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The physiological, microbiological and chemical quality changes were studied in carrots that received preharvest sprays of a commercial plant extract (ComCat) and subjected to disinfection and storage at 1 and 22C. At harvest, ComCat‐treated carrots had less aerobic and coliform bacteria population, higher contents of total available carbohydrates (TACs) and sucrose and lower glucose and fructose concentrations. During storage, ComCat‐treated carrots displayed reduced physiological weight loss (PWL) with lower sucrose, glucose and fructose concentrations. Disinfectants reduced microbial populations in carrots. Chlorine disinfection resulted in an etched surface, which was not observed for anolyte treatment. Anolyte water showed a better positive effect on PWL. Higher temperatures deteriorated quality characteristics of carrots. The TAC accumulated better in ComCat‐treated than in control carrots stored at room temperature. The combined effect of pre‐ and postharvest treatments had significant effect on maintaining postharvest quality and improvement of shelf life of carrots. PRACTICAL APPLICATIONS Preharvest ComCat treatment can be used to improve the overall quality of carrots. Disinfection of carrots using anolyte water was found to be superior to the chlorinated water dipping treatments. Thus, anolyte water is recommended for disinfection of carrots. Combining the preharvest ComCat treatment and disinfection using anolyte water, coupled with refrigerated storage environment should be used in the shelf life extension of carrots.

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Lachenalia bulbs used in the pot plant industry are produced in the nursery phase from bulblets propagated from leaf cuttings. Fertilisation during this phase of enlargement can ultimately influence the growth and flowering of pot plants through the nutritional status of the bulbs. The objective of this study was to determine the response of cultivars (Rupert and Ronina) in the pot plant phase to different nitrogen levels when grown from bulbs whereof the fertilisation history is known. During the nursery phase bulblets of cultivars Rupert and Ronina received three nitrogen levels (0, 250 and 520 kg N ha -1 ) combined with two different application times. The resulting bulbs were planted in the pot plant phase and five nitrogen levels (0, 70, 180, 330 and 520 kg N ha -1 ) applied. Ronina leaf area responded better than Rupert when fertilised in the pot plant phase. The leaf area was also promoted by nitrogen applied in the nursery phase. Nitrogen applied in the nursery and pot plant phases influenced the number of florets formed per inflorescence positively. Only high nitrogen levels applied in the nursery phase (250 and 520 kg N ha -1 ) increased the peduncle length of the plants. Peduncle diameter was increased with an increase in nitrogen levels in the nursery phase as well as in the pot plant phase. This trial showed that Lachenalia has a low nitrogen requirement in the pot plant phase when grown from bulbs that were properly fertilised in the nursery phase but additional fertiliser in the pot plant phase improved the quality of the inflorescence.

During the nursery phase, Lachenalia flower bulb producers plant bulblets propagated from leaf cuttings, for enlargement. They strive for a high yield of good quality bulbs that are of a marketable size within a year. In this regard nitrogen is of vital importance since it stimulates vegetative growth. Very little has been known about the nitrogen requirements of Lachenalia plants that are cultivated in soil. Hence the response of two Lachenalia cultivars (Rupert and Ronina) to combinations of nine nitrogen levels (0, 30, 70, 120, 250, 330, 420 and 520 kg ha-1 ) and three application times C/3 with planting and 2/3 ten weeks after planting; 1/3 with planting, 1/3 ten weeks after planting and 1/3 sixteen weeks after planting; and % with planting, % ten weeks after planting, % sixteen weeks after planting and % twenty one weeks after planting) was studied in a glasshouse using topsoil of a fine sandy loam Bainsvlei form. Nitrogen promoted the growth of Lachenalia plants irrespective of cultivar. The·largest leaf area for Rupert was measured between 250 and 420 kg N ha-1 and for Ronina between 180and 520 kg N ha-1 . Both bulb circumference and firmness were influenced positive by higher nitrogen levels whereas nitrogen application time did not show such a clear trend. Bulb circumference was the largest where 330 kg N ha-1 was applied and the firmest bulbs where 420 and 520 kg N ha-1 was applied for Rupert and Ronina respectively. Nitrogen content of the bulbs increased with an increase in nitrogen levels. Bulbs that received their nitrogen in four equal applications had the highest nitrogen content. The glucose content decreased whereas the sucrose and starch content increased with higher nitrogen levels. Cultivar and nitrogen application times had variable effects on the carbohydrate content of the bulbs. The optimum nitrogen level varied between 250 and 330 kg N ha-1 and the best response was obtained when this nitrogen was applied in four equal applications throughout the season. .