Today’s column was inspired by a conversation with Lubbock AJ reader J.T. about how it is possible to harvest fresh peaches from a garden all summer. To answer, some peach physiology helps to explain how this can be possible.

Peaches bloom and bear fruit on second-year wood, which means a peach fruit that will be harvested in 2018 began its development the previous season in 2017. Development of a 2018 peach was initiated spring and summer of year one (2017) with healthy growth of new wood that became fruiting wood in year two (2018).

The genetically programmed patterns of flowering and fruiting of mature peach trees are classified as early, mid-, or late-season cultivars.

Trees are dormant during winter months and "break" dormancy (begin to bud out) once certain physiological, hormonal changes occur in the tree’s tissues. Without this hormonal trigger, dormant trees fail to break dormancy and will not resume normal growth. These hormonal changes result from complex chemical reactions that occur during a process known as the "chilling requirement."

The chilling requirement is the number of hours of between 32 and 40 degrees required by a peach tree to resume growth following a period of dormancy. It is during this chilling period that the chemical reactions happen. Cultivars of peaches vary in the number of chill hours required to break dormancy. It is this most fascinatingly complex genetic and chemical phenomenon that differentiates early from mid- and late cultivars. Once sufficient chill hours have accumulated and temperatures warm, buds will break and commence growth.

Flowering and fruiting of cultivars depend to large degree upon their chilling requirement. Early blooming cultivars have low chill requirements, some as few as 450 hours, while late blooming cultivars have as many as 1,000 hours. Low chill cultivars could have their requirement satisfied as early as January and, with a few warm days, may bloom. When late spring freezes occur, buds of low-chill peach cultivars will likely be damaged. Thus, by selecting cultivars based upon their chilling requirement it is possible to have trees that bear fruit early, mid-, and late season.

Take notice of the cultivar labels of peach trees available now in nurseries and home improvement centers and look for chill hours.

Two sources that I have found dependable for ordering healthy trees are Stark Bro’s and Womack Nursery.

Stark Bro’s has excellent stock and can be found at starkbros.com or call (800) 325-4180 for a catalog. They have a wide selection of maturity dates but provide only the maturity class, not the actual chill hours.

Womack Nursery provides the number of chill hours for each cultivar. Their website is womacknursery.com or call (855) 993-6497 for a catalog. Womack Nursery is in De Leon, Texas, and a member of the GoTexan program.

If multiple harvest times are something you would like in your garden, take notice of the chill hours and bloom dates and you can enjoy peaches all summer.

 

ELLEN PEFFLEY taught horticulture at the college level for 28 years, 25 of those at Texas Tech, during which time she developed two onion varieties. She is now the sole proprietor of From the Garden, a market garden farmette. You can email her at gardens@suddenlink.net.