Last revised February 11, 2010
TYPES AND VARIETIES
The currently accepted protocol is to divide all melons into two categories -- melons and watermelons. Melon fruit show extreme variations from the common muskmelon, sometimes looking more like an orange, banana, or cucumber! Fruit may be oval, oblong or very long and slender. They may vary in length from three or four inches to more than three feet (snake cucumber-which is really a melon). The surface may be white, grayish green, golden yellow, orange or black! It may be sutured (ribbed or grooved), smooth, or netted (covered with a network of corky tissue). When it occurs, netting may be rope-like and prominent or flat-surfaced, fine, and less conspicuous. The flesh may be white, green, salmon pink or orange. It may be sweet, aromatic, spicy, bland, or a combination of these.
Left: (top to bottom) Honeydew, Canteloupe and Casaba. Photo credit: Bill Mansour, Oregon State University
Right: Charentais Melons. Photo credits: Bill Mansour, Oregon State University
Although all melons are classified as Cucumis melo, several "botanical" or "varietal" subdivisions are recognized. Some of these are:
C. melo var. cantaloupensis (true cantaloupes) are not commonly grown in the U.S.A. They have deeply grooved fruit with a hard, warty or scaly rind and orange or green flesh.
C. melo var. reticulatus are the netted, aromatic melons (muskmelons) and Persian melons.
C. melo var. inodorous include casabas, crenshaws, honeydews, and the late-maturing winter melons.
C. melo var. flexuosus, the snake melon.
C. melo var. conomon, the Oriental pickling melon.
Following are commonly used commercial descriptions. Muskmelons (approx. 70 days from transplanting in the lower Columbia Basin, 75 days in the Willamette Valley) are classified as eastern types or western shipping types.
Eastern type muskmelons: Round to oval, usually sutured, netted rind with sweet orange flesh, not intended for long-distance shipping; Early: Superstar, Earlisweet. For trial: Earliqueen, Earlidawn, Northern Queen, Supermarket. Main season: Saticoy Hybrid, Gold Star, Roadside, Supermarket, Canada Gem, Summet, Pulsar, Eastern Star, Burpee Hybrid Improved, Harper Hybrid, Classic, Fruit Punch, Ambrosia. Green-fleshed, for trial: Passport F1, Rocky Sweet F1.
Western shipping type muskmelons (often called cantaloupe): Round to slightly oval, sutureless, very well netted, with firm, salmon-colored, sweet flesh: Hy-Mark, Top Mark. For Trial: Pulsar, Magnum 45, Durango (sulfur tolerant) Top Score, Starship, Performer, Otero, Easy Rider, and many others.
Long Shelf-Life Melons: Sunseeds has recently developed a series of Western shipping type muskmelons with long shelf life. These melons hold their sugar content in the field, during shipping, and in the market. Varieties for trial: Voyager I (midseason medium size), Voyager II (very large), Voyager III (medium size).
Many muskmelon varieties are sensitive to air pollution (ozone, sulfur dioxide and sulfur trioxide), as well as to applied sulfur (for disease control). This sensitivity is cultivar dependent: Sensitive cultivars are Harper Hybrid, Gold Star and many others. Tolerant cultivars are Top Mark, Durango and Otero.
Honey Dew (approximately 110 days in the Columbia Basin): Smooth, greenish-white rind, turning creamy when ripe. Light green, sweet flesh with some orange-fleshed varieties available. Fruit 7" x 7.5", 5-6 lb: Earlidew, Honeybrew, Honey Dew Green Flesh, TAM Dew. For trial: Honey Dew Orange Flesh.
Casaba (approximately 110 days in the Columbia Basin): non-slip, late maturing, corrugated bright yellow, sometimes greenish-yellow rind, not netted or ribbed. With white, spicy, sweet and tender flesh. Fruit acorn-shaped, 8" x 7", 7-8 lb: Casaba Golden Beauty, Casaba Sungold (earliest of the casaba types).
Crenshaw (approximately 110 days in the Columbia Basin): Large, late maturing, yellow and green corrugated, rough rind without netting. Pinkish-orange, sweet, tender flesh with distinctive flavor. Fruit is elongated with a flattened stem end (elongated acorn-shape), 9" x 7", 7-10 lb: Crenshaw, Early Hybrid Crenshaw, Crenshaw Blanco, Golden Crenshaw. For trial: Carnival (early hybrid).
