Several methods of keeping watermelon fresh

First, use sand storage method to keep fresh. After 40-50 days of storage, it can maintain its color, aroma, taste and nutrition. Specific methods: select ventilated and transparent houses, clean up, cover the bottom 70 cm with fine river sand, harvest medium well's watermelons on a sunny evening or cloudy days, and require that the shape of the watermelon is positive, no damage, no diseases and insect pests, and each watermelon has three vine knots. Cut off 33 cm away from both ends of the joint, and the incision is immediately stained with hay wood ash to prevent bacteria from invading. Each vine node leaves a green leaf, watermelon on the sand bed, and then covered with fine river sand, covered with watermelon 5 cm thick, three melon leaves exposed to the sand.

Should pay attention to several problems: 1, carry watermelon lightly, light, light, prevent damage to watermelon peel. 2. Only one layer of watermelon is stored in the sand bed to prevent crushing. 3. Topdressing 50 kg of water with 50 grams of potassium dihydrogen phosphate every 10 days to keep the leaves green. 4. The sand on the surface should be sprayed properly when it is dry and white to improve the humidity. 5. Make sand bed on the same day, harvest, transport and store on the same day.

Second, ozone preservation method. Choose watermelons with strong, well-shaped, disease-free, 60-70% ripe watermelons, cut off the vines, wear melon covers to hold them, avoid vibration or bumping, and transport them to the storage cellar. Disinfect the cellar first, store the watermelons in stages, use soft straw mats, do not touch the ground or plastic film directly, and cover them with loose straw bags to prevent dust and water droplets from falling on the melons. It is better to keep it at 4 ℃ during storage, the respiration is strengthened above 5 ℃, and when it is lower than 3 ℃, it will be frozen. With the change of day and night temperature, the heat preservation layer increases or decreases in time, and the humidity is kept above 85%. An appropriate amount of oxygen is released and transported regularly. The application of ozone can play a sealing and sterilizing effect. 150 kilograms of watermelons need 20 grams of ozone every day and night, every 12 hours, 15 minutes at a time, 10 grams. Wear clean gloves every 5 days and gently turn the melon over and pick out the diseased melon in time. Other fruits or vegetables cannot be stored in the cellar where watermelons are stored.

Third, empty room storage. Choose a cool and ventilated spare house and disinfect it with 40% formalin 150-200 times dilution. At the same time, the stalk and peel of the stored watermelon should also be smeared, and then 6% copper sulfate solution should be sprayed once to prevent bacterial disease from infecting the fruit along the vascular bundles. The ground is first covered with a layer of sterilized Reed, and then placed in a single layer according to the watermelon growth posture. The room doors and windows are closed during the day and open at night, keeping room temperature 15-16 ℃ and relative humidity about 80%. The ground can be sprayed properly when the ground is dry. It can be stored for 1 month by this method, and its color and quality are similar to those of freshly harvested watermelon.

Fourth, cellar storage. Select a place with high dryness and solid soil structure, dig a cellar with a small upper mouth and a large lower mouth, which is like a gourd, about 3 meters deep, with a 1 cm thick fine sand at the bottom, disinfect it with 200 times omethoate and 150-200 times formalin solution, and then store the melon while it is cool. Along the cellar around according to the original posture of watermelon growth layered, leaving space in the middle for inspection and loading and unloading. The mouth of the pit is 1 meter square and slightly higher than the ground, using a bracket to hold up the shade and protect against rain. The pit temperature is kept at about 15 ℃, and the carbon dioxide concentration is between 2% and 4%. By using this method, the fresh-keeping can be up to 3 months.

Fifth, silicone rubber film container bag storage. It is a closed bag made of polyethylene plastic film 0.15-0.18 mm thick, with a certain area of silicone rubber gas exchange window, and has a high selective permeability to carbon dioxide and oxygen, so that a certain concentration of oxygen and carbon dioxide can be maintained in the container bag. and play the role of automatic adjustment. For different varieties and ripe watermelons, as long as the silicon window is adjusted, the safe storage can be achieved. Using this method to preserve watermelon can not only simplify the management, but also improve the storage effect, and the cost is low.

Sixth, keep fresh in salt water. Select ripe medium-sized watermelons, soak them in 15% salt water, then pick them up to dry, seal them in polyethylene pockets and hide them in the cellar. You can also set up boards in the cellar to make containers and put the watermelons in the box. Using this method to store fresh watermelon, after one year, the watermelon skin is still fresh and tender, sweet and delicious, and the taste remains the same. This method can also be used for the preservation and storage of grapes, cucumbers, apples and so on.