It's easiest to prevent garden illness by not introducing it. Disease from a novel plant is no one's bonus.
Compost pile components decay at different rates. Other materials may not have decomposed enough for the garden. Long-term composting kills germs by heating the material.
Plant harm from insects goes beyond aesthetics. Bug damage creates an entrance for viruses and bacteria to penetrate a plant.
Even in mild climates, fall is the greatest time to clean out the garden. This deters disease and controls it in your garden.
Fertilizing plants too much might burn roots, limiting their water absorption. This makes plants more susceptible to drought, cold, and heat stress.
Disease-resistant plants may battle a disease instead of dying from it. Some tomatoes are labeled “VFN resistant,” meaning they resist Verticillium, Fusarium, and nematodes.
Late winter is better for tree and shrub trimming than spring. The plant's dormancy can allow disease to spread from wounded limbs over the winter.
Plants for your zone and site are key to successful gardening. A shade-loving plant like an azalea will develop poorly and be readily damaged by diseases and insects in full light.
Watering your yard is good, but how you do it matters because many illnesses need water too. Many soil and air pathogens need water to travel, thrive, and replicate.