Melons, Cantaloupes

Cucumis melo (Cucurbitaceae or cucumber family)

Production

Soil preparation

Melons should not follow after other cucurbits or nightshades, but they follow well after cole crops, leguminous green manures or sweet corn.
Total nutrient uptake is 158 lbs. of N, 27 lbs. of P and 155 lbs. of K.
Apply compost and other amendments based on the results of a soil test.
Spread lime as needed to increase both the pH and Ca levels. Dolomite lime will also increase Mg levels. Spread gypsum when calcium levels are low but pH is correct.
Incorporate compost and other amendments, and plant melons on high raised beds covered with plastic mulch.
Where phytophthora (phytophthora capsici) is an issue, rotate away from this land. Biofumigation has shown some effectiveness to reduce incidences.

Common recommended fertilizer rates¹

Nitrogen	Phosphorus	Potassium	pH
100	0-160	0-160	6.0-6.4
¹Rates are for New York and are from Cornell University’s Nutrient Guidelines for Commercial Vegetable Production (2019). Check the Cornell website for updated guidelines, or consult with local experts for recommended rates outside New York.

Indiana variety trial
Athena is still the most popular variety among organic growers.

Greenhouse guidelines

EZ Seeder seeding plate #5
If starting melons early in the season, germinate seeds in a germination chamber, unless you can keep your greenhouse warm both day and night. Germination improves greatly at optimum temperatures.
Grow melons in a 1020 tray with 24 cells if you want more flexibility at planting time. Melons in a 38-cell tray can get leggy when left too long in the greenhouse.

Cell pack tray	Germination temp	Growth temp	Hardening off	Notes
24 or 38	80°–90°	75°	Reduce water and temperature for 1 week.	Put plug trays on a wire mesh bench to encourage air pruning. Plants should be ready for transplanting within 4 weeks.

Number of successions

Start seedlings 3 weeks before the last frost date. Plant a short-season variety.
The number of successions is based on the willingness to risk a crop loss due to downy mildew. In the Northeast, downy mildew pressure is highest from the middle of July through August. So far, there are no downy-mildew-resistant cantaloupe varieties.
For continuous harvest, the next successions are planted on a 10- to 14-day schedule until 2 ½ months before the first frost.

Transplant readiness indicators

Harden plants off outside; plants that are lush don’t perform well in the field.

Transplant tips

Transplant in the field when plants have enough of a root ball to hold the soil in the pot or cell pack together. When they can’t, their roots will be damaged and the plants have a higher fatality rate.
Lay plastic mulch at least a week before planting to allow weed seeds to germinate and the soil to warm. Use infrared transmitting (IRT) mulch for early plantings. Planting on the same day as laying plastic will cause weed pressure in the planting hole.
Avoid transplanting in plastic mulch during the heat of a hot summer day. The heat of the plastic can cause damage to the young seedlings. To avoid burning the young plants, transplant in the evening, use stocky transplants and water deeply. If planting by hand, water plants with a watering can. Avoid applying row covers in hot conditions. When hot weather is expected after transplanting, only use insect cover for protection.
To help resist cucumber beetle damage, dissolve Kaolin clay (as in Surround) in plenty of water and drench the complete tray in the solution before transplanting.

Water wheel transplanter

Rows	In-row spacing	Planting depth (inches)	Notes
1	12 inches	Normal	Add kelp to water as a 0.5% solution in the water wheel planter. Use wider in-row spacing for later plantings.

Cultivation procedures

When using plasticulture, plant at least a week after laying the plastic mulch to allow weeds to germinate under the plastic. Use IRT plastic to warm the soil earlier in the season.
After transplanting, cultivate once or twice between plastic with a rolling cultivator or Spyder. Cover the wheel tracks with rye straw at a rate of 3 lbs. per foot. (One 600 lb. round bale covers 200 feet of wheel track.) Increase this amount when using an early cutting of orchard grass because hay breaks down much faster than straw. Over time, hay and straw mulch will release a significant amount of K and other beneficial properties like silicon, contributing to long-term soil health. Mulching also protects crops from soil splashing. This reduces soilborne diseases and time spent cleaning produce after harvest.

Deer, frost, disease and insect protection

Plant early plantings downwind from later varieties, as both powdery and downy mildew are windborne.
For your earliest plantings, use floating row covers to protect against frost and striped cucumber beetles. For varieties that require pollination, remove the covers at flowering. Use 10-gauge wire to support the row cover, since abrasion against the cover will damage the plants. If frost protection or providing a warm environment isn’t necessary, you can use the longer-lasting insect covers to provide protection against beetles.
Powdery mildew: The best way to avoid losses from powdery mildew is to use tolerant or resistant varieties. Powdery mildew can be somewhat controlled with a mixture of Bacillus subtilis, as in CEASE, and potassium bicarbonate, as in MilStop SP. Sulfur causes phytotoxicity in melons, so be careful if you’re applying sulfur in any form to control powdery mildew. Also, consider using tolerant or resistant varieties. A full list of OMRI-listed control products on powdery mildew is available from CALS.
Downy mildew can be somewhat controlled with the biological Pseudomonas aeruginosa, as in Zonix. Also, consider using tolerant or resistant varieties.
To prevent deer damage, build a temporary fence using 4-foot fiberglass posts and attach 1 clearly visible wire like IntelliTape at about knee height. Build a second fence inside the first fence, but attach 2 wires or twine whereby the top line is about 7-feet tall. Deer don’t have very good depth perception and won’t attempt to jump this fence without checking out the first fence, so electrifying the second fence is often not needed. Bait the outside deer fence with peanut butter and electrify it. Make sure you build the fences, bait and electrify on the same day. The surprise effect is what matters most with this particular deer control.

