Cultivation Guide for Bitter Melon Variety Series

Bitter melon belongs to high-yielding crops, which is characterized by well-developed root system, more lateral root, fonding and endurant to fertile and fear waterlogging, fonding of light and intolerant to heat. The culture mode of seedling falls into the following patterns: grafting, direct sowing and transplanting after culture of seedling. Here below is the introduction by three parts.

Part one, Direct Sowing or Transplanting

1, Sowing Time and Methods

1.1, Sowing
For Spring sowing, it is generally unified in middle to late Feb. The seedling is cultured in nutrient pot, with one grain of seed each hole. After sowing, cover the low tunnel with thin nylon film. The seedling stage lasts for about 20 days generally. The seedlings can be transplanted when they’ve grown out 2-3 pieces of main leaves. For Autumn sowing, it is usually arranged in late Jul. to Aug. It is suggested to transplant the seedlings after culture.
1.2, Preparation and Disinfection of Nutrient Soil
Break the dry land soil or pond scum into pieces, and then add in proper amount of finished pig and cattle manure, and also a little compound fertilizer, approximately 100g for 50kg of soil. After mixed equally, pack the soil into bags. Before sowing, drench the bags one by one thoroughly by 800-1000 times of 50% carbendazim liquid, or 400 times of 50% dexon WP, for disinfection.
 
As bitter melon seeds have thick shell and also contain wax, they absorb water slowly, pay attention to the method of sprouting. Following is the concrete method. Soak the seeds in 50-60 degree celsius of water for 10-15 minutes, stir them while soaking, until the water temperature drops to room temperature, then soak the seeds for another 10-12 hours. After soaking, lay the seeds under 25-30 degree celsius environment for pregermination. The seeds will germinate after about 48 hours. If the temperature is low, the seeds will germinate slowly. There are something which must be paid special attention to. Before germination, the seeds must be scrubbed once by clear water each day to remove the mucus from seeds surface, so as to prevent seeds from mildewing and rotting, and to promote the germination. After germination, broadcast the seeds to the seedbed or nutrient pot, and pay attention to watering until the seedlings come up of soil.

2, Cultivation Season and Selection of Variety

For Winter and Spring cultivation, it is suitable to sow in Sept. to Feb. next year. And for Autumn cultivation, it is suitable to sow in Jul. and Aug. For selection of varity, choose varieties such as Green-White Jade Bitter Melon, Green-Jade White Bitter Melon, Bright Pearl No. 101 Bitter Melon, Yushuai Bitter melon, Kanira Bitter melon and so on as Green-white family, and Hybrid Oil Bitter Melon, Pearl Bitter Melon and so on as Oil bitter melon.

3, Field Preparation and Plant Setting

According to the growth characteristics of bitter melon, it is better to cultivate on loam field which can receives plenty of sunlight, rich in organic matter, with well drainage and water retention, and with deep soil layer. And to avoid continuous cropping field. The field should be rotated with non-melon crops for more than 3 years.

Plough deep and sun the soil to white. For field preparation, make ridge in 30cm high and 2.7m wide including ditch. Along with preparation, supply base manure adequately in the trenches which are dug in the middle of ridge. For each acre of field, suply 12000-18000kg of mixed manure, and 300kg of 45% compound fertilizer(15N:15P:15K), and then earth up the trenches. Choose sunny afternoon for sowing. Dig planting hole by the planting distance of 0.6m by 0.5m. When sowing, pluck away the nutrient bag and transplant the seedling with soil. Cover the hole with soil to overtop the ridge surface slightly, and then pour adequate root-fixing water.
 
It is suggested to plant thinly and with flat shed. Cultivate about 900-1200 plants per acre in Spring, and 1500-1800 pieces in Autumn. If using A-bracket, cultivate 1800-2400 plants per acre.

