We're well into fall now. The vegetables have been harvested, the flowers have come and gone, and there's nothing left to do in the garden, right? Wrong! A little bit of late-season cleanup now can head off many plant disease problems for next year.
Many of the fungi and bacteria that cause spots, blights, and rots of our plants survive over the winter in the dead leaves, stems, and other plant parts that are left behind in the garden. When warmer temperatures return next spring, those pathogens will come out of dormancy, ready to attack next year's tender plants. Why let the pathogens have that head start?
Even though the weather is colder now and it's not as fun to be outdoors, we should spend a few minutes raking up and disposing of any infected plant debris that's left over in the garden. Perennials like peonies can be pruned back to get rid of leaves full of fungus. Good sanitation is essential for a healthy garden. It's tempting to wait and clean up the garden in the spring, but most dead leaves become brittle and crumbly over the winter, making removal very difficult in the spring.
How can you dispose of the infected debris? Composting is a good option, assuming you have a "real" compost pile that actually heats up to at least 140 degrees F, which will kill most pathogens. Most home compost piles do not reach this temperature, but most municipal composting facilities do. Another option is burning, where legal.
Another way to prevent plant diseases next year is to take good notes now of where in the garden each type of plant grew this year. Next year, you can rotate where each kind of plant is placed in the garden, further reducing the chances that your new plants will run into this year's overwintered pathogens. A rotation cycle of several years is best to minimize disease, but even a two or three year rotation will help.
Take a few minutes this fall to clean up the garden and take good notes to help ensure that next year's plants are as healthy as possible.