Flower and Nursery Stock Care Methods and Key Points for Fertilizing Potted Flowers

1. Fertilize according to the season. Spring and summer are the peak periods of flower growth. During this time the plants grow rapidly and their metabolism is vigorous, so they need more nutrients. Therefore, a three-element fertilizer based mainly on nitrogen should be applied, to make the root system well developed and robust, enhance its absorption capacity, and promote the growth of branches, so as to favor flowering and fruiting. After summer, if nitrogen fertilizer continues to be applied, it will be unfavorable to plant development and will affect flowering and fruiting; moreover, applying too much nitrogen fertilizer also easily invites disease and pest damage, or makes the stems and leaves weak and the flower colors dull. Therefore, before the plant enters the reproductive growth stage (flower bud differentiation stage), nitrogen fertilizer should be stopped. In autumn the plants grow slowly and their fertilizer requirement decreases. In order to improve their cold resistance for overwintering, a small amount of phosphorus and potassium fertilizer can be applied. Besides being beneficial to the reproductive growth of plants, phosphorus and potassium fertilizer can also make the plants strong and the flower colors bright. In winter the flowers enter dormancy, so do not fertilize; however, some potted flowers brought indoors in winter can continue to grow, and in this case a small amount of fertilizer can be applied to meet the needs of growth.

2. Fertilize according to the plant's growth condition. Robust plants have vigorous physiological activity, grow fast, have a strong absorption capacity and need more nutrients, so nitrogen fertilizer should be applied frequently. Diseased and weak plants grow slowly, have sluggish metabolism and poor absorption capacity, and need little fertilizer, so little or no fertilizer can be applied. Flowers can also suffer from being too weak to take tonics; if the nutrient concentration in the soil is high, it easily causes reverse osmosis, leading to scorched roots and death of the plant.

3. Fertilize according to the flower's growth stage. ① Fertilizing at the bud stage. Flowers need a large amount of nutrients at the bud stage, and a fertilizer based mainly on phosphorus and potassium should be applied to promote flower bud differentiation and produce more buds and more flowers. But do not fertilize when the flowers are blooming, so as to avoid prematurely inducing new branches, forcing the flowers to fade early and shortening the flowering period. ② Fertilizing at the fruit enlargement stage. Fruiting flowers and trees need a large amount of nutrients after fruit set, but do not fertilize when the fruit has not set firmly, so as to avoid causing a large amount of fruit drop. Once the fruit has set firmly, especially at the fruit enlargement stage, phosphorus and potassium fertilizer should be applied; this not only enables the fruit to grow quickly, but also helps the fruit stalk become thick and strong so that it does not easily fall.

4. Fertilize according to the type of flower. For azaleas, gardenias and the like, alkaline fertilizers must be avoided at all costs. ② For flowers that need heavy pruning every year, the proportion of phosphorus and potassium fertilizer should be increased, to favor the sprouting of new branches. ③ For flowers grown mainly for foliage, nitrogen fertilizer can be applied with emphasis. ④ For flowers with large blooms such as chrysanthemums and dahlias, an appropriate amount of complete fertilizer needs to be applied during the flowering period, to promote full blooming and produce flowers of beautiful shape and brilliant color. ⑤ For flowers grown mainly for their fruit, appropriately control fertilizer and water during the flowering period, and apply sufficient complete fertilizer during the fruit-swelling period, so as to favor bearing abundant fruit. ⑥ For fragrant flowers, when they enter the flowering period, an appropriate amount of phosphorus and potassium fertilizer should be applied, to favor a rich fragrance.

5. Precautions. ① Do not fertilize immediately after changing the potting soil. When potted flowers have grown in the pot for a long time, the nutrients in the soil are almost used up, and the potting soil needs to be replaced in time and base fertilizer added, so as to favor flowering and fruiting. However, the roots of newly planted stock after repotting are mostly damaged and their ability to absorb fertilizer and water is weak, so do not fertilize, to avoid the fertilizer solution irritating the wounds, causing root rot and affecting the survival rate. ② Grasp the suitable dryness and moisture of the potting soil. For fertilizing, the timing and the dryness and moisture of the potting soil must be well judged; fertilize when the potting soil is slightly dry, so that the fertilizer solution will directly seep into the soil and be absorbed by the roots; if the potting soil is too dry and gaps appear between the soil and the pot wall when fertilizing, the fertilizer solution will be lost through the gaps. And if fertilizing when the potting soil is too wet, it easily causes root rot and death of the plant. ③ Supplement with foliar feeding. When the climate and potting soil conditions are unsuitable for fertilizing, or when fertilizing has little effect, the method of foliar topdressing can be adopted. Practice has proved that in such cases foliar topdressing can achieve fairly good results.