Canary (approximately 110 days in the Columbia Basin): Late maturing, bright yellow corrugated rind. Flesh is pale green to white with a pale orange seed cavity, sweet and a distinctive flavor. Fruit is oval, similar to crenshaw, 8" x 6", 6-7 lb: Sweet Yellow Canary, Tenerife. For trial: Gold King.
Santa Claus (approximately 110 days in the Columbia Basin). Very similar to "Canary" except rind in mottled green and yellow. The name is derived from the long keeping qualities of this melon... until Christmas?! "Santa Claus" is also the variety name.
Charentais (approximately 90 days): A popular European melon, also called "Chaca" "French" or "Italian melon". Smooth or slightly netted, gray-green rind with dark green, slightly furrowed sutures. Deep orange, firm, sweet flesh. Fruit is slightly elongated but mostly globe shaped 3.5"-4" and 1.5-2 lb. Mainly for greenhouse production, but also grown under plastic tunnels or in the open field: Acor F1 and Alienor F1 (both monoecious and resistant to Fusarium races 0,1 and 2); Charentais Improved, Ido, Panchito (netted rind).
Mediterranean (approximately 110 days): Green rind with slight netting and not sutures, ripening to yellow-gold with some green splotches. Flesh is soft, white, with a touch of pink around the seed cavity when ripe. Fruit oval 6.5" x 7.5", 5-5.5 lb: Casablanca.
Persian (approximately 110 days in the Columbia Basin) : Very late maturity, green rind with slight tan cracks or sparse netting. Orange-pink, sweet, firm flesh. Fruit is round 7.5" x 8", 5-6 lb.
Ogen (or Gallicum types; approximately 100 days): Melons: 3-5 lb round, netted and sutureless. Green, sweet, highly aromatic flesh, rind turns golden yellow as the melon matures. Susceptible to Fusarium wilt. This melon will "slip" like cantaloupe does, and resists splitting during periods of rainy weather: Galia, Gallicum. Also for trial: Haogen, Makdimmon (also called Mediterranean Delight).
Rochet (approximately 100 days): Oval, green rind slightly netted, flesh is greenish-white, sweet and aromatic): Solo (4-5 lb); Toledo (also called frog skin type due to the greenish-yellow rind with dark green blotches), Verdol F1 (dark-green skin slightly netted and crisp, white, sweet flesh (resistant to Fusarium races 0,1 and 2; also referred to as Spanish type).
Chinese "Hami" melon (approximately 110 days in the Columbia Basin): "Hami" is the generic Chinese word for a group of crisp-fleshed "winter" melons. Hami melons may have either red-pink, salmon, white, or green flesh. One group is slightly longer than a football but smaller in diameter (resembles Rochet type). These have yellow, or yellow and green rind, usually slightly netted, and weigh 6-9 lb. The flesh is crisp and very sweet. These melons may be stored for several weeks to a few months with little quality loss. In China, these are even allowed to dry partially for use late into the fall and early winter (Similar to Santa Clause melon). These appear to also be particularly suited for frozen melon balls. Some popular varieties are: Red-Pink Hami, Tiger-Skin Hami.
Round-type Chinese Hami: Snow Charm (better adapted to cooler areas. Fruit can reach very large size (10-12 lb but more commonly 3-4 lb), globe shaped, white to light yellow smooth rind, light-orange to pink flesh, crisp texture, sweet; excellent frozen.
Japanese melons (approximately 100 days): This type generally refers to the high-priced greenhouse grown gift melon found in Japan, but grown in the field in the warmer parts of Oregon. These melons are round or slightly oval, very sweet, about 7"-8", 3-4 lb extremely well-netted green rind. Fruit is non-slipping when ripe: Tokyo King, (the classic Japanese type, white-fleshed); Emerald Jewel (green-fleshed); Emerald Pearl (green, crunchy, sweet flesh), Ginryu and Zuikoh (both have sweet, green flesh; excellent frozen).
