Happy New Year! It is going to be cold this week. The National Weather Service is forecasting lows in the mid 20’s this week (January 5, 2025). Lets discuss some topics that keep on coming up this week.

Will watering my landscape help? I received that question a couple of times this past week. Dr. Bodie Pensi, UGA Ornamental Specialist suggests that hand-watering landscape plants before a freeze can help as well. It is highly advised not to use irrigation systems – they should be shut-off and drained for the winter. Additionally, there has been rain in the last week, and rain is forecast for this weekend, so Mother Nature will help in this regard. Wet soil will absorb more heat during the day and radiate it during the night. If below freezing temperatures are expected, having more moisture in the soil is beneficial; as water freezes, it releases heat. This works only as long as there is liquid water – once it’s all frozen, the temperature will drop below freezing. Plants in containers, are more prone to damage. Containerized plants should be moved to protected areas where heat can be supplied or trapped. If they can’t be moved, placing them closer together and covering them with mulch will reduce heat lost from the container walls. Coverings protect more from frost than from extreme cold. The most effective covers are those that extend to the ground and do not touch the canopy. Setting holiday lights under the cover is an easy method to raise the temperature around the plant.
I want to prune after this cold snap, is that the right thing to do? This is another great question. Dr. Bodie again advises assessing damage but do not prune too soon after the cold weather. Brown leaves can be removed right away but you should wait to do any strong pruning until new growth appears. This way you can be sure you are not removing any live wood and reducing stored reserved even further. Often cold injury is not as obvious, and extent of damage is evident weeks or months later. For woody plants, brown/black cambium layer under the bark and lack of spring bud break and/or an overall weak appearance, is a clear indication of damage.
Plants become acclimated by gradual decreases in temperature over a period of time. Often, we see more damage after a period of warm weather, followed by sudden freeze. Most plant parts can adapt to cold, but fruits and roots do not develop good cold tolerance. With proper plant selection and sitting, much of the damage from cold can be averted. Tree canopy and structures offer protection. New plantings should have a good layer of mulch to serve as insulation.
What about my lawn? According to Dr. Clint Waltz, UGA Turf Specialist, cold injury to turfgrass is generally associated with cold and dry conditions. While the late fall and early winter were dry”ish”, recent (i.e. last week) rainfall has been minimally adequate for keeping the growth points of the grass plant hydrated. Fortunately, the forecast is highly confident for rainfall this Sunday into Monday. So, do turfgrass managers and homeowners need to do anything to prepare lawns for a January cold snap? Simply stated “No”. There are things not to do, however. Do not “freeze” or irrigate your lawn. For some crops (e.g. strawberries) short-term freeze events can be mitigated by encapsulating the plant in ice. That may sound counterintuitive, but water freezing is an exothermic (gives off heat) process. For it to work, irrigation must be continuous until air temperatures rise above freezing. This time of year, warm-season grasses do not have green tissue or fruit to preserve with this technique. Additionally, the excess water can do more harm to the turfgrass root system by saturating the soil. Lastly, there is no need to fertilize for the forecast conditions. Currently, there is minimal biological activity in warm- and cool-season grasses with low nutrient uptake. Applying any fertilizer now has a greater likelihood of leaching beyond the root system than being taken up by the plant. Why spend money on nutrients the plant will not use? Unlike in 2023, the air and 4-inch soil temperatures this January have been cool and have not stimulated a premature green-up. Fully dormant grasses, like now, are resilient enough to handle some cold weather. |
If you have any questions please contact your local County Extension agent.