Ways to Keep Your Garden Healthy
Usefully composted garden waste
Not all of the material in a compost pile decomposes at the same rate. Some materials may have degraded enough to be placed in the garden, while others have not. Careful composting generates high temperatures for long periods, which effectively kills all pathogens present in the material. Infected plant debris that has not undergone this process will reintroduce potential diseases to your garden. If you are unsure of the condition of your compost pile, you should avoid using garden waste as mulch under sensitive plants and avoid including possibly infected debris in your pile.
Keep an eye on your bugs
Insect damage to plants is more than cosmetic. Viruses and bacteria can often only enter a plant through some sort of opening, and insect damage allows for this. Some insects act as a means of transport for viruses, spreading them from one plant to another. Aphids are one of the most common vectors, and thrips spread the impatience necrotic bush virus, which has become a serious problem for commercial growers over the past 10 years. Aster yellow (photo right) is a leafhopper-borne disease and features a wide variety of host plants. Insect attacks are another way to stress a plant, making it less likely to repel disease.
Clean in the fall
It is always best to clean your garden in the fall, even if you live in a temperate climate. It is not only an effective disease deterrent but also a good way to control diseases already in your garden.
Diseases can overwinter on fallen leaves and debris and attack new leaves as they emerge in spring. Iris leaf spot, daylily leaf streak, and black spot on roses are examples of diseases that can be significantly reduced if dead leaves are removed every fall. If you are leaving stems and foliage to create winter interest, be sure to remove them before new growth begins in the spring.