HARVEST AND POSTHARVEST PRACTICES

     Timing

   Time from planting to first harvest is generally 45 to 55 days for the Slicing types, and 52 for the slicing oriental types but varies according to time of year, location and prevailing weather. At higher elevations growth will be slightly slower due to cooler temperatures. The crop is picked for three to as many as 16 weeks depending on weather, plant vigor, and pest incidence.

     Production Yields

   In Hawaii, the average slicing cucumber yields are about 20,000 lbs/Acre with 6,000 plants/Acre, a 100% increase over yields obtained locally in the 1950s. Yields during the winter are 50-60% of those obtained during summer months. University of Hawaii cultivars "Milo" and 'Lani" produced 11 and 8 lbs/plant, respectively, in Maui yield trials. Experimental marketable yields in Hawaii range from 37-64,000 lbs/Acre. The average Florida yield is 25,000 lbs/Acre with 17,500 plants/Acre. Pickling cucumbers yields in California are about 40,000 lbs/Acre with once-over harvest and population of 60,000 plants/Acre.

      Maturity

   

Duration from pollination to harvest in slicing cucumber is 15-18 days, and 5-10 days for pickling cucumber. Cucumber plants set fruit and develop over a long period of time, therefore marketable fruit are ready for harvest over an extended period of time. Size of marketable fruit for slicing cucumbers ranges from 6-10 inches in length and 1.5-2.5 inches in diameter. Slicing cucumbers should be fresh, crisp, of medium size, well formed, uniform and of a deep green color. Consult the Hawaii Grading Standards for specific requirements. The fruit is picked before it has reached full diameter and while the seeds are still small and soft. A light green or yellow skin color is an indication that the fruit is overmature for picking. Minimum market length for European (parthenocarpic) cucumbers is 11 inches (28 cm) and 1.5 in (4 cm) diameter, and these weigh about 1 lb. Fruits from trellised plants are uniformly green whereas fruits from non-trellised plants may have a yellow-green side on the section touching the ground.

    

  

      

  Harvesting Operation

   Cucumbers are picked manually. The fruit should be held near the stem and clipped or snaped with a slight twist motion and not be pulled off the vines to minimize "pulled ends." Pulled off fruits leave an "open wound" where the fruit skin is torn off, and this causes the fruit to shrivel around this spot. The frequency of harvest is usually every other day or daily during the warm months, and 2-3 times per week during cooler weather or at higher elevations. Fruit quality is best controlled when fruit is picked daily especially during warm weather. Daily harvest is recommended for the oriental slicing types. In large operations, cucumbers are picked in 40- to 50-lb buckets and placed in bins, where a truck takes them to a packing shed. An alternative harvesting operation consists of a conveyor belt. Pickers in the field travel a few feet to the conveyor belt where the cucumbers are placed and conveyed into a loading truck. Bruising of fruit from excessive handling and unloading is significantly reduced with the conveyor belt. Simpler harvesting aids, including hand carts to hold picking containers also improve harvest labor efficiency. Cucumbers should be kept in the shade until taken to the packinghouse where they may be hydrocooled, washed, sorted, graded, sized, packed, unitized for shipment, and shipped to their destination market. For maximum shelf-life, cucumbers should be pre-cooled after harvest at a 50F (10C). For maximum harvest efficiency, instruct the field crew to handle vines carefully during picking so that later fruit can size properly, harvest only when the vines are dry to prevent the spread of diseases, and remove larger fruits from the vine to prevent the drainage of plant resources into these unmarketable fruits.

          Washing

 Wash water management practices should be an important consideration during the handlin process to prevent the spread of postharvest diseases. Decayed fruit should be culled to eliminate potential sources of inocolum. Wash water is chlorinated at 150 ppm, and fruits are held in this water for no longer than two minutes in a single layer of floating cucumbers.

   Packing 

      

 
 

 In the continental U.S. cucumbers are often waxed with one of many commercially available formulations. Water loss may reduce 50% of fruit weight in non-waxed compared to waxed fruit. Shrink-wrapping with polyethelene film, a common practice with greenhouse European cucumber, also extends fruit shelf life by preventing water loss. Cucumbers are normally sold in 55-lb cartons or wirebound crates. U.S. Fancy cucumbers have a maximum diameter of 2 3/8 inch and minimum length of 6 inches with a straight shape and very little tapering. Important postharvest diseases in cucumbers exposed to anaerobic conditions or to poor ventilation include soft rot, Erwinia carotovora; bacterial spot, Pseudomonas lachyrmans; Pythium aphanidermatum, and Colletotrichum lagenarium.

     Storage

      

   Recommended storage for cucumbers include temperatures between 50-55F (10-13C) and 90-95 relative humidity. Average storage life is 10-14 days. At storage temperatures above 55F (13C) the fruit will ripen and turn from deep green to yellow. Chilling injury occurs when fruit is held below 50 F (10C) for two days or longer. Cucumbers are compatible in storage with such crops as eggplant, grapefruit, limes, potatoes, and other cucurbits but are not compatible with ethylene-producing fruits such as apples, tomatoes, bananas, and muskmelons.