How to Grow Bitter Melon/Gourd in Greenhouse: A Step-by-Step Guide for Seed to Harvest

Unlike other plants, bitter melon grows in vines. Unlike squash, cucumbers, and watermelons, it has deeply lobed leaves and grows into 13 to 16-foot vines if unpruned. Typically 8 inches (20 cm) long, but it can vary between 2 and 10 inches (5-25 cm) long. The fruits are oblong and smooth or warty.

As the fruit ripens and overripens, its color changes from green to yellow to orange. Watery and crunchy, like the flesh of a cucumber, the flesh of this fruit has a pleasantly sweet taste. Squash, watermelon, muskmelon, and cucumbers are also members of the Cucurbitaceae family. The bitter melon can be grown in a greenhouse, like cucumbers or cantaloupes, but it requires at least three to four months of warm, humid weather to mature.

How to Grow Bitter Melon/Gourd in Greenhouse

Soil Requirements for Growing Bitter Gourd in Greenhouse

The best climate for growing bitter melons is hot and humid. Ensure your plants receive at least 6 hours of sun daily in a warm, sunny location. Bitter melons grow best in compost-rich, well-drained soil with a pH of 5.5 to 6.7. Make sure to prepare growing beds before planting by adding aged compost and aged manure. Bitter melons can tolerate Sandless or silently-loamed soils, but good drainage is essential.

Temperature and Humidity Requirements for Growing Bitter Gourd in Greenhouse

The bitter melon is a warm-season crop that thrives in tropical and subtropical climates. It is best to grow bitter melons in areas where temperatures range from 24 to 31°C during the day. Early summer or late spring is the best time to plant bitter melons. Plant seeds indoors or transplants outside after all danger of frost has passed and the soil has warmed to at least 15-18°C.

Planting Bitter Gourd in Greenhouse

Seeds should be sown in holes about half an inch deep (1.25 cm) and spaced 12 inches (30 cm) apart. Two seeds should be sown in each hole. It takes 8 to 10 days for seeds to germinate, though low and high temperatures and too dry or wet soil can slow the process. Plants trained on trellises or fences should be spaced nine to ten feet apart (2.7-3 meters). For plants allowed to sprawl on the ground, straw or plastic mulch should be used to prevent fruit from resting on moist soil.

It is possible to reduce diseases and make harvesting easier by trellising. Plants should be separated by a trellis at least 6 feet (1.8 meters) high and wide. All lateral branches from the soil up to the 10th node should be pruned or pinched away when the vine reaches the top of its trellis. This will stimulate the growth of the upper branches and result in a higher yield. When the growing tip reaches the top of the trellis, remove the growing tip by pruning the laterals to 2 to 3 feet long (0.6-0.9 meters). Consequently, the plant will produce more flowers and fruit sooner.

Watering and Fertilizing Requirements for Growing Bitter Gourd in Greenhouse

The bitter melon planting beds should be kept evenly moist; regular watering is essential for fruit development and growth. Compost that has aged will be a good source of nutrients for melon plants. A slow-release organic fertilizer, such as 5-10-10, can also be applied early in the growing season around plants. During the growing season, add aged compost to the soil to help retain moisture and add nutrients. Compost or compost tea should be added to the plants’ water every third week during the growing season.

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Common Diseases in Greenhouse-Grown Bitter Gourd

Several diseases can affect bitter melon, including powdery mildew, downy mildew, rust, and rots, as well as the watermelon mosaic virus and bacterial wilts. Vines can be protected against fungal diseases with trellising, which increases air circulation around the vines. If your vines are not trellised, cover the soil with a straw mulch or plastic mulch to prevent melons from resting directly on it. Virus-infected plants cannot be cured. Whenever possible, plant disease-resistant plants.

Common Pests in Greenhouse-Grown Bitter Gourd

Spotted and striped cucumber beetles can attack bitter melon. A cucumber beetle can carry bacterial wilt disease, which will cause vines to collapsing. There is no recovery for vines infected with a virus. Rotenone or pyrethrum-based insecticides should be applied to adult beetles. Don’t use pesticides at dusk to avoid harming honey bees. Bitter melons can also be attacked by fruit flies, which can cause fruit rot. Cover fruits with paper bags or wrap them with newspaper when just an inch long to prevent flies from reaching them.

Pruning Greenhouse Grown Bitter Gourd

When you see the first female flowers on your bitter melon, you can start pruning it. Use gardening scissors to cut vines growing too close to the ground and the tops of bitter melon vines. In addition to making the plant bushier, pruning will help the plant produce more flowers and fruit by redirecting nutrients and energy. Plants produce numerous side shoots, which must be removed to increase yields. Until the runner reaches the top of the trellis, remove the side shoots (lateral branches). To increase the plant’s productivity, leave only four to six laterals and trim the main runner’s tip.

Harvesting Greenhouse Grown Bitter Gourd

It is best to harvest bitter melon about 12 to 16 weeks after planting and 8 to 10 days after blossom drop when the fruits are 4 to 6 inches (10-15 cm) long. Pear-shaped fruits with light green skin and yellow streaks will grow on the trees. When fruits stay on the vine too long, they overripen, turn yellow, grow too large, and become bitter. Melons, both immature and overripe, can taste very bitter when they are on the same vine.

The bitter melon has thin layers of flesh that turn orange to bright red as they ripen. It has a spongy, white pulp with seeds surrounding a hollow interior cavity. Watery and crunchy, the fruit will be similar to a cucumber. Growing bitter melons contains the alkaloid momordicine, which causes bitterness; the darker the bitterness and intensity of the flavor, the bitterer the fruit. After melons begin to ripen, pick them regularly every two to three days. More fruits will form as you pick more.

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Conclusion

You can grow bitter gourd in a greenhouse if you don’t have an outdoor garden. In the same way as growing it outdoors, the process is quite similar. However, giving the plant plenty of room to climb is important. Providing your bitter melon with a trellis that allows it to vine upwards and pruning its top when it has reached its maximum height will encourage the plant to spread horizontally.

How to Grow Bitter Melon/Gourd in Greenhouse: A Step-by-Step Guide for Seed to Harvest