Spring is here, and for most the warmer temperatures and longer days are a welcome sight! We know, however, that based on past experiences, we are likely still in for some cool nights and frosts for the next few weeks. For those with fruit trees, that means the next month will be critical as to whether we have a crop this year.
According to UT Extension Fruit Specialist Dr. Dave Lockwood, once their chilling requirement has been met and the weather begins to warm up, plants begin to de-harden. As fruit buds progress from dormancy through bud swell to bloom and beyond, they become increasingly vulnerable to damage from cold temperatures. For example, a peach tree in full bloom will lose about 10% of its fruit at 27 °F and 90% at 24 °F.
The best frost control methods begin before the crop is planted. Site selection, direction of the slope, and planting design all affect how sensitive a crop is to a late frost. In addition, removing overgrown fencerows and woodlands on the lower side of the slope will eliminate frost pockets and allow better air drainage.
But what if you inherited a site where these items weren’t considered? While your options are limited, there are some control measures that can be taken in the orchard if a late frost is expected. Commercial orchards sometimes use many small fires scattered throughout the field, wind machines or helicopters, overhead irrigation, and row covers placed over the trees.
For most homeowners, these methods aren’t viable options. Still, there are some things homeowners can do to give their peach and apple trees the best shot at surviving a late frost.
1. Apply herbicides now to control winter weeds and maintain a clean, bare strip under trees. This allows more heat to be absorbed during the day and re-radiated back into the atmosphere at night.
2. Mow the orchard floor and make several passes around the orchard border to enhance air flow.
3. Have the brush chopped or pushed out of the orchard.
4. Get rid of overgrown fencerows, hedgerows, and underbrush around and especially below orchards.
5. Irrigate the orchard floor if soil moisture levels are low. The greater percent of the orchard floor that can be irrigated, the more benefit that can be recognized.
History tells us that there are still some frost events likely to occur in early to mid-April. Like most things in agriculture, it is much easier to take steps on the front end when establishing the orchard to protect it as opposed to trying to protect trees on a poor site. For some great educational resources on fruit production, visit uthort.com.
