After the seeds are pressed, the cake can be sold as high-protein livestock feed.
In addition, Central Florida has three biodiesel processing plants—Lakeland, Dade City and Orlando.
Results not all sunny
During the 2007 fall, Chellemi conducted field trials with three sunflower cultivars on ground near St. Lucie that had been in tomatoes and peppers since 2000.
Because of lodging problems with two of the hybrids, he selected the hybrid dwarf S672 from Triumph Seed Co. of Ralls, Texas, to plant in a spring 2008 trial.
What he found was sunflowers do well during unusually dry periods. But they don’t like wet periods, such as after tropical storms that dump inches of rain on fields.
In addition, they are susceptible to rootknot nematodes, sunflower head rot, Bidens mottle virus and phytotoxicity from herbicide residue carryover.
Sunflower head rot, caused by Sclerotinia sclerotiorum, also causes wilt and stalk rot in sunflowers. It’s one of the most prevalent sunflower diseases in the world.
Growing sunflowers in the same field year after year could increase disease incidence, Chellemi says.
Bidens mottle virus is widespread in the weed Bidens pilosa, which is common in Florida. The virus, which is spread most commonly by aphids, also infects lettuce, escarole, endive, and several other ornamental and agronomic crops.
Should sunflower production ever take off, he says the virus could be a limiting factor unless management techniques are developed.
The 5-acre sunflower test plots produced about 1,700 pounds of seed per acre. These were similar to yields reported in earlier trials conducted in North Florida.
After drying and crushing, Chellemi’s plots yielded about 90 gallons of high-grade oil per acre.
What Chellemi says he also discovered was the oil, if exposed to heat during harvesting or storage, quickly oxidizes, decreasing its quality.
Regardless of the cultural challenges, the economics of growing sunflowers for oil don’t pencil out as long as biodiesel remains less than about $5 per gallon, Chellemi says.
Under Florida conditions, growing sunflowers requires about $500 to $600 per acre in production costs. The largest portion—about 60 percent—is from the 140 pounds of nitrogen required by the crop.