Rotating your plants can help prevent plant diseases like late blight in tomatoes.
HATTIE BROWN
CINDY MURRAY
As we approach the last days before summer, we gardeners from northern Arizona breathe a sigh of relief: our gardens may not be threatened by frost until next year. So we look forward to hearing for signs that our indoor vegetable seedlings are sturdy enough to be planted outdoors. For the same reason, we long for the feeling of warm, rich soil seeping through our fingers.
But these are also the days when we need to anticipate and plan for things that can go wrong, like plant diseases. Fortunately, we can now learn what types of diseases to expect in our gardens and how to prevent or remedy them.
I will first discuss dampening diseases that cause seeds to fail to germinate and seedlings to rot and tip over. Pythium is a unicellular organism that enters your crops from contaminated soil, grafts, and irrigation water. In humid conditions, the organism releases floating zoospores into the water, reaches and infects young roots, and ultimately causes seeds and seedlings to rot. One way to prevent Pythium infestation is to avoid overwatering.
Another common means of controlling pathogens, Rhizoctonia, is a fungus that lives on both rotting plant material and living plants. Since it lives indefinitely in the soil, we can accidentally introduce the pathogen into our gardens if we introduce infested soil and plant debris. To prevent disease from lessening, plant your seeds in a new starter mix using sterilized, well-drained pots. Make sure the soil temperatures are suitable for your plants to germinate and grow early.
