---
title: How to Identify and Fix Grey Mould on Plants
description: Learn how to identify and control grey mould in your garden with effective tips on improving airflow, reducing moisture, and managing plant health.
---

[Skip to content](https://www.theonlinegardencenter.com/how-to-garden/how-to-identify-and-fix-grey-mould-on-plants#main-content)

## ![5 step guide to fixing grey mouldStep 1 Remove infected materialCut off affected leaves stems or flowersDispose of them dont compostThis slows the sp-1](https://www.theonlinegardencenter.com/hs-fs/hubfs/AI-Generated%20Media/Images/5%20step%20guide%20to%20fixing%20grey%20mouldStep%201%20Remove%20infected%20materialCut%20off%20affected%20leaves%20stems%20or%20flowersDispose%20of%20them%20%20dont%20compostThis%20slows%20the%20sp-1.png?width=1024&height=1536&name=5%20step%20guide%20to%20fixing%20grey%20mouldStep%201%20Remove%20infected%20materialCut%20off%20affected%20leaves%20stems%20or%20flowersDispose%20of%20them%20%20dont%20compostThis%20slows%20the%20sp-1.png)

## What is grey mould and how to fix it

Grey mould (Botrytis) is a common fungal disease that affects soft plant tissue, especially in cool, damp conditions. It shows up as a fuzzy grey coating and can spread quickly if ignored.

It looks worse than it is — but you do need to act early.

## Quick answer: what is grey mould

Grey mould is a fungal disease that causes soft rot and a grey, fuzzy coating on leaves, stems, or flowers. Improve airflow, reduce moisture, and remove affected material to control it.

## 5 step guide to fixing grey mould

Step 1: Remove infected material

- Cut off **affected leaves, stems, or flowers**
- Dispose of them — don’t compost
- This slows the spread immediately

Step 2: Improve airflow

- Space plants out
- Open up dense growth
- Ventilate indoor areas or propagators

Step 3: Reduce moisture

- Avoid overwatering
- Water at soil level, not over leaves
- Let surfaces dry between watering

Step 4: Adjust environment

- Keep conditions **cool but not damp**
- Avoid high humidity with poor airflow
- Reduce condensation in enclosed spaces

Step 5: Treat if needed

- Use a **fungicide** if the problem persists
- Apply early rather than late
- Combine with better conditions

## Best varieties & why (less prone plants)

- Zinnia 
    - More tolerant of dry air and good airflow
- Marigold 
    - Strong and resilient
- Herbs like thyme and rosemary 
    - Prefer drier conditions

Soft, lush plants and dense foliage are more at risk.

## Common issues, pests & diseases

Grey fuzzy growth on leaves or stems

- Classic grey mould
- Often appears on damaged or dying tissue

Soft rot in stems or flowers

- Tissue breaks down quickly
- Remove immediately

Mould spreading across trays

- Cause: high humidity and poor airflow
- If you’re seeing this early in seedlings, click here: [https://www.theonlinegardencenter.com/how-to-garden/why-mould-appears-during-seed-germination](https://www.theonlinegardencenter.com/how-to-garden/why-mould-appears-during-seed-germination?hsLang=en)

Seedlings collapsing

- Often linked to fungal conditions
- This guide will help you prevent it: [https://www.theonlinegardencenter.com/how-to-garden/how-to-prevent-damping-off-in-seedlings](https://www.theonlinegardencenter.com/how-to-garden/how-to-prevent-damping-off-in-seedlings?hsLang=en)

## Best fertiliser, soil, lighting & growing conditions

- Light 
    - Good light helps keep plants dry and healthy
- Soil 
    - Free-draining compost
- Water 
    - Even watering, not excessive
- Feeding 
    - Avoid overfeeding (soft growth is more vulnerable)

Strong, balanced growth reduces risk.

