If you have lived in Central Virginia for any period of time, you know that the weather can keep you on your toes. And if you don’t like the conditions, wait an hour, and things will probably change. This can make gardening and keeping your plants and trees healthy a real challenge. Sometimes you may feel like you need an advanced degree in horticulture to succeed in keeping a garden.
Over the past few years, we have seen some of the driest years followed immediately by some of the wettest years on record and this has left our plants and urban forest stressed and looking for a reprieve. We as diligent gardeners take it upon ourselves to help balance out the water needs of our plants, but sometimes we do more harm than good.
Often I see a homeowner, with all the best intentions, watering their plants when the soil is already heavily saturated and the plant is beginning to drown. This happens frequently because plants only have one way of showing issues with soil moisture and that is through wilting which is a universal sign to many of drought stress. Overwatering can frequently cause root rot diseases which decay fine root hairs that actually do the heavy lifting of water uptake.
When these root hairs are damaged by root rot organisms, the plant can be surrounded by water but very little is available so the plant shows signs of drought and our first inclination is to add more water to the soil. This then furthers the disease cycle, allowing the root rot to flourish, limiting water uptake by roots, and the feeling that more water is needed, creating a feedback loop that only ends when the plant dies. Another place this can be seen is in areas with poor drainage or locations where we channel and direct runoff, such as culverts and downspout outlets.
The best way to avoid overwatering is to get down and dirty with your plants. If you’re watering and haven’t checked the soil to see what the moisture level is like, it’s similar to a doctor prescribing medication without even seeing you. This can create deadly problems. When plants are wilting and show water stress and your soil is already wet or even saturated, watering needs to be slowed down but not completely stopped. This is akin to the plants going cold turkey which, will almost immediately kill them as they can no longer mine for water due to root loss. A slow drawback on watering is the solution. It allows the plants to slowly acclimate and regrow roots as the root rot diseases reduce.
The best “rule of thumb” for watering is deep and infrequent (or my favorite: the “rule of pinky”). If irrigation is used, infrequent but deep soakings keeps plants hardier as they still get the water they need but have to work for the water in between watering. If watering is needed on individual plants and a hose is used at the base of the plant, a flow of water the diameter of your pinky for an hour or so is great to keep the soil moist deep into the root zone. This should be performed once a week during normal conditions and at least twice weekly during drought conditions. The use of a GatorBag can also eliminate the need to constantly check and remember to water the tree.
Be mindful that water can be a double-edged sword. It is essential for the health and growth of your plants, but too much of a good thing can be just as bad or even worse than not enough. Be water-wise when providing for your landscape and take a minute or two before turning on the water to make sure that your plants actually need it.