Powdery mildew

Saturday, September 8, 2012

You can tell it is late summer by the emergence of powdery mildew and other fungal diseases on your veggies and some flowers like roses and peonies.

Powdery mildew loves squash!  It shows up during hot and high humidity conditions.  It can also be encouraged by overhead watering.  The best watering method is some type of slow drip at the roots of your veggies.  This gets the most actually in the ground to the plant and minimizes evaporation (reducing your water bill).

Overhead watering, besides encouraging mildew and other fungal diseases, can also remove the insects that pollinate the veggie flowers and even the pollen itself, leading to low harvests.

Powdery mildew can be treated by spraying the top and underneath of all leaves with a baking soda solution, copper or fresh whey.  An easy to make, low cost spray is as follows:  2 tbl of baking soda, 1/2 teas of gentle dish soap, 1 gallon of water.  Wet top and bottom of leaves thoroughly.  Reapply after a rain.

You can also purchase organic mildew sprays, like Safer.

Be careful in using sprays; they may be too harsh for some vegetable plants.  Test them on a small area of your plant, wait for a day before spraying the whole plant.  Copper based sprays work great on my peonies, but not so well on my squash.

Many recommend if you cannot get rid of the mildew with a spray, you should remove any diseased leaves and throw away.  Do not compost because if you do not get internal temps in your compost at 140 or greater, it will not kill the spores.

A boost of potassium is good this time of year for your veggies.  Nitrogen supports the greenery of your plants while potassium supports the blooms.  Keeping your plants well fed helps them stay healthy and producing well into fall.

I also heard that using your excess whey to water your tomatoes really boosts their growth.  I am going to try it this week when I make my next batch of cheese.  I’ll let you know how well it works.