Preventing plant diseases in the garden

Simple practices to reduce disease pressure in gardens

Use these preventative maintenance strategies to keep your plants healthy.

Illustration of a boy planting seeds in rows in a garden bed, and a man standing above him watering the seeds with a metal can.

Use clean seed to prevent new pathogens from entering the garden. If using saved seed, treat it with hot water (find specific instructions for temperature and duration online).

Illustration of terra cotta pots on a grassy lawn with trellised tomatoes and other plants growing in the pots.

Rotate the plots where crop families are planted. For example, after planting tomatoes, wait 3 years before you plant solanaceous crops in the same spot. Containers can help with rotations in small gardens.

Illustration of two people in a garden bed, zoomed in to focus on their shoes.

Clean your shoes before entering the garden, especially if you have recently been in another garden.

Illustration of a DIY handwashing stand made of a wooden stand with a blue water container and a catchment bucket.

Wash your hands regularly, and clean and sanitize your tools. Pathogens can travel on shovels, trellises, and other equipment.

Illustration of two parallel garden beds with green plants growing on plastic and straw mulch. The bed on the left has drip irrigation snaking through the plants, and the bed on the right has an overhead sprinkler.

When possible, use drip irrigation or careful hand watering to add water near the roots of plants without splashing water onto the leaves.

Illustration of a garden bed with three rows of plants. The plants in front have straw mulch, and the plants in back have plastic mulch.

Mulch (either straw or plastic) prevents pathogens from splashing up from the soil.

Illustration of a grassy walkway between two garden beds.

Grassy walkways between plots can help to prevent water movement across plots.

Illustration of tomatoes growing in a tall wooden raised bed. Each has a metal trellis supporting it.

Trellises support plants and provide better airflow through the canopy. Clean and sanitize trellises each year.

Illustration of lettuce plants. Some of the lettuce plants have spots, indicating disease.

Remove infected plants and plant tissues to prevent the spread of pathogens to healthy plants. Remove diseased leaves only when plants are dry and no rain is forecast.

Illustration of pepper plants. Some of the peppers have spots, indicating disease.

Identify diseases using tools like Ask a Master Gardener. You may need to send a sample to the UMN Plant Disease Clinic. Once you have a diagnosis, seek resistant varieties the following year.

Illustration of a 3-sided wooden compost bin. A person stands next to the compost and is turning it with a shovel.

Keep compost away from garden beds, and make sure it is fully composted before applying it back to growing areas.

Illustration of a sign that reads "Welcome to the garden! Garden rules:"

In public and community gardens, inform gardeners and visitors about these best practices, especially those related to sanitation.

Author: Natalie Hoidal, Extension educator, local foods and vegetable crops

Illustration: Urban Ecosystems & Stardust Interactive. Download a PDF version of the original illustration.