7 Pro Growing Tips for the Biggest, Juiciest Melons
To savor the sweet taste of summer later, now is the time to plant melons, from watermelons to cantaloupes. The long-maturing fruits thrive in warm temperatures and get to setting young fruits. With patience and practice, we’ll get big, juicy watermelons as they peak late in the season.
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Big, juicy watermelons will be the envy of the neighborhood. Fortunately, there’s plenty to share to revive a hot summer afternoon. With warm temperatures, it’s time to get the heat-loving fruits in the ground. As we keep busy tending to earlier crops, we’ll look forward to the sweet, juicy rewards later in the season.
Watermelons, muskmelons, cantaloupes, and “winter melons” like honeydew are long maturing. It takes time for vines to develop the weighty fruits with thick rinds and tender, juice-filled flesh. Melons mature in about 80 to 100 days, with compact and early varieties often on the shorter end.
Melons soak up long, sunny summer days and seasonal moisture. Avoiding common problems over the course of a long growing season is a labor of love, made worth it by that first bite of a big, juicy watermelon dripping with summer sweetness. A few key techniques bring about the healthiest, tastiest fruits, made that much better by growing your own.
Melon Basics
Melons are in the cucurbit family (Cucurbitaceae) with other favorite warm-season crops like cucumbers, zucchini, winter squashes, and pumpkins. Optimal growing temperatures for the frost-sensitive annuals are between 70-85°F (21-29°C). Direct sow seeds after spring’s final frost and when soil and air temperatures warm to the 60s (around 16°C). Melons have roots that are sensitive to transplant disturbance, and direct sowing reduces damage.
But, in cool climates with short growing seasons or to get a jumpstart on lengthy development, start seeds earlier indoors in biodegradable pots or soil blocks. Start melons indoors two to four weeks before you plan to transplant. If planted too early or in cool weather, they’ll be slow to start with delayed flowering and fruiting.
Melon vines sprawl and run, taking up a lot of space as they develop. Compact selections stay short or even bushy, depending on the variety. The biggest, juiciest melons come from standard varieties with long vines. But that’s not to take away from dwarf and compact varieties that produce smaller fruits that are just as sweet and juicy.
Melons perform well in the ground, raised beds, and vertically, depending on the variety.
Optimal growing conditions include:
- Full sun (six plus hours of sunlight daily)
- Well-draining, sandy loams
- Slightly acidic to neutral soil with a pH near 6.8
- Warm conditions (sow seeds when soil temps reach 65°F (18°C) or higher)
- One to two inches of water per week (rainfall and/or irrigation)
Boost Pollination
Melons produce male and female flowers and rely on insects, especially bees, for pollination and fruiting. Sometimes, they’ll flower, followed by underdeveloped or misshapen fruits. The oddballs are often due to poor pollination. Without a strong show of pollinator visits, fruiting decreases in number and quality. Newer seedless or nearly seedless varieties produce sterile pollen and need a standard type nearby for insect transfer.
Cucurbits rely on repeat visits from bees and other insects, and pollination can be tenuous with insufficient activity. Rainy, cool weather, urban pollution, balcony setups, greenhouses, and a lack of local bee presence – all influence bee activity. Other crops utilize self-pollination, wind, and insect pollination, but melons need insect visits solely.
Bees shimmy into the bright yellow tubular blooms to collect nectar and pollen, capturing it on their fuzzy bodies. They distribute the granules as they travel from flower to flower. Insects are necessary to transfer to the large, sticky grains.
The easiest way to boost pollination is to grow flowering plants in the vicinity. Nectar-rich herbs, perennials, and annuals attract bees and other flying pollinators, who, in turn, visit the watermelon blossoms. Diverse blooms also draw beneficial predators to manage pest populations.
To enhance pollination for big, juicy watermelons, you can also opt for hand-pollination. Use a Q-tip or paintbrush to transfer pollen from male to female flowers. Male flowers have stamens, while females have a stigma in their center and a small, undeveloped melon at their base. Female blooms last only a day, so catch them in the morning for the best receptivity.
