Barbara Leach: Late Summer Early Fall in The Garden

By far, the diagnosis for the majority of samples that were brought in to the VCE Master Gardener Help Desk lately have been weather related.  It is easy to underestimate how dry it is, because of our occasional sprinkles.  Though it seems I have had fairly regular rains at my house, when I tried to take a soil test I could not even get the probe into the ground.

These light rains are problematic for many reasons.  They are not adequate to sustain the plants.  Even in cases where supplemental watering is used, in the kind of regular sustained heat we had this past summer we the plants lose moisture through their leaves faster than the roots can replace it.  With heat day after day, the plant has no chance to catch up and recover.

If you have garden beds where a landscape fabric has been used beneath mulch, water will percolate until it hits that horizontal layer and then moves sideways.  Only if it is a substantial rain will it begin to filter through, even though the fabric is permeable.  I challenge you to occasionally pull up a corner of the fabric and I think you will be surprised at how dry it is under there.

It is that same principle of water following a plane that makes it difficult for spring-planted plants to establish.  When you water, you must water in that nursery soil ball as well as the ground around it.  If you only get the native soil wet, it will not transfer into the nursery soil.  It will follow the edge of the root ball down and under and away.

Likewise, heavy layers of mulch will prevent the water from getting through to the nursery soil.  You need to water enough to wet the soil down 3”-4” deep.  A screwdriver or similar probe will help you judge when it has softened up at that depth.

Often our showers are in the late afternoon and that sets us up for a whole host of diseases as we go into the night with wet foliage.  High humidity contributes to disease, as well.  Tomato and pepper diseases abound and we have seen many diseases on dogwoods, hydrangeas, strawberries and other plants.

Let’s not forget about spider mites and scale.  These insects, which are sucking insects, attack stressed plants, often stressed from drought.  Mite populations, especially, explode when it gets hot, dry, and humid.  So imagine you are a helpless little plant, standing in the hot sun, thirsty as can be and you have a vampire sucking on you.  You don’t stand much of a chance.

In contrast, some crops do like it hot.  This has been a bumper-crop year for eggplant, in spite of the holes in the leaves from flea beetles.  Figs are from the Middle East and Asia so, with adequate water, enjoy the heat.

A regular client at the Help Desk, Dennis Woodson of Roanoke, sent a picture of part of his bountiful harvest of figs this year.  He also sent along a picture of a young copperhead he found near his home on a hike with his dogs.  When the woods get really dry snakes begin to search for water and are often encountered late in the summer like this.

We have had lots of snake calls lately.  I would like to remind you that snakes are protected in Virginia, so should not be destroyed.  They are very beneficial.  They keep insects, rodents and small creatures under control and can often be relocated away from the home or taken to a rescue organization.  The best method of dealing with snakes is to remove food, cover, and water.

If you are engaged in activities that attract wildlife you are setting yourself up for visits from snakes, too.  While I am perfectly happy with some snakes living in my yard, I would not relish a copperhead that close to the house.  Fallen bird seed is often one of the major attractants to the rodents that snakes thrive on.

Barbara Leach

Horticulture Technician / Virginia Cooperative Extension