Low Brix has been a major problem plaguing the Florida citrus industry in recent years. While many growers are struggling to achieve the minimum required Brix level, this has not been an issue for citrus grower Chip Henry. He recently shared how he believes his organic production techniques contribute to high Brix as well as stopping premature fruit drop in his grove.
Henry grows 12 acres of Valencia on primarily sour orange rootstock in Apopka. The grower began converting his grove to organic production in 2015 because HLB-infected trees were not responding to conventional methods. Since that time, he has seen the health of his trees steadily improve. While he admits his yields aren’t spectacular, his fruit quality is.
For the 2022–23 season, Henry’s oranges tested at the 13.4 Brix level. In 2021–22, the Brix was 13.3. Since 2017, his fruit has consistently come in at 13.0 or higher Brix.
“Since going organic, fruit drop in my grove has gradually decreased. By 2019, fruit drop virtually ceased,” says Henry.
He says several factors contribute to these positive results. According to Henry, orange trees on sour orange generally produce higher Brix than those on Swingle. In addition, he believes that backing off on synthetic nitrogen applications and implementing cover crops are keys to his success. Lastly, the use of a stabilized aerobic microbial solution is a main component to keeping quality fruit on his trees.
“Reducing nitrogen applications and slowing down the growth of the tree gives beneficial microbes the opportunity to sequester and reduce the population of HLB bacteria in the trees,” Chip theorizes. “Too fast of growth increases photosynthesis and produces more citrates as a food source for the bacteria. More soil organic matter and less nitrogen is key.”
Henry applies less than half of the U.S. Department of Agriculture National Organic Program annual maximum allowable nitrogen amount per acre, which is limited to no more than 20% of the total recommended amount for conventional production practices. He applies sodium nitrate (15-0-2), the sole organic-approved nitrogen product, three times per year. Additional nitrogen is derived from cover crops and from the atmosphere.
Sunn hemp has been a popular leguminous cover crop choice in Florida citrus. But Henry says iron clay peas are his preferred legume because he has experience growing this crop as a food source, it is well suited to his soil and is somewhat tolerant to drought. Another advantage of iron clay peas is that some plants will reseed, which cuts down on the replanting cost. Henry plants his iron clay pea cover crop in June. He then mows and discs it into the grove in October to activate the soil microbes.
Wild mustard, which is naturally occurring in his grove, serves as Henry’s winter cover crop. He says the wild mustard provides biomass and organic matter with the added benefit of retarding germination of weed seeds. The result is a reduction in Spanish needles, pusley and croton weeds.
The key input in Henry’s production program is a microbial solution he applies no less than three times per year. Applications are made at spring flush, at the time of summer cover crop planting and in late fall in between turning under of the summer cover crop and establishment of the winter cover crop.
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