Answer: Production practices have a tremendous effect on the quality of fruit at harvest, postharvest, and during shelf life. For example, some cultivars are known to have a longer shelf life and to ship better than others. Because of this, you should consider your market before considering which varieties to plant. In addition, environmental factors such as soil type, temperature, frost, and rainy weather also have unfavorable effects on the crop’s harvest quality. For example, some tomato varieties have a tendency to crack after a rain. Therefore, choosing varieties such as Sapho and Mountain Fresh, which are resistant to cracking, may help alleviate the problem of poor fruit quality at the time of harvest. Management practices such as too little or too much water, mechanical injury, or high fertilizer rates can also affect postharvest quality.
Tomatoes should be harvested during the coolest time of the day, which is typically in the morning, and produce should be kept shaded in the field. Harvesting tomatoes requires extensive labor; harvesting may be done every day during the peak of the season along with continuous discarding of culled fruit from the field to prevent the spread of diseases and pests. Harvesting is done either by hand or with a harvesting aid; only process¬ing tomatoes are harvested by machine due to increased bruising of the produce. Produce should be graded, separating the marketable tomatoes from the cull tomatoes that show signs of bruises, cracking, spots, rots, or decay. Damage such as this can be prevented if tomatoes are handled with care at the time of harvest, harvested at proper maturity, harvested during dry weather, and handled minimally. Tomatoes should be harvested with no more than two to three stacked deep into strong cardboard or stackable flat boxes. Growers have used bread racks in the past with great success. Check with a local bakery to see if they would be willing to sell some to you.
Tomatoes are very susceptible to chilling injury; therefore, maintaining precise storage temperature is critical for postharvest storage quality. Storage temperatures differ with the maturity of the fruit. Tomatoes picked with a slight pink color all the way up to a mature red color should be stored at temperatures between 48ºF to 50ºF. These fruits will have a maximum shelf life of two weeks. Tomatoes that are picked green are best stored at temperatures between 58ºF to 60ºF and have a three- to four-week shelf life.
Proper sanitation is of great importance in preventing postharvest diseases and the spread of foodborne illnesses. Thus, strict regulations of sanitary facilities and the use of disinfectants in wash water are used to help prevent both the spread of postharvest diseases and foodborne illnesses. Disinfectants such as chlorine, at a residual of 4 ppm, or hydrogen peroxide, at a concentration of 0.5%, have been effective disinfectants in organic programs. Always check with your certifying agent to see what concentrations are allowed under the regulations.
You can learn much more on this topic in the ATTRA publication Organic Tomato Production. It focuses on the specific production challenges, including site selection (soil and climate), variety selection, sources of organic seeds and organic annual transplants, organic grafting, planting and training/staking arrangements, soil fertility and fertilization, crop rotation, and pest (insect, disease, and weed) management. Harvest and yield/productivity are closely related to marketing possibilities. While market conditions are extremely region-specific, this publication also addresses a few general principles on marketing and economics of organic tomatoes.
In addition, the ATTRA publication Postharvest Handling of Fruits and Vegetables is an excellent source for additional information on postharvest and storage considerations.
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