Maximizing onion and economic feasibility of growing onions from plug transplants
Growing onions from transplants is a growing trend in New York, because of the economic benefits of larger sized bulbs and earlier entry into the marketplace with approximately 15% of the 13,000 acres of onions now being grown from transplants. Most transplants are grown from bare root transplants imported from Arizona, which have been found to harbor the causal pathogen of neck rot, Botrytis allii, Iris yellow spot virus and onion thrips. Cost, availability and frustrations associated with labor are increasingly more of a problem for onion growers who grow their onions from transplants. The deterrent to the alternative of purchasing locally grown plug transplants is that they cost 3-4 times more to purchase, and that in a previous study, they did not yield as many of the more lucrative jumbo-sized bulbs as bare roots. However, there may be labor savings, especially in light of a new automated plug transplanter now available, and improved quality that would more than make up for the higher initial cost of plug transplants. In this study, we demonstrated and evaluated adjustments to the standard planting configuration of onions grown from plug transplants and thoroughly compared return on seed, cost of transplants, labor costs, stand establishment, pest management, yield, grade and economic return. We found that onions grown from plugs in 288 cell trays with 2 and 3 plants per cell yielded comparably to onions grown from bare roots. In 2009, the new Ferrari® Futura Automatic Plug Transplanter will be demonstrated in the Elba muckland, NY on two onion farms. Once this new technology is successfully demonstrated to be economically feasible, it will be readily adopted by onion growers, and growing onions from transplants will continue to be sustainable.
- To demonstrate and evaluate yield, bulb size and economic return of three adjustments to the standard method of growing red onions from plug transplants in comparison to the standard plug method and to growing onions from bare roots.
To take into consideration all aspects of the different transplanting methods including the costs of transplant seedlings, shipping, and labor, stand establishment, pest management, yield, grade and economic return.
- The trial was established and harvested successfully in 2008. A red onion variety, cv. Red Zepelen, was grown from imported bare roots, from the standard plug transplant configuration (288 cell trays with 3 plants per cell), and two adjustments to the standard plug configuration, including 288 cell trays with 2 plants per cell and 512 cell trays with 2 plants per cell, and evaluated for performance in side by side in-field comparisons. Return on seed, stand establishment, plant size and vigor, disease and onion thrips evaluations were made several times throughout the growing season. Final yield and bulb size distribution were quantified. A preliminary economic analysis was conducted. Onions are currently in storage awaiting quality evaluations in early January 2009.
Preliminary results were presented at the Annual Elba Muck Onion Twilight Meeting on August 5, 2008, where 40 onion growers, allied industry representatives and Cornell Cooperative Extension professionals were in attendance.
This research project was highlighted on the front page of the newspaper, the Batavia “Daily News” on August 19, 2008, along with the other 2008 Partnership project funded by NESARE that was conducted by Hoepting, “Preventing erosion of muck soils by reducing tillage in onion production”.
Preliminary results of this project were presented by Hoepting to 12 Cornell research faculty and Extension Educators at the onion session of the Annual Agriculture In-Service training in Ithaca, NY, on November 12, 2008.
Results from this project as well as the NESARE Partnership project, “Economic Feasibility of Using Locally Grown Plug Transplants as an Alternative to Importing Bare-root Transplants in Onions”, funded in 2006, were presented by Hoepting at the National Allium Research Conference, held in Savannah, Georgia, on December 11, 2008 to an audience of 94 university and government researchers, allied industry representatives and growers from the United States, Canada, Holland, New Zealand and France. A manuscript has been published in conference proceedings.
Return on seed: This is the percentage of the total seed sent to the transplant producer that is returned to the grower as transplant seedlings. Return on seed of bare roots was estimated by the grower cooperator to be approximately 70% in 2008. Plug transplants yielded a higher percent return on seed (86 – 91%) with the 512 cell trays with 2 plants per cell producing the most plants (91%). The accuracy of the number of plants per cell was just over 50% in the 288-cell trays, due to high percentages (~ 30%) of cells planted with one less than desired number of plants per cell.