Other cultural practices

Irrigate frequently for optimum yield and plant health. Frequency depends on soil type, evaporation, precipitation and the particular needs of the crop.
When melons have sized up, hold back on irrigation to avoid splitting.

Cover cropping and/or double cropping

Work under any harvest remains to avoid insect or pathogen buildup, and plant a cover crop. In the northern United States and Canada, you can follow summer- and early-fall-harvested cantaloupes with a cover crop of oats and peas in September, or rye and vetch planted at later dates. Adjust accordingly in other regions.

Harvest

Yield	An average of 1 marketable melon per row foot, although this depends greatly on the variety. For example, smaller types, like sugar cube, usually yield 2–3 melons per foot.
Standards	Harvesting¹ 75–100 melons per person, per hour. It takes a crew of 5 people about 45–60 minutes to harvest and sort 350 melons.
Standards	Washing Not necessary when using mulch between plastic. Sort melons in the field to save time in the pack shed.
Tools and supplies needed	1 ¾-bushel plastic boxes or 20-bushel bins and a forklift to move the bins
¹Harvest rates don't include the time required to transport crops from the field to a wash and pack shed or storage facility.

Ready-to-harvest and quality indicators

Cantaloupes are of good quality when they have developed a good netting with full yellow color on the outside, and when the flesh is orange, sweet and juicy.
Each type of melon has its own harvest readiness indicators. Open up a few melons when they look ready, taste them and look for characteristics that indicate harvest readiness.
Cantaloupes and melons cannot be overripe, soft or wilted and must be free of any defects.
Good cantaloupes and melons come from a field where the foliage is still healthy and the plants are in full production.
Cantaloupes are ready to harvest when the stem is either at the half-slip or full-slip stage. This refers to how easily a melon’s stem will break off the vine, and indicates ripeness. When a cantaloupe is fully ripe, the stem will detach from the fruit with a gentle nudge, which is the full-slip stage. At the earlier half-slip stage, the stem will only partially break off. For full flavor pick at full slip, but include all the fruit that is at half-slip as well, if you don’t want the fruit to over ripen. Using full- and half-slip as harvest indicators works best on cantaloupes and doesn’t apply when determining the ripeness of real melons.
Cantaloupes picked at full slip won’t tolerate shipping, so you should sell them in retail settings. For shipping, harvest cantaloupes at half slip.
Cantaloupes ripen over a period of 2 weeks, but the fruit is smaller and less netted at the last picking, which is an indication that the quality has decreased. To maintain a satisfied customer base, many growers leave those last cantaloupes in the field and move on to the next succession.

Harvest procedures

One or 2 people stand on a harvest wagon while the others each take a row of melons.
After a picker harvests a melon, they toss the melon underhanded to one of the people on the truck. Make sure you have eye contact with the catcher before you toss the melon.
Move the harvest wagon down the harvest lane as you pick.

Washing procedures

Using adequate straw mulch can keep the fruit clean and make washing unnecessary. This is preferred over washing melons.
If washing is necessary, wash your hands before handling melons and use a rinse conveyor washer or brusher washer, or spray off the melon. Add a sanitizer like hydrogen peroxide and peracetic acid to the water in the circulation tank of the rinse conveyor vegetable washer. Use the guide How to Wash Produce Using a Peracetic Acid Solution to establish how much sanitizer solution to add to water.
Under no circumstances should you dunk melons in cold water, as this can create cross-contamination of pathogens that are absorbed through the skin of the melon. When muskmelons are submerged in water (which almost always has a lower temperature than the melon), ensure that they are washed in an ambient sanitizing solution. Aside from tubs, even rinse conveyors are known to be challenging in making sure that the correct peracetic acid solution is present.
Inspect the melons after washing for any defects. Any possible puncture is a food-safety issue and you’ll need to cull these melons from the packing line. Any cosmetic issue will impact storage life.

Additional resources

Production Guide for Storage of Organic Fruits and Vegetables

Packing and storage summary for melons

Cleaning in the field	Brush off any soil or straw mulch.
Packing in the field	If possible, sort by size in the field to accommodate easier sorting in the packing shed.
Packing for delivery	Sort by size and pack anywhere from 8–12 melons per 1 ¾-bushel box or 4–6 melons per 1 ⅑-bushel box. See the International Federation for Produce Standards for the correct PLU code. Add the prefix 9 for organic crops.
Storage	Store cantaloupes at 37°–45° and 95% humidity, and honeydew melons at 45°–54°. Cantaloupes are ethylene producers but are also sensitive to ethylene exposure, which will turn them soft. Allow for good air exchange in the cooler.

This material is based upon work that is supported by the National Institute of Food and Agriculture, U.S. Department of Agriculture through the Sustainable Agriculture Research and Education (SARE) program. Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the author(s) and should not be construed to represent any official USDA or U.S. Government determination or policy.