When to Water, and When to Stop
Melons do best with consistent moisture throughout the growing season. One to two inches a week, including rainfall and irrigation, is usually sufficient. Cucurbits are susceptible to a number of fungal diseases, including powdery mildew.
If disease is a problem, avoid splashing the leaves during watering sessions. Irrigate at the ground level through drip irrigation or soaker hoses to avoid overly wet conditions that harbor and spread spores.
Avoid Fluctuations
Fluctuations in water cause stress and energy conservation, leading to halted vine growth and dropped blossoms. Melons are also susceptible to the physiological disorder blossom end rot, like tomatoes. A watermelon looks perfectly healthy until suddenly it develops a rotting patch.
Blossom end rot occurs from water fluctuations, where extreme moisture and dryness cause a lack of nutrient uptake, including calcium. Calcium is necessary to prevent blossom end rot. At planting, scatter crushed eggshells or bone meal to promote calcium availability with even watering.
Withhold Water
To avoid the heartbreak of a cracked melon after waiting all season, reduce irrigation when the fruits are nearly ripe. When they reach maturity, the fruits stop growing in size but continue to absorb water. Watermelons are already 92% water, and the extra moisture surpasses maximum capacity. The rinds split open as the fruit bursts at the seams.
Too much water near peak ripeness also reduces sweetness. As the melons reach their prime sugar content, extra water dilutes the concentration. Decreasing irrigation just before harvesting helps prevent cracking and splitting.
Balance Nutrients, Limit Nitrogen
Organic, well-draining soils are best for growing big, juicy watermelons and melon relatives. Sandy loams are optimal. Amend with compost at planting for a nutrient-rich foundation. A low-grade, balanced fertilizer at planting gives a boost as roots, vines, and leaves establish. After the initial feeding, opt for a fertilizer with a higher phosphorus rate than nitrogen (the P in the N-P-K ratio) to promote flowering.
Too much nitrogen promotes leafy vines but reduces flowering as energy goes into foliage and stem growth rather than fruiting. A lack of buds and blooms may be a sign of overfertilizing.
Phosphorus and potassium are necessary for flowering and fruiting. While nitrogen is helpful early on as crops establish, too much of a good thing is a detriment. Avoid applying excess nitrogen through manure or compost during the growing season.
Space Considerations and Overcrowding
Big, juicy watermelons imbue all the goodness of summer. And they take up a lot of space to get to their ample size. Classic large melons and their long vines are best left to run on the ground or spill over beds.
In smaller spaces or to conserve growing room, more compact vines with smaller fruits are easy to trellis for vertical growth. Whether growing at ground level or upright, accounting for mature vine length reduces competition among the fruits.
Growing Vertically
The best small watermelon and muskmelon varieties are just as sweet and juicy as their larger counterparts. They produce a hearty yield on compact vines, and the hybrids often have good disease resistance.
Growing melons on a trellis is a space-saving technique with added advantages. It reduces diseases by increasing air circulation among leaves and stems. It can lessen rot as the shapely fruits develop. It provides all-over sunlight, necessary for photosynthesis but also for the development of healthy skin. Pest scouting becomes more manageable, and it’s rewarding to see the melons develop as they hang from the vine.
Thinning and Mounding
Give vines plenty of space to prevent crowded conditions and undersized fruits. Overcrowding occurs when vines grow too closely and compete for resources. Cramped quarters also decrease air flow, which affects health and vigor.
Mounding is a way to reduce root and vine competition. Growing the cucurbits in mounds increases drainage and minimizes damp conditions that lead to disease issues. Two to three vines planted in low, 16-inch tall mounds give vining stems room to run while elevating the crown. Add straw or mulch around the crowns to retain moisture and regulate soil temperatures. Allow six to seven feet between mounds for vines to run.
Keep an eye, too, on how many fruits the vine produces. Too many fruits per vine deplete the energy they need to fully develop into massive specimens. Two melons for large varieties and four for small is common. Thin fruits early if you have a bigger yield forming.
