Damping off

Soil-borne fungi that make seedlings collapse at the base. Infected seedlings can't be saved, so the focus is clean kit, fresh medium and careful watering.

Symptoms

Seedlings collapse and fall over, often in patches.
The stem looks pinched, thin, brown or water-soaked at soil level.
Seeds may rot before they come up.
White, fluffy fungal growth on the compost surface in damp conditions.

Quick checks

Is the medium constantly wet?
Were trays and lids cleaned before sowing?
Is the propagator lid vented daily?
Is the water from the mains tap?

How to fix it

1
Physical
Remove affected seedlings
Infected seedlings can't be saved. Remove them and the medium immediately around them, and don't reuse it.
2
Environment
Dry it back and ventilate
Water lightly from below, let the surface dry slightly between waterings, vent the propagator and keep things warm but not stuffy.
3
Prevention
Start again clean
Use new or disinfected trays, fresh sterile seed medium and mains water, and sow thinly.

Likely causes

Wet, cold, airless medium.
Dirty trays, containers or reused compost.
Sowing too thickly.
Using stored rainwater rather than mains water.
Poor ventilation in propagators.

What to avoid

Don't overwater seedlings.
Don't reuse old medium or unwashed trays.
Don't leave propagator lids sealed all day.

Prevention

Clean kit and fresh medium every time.
Mains water.
Sow thinly and keep air moving.
Keep seedlings at a steady temperature within 20–27 °C.

Monkey products that can help

Root Shoot

Designed to support rapid early root growth and a healthy root zone. Use it from growth week 1, at the chart rate.

Follow the feed chart: 2 ml per 10 L in growth weeks 1–2, then 3 ml per 10 L from growth week 3 to flower week 5.

View product →

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

When to get help

If seedlings keep collapsing even with fresh medium and clean trays, email info@monkeynutrients.co.uk with photos.

Email info@monkeynutrients.co.uk