Fresh cut flowers adopt cold storage technology to effectively improve flower quality
Cold storage can be divided into wet storage and dry storage. Wet storage means immersing the stem ends of fresh cut flowers in water or a preservative solution for cold storage; this method is usually suitable for short-term storage. Dry storage means wrapping fresh cut flowers that have been treated with a pretreatment solution in polyethylene film for cold storage; this method is mainly used for long-term storage. For the vast majority of fresh cut flowers, such as carnations and chrysanthemums, harvesting at the bud stage and then using dry storage results in a longer preservation time than wet storage, and the cut flower quality is better. However, for some cut flowers such as gerberas, wet storage is better than dry storage.
The general technical requirements for dry storage are as follows:
1. Harvesting. Generally harvested when the flower buds have developed and matured but have not yet opened. If harvested too early, development is not mature, nutrient accumulation is insufficient, which is not conducive to forcing flowers to open after storage, causing buds not to open or flowers to be small. Roses will also show bent necks, seriously affecting the quality of the cut flowers.
2. Sterilization treatment. To prevent virus damage during storage, fungicides can be used to dip the stem ends, spray the leaf surfaces, or fumigate. Choose agents with low toxicity, no pollution, and efficacy matching the storage time.
3. Pretreatment. Before storage, immerse the stem ends of the cut flowers in a pretreatment solution for pretreatment. The purpose is to inhibit ethylene production, provide nutrients or sterilize, and promote water absorption, etc. Different cut flowers have dedicated pretreatment solutions. The treatment time depends on the type and concentration of the pretreatment solution, ranging from as short as 10-30 minutes to as long as 12-24 hours.
4. Packaging. Usually, agricultural polyethylene film with good air permeability is used for packaging, and small packets of oxygen, ethylene, or carbon dioxide adsorbents can be placed inside the bag. Commonly used oxygen adsorbents include bisulfites, etc., and ethylene and carbon dioxide adsorbents include carbon molecular sieves, activated carbon, etc. After packaging, place them in perforated cardboard boxes and move them into the cold storage room for storage.
5. Storage. The suitable humidity is 90%-95%. The temperature depends on the type of cut flower. Generally, cut flowers native to temperate zones are 0°C-4°C, while cut flowers native to subtropical and tropical zones are 4°C-7°C and 7°C-15°C respectively. Storage time varies with the type of cut flower. For example, carnations can reach 4-6 months, chrysanthemums 3 weeks, and roses about 2 weeks.
6. Flower forcing. Under suitable temperature and light conditions, immerse the stem ends of the cut flowers in a flower-forcing solution for flower-forcing treatment. The general temperature is 20°C-25°C, and the light is 1000-2000LX. Most cut flowers can be forced to open within one week, reaching the market standard for cut flowers. Different cut flowers have dedicated flower-forcing solutions.