Overwintering potted flowers: mastering the solar terms is key

In the north, potted flowers are kept indoors for about half a year, and they should be cared for scientifically according to the different habits of each potted flower and the changes of the solar terms.

1. At Frost's Descent, move potted flowers indoors. After Frost's Descent, the temperature drops noticeably. Some cold-sensitive flowers native to tropical or subtropical regions, such as Aglaia odorata, jasmine, hibiscus, poinsettia, croton, Clerodendrum thomsoniae, as well as succulent plants like Epiphyllum hybridum, Hylocereus undatus and Epiphyllum oxypetalum, need to be moved indoors in time to avoid damage from low temperatures. A warm south-facing windowsill with plenty of light is good for potted flowers to get through the winter and grow vigorously. At this time, indoor potted flowers should be watered and ventilated with care, lest too high a room temperature cause yellowing and leaf drop.

2. At the Start of Winter and Minor Snow, step up hardening of the plants. Around Minor Snow, hibiscus, Aglaia odorata, geranium, azalea and Michelia alba that have been brought indoors should have watering controlled and fertilizing stopped, so that they enter a dormant or semi-dormant state. For example, rubber plant can be watered once a month; for Michelia alba and Aglaia odorata, water only when the potting soil is dry; Epiphyllum hybridum, snake plant and Christmas cactus are best kept rather dry. Otherwise, the plants will have vigorous metabolism, spindly stems and leaves, and soft tissues, making them vulnerable to cold damage.

3. In the two Cold periods, guard carefully against freeze damage. Minor Cold and Major Cold are the coldest periods of the year, and this is the critical time for potted flowers to get through the winter. Aglaia odorata, hibiscus, croton and all kinds of cacti grafted onto Hylocereus undatus should be covered together with their pots using plastic bags, or a temporary double-layer plastic shed should be built for cold protection. At night, cover the shed with a thin cotton pad to prevent heat loss overnight; if conditions allow, use an electric light or a temporary stove inside the shed to raise the room temperature. Michelia alba and jasmine can also have some leaves removed to strengthen their cold resistance. In terms of care, choose a sunny, windless noon to water, preferably spraying with water close to room temperature, but do not overwater. On rainy and snowy days, for geranium, African violet and Begonia coccinea that bloom in winter, it is even better if supplementary lighting can be added, and pay attention to opening doors and windows and sealing cracks, strictly preventing cold wind from entering the room and causing croton, hibiscus, jasmine and others to drop large numbers of leaves or even wither and freeze to death.

4. Around the Start of Spring, protect against cold and safeguard the plants. After the Start of Spring, the temperature begins to rise and potted flowers begin to sprout and grow, but the root system has not yet fully recovered its normal function. A little carelessness can cause an imbalance of water in the plant and harm from spring cold. For potted flowers that have overwintered, special attention should be paid at this time to regulating temperature and humidity to ensure their safety.

5. After Qingming Festival, move them outdoors safely. By then the temperature has steadily risen, and the flowers can be moved outdoors one after another according to their degree of cold resistance. After being moved outdoors, pay attention to ventilation and let them gradually adapt to the outdoor environment. The more cold-tolerant camellia, orchid and azalea can be moved outdoors a little earlier, while hibiscus, jasmine and Aglaia odorata should be moved out later rather than earlier. To prevent damage from late frost, cover the potted flowers with reed curtains or film at night to ensure the safety of the potted flowers moved outdoors.