Gardening: Cooler weather, powdery mildew and harvesting

Summer is beginning to wind down. Earlier this week, my husband picked the last of the raspberries on our epic raspberry cane that grew up between the deck boards. The hummingbird feeder isn’t being drained quite as fast, so the feisty little birds are probably headed south. As are the robins. I no longer hear their calls in the evening just after sunset.

So, what’s next in the garden? As the temperatures begin to cool, especially at night, powdery mildew will begin appearing on vegetables particularly squash plants. There is no cure for it, but you can start putting a preventive spray on them now to slow it down.

Powdery mildew is a fungus that looks like someone dumped talcum powder on the leaves of the plants. It forms when plant foliage is dry and the evening temperatures are cooling but the days are still warm, the humidity rises and sunlight decreases as we head into fall.

To prevent the emergence of powdery mildew, mix 1 tablespoon of baking soda and a ½ teaspoon of liquid dish soap in a gallon of water and fill a sprayer. Liberally spray over the leaves of all the squash and pumpkins, lettuce, melons, cucumbers, potatoes, grapes, tomatoes and peppers.

Another preventive is cow’s milk mixed 1 part milk to 2 to 3 parts water.

In both cases, the spray will need to be reapplied every three to five days as irrigation will wash it off the leaves. The mildew doesn’t kill the plant, but it does reduce photosynthesis of the leaves. Not something you want when you are racing the frost to get a ripe pumpkin or the last zucchini.

Sometimes it’s hard to tell when certain vegetables are ripe and ready to pick.

Corn is generally ready about three weeks after the silk first appears or when the ears feel full and the kernels are filled out at the tip of the ear. To check, gently pull the husk apart at the ear tip and pop a kernel with your thumb. If milky juice comes out, its ready.

Potatoes and onions are ready to harvest when the tops begin turning yellow and falling over. In the case of onions, gently dig them, and without washing them, lay them in a shady place protected from rain for a couple of weeks to dry. This helps them keep longer before going bad.

Potatoes are ready to harvest when the tops begin to fall over. Gently dig through the mound for the potatoes. Brush the worst of the dirt off and then let them dry in the open air for a day or so. Pack them into cardboard boxes and store in a cool, dark place. We store ours in the garage in old fruit boxes covered with a black garbage bag. We move them into the house when the temperatures are forecast to be below freezing for an extended time. The black plastic blocks light that can turn the potatoes green and a little toxic because potatoes are in the nightshade family.