## Time of year

- Most common in **cool, damp conditions**
- Often seen in **spring and autumn**
- Common in greenhouses and indoor setups

## Climate and regional notes

UK & Ireland

- High risk due to damp conditions
- Ventilation is critical

Europe

- Northern regions similar to UK
- Southern regions less affected unless humidity is high

USA

- More common in humid climates
- Indoor environments can create ideal conditions

## Pro tips for prevention

- Always prioritise airflow
- Avoid overcrowding plants
- Remove dead or damaged material quickly
- Water early in the day
- Don’t let moisture sit on leaves

## 10 frequently asked questions about grey mould

**What causes grey mould**  
Damp conditions, poor airflow, and plant stress.

**What does grey mould look like**  
Grey, fuzzy coating on plant tissue.

**Is grey mould dangerous**  
It can spread quickly, but is manageable.

**Can plants recover from grey mould**  
Yes, if treated early.

**Should I remove infected leaves**  
Yes, immediately.

**Can I compost infected material**  
Best not to — it can spread spores.

**Does watering affect grey mould**  
Yes, excess moisture increases risk.

**Is grey mould the same as damping off**  
No, but both are fungal and related to moisture.

**Do I need fungicide**  
Only if conditions alone don’t control it.

**How do I prevent it coming back**  
Improve airflow and reduce moisture.

## Related guides

- If you’re seeing mould early in seedlings, fix it here: [https://www.theonlinegardencenter.com/how-to-garden/why-mould-appears-during-seed-germination](https://www.theonlinegardencenter.com/how-to-garden/why-mould-appears-during-seed-germination?hsLang=en)
- If seedlings are collapsing, this is likely the issue: [https://www.theonlinegardencenter.com/how-to-garden/how-to-prevent-damping-off-in-seedlings](https://www.theonlinegardencenter.com/how-to-garden/how-to-prevent-damping-off-in-seedlings?hsLang=en)
- Watering is often the root cause — check this: https://www.theonlinegardencenter.com/how-to-garden/how-often-to-water-seeds-during-germination

## Related Articles

### [How to prevent mould during Seed Germination](https://www.theonlinegardencenter.com/how-to-garden/how-to-prevent-mould-during-seed-germination?hsLang=en)

## Why mould appears during seed germination

Mould during seed germination is a common issue,...

by [Mark Foley](https://www.theonlinegardencenter.com/how-to-garden/author/mark-foley)

[![](https://www.theonlinegardencenter.com/hubfs/AI-Generated%20Media/Images/CloseUp%20Pot%20Dark%20Soil%20White%20Mold%20Seedlings%20Fan%20Watering%20Can-1.png) ](https://www.theonlinegardencenter.com/how-to-garden/why-is-mold-growing-on-my-soil-causes-and-solutions-explained?hsLang=en)

### [Why Is Mold Growing on My Soil? Causes and Solutions Explained](https://www.theonlinegardencenter.com/how-to-garden/why-is-mold-growing-on-my-soil-causes-and-solutions-explained?hsLang=en)

# Why Is My Soil Growing Mold?

## Intro

You water your soil, come back a day or two later—and suddenly...

by [Mark Foley](https://www.theonlinegardencenter.com/how-to-garden/author/mark-foley)

[![](https://www.theonlinegardencenter.com/hubfs/AI-Generated%20Media/Images/Potted%20Plant%20CloseUp%20With%20Healthy%20Leaves%20And%20Sticky%20Trap-1.png) ](https://www.theonlinegardencenter.com/how-to-garden/how-to-effectively-get-rid-of-fungus-gnats-in-your-houseplants?hsLang=en)

### [How to Effectively Get Rid of Fungus Gnats in Your Houseplants](https://www.theonlinegardencenter.com/how-to-garden/how-to-effectively-get-rid-of-fungus-gnats-in-your-houseplants?hsLang=en)

# Why Do I Keep Getting Fungus Gnats?

If fungus gnats keep showing up around your plants, it’s not...

by [Mark Foley](https://www.theonlinegardencenter.com/how-to-garden/author/mark-foley)

```json
{
  "@context" : "https://schema.org",
  "@type" : "BlogPosting",
  "author" : {
    "@type" : "Person",
    "name" : "Mark Foley",
    "url" : "https://www.theonlinegardencenter.com/how-to-garden/author/mark-foley"
  },
  "dateModified" : "2026-03-28T23:40:50.248Z",
  "datePublished" : "2026-03-28T23:40:50.000Z",
  "headline" : "How to Identify and Fix Grey Mould on Plants",
  "mainEntityOfPage" : {
    "@id" : "https://www.theonlinegardencenter.com/how-to-garden/how-to-identify-and-fix-grey-mould-on-plants",
    "@type" : "WebPage"
  },
  "publisher" : {
    "@type" : "Organization",
    "logo" : {
      "@type" : "ImageObject",
      "url" : "https://www.theonlinegardencenter.com/hubfs/Logo_colour-03-3.png"
    },
    "name" : "TOGC"
  }
}
```