Left: Persian Melon
Right: 'Snow Charm' Hami Melon. Photo credits: Bill Mansour, Oregon State Unversity
SOILS AND SITE SELECTION
Choose light, well-drained soils for earliest crops and reduced risk of stand establishment problems. Avoid using fields in your rotation in which muskmelons, watermelons, pumpkins, squash cucumbers or other Cucurbits have been planted.
Direct seed melons when soil temperatures exceed 65 F. Set transplants only after all danger of frost has passed or use appropriate protective structures or covers (see item on row covers below). Approximate dates are:
Western Oregon: Begin direct seeding in the middle of May.
Eastern Oregon: Begin direct seeding from April 10 to May 5.
Seed at a rate of 4 seeds per foot and thin to 18 inches Plant the seed 1 inch deep, and space the rows 5-6 feet apart. This will require 3-4 lb/acre of seed. Avoid excessively high plant populations that may reduce sugar content of fruit. Allow at least 6 sq. ft. of leaf area/plant for maximum sugar production.
The use of transplants is recommended for western Oregon, and for early production in eastern Oregon. Transplant production requires 4 to 5 weeks under proper greenhouse conditions.
SEED AND SEED TREATMENT
Muskmelon seed numbers approximately 19,200 per pound. Use fungicide treated seed. Muskmelons are sensitive to damping off, especially under cool, wet soil conditions.
The minimum soil temperature required for germination of these crops is 60 F, with the optimum range between 70 to 95 F.
FLOWERING AND POLLINATION
Depending on cultivar, muskmelon plants may bear separate male and female flowers on the same plant (monoecious), which is typical of elongated-fruit varieties. Most American round-fruited cultivars bear male and perfect flowers (male and female organs in the same flower) flowers on the same plant (andromonoecious).
Young plants begin bearing male flowers and do so all through flowering. Depending on the cultivar, perfect flowers, or female flowers, which are fewer in number, begin appearing 1 to 2 weeks after initiation of the male flowers and are found only on branch runners.
Bees transfer pollen from male flowers to the female flowers, making fruit set possible. Melons are not pollinated by wind, and since melon pollen is heavy and sticky, even those varieties that have perfect flowers, need bees for adequate pollination. It is recommended that at least one honey bee colony be introduced for every acre during the blooming period since native bee populations may not be adequate, or may not coincide properly with the blooming period. Research in California indicates that "a higher quality marketable crop results (50 crates per acre increase with two colonies; 100 crates per acre with three colonies)". Furthermore, "the harvest period was advanced a week or more and shortened by one week, reducing the pickings necessary by 33%."
Placement of colonies in the field has an effect on the number of bee visits per flower. Visits per flower were more than doubled with colonies spaced no more than 175 yards apart in comparison with colonies placed at only one spot in a (40 acre) field. At no time should any portion of a field be more than 250 yards from a bee hive. Avoid using insecticides injurious to bees and manage application of pesticides in a manner to protect bees and apiaries from injury.
Gibberellic acid (GA) is labelled for stimulation of fruit set in muskmelon during periods of cool temperatures. The rate is 2 g ai/acre in sufficient water to obtain thorough foliage coverage. The label calls for one application before bloom followed by two more applications at intervals of 10-14 days. Caution: The efficacy of GA applications for fruit set in melons has not been confirmed by research in the Pacific Northwest.
Use windbreaks as necessary especially in eastern Oregon. Grain windbreaks have been found effective when grain rows are used for each melon row. Winter wheat varieties, rye, or oats can be used. Spring barley may be used for February plantings. Seed grain thickly, 2-3 seeds per inch. This requires about 10 lb barley, 9 lb wheat, or 8 lb rye to seed grain rows 12 feet apart.
Windbreaks may be cultivated out after the melon plants are well established. If they are not, windbreaks should not be allowed to touch the plants because abrasion of the enlarging fruit can cause that fruit to be misshapen. Windbreaks may be cut off or rototilled around June 25, before melon vines develop long runners that may be damaged by tractor tires.
GROUND MULCH AND ROW COVERS
Black plastic ground mulch controls weeds, may increase soil temperature, conserves moisture, and protects fruit from ground rots. Mulch increases yield and earliness and is recommended particularly in Western Oregon where temperatures are limiting. For black plastic mulch to increase soil temperature, it is critical that the soil surface be smooth and that the plastic be in close contact with the soil. This can only be achieved by laying the plastic with machines specifically designed and adjusted for this task. Clear plastic mulch is excellent for transferring heat to the soil but does not control weeds.
