There is nothing like refreshing melons on a hot summer’s day. Today there are so many types available, from cantaloupe and watermelon to unique muskmelons. The secret to a good melon crop in Oregon is lots of heat, and planting short season varieties. You can start directly from seed or transplants. Dwarf varieties can be grown in large containers.
You should plan to plant melons in the hottest spot in your garden. They thrive in full sun, at least 7 hours of direct sun, and in rich, well‐drained soil. Prepare the planting area by mixing 2‐4” of composted manure and lime into the top 6‐10” of the soil. You can even cover planting area with black plastic to help retain heat.
Melons thrive in warm weather and are best planted outdoors June through the first week of July when soil temperatures are 65° or above. Space groups of seeds 3‐4’ apart in hills, or in raised beds spaced 5‐6’ apart. Be sure to mix an all‐purpose fertilizer into the bottom of each hole. Sow 2‐3 seeds 1⁄2” deep and cover seeds with a thin layer of soil. Once seeds have germinated, pinch off the weakest ones so you are left with the strongest one.
You can start seeds indoors in the last week of May, or three weeks before desired transplanting date. It is recommended to start seeds indoors in pots which can be planted in the ground directly, because melons do not like roots disturbance. When seedlings have their first true leaf, move them to a cold frame for a 4‐7 days. Water in freshly planted seedlings with a diluted liquid seaweed or B1.
Keep new beds well weeded and slightly moist. You can cover new plantings with floating row cover to prevent cucumber beetles and other insects. Remove row covers when plants begin to flower. Plastic or organic mulches can help heat the soil and retain moisture. It also helps to trellis your melons to save space and prevent diseases.
How much water your plants will require depends on the soil and weather. Melons want consistent, moderate watering. If the top four inches of the soil is dry or the plants wilt early in the day, water slowly and deeply. Mulch with a 1⁄2” layer of compost to retain moisture and prevent over heating. Drip irrigation is the best way to provide even moisture and avoid disease issues.
Melons are heavy feeders. Fertilize with an all purpose fertilizer or compost when vines are 12‐18” long. Apply a liquid fertilizer or foliar spray when the first fruits form.
In midsummer, pinch the growing ends off all shoots to help concentrate energy into the fruits. Also remove baby melons at the same time. Smaller fruited varieties will produce 4‐6 melons per vine, and lager fruited varieties (such as watermelons) produce about 2‐3 melons per vine. Lift melon vines off the ground with a trellis or “A” frame structure. This provides better air circulation for optimum plant health, and keeps fruits from rotting on the soil.
Every variety has different cues for ripeness. Muskmelon and cantaloupe develop a crack around the stem and easily “slip” from the vine when they are ripe.
Watermelons ripen about 35 days from when the first female flowers fully open. Also, the tendril on the fruit stem dries up, the color around the stem becomes dull, the spot resting on the soil turns from white to yellow or cream, and the fruit gives a hollow sound when thumped. Honeydew and charentais must be cut from the vine.
Ripe honeydew and relatives will lighten in skin color, the hairs on the skin will fall off easily and the end of the fruit will have a sweet scent. Melons can store for a month if kept refrigerated.
Good gardening practices such as crop rotation, drip irrigation, proper planting time, floating row covers, and removal of entire plants when harvest is done all help prevent many pest and disease challenges.