How to Keep Watermelon Fresh? A Few Practical Methods
Several Methods for Keeping Watermelon Fresh
1. Sand storage for freshness. After 40-50 days of storage, it can maintain its color, aroma, flavor and nutrients. Specific method: choose a well-ventilated, light-transmitting room, clean it thoroughly, spread a 70 cm base layer of fine river sand, harvest watermelons at seven-tenths ripeness on a clear evening or an overcast day, requiring the melons to be well-shaped, undamaged and free of pests and diseases, keep three vine nodes on each watermelon, cut at 33 cm from the nodes at both ends of the vine section, and immediately dip the cuts in dry plant ash to prevent bacterial invasion. Keep one green leaf on each vine node, place the watermelons on the sand bed, then cover with fine river sand to a depth of 5 cm over the watermelons, with the three melon leaves exposed outside the sand.
Several points should be noted: 1. When handling watermelons, carry, load and set them down gently to prevent damage to the rind. 2. Store only one layer of watermelons on the sand bed to prevent crushing damage. 3. Every 10 days, apply a foliar fertilizer of 50 g potassium dihydrogen phosphate mixed with 50 kg water to keep the leaves green. 4. When the surface sand dries and turns white, spray water appropriately to increase humidity. 5. Build the sand bed, harvest, transport and store on the same day.
2. Ozone freshness preservation method. Choose watermelons with robust vines, regular shape, no disease spots and six-to-seven-tenths ripeness, cut off the vines, carry them with melon sleeves to avoid vibration or bumping, and transport them to the storage cellar. First disinfect the cellar, store the watermelons by grade, prop them up with soft grass pads, do not let them directly touch the ground or plastic film, and cover them with loose soft grass bags on top to prevent dust and water droplets from falling on the melons. During storage, maintaining 4°C is better; above 5°C respiration intensifies, and below 3°C they will freeze. Increase or decrease the warming layer in time as the day and night temperatures change, and keep humidity above 85%. Release an appropriate amount of oxygen and turn and move them regularly. Releasing ozone can seal and sterilize. For 150 kg of watermelons, 20 g of ozone is needed per day and night, released once every 12 hours, 15 minutes each time, releasing 10 g. Every 5 days, wear clean gloves and gently turn the melons once, and promptly pick out any diseased melons. Other fruits or vegetables must not be stored in the same cellar as watermelons.
3. Empty room storage. Choose a cool, ventilated empty room and disinfect it with a 150-200 times diluted solution of 40% formalin. At the same time, also apply the solution to the fruit stalk and rind of the watermelons to be stored, then spray once with a 6% copper sulfate solution to prevent bacterial diseases from infecting the inside of the fruit along the vascular bundles. First spread a layer of disinfected reeds on the ground, then place them in a single layer in the posture of growing watermelons, close the doors and windows during the day and open them at night, keep the room temperature at 15-16°C and relative humidity at about 80%, and spray water appropriately when the ground is dry. With this method, they can be stored for 1 month, and their color and quality are similar to freshly harvested watermelons.
4. Cellar storage. Choose a place with high, dry terrain and a relatively solid soil structure, dig a cellar with a small upper opening and a large lower opening, shaped like a gourd, about 3 m deep, level the bottom and spread 1 cm of fine sand, disinfect with 200 times omethoate and 150-200 times formalin solution, then store the melons while cool. Place them in layers around the cellar in the original posture of watermelon growth, leaving space in the middle for inspection and loading and unloading. Leave the cellar opening 1 m square and slightly above the ground, use supports to hold up shading materials for shade and rain protection. Keep the cellar temperature at about 15°C and the carbon dioxide concentration between 2% and 4%. With this method, freshness can be maintained for up to 3 months.
5. Silicone rubber film container bag storage. It is a sealed bag made of 0.15-0.18 mm thick polyethylene plastic film, with a certain area of silicone rubber gas exchange windows, which have high selective permeability to carbon dioxide, oxygen, etc., so that a certain concentration of oxygen and carbon dioxide is maintained inside the container bag, and it plays an automatic regulating role. For watermelons of different varieties and ripeness, as long as the silicone windows are adjusted, the purpose of safe storage can be achieved. Preserving watermelons with this method both simplifies management and improves storage results, and the cost is low.