A new generation of plastic mulch films allows for good weed control together with soil warming that is intermediate between black plastic and clear film. These films are called IRT (infrared-transmitting) or wavelength-selective films. They are more expensive than black or clear films, but appear to be cost effective where soil warming is important.
Plastic, spunbonded, and non-woven materials have been developed as crop covers for use as windbreaks, for frost protection, and to enhance yield and earliness. They complement the use of plastic mulch and drip irrigation in many crops.
Non-woven or spunbonded polyester and perforated polyethylene row covers may be used for 4 to 8 weeks immediately after transplanting. Covers should be removed when plants begin to flower to allow proper pollination. Row covers increase heat unit accumulation by 2 to 3 times over ambient. Two to four degrees of frost protection may also be obtained at night. Soil temperatures and root growth are also increased under row covers as are early yields, and in many cases, total yields.
Row covers may be replaced after pollination is completed (after 3-5 fruits per plant have been pollinated) to further enhance earliness. However, some abrasion of fruit may occur if the covers are allowed to be in contact with the plants.
Preliminary research in California indicates that soil-supported covers or mini-tunnels have been used to promote early production of some crops. Similar to hoop-supported tunnels, these increase soil and air temperature around the plants, maintain surface soil moisture, and prevent crusting. They may also provide about 7 days advantage in earliness and harvest season, depending on crop and time of planting.
Soil to form the sides of the tunnel is brought from the sides of the plant row, which may be direct seeded or transplanted at the same time, or prior to tunnel installation. A modified bedshaper is used to form a ridge on each side of the plant row, leaving a suitable area for planting. A 36-inch-wide piece of embossed clear plastic is then used to cover the plant row, leaving a 5 to 6 inch-high space between the planted row and the plastic cover.
Mean temperatures may be increased 10-20 F depending on time of planting and sunlight availability and intensity. Care should be exercised that crops are not damaged from excessive heat. Covers should be removed from most crops when temperatures under the cover exceed 90 F for more than three consecutive days.
For the most current advice, see Nutrient Management for Sustainable Vegetable Cropping Systems in Western Oregon, available as a free download from the OSU Extension Catalog
Good management practices are essential if optimum fertilizer responses are to be realized. These practices include use of recommended varieties, selection of adapted soils, weed control, disease and insect control, good seed bed preparation, proper seeding methods, and timely harvest.
Because of the influence of soil type, climatic conditions, and other cultural practices, crop response from fertilizer may not always be accurately predicted. Soil test results, field experience, and knowledge of specific crop requirements help determine the nutrients needed and the rate of application.
The fertilizer program should insure adequate levels of all nutrients. Optimum fertilization is essential for top quality, yields, and returns.
Recommended soil sampling procedures should be followed in order to estimate fertilizer needs. The OSU Extension Service agent in your county can provide you with soil sampling instructions and soil sample bags and information sheets.
Recommendations are based on a row spacing of 60 inches. With decreased row spacings fertilizer rates should be increased.
Rates of 80 to 150 lb N/A are suggested with the lower rates of N being applied when legumes were grown the preceding year or a legume or mixed legume-cereal green manure crop is incorporated into the soil before planting. Apply one-half the nitrogen at or just prior to planting and the rest when vines begin to "run".
If the application of N plus potash (K2O) exceeds 50 lb/A, there is danger of seedling injury from the concentration of salt when fertilizer is banded at planting time.
There is less danger if the band application is split into two bands. The danger is aggravated as the band comes closer to the seed. The danger is greater with sandy than with finer textured soil. Immediate irrigation at the first sign of burn should reduce further injury. There is more possibility of damage to seedlings on acid soils where the pH is below 5.5.
Phosphorus fertilizer should be banded at planting for vigorous early seedling growth. Bands should be located 2" to the side and 2" below the seed.
If the soil test* for P reads (ppm):
Apply this amount of phosphate (P2O5) (lb/A):
|0 to 15
|15 to 60
*Assumes extraction procedures similar to those used by the OSU Central Analytical Laboratory. Specific information on soil test procedures is available from the Dept. of Crop and Soil Science.