4, Field Management

4.1, Water and Fertilizer Management
The fruiting period of bitter melon lasts for a long time, and the requirements of water and fertilizer is strict. Fertilization should base on the following principles: supply base manure heavily, light in early period, heavily in middle period, and complementally in late period. 8-10 days after transplanting, lightly supply once 10% human excreta, and 20% of human excreta after 8 days, adding 50g of urea each barrel. For the 3rd-10th fertilizeration, add 60kg of compound fertilizer per acre. At the beginning of blossom, along with cultivation, dig ditch in the middle of the ridge for top dressing of 90kg of compound fertilizer per acre. When comes to the picking fastigium, process once improvement of fertility, by broadcasting the fertilizer on both side of the ridge, and then cover with ditch soil. Each acre of field supplied 180kg of compound fertilizer and 60kg of urea. In addition, spray 2%-3% monopotassium solution as top dressing constantly. Bitter melon is fond of wetness, but fears accumulated water, so to drain in time in raining season, to prevent the root from rotting in accumulated water. Water the plant constantly in drought weather. Supply of plenty water is the main guarantee of high yield and quality.
4.2, Shelving and vine-leading, pruning and flower-thining
When the seedlings grow to be 30-40cm tall, stick bamboo and lead the vines in time, using dual-lines of A-bracket. The plant bears fruits mainly on chief vines, so when the first female flower appears on chief vine, the pruning can be done by wipe out the side buds and branches which are 1m below the chief vines. In late growing period, pick off the old yellow leaves at the bottom, and cut off old vines which are without melons and also the thin-week vines.
 
For flat or arched shed, it is 1.8-2m high, each for two lines, covered with nylon mesh (25-30cm by 25-30cm). For flat shed, do not pruning before picking. After fruiting, the pruning is mainly by top removal, which is conducive to the growth of root, and improving disease-resistance and resistibility. This pruning method is convenient and cost-effective, it is the best one for open field cultivation, and also one of the main ways to achieve high benefit.

5， Control of Insect Pest and Disease

5.1, Disease
5.1.1, Damping-Off disease
The disease will develops seriously in moist soil when supplying unfinished farmyard manure. Prevention and control is as follow. Disinfect the seedbed using Dixon or Carbendazim. In the early period of disease, spray 4000 times of hydroxisoxazole on the whole plant, or pour 800-1000 times of Dixon, once in every 7 days, continue for 3-4 times.
5.1.2, Downy Mildew disease
The disease will easily occurs in cloudy and rainy day.
Prevention and control is as follow. Pay attention to the ventilation, to reduce the field humidity. For chemical control, spray 800-1000 times of Dupont, or 500 times of 580 Ridomil-MZ, once in every 7 days, continue for 3-4 times.
5.1.3, Powdery Mildew disease
The plant will gets serious disease in poor ventilation and drainage situation.
Prevention and control Methods is as follow. Choose field in good ventilation and drainage situation to cultivate on. Supply more phosphate fertilizer and potash fertilizer in proper amount. In the early period of disease, the following pesticide can be sprayed once in every 7 days and continue for 3-4 times. 1000 times of 12.5% Diniconazole WP, or Thiophanate Methyl, or 1000-1500 times of Antimycoin, Divdend or Triadimefon.
 
In addition, for control of blight disease in late period, pour 4000 times of Hydroxisoxazole No. 1 or 800 times of 58% Ridomil-MZ on root, and for Anthracnose disease, spray 800 times of 50% Carbendazim, 800 times of 70% Thiophanate or 500 times of Kypzin, once in every 7 days, continue for 3 times.
5.2, Pests
5.2.1, Yellow melon leaf beetle
It damages leaf and stem, and also flower and young melon. The larva eats root in soil, causing death of plant.
 
Prevention and control methods are as follow. Broadcast Phoxim on the ridge surface, or spray 1000 times of Phoxim to control imago.
5.2.2, Melon Fly
The Diaphania Borer damages leaves and fruits, and the Melon Fly lays eggs into young melonand the larva eats inside the fruits, causing the sick melon turns yellow partly or becomes abnormal, and rotten in the end.
 
Prevention and control Methods are as follow. Alternately use Phoxim Permethrin and biological pesticide BT, to spray at nightfall.
5.2.3, Mites
Spray 1500 times of N23, Propargite, or Abamectin for control.

6, Timely Harvest

Generally harvest begins in 15 days after blossom fall. By then, the top of the melon begins to light up, with shoulder papilloma grows thick and full. Shorten the picking interval appropriately can promote the forming of female flowers which is significant to the extension of fruiting and increasing of yield.

Part two, Graft Technique and Management

In recent years, the soil-borne diseases in vegetable production base is getting worse because of the multiple cropping of vegetable all the year round. The blight disease of bitter melon is widespreadly happened, usually bring destructive damage to the vegetable base. The attack rate of blight disease is usually 10%-50%, even 100% in some field, impacting the yield and income seriously, resulting in frustrating farmer’s enthusiasm and sharply decreasing cultivation areas. For the application of graft cultivation technique in production, the general mortality rate for graft cultivation is 1% -3%. This technique radically overcome the obstacle to the continuous cropping, effectively prevent blight disease from damage. The yield will increases by 20%-60%. This technology can be applied to other vegetables such as watermelon, eggplant, cucumber and so on. It will create the conditions for the pollution-free production technology and sustainable development of vegetables, especially for melons vegetables. This technique own broad prospects in production application.