Stand establishment: A higher percentage of the bare roots (72%) were planted correctly compared to the plugs (44 – 56%). However, the bare roots had 111% of the targeted plant population due to 16% and 3% of the holes having 2 and 3 plants instead of 1. The less accurate planting of the plugs grown from 288 cell trays with 38 – 45% of the holes having 1-2 less plants per hole than desired, reflected the inaccuracies of the original seeding in the trays in the greenhouse. The actual plant population of the onions grown from plug transplants grown in 288 cell trays was 81 and 84% of the target population for 3 and 2 plants per cell, respectively. Of the plug transplants, those grown in 512 cell trays with 2 plants per cell were planted with the most accuracy (56% of holes planted correctly). Because 15% of the cells had one less and 15% had one more plant than desired, the resulting actual plant population was 95% of the targeted population.
Plant size: Bare root transplants had significantly more leaves per plant (22-May: 1.8; 11-Jun: 6.5; 16-Jul: 9.6) than any of the plugs, followed by the plug transplants grown in 288 cell trays with 2 plants per cell (22-May: 1.6; 11-Jun: 5.5; 16-Jul: 9.2), which had significantly more leaves per plant than plug transplants grown in 288 cell trays with 3 plants per cell (22-May: 1.4; 11-Jun: 5.0; 16-Jul: 8.6) and plugs grown in 512 cell trays with 2 plants per cell (22-May: 1.4; 11-Jun: 4.6; 16-Jul: 8.5) at 2, 5 and 12 weeks post transplanting. The plugs grown in 288-cell trays with 2 plants per cell had significantly the tallest plants by 2-8 cm and 5-10 cm, 2 and 6 weeks after transplanting, respectively, but by 11-Aug they were not significantly different than the bare roots. Plugs grown in 512 cell trays with 2 plants per cell had significantly the shortest plants all season long. Often, plant size, especially number leaves, directly translates into final bulb size. Large, healthy plants during the growing season are an indication of big bulbs at harvest.
Pest pressure: Onions grown from plug transplants consistently had significantly higher numbers of onion thrips per plant, which was observed in the previous study. These differences were to the extent that the threshold to start spraying insecticides for onion thrips would have been reached sooner in the onions grown from plug transplants. No differences in Botrytis leaf blight or Purple blotch were observed among the different planting configurations.
Yield and bulb size: Onions grown from plugs in 288 cell trays with 3 plants per cell had the highest yield in the trial (387 cwt/A), which was 44, 47 and 80 cwt/A higher than plugs in 288 cell trays with 2 plants per cell, bare roots, and plugs in 512 cell trays with 2 plants per cell. The plant population was also highest for plugs in 288 cell trays with 3 plants per cell. Bare roots had significantly 3 times as much jumbo weight and 3.5 times less small weight as plugs in 288 cell trays with 3 plants per cell. Compared to bare roots, plugs in 288 cell trays with 2 plants per cell had similar yield, and significantly the same weight of jumbos and smalls per acre. Plugs grown in 512 cell trays with 2 plants per cell had the lowest yield, no jumbos and similar weight of smalls as plugs in 288 cell trays with 3 plants per cell. Bare roots had the highest cull weight per acre due to rots, double bulbs and undersized bulbs. The 2008 trial was severely damaged by a hail storm on June 16 that caused high incidences of culls, especially to plants that had the most leaves, specifically, the bare roots and plugs in 288 cell trays with 2 plants per cell.
Botrytis allii contamination of transplants and storage quality: Bioassays resulted in no detection of latent Botrytis allii infection in the bare roots or plugs. Bulbs are in storage and will be evaluated for rot in January 2009. It is unknown why the bare roots were clean in 2008, but historically, these transplants have been contaminated with B. allii (Hoepting et al. 2006).
