How to Prevent and Treat Rust on Leeks and Beans

There’s nothing more disheartening than seeing your once-pristine leek leaves or bean plants freckled with orange pustules. Rust is a fungal disease that affects both crops and spreads like wildfire in warm, damp conditions. The good news? It’s totally manageable and with a few strategic changes, you can prevent and treat rust on leeks and beans effectively and naturally.

What Does Rust Look Like?

Rust on leeks and beans is easy to spot once you know the signs:

• Orange or reddish-brown spots or pustules on the undersides of leaves
  
• Yellowing and wilting leaves as the infection spreads
  
• Premature leaf drop, reduced yields, and stunted growth

This fungal disease thrives in humid, overcrowded, and poorly ventilated conditions, especially after rain or overhead watering.

Avoid Overcrowding and Improve Airflow

Fungal spores love moisture, so our first priority is to keep leaves dry and airflow moving:

• Space leeks generously, at least 15–20 cm apart
  
• For beans, use wide rows and trellis vertically to open up the canopy
  
• Remove lower leaves if they become dense or touch the soil

In greenhouses or tunnels, leave doors or vents open to help dry foliage quickly after watering.

Water Smart

Avoid overhead watering at all costs with rust-prone crops. Instead, try:

• Water early in the morning, so any splashes dry quickly
  
• Always water at the base of plants using a watering can or drip line
  
• Keep watering consistent but not excessive, to avoid stress that makes plants more susceptible

Dry leaves = less fungal infection.

Feed for Fungal Resistance

Strong plants are naturally more resistant to fungal attack. Feed with:

• A balanced organic fertiliser to support steady growth
  
• Seaweed extract every couple of weeks for added micronutrients and plant-strengthening hormones
  
• Avoid high-nitrogen feeds which encourage soft, lush growth that’s more vulnerable to rust

We also mulch leeks with compost to retain moisture and slowly release nutrients.

Remove Affected Leaves Immediately

As soon as you spot signs of rust, act fast:

• Snip off infected leaves and dispose of them (don’t compost!)
  
• Clean your tools with vinegar or soapy water between cuts
  
• For beans, cut back affected stems if needed, they’ll often regrow more cleanly

Early intervention stops rust from spreading further through the crop or onto neighbouring plants.

Keep the Garden Clean

Rust spores can overwinter on fallen leaves and plant debris. At the end of the season:

• Remove and destroy all old foliage from leeks and beans
  
• Rotate crops, try not to grow beans or leeks in the same spot next year
  
• Avoid composting infected material, unless you hot-compost at 60°C+

A tidy garden means fewer spores next season.

Natural Remedies for Ongoing Control

If rust is a regular visitor in your patch, try these organic options:

• Milk spray (1 part milk to 9 parts water): mist foliage weekly as a preventative
  
• Baking soda spray (1 tsp baking soda, a drop of soap, in 1L water): adjust leaf pH to discourage fungal spores
  
• Garlic or chamomile tea spray: both have antifungal properties and can be used preventatively

Use these after rain or during humid spells to stay one step ahead.

Rust might be stubborn, but it’s not unbeatable. By improving airflow, avoiding overhead watering, feeding plants well, and acting quickly at the first signs, you can prevent and treat rust on leeks and beans without reaching for harsh chemicals.