Weekend chill could be harmful to plants

This weekend will mark the first big cool down that we've seen so far this season.  High temperatures are expected to range 10° to 15° below our average, which is in the upper 60s for the beginning of October.  As overnight lows fall back into the 30s, we could very well end up with our first frost, if not freeze.  A fairly significant Canadian high will settle in behind a cold front slated to move through Friday afternoon.  This will pull down a chilly and very dry airmass.  Our dew points will likely be in the upper 20s/lower 30s range.  The dew point plays a role in whether or not we will see a frost or freeze.  A frost is more likely to occur when the dew point is higher near the ground.  A freeze, however, is usually harder on plants and will occur when there is a dry airmass in place.  Dry air has a low dew point and low relative humidity.  It is also able to warm up quickly during the day but cools quickly at night due to raditional cooling. 

So what are some ways you'll be able to protect your plants this weekend?  First, bring the plants that you can inside and cover up the ones you can't.  Drape them loosely and secure with either a stake, rocks or bricks.  You'll want to cover them up before dusk and make sure to remove the cover the next morning when the sun comes up.  Another way, water them a day or two before.  Wet soil will hold more heat than a dry soil.  But make sure not to saturate the plants while the temperatures are extremely low.  This will result in a frost heave and ruin the plant.  You can water them in the evening before the temperature drops.  This will raise the humidity levels and reduce frost damage.