1, Selection of appropriate rootstocks and scion varieties

Select the melon varieties which has strong affinity and resistance for rootstock, flesh towel gourds are the best choice. For the scion varieties, it is better to select Gren-Jade White Bitter Melon, Green-white Jade Bitter Melon, Jade green Bitter Melon and Kanira Bitter Melon.
2, Soaking Treatment, Preparation of Nutrient Soil, and Timely Sowing
2.1, Soaking Treatment
Before sowing, break off the shell of the sieved bitter melon seeds carefully not to injure the kernel. And then soak the bitter melon seeds and flesh towel gourd seeds respectively in 55-60℃ hot water, and keep stirring so that the seeds are heated evenly. In about 10-20 minutes later, when the water temperature drops to 30℃, continue to soak. Bitter melon seeds are generally soaked for 8-10 hours, and the flesh towel gourds seeds for 8 hours. After that, wash mucilage from seeds by clean water, soak and then fish them out of water, and spread flat on plate, cover with double-layer wet cloths. Put the plates in the incubator in 28-32℃ for sprouting. Replace with heating branket if incubator is not available. During the sprouting period, clear up the seeds 1-2 times a day, to wash off the mucilage and promote sprouting. The seeds can be sown after sprouting.
2.2, Preparation of Nutrient Soil
The culture of seedlings for sowing of Flesh luffa should be in nutritient pots. For the preparation of nutrient soil, choose field soil in on which the melon is not cultivated for many years, and then add in finished barnyard manure or compost, mix round by the ratio of 3 by 1. Each CBM of nutrient soil adds in 50kg of finished human and animal droppings and 1.0kg of Calcium Superphosphate, and then mix with 50 times of 40% Formalin, mixed with100g of Carbendazim or 200g of Chlorothalonil. Cover the soil compost with film tightly for about 10-15 days, making the fermentation and disinfection fully. And then, spread out the soil and turn over to dry in the air, then load into the nutrient pot.The culture of seedling and sowing of bitter melon should use pure soil, to prevent from infecting diseases in the seedling stage.
2.3, Appropriate planting period
For Winter and Spring cultivation, it is suitable to sow from September to February next year, and from July to August in Autumn. For Winter and Spring cultivation, if the culture is brought forward, the electric heating bed or warm-soil seedbed should be used. Generally, the sowing of flesh towel gourd is 3-5 days earlier than bitter melon.
3, Timely Graft, Strengthening Grafted Seedling Management
When the flesh towel gourds grow out main leaves (interior leaves), and the bitter melon seedlings grow out one leave with one bud, they can be grafted. Cloudy, calm and high humidity weather is more suitable for grafting. Before graft, the seedbed should be watered appropriately. Grafting methods using top-inserting grafting or pin-type grafting. For top-inserting grafting, prepare two small bamboo sticks which are 8cm long, 0.5cm wide and 0.25cm thick, and then cut one end to be small slope in 1cm wide. When grafting, use grafting blade to cut off the main leaves of flesh towel gourd, and then insert the stick into the top of cotyledon arrisways in the direction of cotyledon. Cut the hypocotyl of bitter melon to be wedge, pull out the sticks which are inserted into the rootstock, and then insert the hypocotyl of bitter melon into the section of flesh towel gourd as fine as possible, and fasten by grafting clips. For pin-type grafting, firstly cut off the main leaves of flesh towel gourd, and smooth the section, and then cut the hypocotyledonary off bitter melon. Then insert one end of exclusive grafting pin into the hypocotyl of bitter melon, with another end into the top of cotyledon of towel gourd which main leaves are cut off. It is required that the hypocotyl section of bitter melon seedling and the main leaves top section of the towel gourd seedling must be inosculated as closely as possible. And finally, fasten by grafting clips.
 
Covering the seedling when grafting. After the graft is fished, shade the seedlings by black film. Within 1-3 days after grafting, shade them all day and keep warm and moist. After then, according to the weather, shade the seedling from 10 a.m. to 3 p.m., with rest time illuminated. Inside the low tunnel, the temperature should be controlled in about 32 degree celsius during daytime, and 20 degree celsius at night, with humidity controlled in about 90%. 7 days later, illuminate the seedling all day, and ventilate and cooling down step by step for seedling exercise treatment, with temperature maintaining in about 25 dgree celsius in daytime and 15 degree celsius at night. 10-15 days after grafting, remove the clips, and manage the seedbed as general. Remove the buds sprouted in the rootstock in time after the grafting seedlings have survived.

