Why does the whole plant wither and the stem turn black?

If it's black from the bottom, it's rotten roots, maybe there's not enough fertilizer. Add a little nitrogen and potassium fertilizer.

1, growth habit: like cool, humid and ventilated climate, afraid of high heat, hate cold and like light, but cultivation should avoid sun exposure and shade in summer, and grow well at 7~ 15℃. Strict requirements for soil, sandy soil rich in humus is the best, to avoid soil moisture, and good ventilation and drainage, especially slightly acidic soil. Vegetative growth above 15℃, flower bud differentiation after 4~6 weeks below 15℃.

2. Pest control: cultivation and maintenance: humus soil or mixed culture soil is the best soil for potted flowers. From the first sowing to planting, it is generally necessary to water the pot three times, and the diameter of the planting pot is 13~ 17cm. During the growing period, the diluted fertilizer should be applied once a week to maintain a high air humidity, but the water in the basin soil should not be too large. If the air is too dry, it is necessary to spray more water and water less, and water should master the principle of dryness and wetness to prevent root rot. Water and fertilize. Don't let the fat water stick to the leaves, it will cause the leaves to rot. In winter, the indoor temperature should be kept at 5~ 10℃, and attention should be paid to shading if the light is too strong. Calceolaria is a plant with long sunshine time. It can blossom ahead of time by using artificial light to extend the daily sunshine time in greenhouse. Calceolaria blooms from February to May of the following year. Calceolaria has poor natural pollination ability and needs artificial pollination. The corolla should be removed after pollination to avoid mildew and improve the seed setting rate. The seeds gradually mature from May to June, and should be harvested in time when they turn brown before cracking.

3. Plant culture:

Flower language: aid, wealth, wealth

Huabu: You are a devoted and single-minded person. You are very cautious about love and will not fall in love easily. Once you are right, you will love it until death do us part. If you find that your lover is not special to you, you cannot forgive him, so you need to make more friends.

Flower proverb: The value of marriage is to make people more mature.