Honeydew Melon

The maturity of honeydew melons at time of harvest is critical to the eating quality, as the sugar content of honeydew does not significantly increase after harvest. Conditioning or ripening these melons with ethylene will not make them sweeter; however there are benefits to ethylene exposure, including improved aroma, color and softening.

The degree of maturity will indicate whether the melon should be exposed to ethylene. Melons which are fully mature at harvest (with white surfaces, hard to springy blossom ends, skin with very little wax or fuzz) should not be treated with ethylene if they are to be stored for an extended period of time. Melons of minimum commercial maturity (well filled-out, have a white color with a greenish tint, blossom ends that are hard to firm, have no aroma and a skin that is not waxy but is slightly fuzzy) will benefit from a treatment of ethylene.

Ripening protocol:

To begin ripening, bring honeydew pulp temperature to 68 – 77°F (20 – 25°C).

Apply 100-150 ppm ethylene for 24-48 hours during the initial phase of the ripening cycle. To achieve this, the generator setting will depend on the size of the ripening room.

  • Setting 1 for rooms 1600 – 2500 cubic feet.
  • Setting 2 for rooms 2500 – 5000 cubic feet.
  • Setting 3 for rooms 5000 – 7500 cubic feet.
  • Setting 4 for rooms 7500 – 10000+ cubic feet.

Please note that all rooms vary in terms of how air-tight they are, so if more precise PPM determination is required, air testing for ethylene PPM levels is recommended.

Note: If using a Sure-Ripe® generator, this unit will convert 1 US quart of Ethy-Gen® II to ethylene in approximately 12 hours. This will be enough ethylene for 1 ripening cycle depending on the size and condition of the room.Use our generators in rooms of 1600 ft3 or more (45 m3).

Carbon dioxide will build up during ripening. If no automatic ventilation system is in place, then be sure to vent the room approximately every 12 hours by opening the doors for 20 minutes even while applying ethylene. The actual CO2 level must be kept below 1% for proper ripening.

Maintain humidity at 90% to prevent shrinkage during ripening.

Once melons lose most of their greenish tint, have no noticeable peel fuzz and emit an aroma, they are producing their own ethylene and no longer need external ethylene.

Melon storage temperature is dictated by the degree of ripeness:

  • Unripe: 45 – 50°F (7.5 – 10°C)
  • Slightly ripe: 41 – 45°F (5 – 7.5°C)
  • Ripe: 36 – 41°F (2.5 – 5°C).

Note that storing less ripe fruits below 41°F (5°C) may result in chilling injury. If unsure about the degree of ripeness, store melons at the warmer temperature ranges to avoid chill damage.


Some of these recommendations are adapted from “Optimum Procedures for Ripening Melons” by Marita Cantwell, University of California / Davis. For more information on Melons and other fruits, please visit the web site of UC Davis. A great resource for any Fruit Ripener is a publication from UC Davis entitled “Fruit Ripening & Ethylene Management”. Click this link for more information.

These recommendations are provided by and for the use of clients of Catalytic Generators, LLC. While we have made great effort to provide accurate and current ripening techniques, Catalytic Generators makes no warranties regarding these recommendations or the applicability of such information to a particular ripening operation. Please note that we do not provide these recommendations as a replacement for technical ripening experts; if having ripening problems or starting a ripening program, we suggest that professionals be consulted.