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Charles S. Vavrina

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Charles S. Vavrina

The research reviewed here represents the majority of the information available on transplant age to date. When the results of these studies are distilled down to the “ideal” transplant age for setting of a specific crop, we generally arrive at the recommendations found in the 1962 edition of Knott's Handbook for Vegetable Growers. The conflicting results in the literature on transplant age may be due to the different environmental and cultural conditions that the plants were exposed to, both in the greenhouse and in the field. The studies did reveal that the transplant age window for certain crops might be wider than previously thought. Older transplants generally result in earlier yields while younger transplants will produce comparable yields, but take longer to do so. Our modern cultivars, improved production systems, and technical expertise enable us to produce high yields regardless of transplant age. The data, in general, support the view that if a vegetable grower requires resets after an catastrophic establishment failure (freeze, flood, etc.), they need not fear the older plants usually on hand at the transplant production facility.

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Charles S. Vavrina

Tomato transplants when planted to the cotyledon leaves, or to the first true leaf, yielded more than transplants set to the top of the root ball. Yield increase appears to be a function of increased extra-large fruit number, which suggests advanced maturity. Results held across four widely separated geographic locations for both spring and fall plantings. These data suggest that planting tomato transplants deeper is commercially beneficial in Florida.

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Charles S. Vavrina and George Hochmuth

`Allstar” tomatoes raised from seed in Todd™ containerized transplant trays were treated with 1/4 strength Hoagland's solution modified to supply 0, 15, 30, 45, 60, or 75 mg·l-1 N daily. Nutrient application was achieved via ebb and flow irrigation. N was supplied as ammonium nitrate. Tissue sample values for elements tested, excluding N, were essentially adequate for all treatments at transplanting (6 weeks after seeding). Visible transplant differences in the plant house did not translate to significant yield differences in the field when rates of 30 mg·l-1 or greater were used in either spring or fall plantings in FL. A similar trial shipped to PA showed that 75 mg·l-1 in the plant house resulted in the greatest early field yields, but 45 mg·l-1 produced the greatest overall yield.

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Charles S. Vavrina and William Summerhill

Thirty-four operators produced > 1.15 billion vegetable transplants in Florida in the 1989-90 season. Sales, concentrated in the winter and spring, were estimated at $30 million. Firms in the industry also made additional sales of ornamental and agronomic plants. Nine large firms accounted for 88% of all transplants produced. More than 109 acres (44 ha) of greenhouse area are allocated to containerized vegetable production. The majority (83%) of Florida s vegetable transplants were from three crops--tomatoes (45%), peppers (28%), and cabbage (10%). Only 36% of the transplants produced in the state were shipped out-of-state. This report discusses various facets of production, marketing, labor, and general business conditions of the containerized vegetable transplant industry.

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Charles S. Vavrina and Michael D. Orzolek

As early as 1929, university scientists began the quest to determine the ideal age at which to transplant tomatoes (Lycopersicon esculentum Mill.). Investigations have included seedlings of 2 to 15 weeks of age produced in wood, peat, plastic, or Styrofoam containers. Early researchers often omitted descriptions of soil mixes and nutrient regimes, and used a wide variety of container types. Later investigators were inclined to use commercial soilless mixes, well-defined nutrient regimes, and polystyrene trays. Pioneers of transplant age research tended to use plants of 7 weeks and older, whereas work within the past 30 years has concentrated on younger plants. Many researchers drew conclusions after only 1 year of experimentation, while others found that results varied across years. Prior to the 1980s, virtually all studies were initiated and conducted in areas far from the thriving transplant industry established in the southeastern United States. Southern-grown transplants often were not in cluded for comparison, and few studies were implemented using plants grown under commercial conditions. After more than 60 years of transplant age research, it appears that transplants of 2 to 13 weeks can produce comparable yields, depending on the many factors involved in commercial production.

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Daniel I. Leskovar and Charles S. Vavrina

The effect of cell volume and age of `Texas Grano 1015Y' onion transplants on survival, growth, and yield were evaluated. Transplant ages and cell volume were 5, 7, 9, and 11 weeks (W) and 6.5 cm3 and 20.0 cm3 in Florida; and 6, 8, 10, and 12W, and 4.0 and 7.1 cm3 in Texas. In Florida, total yields were unaffected by transplant age and cell volume, but jumbo size bulbs increased with increasing age from 5 to 9W in 6.5 cm3 cells. Bulb size increased significantly for 11W transplants only in 20.0 cm3 cells. In Texas, survival was reduced for 6W compared to ≥8W transplants. At planting, root count increased linearly with age. Cell volume did not affect root count, plant height, or leaf number, but shoot dry weight was greater in 7.1 cm3 compared to 4.0 cm3. Total jumbo and large size yields were highest for ≥10W in 7. 1 cm3 and ≥8W in 4.0 cm3 cells. Total yields were unaffected by cell size but seedlings in 4.0 cm3 had a 16% decrease of jumbo size compared to 7.1 cm3. The use of 10 and 12W transplants produced in small cell sizes may be viable for onion establishment.

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Charles S. Vavrina and Doyle A. Smittle

Six onion (Allium cepa L.) cultivars were grown during 2 years to evaluate the effects of environment on bulb quality as measured by sugar and pyruvate (pungency) concentrations. Within each year, bulb fresh weight was not affected by cultivar; however, bulb fresh weights were 36% higher in a year when most of the rain fell during maximum bulb expansion. Total bulb sugar concentration and pungency varied among cultivars and years. Pungency was higher and the sugar: pungency ratio was lower in `Texas 1015Y' and `Sweet Georgia' than in `Dessex', `Rio Bravo', 'Hybrid Yellow Granex', and `Granex 33'. Under low S nutrition, market acceptance of “sweet” onion cultivars that vary slightly in nonstructural water-soluble carbohydrates may be assessed more precisely by the sugar: pungency ratio than by sugar or pungency assessments.

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Anne K. Carter and Charles S. Vavrina

The germination of five commercial cultivars of jalapeño and cayenne pepper were tested to determine cultivar response of Capsicum annuum L. to supra-optimal temperatures. Two seedlots of `Cayenne, Large Red Thick', `Ole', `Jalapeño M', `Mitla', and `Tam Veracruz' were evaluated on a thermogradient table at temperatures of 20, 25, 30, 35, and 40 °C. Percent germination and time to 50% of final germination (T50) were calculated. All cultivars exhibited thermodormancy, but the degree of inhibition varied within temperature and cultivar. No cultivar had >1.0% germination at 40 °C. Generally, the T50 varied among cultivars, but not among temperatures within a cultivar (T50 at 40 °C was not measured). Cultivar selection should be considered when growing fall transplants in Florida.