How to Grow Cantaloupe

What Americans call cantaloupe

The netted, orange-fleshed melon sold as cantaloupe in the US is botanically a muskmelon. True European cantaloupes have smooth or warty, ribbed rinds, and Clemson notes that they aren’t grown commercially here. Honeydews belong to the same species and are grown the same way, but they ripen differently (see harvest below).

Site and soil

Cantaloupe wants full sun (at least 6 hours, more is better) and fertile, well-drained soil. Iowa State gives a pH range of 5.5 to 7.0, and Penn State 5.8 to 6.6. Sandy, organic soils are ideal, but almost any soil works if it drains. Clemson finds the plants grow best at average air temperatures of 65 to 75°F. Penn State gives a wider growing-season range of 65 to 95°F and notes that growth slows above 95°F or below 50°F. Even a light frost injures the vines.

Rotate. Don’t plant melons where cucumbers, squash, pumpkins, watermelon or other melons grew in the last 3 years (Clemson) or 3 to 4 years (Iowa State).

Planting

Wait until frost danger is over and the soil reaches 60 to 65°F (Clemson); Iowa State allows 60 to 70°F and Utah State waits for 65°F. Use the dates for your zone above. Cold, wet soil invites damping-off, so a slightly late planting is safer than an early one.

Transplants ripen about two weeks before direct-seeded melons (Clemson, Utah State), which matters in short-season areas. Start them in peat pots or other plantable containers, because melons dislike root disturbance. Timing advice differs: NC State starts seed 4 to 6 weeks before the last frost, Iowa State 3 to 4 weeks before planting out, and Utah State allows 6 weeks. Iowa State sets transplants out at 1 or 2 true leaves after a few days of hardening off.

For direct seeding, sow 4 or 5 seeds per hill and thin to the 2 or 3 strongest. Depth advice ranges from ½ to ¾ inch (Clemson) to 1 inch (Iowa State) and 1 to 2 inches (Utah State). Spacing also varies by source:

• Iowa State: hills 1½ to 2 feet apart, rows 5 to 6 feet apart.
• Clemson: plants 18 to 24 inches apart in rows 6 to 8 feet apart.
• Utah State: mounds 4 feet apart, or transplants 2 feet apart through black plastic in rows 4 to 6 feet apart.

Black plastic warms the soil, saves water, stops weeds and, Clemson notes, reduces fruit rot. Lay it over moist soil and run drip line underneath. With plastic plus row covers, Utah State plants about 2 weeks before the last frost. Vent covers above 80°F and remove them at flowering or above 90°F. Hold off on straw or other organic mulch until the soil passes 75°F.

Fertilizing and watering

Fertilize by soil test if you can. Without one, Iowa State uses 1 to 2 pounds of 10-10-10 per 100 square feet, and Clemson uses 5-10-10 at 30 pounds per 1,000 square feet. Side-dress with nitrogen as the vines start to run: Clemson uses 1 pound of 34-0-0 or 2 pounds of calcium nitrate per 100 feet of row, with a second dose after bloom, and Utah State uses 3 to 4 tablespoons of 21-0-0 per plant. Too much nitrogen, or crowded plants, gives lush vines and few melons.

Give 1 to 2 inches of water a week in dry weather, ideally by drip. Clemson wants the soil moistened at least 6 inches deep. Don’t let plants dry out: drought at bloom causes poor set and misshapen fruit, and drought near harvest shrinks melons and makes vines decline (Iowa State). In the final week or two, cut back. Iowa State halves each watering, because wet soil at ripening lowers sweetness and can crack fruit.

Pollination

Bees must carry pollen from male to female flowers, and each female flower is open for just one day. More bee visits mean bigger, better-shaped fruit. Cool, rainy or windy weather and daytime insecticide sprays both cut fruit set; spray, if you must, early in the morning or in the evening. Utah State adds that very hot weather and water stress also cause female flowers to fail.

Varieties by region

• Iowa (Iowa State): Aphrodite, Athena, Ambrosia, Divergent, Goddess, Hale’s Best, Sarah’s Choice, Sugar Cube, Superstar and Wrangler, plus the honeydew types Earli Dew and Snow Leopard.
• Pennsylvania (Penn State, commercial list): hybrids such as Goddess (68 days), Athena (79 days), Aphrodite and Sarah’s Choice, all listed with powdery mildew and Fusarium wilt resistance.
• Utah (Utah State): Ambrosia, Classic Hybrid, Hales Best, Mission, Rocky Sweet and Summit Hybrid.
• South Carolina (Clemson): Athena, Ambrosia, Burpee Hybrid, Lilliput Hybrid, Park’s Whopper and Scoop II, and the honeydew Earlidew.
• Florida (UF/IFAS): Athena, Ambrosia and the green-fleshed Galia.

Regional timing

In central Iowa, melons go in around mid-May, and June 20 is the last practical sowing date for early varieties. Clemson plants from March 15 to May 15 on the South Carolina coast, with a second coastal window in July, and from April 15 to June 5 in the Piedmont. Florida plants late March to April in the north, January to March in Central Florida and December to March in the south, so melons ripen before the rainy summer. UF/IFAS warns that the crop is disease-prone there and that heavy rain during ripening lowers sugar. In the Phoenix low desert, the University of Arizona calendar allows seeding from mid-February into July.

Pests and problems

Cucumber beetles are the most serious pest, because they spread bacterial wilt. Penn State notes that early feeding on young transplants is what infects them. Cover plants with row covers from planting until first bloom, then uncover so bees can work. Aphids spread mosaic viruses, which cause mottled, curled leaves and deformed fruit; remove infected plants. Powdery mildew, downy mildew, gummy stem blight and Alternaria leaf blight thrive on wet leaves, so water at the base in the morning and choose resistant varieties. Utah State notes that when mildew kills the leaves, the exposed fruit sunburns and ripens prematurely.

Harvest

Most cantaloupes are ready 30 to 35 days after pollination (Clemson); Utah State says 35 to 45 days. At full slip, the stem separates cleanly with light pressure, the skin between the netting turns yellow, the netting coarsens and the blossom end smells strongly musky. Clemson notes that sugar peaks at full slip and quality declines unless you eat or chill the melon soon after. Honeydews don’t slip. Pick them when the rind turns from pale green to yellowish white and the blossom end softens slightly, and leave 2 inches of stem.

Bag whole cantaloupes and refrigerate them for up to two weeks; Iowa State gives 36 to 45°F as the best range. Utah State expects about 100 fruits per 100 feet of row.