4, Transplanting and Field Management

4.1, Supply of Abundant Base Manure, Proper Dense Planting
Along with plowing and preparation of field, supply 18000-21000kg of organic manure and 420kg of S-NPK per acre, and then make ridge. Cultivate on narrow high ridge which is covered with films. The width of ridge including ditch is about 1.2-1.5m, planted in one row by planting distance in 33cm. Transplant after the grafting seedling grows out 4-6 pieces of leaves. When transplanting, choose seedlings which are absolutely survived, to make sure that the growth is trim after setting. For transplanting grafted seedling, the grafting part should be 1-3cm above soil.
4.2，Strengthening Field Management
4.2.1, Fertilizer and water mangement
In the early growing period, supply thin fertilizer frequently. From the beginning of blossom to the picking period, supply adequate fertilizer and top dressing for more times. Along with top dressing in high temperature and drought season, supply water in time to meet the needs of continuous growth and the fructification of bitter gourd.
4.2.2, Leading Vines onto Shed
The shelf should be built up in time after the plants spread out vines, in flat shed or A-type bracket is better. When the vines grow to about 30cm long, bind the vines manually. Afterwards, bind one time at 4-5 nodes interval. When the first female flower blossoms in the chief vine, reserve 2-3 side vines each plant. As the grafting seedling has strong growth potential, the pruning should be done properly in the early stage. There is no need to prune in the middle and late period, but to cut off week and thin branches at bottom, senile yellow leaves, sick leaves, and excessive growth of branches and vines, so as to benefit the ventilation and illumination, and increase the rate of fruit setting and quality of sale melons.
4.2.3, Manual Pollination
To pollinate from 6-8 a.m. in sunny and warm day, by daubing the male flower which is shucked off the corolla on the stigma of the female flower, to benefit the fruit setting.

 

5, Harvest

It’s better to pick the tender melons in time for bitter melon, especially for the precocious ones which are cultiveted by high tunnel covered with more films, to enter market in time. When the melons are fully growing, with pappilomas outstanding and intumescent, and top of melons starts to shine, they should be picked, to ensure the quality of the melons and increase the rate of fruit setting.

6, Prevention and Control of diseases and Pests.

The section is same as the first part mentioned above.

Part three, Cultivation in Preserved with High Tunnel

In recent years, with the continous improvement of people’s living standards, the vegetable yield is far from meeting the market demand. The implementation of pollution-free greenhouse cultivation techniques, will not only to increase production, but also to supply vegetable to market during the Spring Festival to obtain a high economic efficiency.

1, Selection of Variety

The bitter melon is thermophilous, hygrophilous and heat-resistant, with wide adaptability, but they are unable to bear waterlogging. For greenhouse cultivation, it’s better to select the precocious or mid-maturation varieties which have medium branching power, strong growth potential, well resistibility, high yield and quality, such as Hybrid Oil-Body bitter melon, Pearl bitter melon, Kanira white bitter melon, ans so on.

2,Timely Sowing

It takes about 100 days from sowing to picking. According to the plant conditions of the greenhouse, to ensure as far as possible that the melons can be picked and enter market during the Spring Festival, the suitable sowing time is usually from late September to early October.

