Row covers can be used to accomplish a few different things in strawberry plasticulture. For us in Georgia, they are best suited for protecting blooms and small fruit from frost as we near our first harvest dates.
In other, colder areas of the southeast and mid-Atlantic row covers are used to guard against damage to plants and crowns in severe cold events. These are events with temperatures that drop into the teens and sometimes single digits. This would be the only time I would worry about seeing irreversible damage to plants and crowns.
Row covers can give you protection by providing a physical barrier to frost, and by trapping warm air near the soil surface. Most row covers in Georgia (depending on thickness) will give growers between 3 and 5 degrees warmer temperatures than the outside air. If you have questions about the weight or thickness that you need for your operation you can contact your County Agent to assist with this decision. Obviously, colder areas of the state would benefit from thicker heavier row covers. we typically use row covers from 0.5 oz to 1.0 oz and up to 1.5 oz in higher elevations.
We can use overhead irrigation to protect the fruit and flowers, but this practice seems to cause more problems and can be hard to manage. When considering row covers you need to realize there is significant costs associated with purchasing row covers and labor requirements to deploy them when frost threatens. Another consideration is when to deploy row covers. Wet row covers can sometimes cause greater damage than no covers at all. They are also tricky to deploy in high winds which typically come in ahead of severe cold. Although row covers can be challenging to use I feel that they are our best practice for protecting strawberries from damaging cold and frost.
Some growers apply row covers and leave them in place for extended periods to “push” the crop. In normal years I do not think it is necessary to push strawberries. However, if you decide to use row covers to advance your strawberry plants, you need to thoroughly scout for spider mites ahead of covering. If you find any signs (eggs or nymphs) of an infestation you should treat with an approved miticide before covering. Row covers can provide protection to spider mite populations just as well as they protect your plants.