Economic analysis: In 2008, the target plant population per acre was 104,544 with exception of onions grown from plug transplants in 288 cell trays with 3 cells per plants, which had ⅓ more plants per acre at 156,816 plants per acre. Due to an increased cost of shipping because of higher fuel costs, and a poorer return on seed (~70% vs. 80% in 2006) of bare root transplants, plug transplants grown in 288 cell trays with 3 and 2 plants per tray cost only 2 times more than bare roots, down from 3 times more in 2006. Due to the use of 44% less greenhouse space, plugs grown in 512 cell trays with 2 plants per cell cost only ¼ or $154 per acre to purchase than bare roots. It took less time to transplant plugs than bare roots by 45 minutes for plugs grown in 512 cell trays, and 1 hour 15 minutes for plugs grown in 288 cell trays. Faster planting time of plugs resulted in lower labor costs by 21 to 31% or $135 to $190 per acre for 512 and 288 cell trays, respectively. Additionally, faster transplanting will allow the onion crop grown from plugs to be planted sooner. Generally, there is a direct relationship between early planting and increased bulb size, thus, increasing the proportion of jumbo sized bulbs and net profit of onions grown from plug transplants. In this case, 0.3 to 0.6 acres more of plug transplants can be planted in a 10 hour work day, which means that a 50 acre field could be planted in 6 days less time than it would take to transplant bareroots.
Unfortunately, due to severe hail damage that occurred on July 16th 2008, yield and bulb size per acre was down significantly. Thus, most of the bulbs were in the lower-valued medium size class and total profit was down $7950 or 58% from 2006. The onions grown from plugs in 288 cell trays with 3 plants per cell grossed the highest, which was $667, $606 and $1492 more per acre than onions grown from bare roots, plugs in 288 cell trays with 2 plants per cell and plugs in 512 cell trays with 2 plants per cell, respectively. The reason that onions grown from plugs in 288 cell trays with 3 plants per cell performed the best was because they were grown at a higher plant population. However, it was at the expense of producing jumbo sized onions. Comparatively, the onions grown from plugs in 288 cell trays with 2 plants per cell grossed only $61 per acre less than the bare roots, and had twice as many jumbos as the plugs in 288 cell trays with 3 plants per cell. When a greater proportion of the total yield falls into the jumbo bulb size class, the difference between growing onions from plug transplants with 2 and 3 plants per cell has a greater economical impact (as previously demonstrated in 2006) with 2 plants per cell being more favorable. Further research is warranted to demonstrate this point.
Once the more expensive cost of producing plug transplants is factored in, onions grown from plugs in 288 cell trays with 3 plants per cell netted $208, $470 and $1052 per acre more than onions grown from bare roots, plugs in 288 cell trays with 2 plants per cell and plugs in 512 cell trays with 2 plants per cell, respectively.
Impacts and Contributions/Outcomes
- The demonstration of this project at the Annual Muck Twilight Meeting that showed that onions grown from plug transplants could yield comparable yield and cost, especially with the advantages of the faster planting times, encouraged our grower cooperator to continue to grow some of his onions from plug transplants again in 2009. In addition, another grower in Elba will be experimenting with onions grown from plug transplants in 2009.
As a result of this project, arrangements have been made with Oxbo International, located in Byron, NY, to have a demonstration unit of the new Ferrari® Futura Automatic Transplanter available in April and May of 2009 in the Elba muckland, NY. This unit is specifically designed for plug transplants, and will not work with bare roots. It has the potential to reduce labor costs by 90% or more, and reduce transplanting time by 50 to 75%, as an alternative to the labor-intensive process of using people to transplant onions. Two onion grower cooperators in the Elba muckland have already ordered enough plug transplants to trial the automated unit on 0.33 to 1 acre of onions for each of 5 planting configurations to be used in this study (2009 NESARE Partnership grant proposal, “Reducing labor needs by adopting new automated technology to sustain profitability of producing onions from transplants” by Hoepting). The only way that onion growers would be willing to invest in this new technology would be if they could see it successfully demonstrated on a large scale.
Once onion growers are convinced and confident in this new economically feasible system of growing onions from plugs that are transplanted with automated technology, they will adopt it readily, and save thousands of dollars in labor costs. The local economy will benefit from increased sales of locally grown plug transplants as more acreage will be converted from being grown from bare roots transplants to plug transplants. The risk of introducing pests and invasive species on bare roots imported from Arizona will be greatly reduced, which could result in savings of thousands of dollars per acre in losses and reduced pesticide sprays. Most importantly, the viability of the northeastern onion industry will be sustained.
Triple G Farms, Inc.
5407 Oak Orchard Road
Elba, NY 14058
Office Phone: 5855894134