3, Culture of Strong Seedling and Preparation Before Sowing

3.1, Seedbed Preparation
15-20 days before sowing, supply 24000-30000kg of finished barnyard manure equally per acre. After that, plough the soil deeply and expose to the sun for about 7-10 days, and then cover with shed to seal up for 5-7 days. By means of insolation by sun and stifled by hot shed, the soil will be disinfected throughly. And then choose one side in the greenhouse to begin setting up seedbeds which are 6-7m long and 1.1-1.3m wide in north-south direction.
3.2, Soaking and Sprouting
As the seed shell is thick and hard, the seeds should be soaked and sprouted before sowing. Put the seeds into 60 ℃ water, to soak for about 20-30 min, and then scrub the mucilage off the seed surface, and immerse in 30 ℃ warm water for 6-8h. After that, fish out the seeds and soak them in 10% trisodium (ortho)phosphate solition for 15-20min for disinfection. The seeds can be laid in the condition of 30-35 ℃, moisturizing for sprouting. It takes about 4500-6000g of seeds per acre. For the tunnel culture, the seedling can be sown when more than 50% of seeds sprout out embryo bud. Water the seedbed throughly, and waiting for the base water infiltrate completely, then, pointly sow the sprouted seed in the seedbed in the density of 10cm by 10cm, and equally cover with 1.5-2cm thick fine soil. Build up low tunnel, and keep the temperature inside around 25℃. When the small seedlings grow out two pieces of leaves with one bud, raise the films which are covered on the tunnel step by step, letting in winds to train the seedling. In the seedling stage, supply as little water as possible, so as to prevent excessive growth. If the aphid or whitefly damage exist, use 2500 times of 10% imidacloprid WP to spray for pest control, so as to cultivate drug-free seedlings.
3.3, Timely Transplanting
When the seedlings grow 4-5 pieces of leaves,they can be transplanted. Before transplanting, cover along the beds with mulching film, and punch holes according to the planting distance of 70-80cm by 30-35cm. When fetching seedlings, manage to make the mass of soil as completely as possible, to avoid any injuries to root. For the planting depth, it is suitable when the main leaves levely exposed out of soil surface. After transplanting, water along the film holes, and press the film mouth tightly with moist soil, then seal up the shed to increase the temperature for recovering seedlings.
3.4, Pruning and Vine Leading
After recovering stage, start to let in fresh air to keep shed temperature in 20-25℃ in daytime, and 15～18℃ at night. After the vines spread, make use of the beams in the south and north trim along right above the seedling bed, to drew the waste phone lines or iron wires tightly along the rows. According the planting distance, tie the nylon ropes on the drewing lines, and lead vines onto shed in time. As the bitter melon has strong branching power, the side vines grows prosperously. If let the side vines grow freely, it is not only a waste of nutrient, but also disturbs the normal growth of chief vines, blossom and fructification, and creates crown closure which will affects the ventilation and illumination. Therefore, during the vines leading, thin the side vines, and pick off the dense old leaves and yellow leaves, so as to strengthen the photosynthesis and concentrate the supply of nutrient, to benefit the growth of chief vines and the tinting of the melons.
3.5, Regulation of temperature and illumination
The suitable blossom temperature for bitter melon is about 25℃. When the tunnel temperature is more than 25℃ in the daytime, open the film to let in fresh air. The tunnel temperature at night should be maintained around 15℃, and the lowest temperature in wee hours should not be below 12℃. In the sunny weather, open the meadow at 9 a.m., and put down again at 4 p.m. When the outside temperature decreases, cover the tunnel with another paper quilt or old film on the meadow, and also shorter the time of letting in fresh air, so as to protect against cold and keep warm. When comes across raw or sleet weather, beside extending the time of meadew covering, the residual snow and dirt on the tunnel film should be cleared away as soon as possible, and adding reflector screen and fill lights, so as to enhance the tunnel illumination and increase the temperature, to meet the growth demand of bitter melon.
3.6, Management of Fertilizer and Water
From transplanting to blossom, the plants are small, so they do not need much fertilizer and water. When comes to the blossom period, the demand of fertilizer increases rapidly, top dressing by stage in the period of flower budding stage, fruit setting period and the beginning of picking. Along with watering, the finished fowl manure or Humic Acid compound fertilizer can be fertilized properly. The watering is usually done in the sunny day morning, less by more times, not flood irrigation, and should not be in gloomy and cold weather.
3.7, Manual Pollination
Bitter melon is cross pollination crop. In the greenhouse cultivation environment, because there are few pollination insect agents, the manual pollination can increases the rate of fruit setting and the quality of melons effectively. The polligation is usually done at 6 a.m. to 10 a.m. Use 2,4-D to daub on the female flowers to reduce the flower dropping and increase the rate of fruit setting significantly.

4, Prevention and Control of diseases and pests.

Bitter melon is seldom attacked by diseases and pests in greenhouse cultivation because of the strong resistibility. If the damage by aphid and whitefly or melon fly, or infection by anthracnose and spots diseases is found reaching the control index, make use of the hermetic environment formed naturely by the greenhouse, choose the pollution-free pesticide which is highly efficient, low poisonous and low persistant, such as imidacloprid, avermection, chlorothalonil smokes, and so so on, for symptomatic treatment.

5, Timely Harvest

The consumption of bitter melon is mainly by tender melon, so the picking period is strictly. Generally 10-12 days after blossom, the corolla on top will dry and fall off. The melon grows fully, and the pappilomas expand rapidly and outstanding, fully and brightly. When the veriety character appears fully, the melons can be picked. When pick, nip off the melon stalk using fruit shears, instead of pulling voilently, so as to prevent injuring the melon and affecting the storage and improvement of sale quality of bitter melon.