Potassium should be applied before planting or banded at planting time. Amounts above 40 lb K2O/A should be broadcast and worked into the seedbed. See statements on fertilizer banding under "NITROGEN".
If the soil test* for K reads (ppm):
Apply this amount of potash K2O (lb/A):
|0 to 75
|75 to 150
|150 to 200
*Assumes extraction procedures similar to those used by the OSU Central Analytical Laboratory. Specific information on soil test procedures is available from the Dept. of Crop and Soil Science.
Include 20-30 lb S/A in the annual fertilizer program for vine crops. S is sometimes contained in fertilizers used to supply other nutrients such as N, P, and K but may not be present in sufficient quantity.
Plants absorb S in the form of sulfate. Fertilizer materials supply sulfur in the form of sulfate and elemental S. Elemental S must convert to sulfate in the soil before the S becomes avail able to plants. The conversion of elemental S to sulfate is usually rapid for fine ground (less than 40 mesh) material in warm moist soil.
Sulfur in the sulfate form can be applied at planting time. Some S fertilizer materials such as elemental S and ammonium sulfate have an acidifying effect on soil.
CAUTION: Many muskmelon and specialty melons are sensitive to foliar applications of sulfur used to control a number of foliar diseases. This sensitivity is cultivar dependent. A number of varieties resistant to sulfur-induced foliar damage are available. Applications of foliar sulfur to non-resistant varieties can result in severe foliar damage.
When the soil test value is below 1.5 meq Mg/100g of soil or when calcium (Ca) is ten times more than the Mg, apply 10-15 lb Mg/A banded at planting. If Mg deficiency symptoms appear, spray with 10 lb Epsom salts in 100 gal water/A.
Magnesium can also be supplied in dolomite, which is a liming material and will reduce soil acidity. Dolomite should be incorporated into the seedbed at the rate of 1-1.5 T/A.
In general, boron deficiencies are uncommon. If the soil test value for B is less than 1 ppm, an application of 3 lb B/A is suggested. Boron should be applied uniformly to the field as a spray or broadcast. Never band B fertilizer.
Zinc deficiencies are uncommon in Willamette Valley soils. When the soil test is below 1 ppm Zn, a response to Zn is expected and 4 lb Zn/A should be included in the fertilizer band.
Muskmelons are sensitive to soil acidity. Maintain soil pH above 6.0 by liming. Soil pH levels below 5.5 can result in manganese toxicity (leaf levels of above 800 ppm Mn may be toxic). Lime applications are suggested when the soil pH is 5.6 or below, or when calcium (Ca) levels are below 5 meq Ca/100g of soil.
The rate of lime application can be estimated from the following SMP buffer table.
If the SMP buffer* test for lime reads:
Apply this amount of lime (T/A):
|5.2 - 5.6
|5.6 - 5.9
|5.9 - 6.2
*Assumes extraction procedures similar to those used by the OSU Central Analytical Laboratory. Specific information on soil test procedures is available from the Dept. of Crop and Soil Science. The liming rate is based on 100-score lime.
Lime should be mixed into the soil at least several weeks before planting. A lime application is effective over several years.
Some soils may have a fairly high SMP buffer value (over 6.5) and a low pH (below 5.5). This condition can be caused by the application of acidifying fertilizer. In this case the low pH value is temporary and the pH of the soil will increase as the fertilizer completes its reaction with the soil. This temporary "active" acidity from fertilizer is encountered following recent applications of most N fertilizer materials. Acidifying fertilizers also have a "long term" acidifying effect on soil that is cumulative and leads to lower SMP buffer readings.
Sandy soils to which fertilizers have not been recently applied sometimes record low pH and high SMP buffer values. In such cases, a light application of 1-2 T/A of lime should suffice to neutralize soil acidity.
For acid soils low in Mg (less than 0.8 meq Mg/100g of soil), 1 T/A of dolomite lime can be used as a Mg source. Dolomite and ground lime stone have about the same ability to neutralize soil acidity.
The possibility of seedling injury from the band application of fertilizer is less when the soil pH is 5.6 or above. Some Willamette Valley experiments have shown decreased uptake of phosphorus from band applications of phosphorus when the pH approaches 5.5.
Lime applications should be broadcast, preferably in the fall, and incorporated into the seedbed. Do not plow lime down leaving the surface soil unlimed.
