18 or the Resin programme (never both).

3. 3
   Monitor

   Judge by new growth

   Give it 3–5 days and look at the newest leaves.

Likely causes

• pH out of range.
• Feed too weak, or not following the flowering programme.
• Salt build-up interfering with uptake.
• Cold or waterlogged roots.

What to avoid

• Don't mix up burn and deficiency: if run-off EC is high, cut back instead.
• Don't use PK 9/18 and Resin together.

Prevention

• Feed to the chart.
• Weekly run-off checks.

Monkey products that can help

Bloom A+B

The flowering base feed, with raised phosphorus and potassium for flower development.

Follow the flowering chart for the week: equal amounts of Part A and Part B, added separately and never mixed together neat.

View product →

PK 9/18

A phosphorus and potassium flowering supplement for the PK programme. Choose PK 9/18 or Resin, never both.

Follow the PK chart (flower weeks 4–6). Use PK 9/18 OR Resin, never both.

View product →

Products support a healthy plant. They don't replace fixing the cause.

When to get help

If edges keep browning with correct pH and EC, email info@monkeynutrients.co.uk with photos, your readings and week.

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