I hate to start the season with a frost warning post, but this has become our new norm anyway.

The good news is that, based on the forecast so far, I do not think the cold weather expected Tuesday night into Wednesday morning will be a major concern for many of us. I checked the forecast across several apple-producing regions in Virginia, and temperatures appear likely to range between about 23 and 25°F from midnight through sunrise on Wednesday morning. Those temperatures could cause at least some level of injury in certain fruit crops, depending on location and, more importantly, the developmental stage of the trees.

Here in Winchester/Frederick County, peaches are generally between calyx green and calyx red, and most apple cultivars are still not much beyond green tip. At these stages, this event should not be a major issue for either crop. That said, conditions may be different in other parts of the state. In central Virginia, for example, some peach cultivars may already be at 20–50% bloom, and those blocks could see damage if temperatures fall below about 24°F for a couple of hours. The same concern applies to apple cultivars that have reached tight cluster, where some injury can occur around 24°F, especially when dew points are low.

So, is there anything you can do?

Yes — if your trees are at a stage that could be truly affected, and you have frost protection options available, this may be the time to consider using them. Based on the current forecast, this looks like a fairly typical radiative frost event, with light winds, mostly clear skies, and low dew points. Under these conditions, tools such as wind machines, propane heaters, and irrigation can all be effective. Both under-tree and over-tree sprinklers may help raise orchard temperature by a couple of degrees, but protection efforts would likely need to begin Tuesday night.

For more information on sprinkler use for frost protection, check out this previous post:
https://tree-fruit-horticulture.vaes.vt.edu/2023/03/07/sprinklers-for-frost-protection-what-you-need-to-know-before-turning-them-on/

As always, this post reflects what I can see in the forecast right now. Please continue to monitor your local weather closely and use your own judgment based on your site conditions, crop stage, and available frost protection methods.