These fertilizer recommendations are based on research conducted by OSU Horticulture and Crop and Soil Science Department faculty, and are quoted from OSU Fertilizer Guide FG 68.
Avoid excessive soil moisture. The soluble solids content may be reduced when muskmelons are grown under unusually heavy rainfall and/or poor water drainage conditions. As might be expected, the effect of soil moisture on sugar content of muskmelon is particularly serious when prolonged periods of saturated or near-saturated soil moisture occur during the final stages of fruit development. Other conditions that limit photosynthesis during this time would accentuate the excessive moisture effect on muskmelon quality. This effect may differ with variety; thus growers should select less responsive varieties when excessive soil moisture may be a problem. Planting on beds is recommended for soils with potential drainage problems, and reduce irrigations after fruit begins to mature. Approximate summer irrigation needs for the Hermiston area are: 3.5 inches in May, 5.0 in June, 7.5 in July, and 7.0 in August.
Research has shown that the use of drip irrigation under black plastic mulch is superior to sprinkler irrigation with black plastic mulch. Yields usually increase dramatically. This was true of 10 of 13 varieties tested, and particularly true of later-maturing types.
Soil type does not affect the amount of total water needed, but does dictate frequency of water application. Lighter soils need more frequent water applications, but less water applied per application.
Melons are often grown with furrow irrigation in eastern Oregon. Water soluble polyacrylamide (PAM) is useful for flocculating soil particles in irrigation furrows and reducing erosion of soil from the furrow.
HARVESTING, HANDLING, AND STORAGE
Good yields of large (4-6 lb) melons will range from 7000 to 9000 fruit per acre. Smaller fruited (3-4 lb) varieties will range from 12,000 to 15,000 fruit per acre assuming excellent cultural practices and pollination.
Muskmelon yields in California are reported as 450 to 750 cartons/acre, or about 200 to 250 cwt/acre. Honeydew yields range from 175 to 250 cwt/acre and Persian melon yields are reported at about 120 to 150 cwt/acre.
When using appropriate plasticulture techniques, eastern muskmelon yields of 8000-9000 fruit/acre at 4-6 lb/fruit and western muskmelon yields of 12,000 to 15,000 fruit/acre at 3-4 lb/fruit, have been reported.
These melons should be firm, well netted, well formed and pulled at full slip for best quality. "Full slip" is the stage of ripeness at which the melon comes away easily from the stem attachment and where the skin begins to take on a slightly yellow appearance under the netting. For distant shipment, less mature cantaloupes are picked at "half slip" but when the stem attachment area is smooth, rounded and slightly depressed. During the early part of the season harvest every other day. Later in the season, daily picking is best. Some varieties are non-slip types and have to be cut from the vine.
Muskmelons develop their highest dessert quality a day or more after harvest, even though the sugar content does not increase. Therefore, muskmelons attain their highest quality in fruits that have been harvested when they have reached their maximum sugar content. U.S.D.A. grade 1 melons must have a minimum soluble solids level of 8% however a sugar level of 10% is considered a minimum level for good eating quality. Melons for local market sales should have sugar levels of 12-14%. These high sugar levels, obtained from harvesting muskmelons at a more mature stage, result in lower shelf life in muskmelons intended for long distance shipping.
Maintain healthy, green foliage until final harvest. The edible quality of muskmelons is frequently undesirable, particularly those harvested the last half of the picking season, because the sugar-producing (photosynthetic) potential of the leaves is not maintained through harvest. Drought, nutrient deficiencies, and weed, insect, and disease stresses can seriously limit the plant's capacity to produce and translocate sugars to developing fruit. Almost half of the final concentration of sugars is accumulated during the last week of fruit maturation. During this "critical" few days, the fruit passes from immature green to ripe (full slip). Thus, spray programs, irrigations, and nutrient supply must be maintained to "keep the plant going" during this critical last week. Plants are naturally weakened and more susceptible to moisture, nutrient, and biological stresses during heavy fruiting. Neglect at this time can seriously reduce fruit quality. Disease-resistant varieties should be used where possible to help maintain healthy foliage for a longer period for maximum sugar production.
After melons have been picked, they should be placed in the shade or in a cold room and handled carefully.