6. Salt water freshness preservation. Select mature medium-sized watermelons, put them into 15% salt water to soak, then take them out to dry, then seal them in polyethylene bags and store them in a cellar; wooden boards can also be set up in the cellar to make containers, and the watermelons placed in the containers. Using this method to store and preserve watermelons, when taken out after one year, the rind of the watermelons is still as fresh and tender as at the beginning, sweet and tasty, and the flavor is unchanged. This method can also be used for the fresh-keeping storage of grapes, cucumbers, apples, etc.
Several points should be noted: 1. When handling watermelons, carry, load and set them down gently to prevent damage to the rind. 2. Store only one layer of watermelons on the sand bed to prevent crushing damage. 3. Every 10 days, apply a foliar fertilizer of 50 g potassium dihydrogen phosphate mixed with 50 kg water to keep the leaves green. 4. When the surface sand dries and turns white, spray water appropriately to increase humidity. 5. Build the sand bed, harvest, transport and store on the same day.
2. Ozone freshness preservation method. Choose watermelons with robust vines, regular shape, no disease spots and six-to-seven-tenths ripeness, cut off the vines, carry them with melon sleeves to avoid vibration or bumping, and transport them to the storage cellar. First disinfect the cellar, store the watermelons by grade, prop them up with soft grass pads, do not let them directly touch the ground or plastic film, and cover them with loose soft grass bags on top to prevent dust and water droplets from falling on the melons. During storage, maintaining 4°C is better; above 5°C respiration intensifies, and below 3°C they will freeze. Increase or decrease the warming layer in time as the day and night temperatures change, and keep humidity above 85%. Release an appropriate amount of oxygen and turn and move them regularly. Releasing ozone can seal and sterilize. For 150 kg of watermelons, 20 g of ozone is needed per day and night, released once every 12 hours, 15 minutes each time, releasing 10 g. Every 5 days, wear clean gloves and gently turn the melons once, and promptly pick out any diseased melons. Other fruits or vegetables must not be stored in the same cellar as watermelons.
3. Empty room storage. Choose a cool, ventilated empty room and disinfect it with a 150-200 times diluted solution of 40% formalin. At the same time, also apply the solution to the fruit stalk and rind of the watermelons to be stored, then spray once with a 6% copper sulfate solution to prevent bacterial diseases from infecting the inside of the fruit along the vascular bundles. First spread a layer of disinfected reeds on the ground, then place them in a single layer in the posture of growing watermelons, close the doors and windows during the day and open them at night, keep the room temperature at 15-16°C and relative humidity at about 80%, and spray water appropriately when the ground is dry. With this method, they can be stored for 1 month, and their color and quality are similar to freshly harvested watermelons.
4. Cellar storage. Choose a place with high, dry terrain and a relatively solid soil structure, dig a cellar with a small upper opening and a large lower opening, shaped like a gourd, about 3 m deep, level the bottom and spread 1 cm of fine sand, disinfect with 200 times omethoate and 150-200 times formalin solution, then store the melons while cool. Place them in layers around the cellar in the original posture of watermelon growth, leaving space in the middle for inspection and loading and unloading. Leave the cellar opening 1 m square and slightly above the ground, use supports to hold up shading materials for shade and rain protection. Keep the cellar temperature at about 15°C and the carbon dioxide concentration between 2% and 4%. With this method, freshness can be maintained for up to 3 months.
5. Silicone rubber film container bag storage. It is a sealed bag made of 0.15-0.18 mm thick polyethylene plastic film, with a certain area of silicone rubber gas exchange windows, which have high selective permeability to carbon dioxide, oxygen, etc., so that a certain concentration of oxygen and carbon dioxide is maintained inside the container bag, and it plays an automatic regulating role. For watermelons of different varieties and ripeness, as long as the silicone windows are adjusted, the purpose of safe storage can be achieved. Preserving watermelons with this method both simplifies management and improves storage results, and the cost is low.
6. Salt water freshness preservation. Select mature medium-sized watermelons, put them into 15% salt water to soak, then take them out to dry, then seal them in polyethylene bags and store them in a cellar; wooden boards can also be set up in the cellar to make containers, and the watermelons placed in the containers. Using this method to store and preserve watermelons, when taken out after one year, the rind of the watermelons is still as fresh and tender as at the beginning, sweet and tasty, and the flavor is unchanged. This method can also be used for the fresh-keeping storage of grapes, cucumbers, apples, etc.