Maintaining a disease-free garden

January 27, 2021 3 min read

Maintaining a disease-free garden

Often plant diseases are easy to spot; we can see them drooping or see marks on the leaves. As the saying goes, prevention is better than cure, and there are ways to keep your garden in shape and make it more resilient to the damage that diseases can cause.

Disease Prevention: Top Tips

  • Check plants before you buy them. Make sure they look healthy and you can’t see any spots or discolouration
  • Some plant varieties are bred to be disease resistant- research the best varieties for your garden
  • Prior to planting, ensure you’ve picked the optimum location for that plant to thrive in
  • Keep your garden well maintained. This prevents infections spreading from fallen leaves and other debris
  • Don’t skip the pruning, weeding and dead heading
  • Avoid overwatering, and frequently check leaves and base of stems for signs of pests or disease
  • Most importantly, use a natural biostimulant throughout the plant’s lifecycle.

Common Diseases

Despite lots of care, preventative measures are not always enough. Below we’ve listed some common diseases found in garden plants, and some suggestions for remedying them.

Sooty Mould

This is a combination of many varieties of fungi that leaves dark powdery spots on the top of leaves, garden paths, and garden furniture. It is caused by a sap sucking insect, which leaves a sugary residue, which then turns into a crust, weakening the plant.

Wipe mould off with lukewarm water, check frequently, and investigate the underlying insect problem. 

Sooty Mould image

Bacterial spot

Tiny microscopic organisms cause these bacterial dark spots on leaves. They thrive in wet, cool conditions which are ideal for bacteria. Eventually leaves will be killed.

Remove leaves to prevent the spread. If damage is widespread, destroy the plant.

Bacterial spot image

Bacterial blight

Blight is shown on leaves as yellow spots. As they turn brown, they cause leaves to shrivel and rot. The bacteria spreads infection in the soil and into the roots of your plants.

Ensure plants have enough spacing when planting. Remove plants with signs of infection.

Bacterial blight image

Black Root Rot

Black root rot happens in over-fertilized and waterlogged areas of the garden where plants are not getting the right mix of nutrients. The bacteria cause the plants to grow unevenly, with stunted leaves and roots.

Plants with this disease can be managed by lowering the pH of the soil to under 5.6. Infected areas of the plant will need discarding. Clean around the plant to get rid of any remaining bacteria.

Black Root Rot image

Botrytis (Grey Mould)

This affects soft fruits and plants grown in greenhouses. The fungus botrytis causes a soft decay of the plant tissue. This fuzzy brown mould happens in humid conditions.

Remove dead and dying flowers and buds to stop the infection. Dispose of any areas of a plant that looks to be infected and make sure plants are not overcrowded, with good ventilation.

Botrytis (Grey Mould) image

Downy Mildew

Similar to powdery mildew, downy mildew is caused by microscopic fungus like organisms that leave a white covering on the underside of leaves. It thrives in wet conditions, and its spores can remain in the soil after the infected plant is removed.

Avoid dense planting to allow for good air circulation and ensure leaves are not left in a damp, wet environment. Spores will rest on the soil, so rotating plants is advised. 

Downy Mildew image

Angular Leaf Spot

This disease is a mix of several bacteria that survive in debris left by seeds and plants. The bacteria damages leaves by causing holes in the surface. It spreads quickly in moist conditions with bad drainage.

Make sure debris is cleaned up as it falls, and destroy infected plants. A 3 year rotation of plants is recommended to prevent the spread of this.

Angular Leaf Spot image


This is a fungus that affects the soil. It causes dry stems and rot at the soil line when there is too much moisture in the soil. It can live in the soil or in plant tissue for years.

In all cases remove infected plants and do not use the soil. Make sure you thoroughly sanitise pots and containers.

Rhizoctonia image


This is a fungal disease that thrives in cool, rainy weather. Leaf tips discolour to yellow, then brown.

Once spotted, remove the infected leaves and avoid over watering.

Anthracnose image

Our range of biostimulants are designed by The Magic Molecule Co. to boost your garden plants, encourage development and growth, as well as strengthening their immune systems and natural resilience. Consistent use will ensure your plants are healthy, with a better ability to recover and heal themselves after any damage. Have a look at our full range here