Cradle the Fruit
A little extra protection helps big, juicy watermelons grow to maximize size. Cradle them in straw to keep them above the soil level. The idea behind the lift is to lessen moisture and dampness by improving circulation and insulating the fruit. It also forms a barrier between the skin and soil-dwelling pests.
On a sturdy trellis, melons need additional support. The stems aren’t strong enough to hold the weight on their own. When the fruit reaches a few inches, use a net, sling, or ties to lift the weight off the stem. You can buy supports that are easy to slip over the melon. Flexible and airy, the net expands as the melon grows. Twine slings and nylon hose are easy DIY solutions.
Scout for Common Pests and Diseases
Melons are susceptible to the same pests as other cucurbits, including squash and cucumbers. Pests include the cucumber beetle, the squash vine borer, and the squash bug. Each feeds on plant parts and causes damage. Melons aren’t their primary host, but it’s best to separate cucurbits when possible.
Squash vine borers burrow into the stem as larvae and feed on tissues. The stem weakens and becomes unable to absorb water, causing sudden wilt. There are ways to lessen the damage through regular scouting and growing melons away from other cucurbits in infested areas.
The squash bug is a sap-sucking pest that causes leaves to lose water and nutrients. The leaves become speckled, eventually wilting, blackening, and dropping. Cucumber beetle adults feed on leaves, blossoms, and fruits, while larvae feed on roots and stems. Regular scouting for each pest benefits the group. Pyrethrin sprays help treat the squash bug and cucumber beetle.
Disease is another cause of damage and a lack of full-size rounds. Anthracnose is a common leaf blight, as are powdery mildew and downy mildew. A horticultural oil, like neem, can stave off early infections.
Prevention through cultural management is the best means of defense. Provide plenty of air circulation around vines to avoid damp conditions and water consistently to prevent overly wet or dry situations.
Harvest at Peak Ripeness
The best part – harvest time! There’s a limited window for the sweet spot of harvesting melons for optimal flavor, texture, and juiciness. While some fruits continue to ripen after picking, the best big and juicy watermelons ripen on the vine. They won’t continue to develop flavor or increase sugars post-harvest. An underripe melon will be pithy, less color-rich, and less sweet and juicy. An overripe one may be mushy and off-flavored.
The “days to maturity” on the seed packet is a helpful indicator of when to check for ripeness. Make a note of your sowing date and count out the days to maturity (Google is useful in giving the projected date; ask for “X days from today”). Melons usually mature in 65 to 100 days, depending on the selection and weather.
Watermelons
For watermelons, readiness is about 35 to 45 days after flowering. The best indicator is color. Look for the color of the “field spot,” where the melon touches the ground. When ripe, this patch transitions from greenish-white to yellow or cream. Shiny skin may also lose its luster, becoming dull and rough when ripe.
Ripe watermelons have a brown, withered tendril or “pigtail” stem at the main vine. And when tapped, the melon should make a “thump” noise. The big, ripe oblong should sound hollow and dull with the tap of a finger. Unripe ones sound more metallic with a lighter tone.
Cantaloupes/Muskmelons
Muskmelons (what we commonly call cantaloupes) have fewer guidelines. The best measure is to look for color, scent, and “slip.” For yellow varieties, the melons are ripe when the original green skin turns golden yellow and is fully netted. For all types, they’ll have a fresh fruit perfume, and a frequent scent test is helpful for a near-ripe muskmelon. The aroma changes quickly as the melon ripens, and when it shifts to acrid, it’s overripe.
If a cantaloupe is a “full slip” variety, it separates easily from the stem when ripe. The slip is where the stem meets the fruit. If the slip is green and sealed, the melon isn’t ready. If the slip is brown and separating from the fruit, the melon is ripe. Give the round a test pull. It will pop off the stem easily when ready. If you have a non-slip variety, the gauge won’t be the same. Non-slip types need to be cut from the stem. Use the color and scent tests to check for optimal sweetness.