STORAGE (Quoted or modified from USDA Ag. Handbook 66 and other sources)
Hold melons temporarily at 36 to 41 F and 95 % relative humidity. Cold storage is little used for melons except to avoid temporary adverse market conditions.
Muskmelons harvested at the hard-ripe stage (3/4 to full-slip) can be held about 15 days at 36 to 41 F, but lower temperatures for this period may cause chilling. Symptoms of chilling injury are pitting and surface decay.
Full-slip melons are more resistant to chilling injury and can be held 5 to 14 days at 32 to 36 F. Soluble solid content of muskmelon at harvest should be at least 10 % for good dessert quality. Muskmelons ripen after harvest but do not increase in sugar content.
Muskmelons need precooling soon after harvest to reduce high field temperatures. In some packing sheds, muskmelons are first dipped in hot, water to cleanup surface bacteria. Research indicates that muskmelons dipped in 140 F water for 3 minutes, dried quickly then wrapped in plastic film, sealed in shipping boxes, and cooled to 40 F can be stored in cold storage for up to 7 weeks. Chlorination of the hot water has not been shown to add any benefit. Warm, wet melons are subject to invasion by micro-organisms. Therefore drying and cooling should immediately follow this treatment. Melons treated in this way, and stored for extended periods have a shortened shelf life (3-4 days) after removal from storage.
Cooling can be done with cold water, cold air, or ice. The choice depends primarily on economic factors and type of container. Hydrocooling is the most efficient method for rapidly cooling muskmelons, and they should be cooled to at least 50 F. Crushed ice is still used to remove field heat from muskmelons. Cooled melons should be stored in a cold room and shipped in refrigerated trucks.
Ice is blown in between rows of crates or waxed cartons and over a load packed for shipment. Although melons are chilling sensitive, they are not injured by extended contact with ice.
Research has also shown that desiccation in shipping is a major cause of loss in quality. Film wrapping has been shown to markedly increase shelf life and this should be considered for melons intended for long distance shipping.
Honeydew, Casaba, Crenshaw, and Persian melons:
Honeydew melons should be harvested when the stem end is slightly springy and the skin begins to take on a creamy yellow appearance. Crenshaw melons are picked when the blossom end begins to soften and the skin is golden yellow and green. The flesh should be a golden pink. Casabas are ready for harvest when the skin is slightly golden and the flesh is white. Persian melons when ripe have a skin that begins to turn a mauve color under the net, the blossom ends begins to soften and the flesh has a tinge of orange.
These melons are chilling sensitive and should not be held below 40 F. The best prolonged holding temperature is 45 F for Honey Dew, Crenshaw, and Persian melons, and 50 F for Casaba melons. The crenshaw and Persian melons should keep for 2 weeks, and Honey Dew and Casaba melons for 3 weeks, before the quality of the ripened melons becomes unacceptable. These melons may keep longer, but with extended holding, the may fail to ripen or may ripen but fail to develop the desirable flavor and aroma.
When these melons are stored too long or at too low a temperature, they deteriorate (decay, surface breakdown, softening, or off-flavors) so rapidly upon transfer to room temperature that they soon become worthless. Honey Dew melons are less perishable than most other melons. Storage at as high as 65 F has been recommended for them.
Honeydew melons are usually given an 18 to 24-hour ethylene treatment (5000 ppm) to ripen uniformly. Other concentrations (40 to 1000 ppm) have proved effective experimentally. Pulp temperature should be 68 or above during treatment. Honey Dew melons must be mature when harvested; immature melons fail to ripen even if treated with ethylene. Honeydew melons are less sensitive to chilling injury as the fruit ripens, and a 24-hour treatment with 1000 ppm ethylene will ripen the fruit sufficiently to make it less sensitive to chilling injury.
Dipping melons (muskmelons - see above) for 3 minutes in hot water (138- 140 F) has been reported to reduce stem-scar and surface molds, and extend shelf life, and may be useful with these types.
Muskmelons are commonly packaged in 38 to 41-lb half-cartons containing 9, 12, 18 or 23 melons; 53 to 55-lb two-thirds cartons, packed 12, 14, 18, 24, or 30 melons; 80 to 85- lb jumbo crates, packed 18-45 melons; 70-lb standard crates; or 45 to 50-lb half wirebound crates.