Detailed Explanation of Key Techniques for Autumn Fertilization of Bonsai

  The general characteristic of tree growth is that the shoots of spring and summer have already lignified, and a new root and leaf system has formed, increasing the tree's assimilation area and accumulating nutrients for autumn shoots and flower bud differentiation. In evergreen trees, autumn shoot growth and flower bud differentiation occur at the same time, and the competition for nutrient distribution is fierce, with vegetative growth taking precedence over reproductive growth, reproductive growth consuming more than vegetative growth, and the two being able to inhibit each other.

  Autumn is an important period for bonsai management, and soil, water, fertilizer, and light should all be strengthened in a targeted way. Evergreen trees should also be pinched back to prompt the autumn branches to lignify as quickly as possible, creating conditions for overwintering. Conifers and deciduous trees form buds but do not sprout in autumn, so in late autumn they should be encouraged to enter dormancy on schedule, so as to avoid wasting nutrients and affecting their smooth overwintering.

  Fertilizer should be applied at the right time and in the right amount, with timely and repeated light applications in early autumn. Fellow bonsai growers can use Yu fertilizer, which is convenient, hygienic, has no unpleasant odor at all, and is rich in fertility. Apply less in mid-autumn, and control fertilization in late autumn, so as not to stimulate late autumn shoots. Using fertilizer in this way can prompt autumn shoots to emerge early and grow vigorously, allowing vegetative growth and reproductive growth to proceed at the same time, and next year the leaves will surely be lush, the flowers abundant, and the fruit plentiful. If the tree is very vigorous and there is more autumn fertilizer, spring flowers blooming in autumn may occur. My Chinese persimmon and Buddhist pine have repeatedly shown the phenomenon of spring flowers blooming in autumn and spring fruit setting in autumn. Early autumn fertilization is used more in fruit tree production, while stump management is more refined, so early autumn fertilization should be applied even more.

  How should bonsai be fertilized? Generally, apply light fertilizer frequently:

  1. For flowering and fruiting bonsai such as pomegranate, crabapple, wisteria, firethorn, and heavenly bamboo, apply more phosphorus and potassium fertilizer.

  2. For foliage bonsai such as five-needle pine, boxwood stump, and ivy, nitrogen fertilizer should be the main component, supplemented with phosphorus and potassium fertilizer.

  3. For pine and cypress bonsai, you can make your own diluted fertilizer from fully rotted soybean cake water, 3 times a year.

  4. Fertilize during the spring, summer, and autumn growing seasons, and stop fertilizing during the winter dormant period.

  5. For trees that have just been potted, new roots have not yet grown, so do not fertilize.

  6. Liquid fertilizer must not be too concentrated; it must be diluted before use, otherwise fertilizer damage will occur.

  7. Organic fertilizer and cake fertilizer must be fully rotted before they can be used, otherwise they will ferment in the potting soil and generate high temperatures that burn and kill the root system.

  8. Do not sprinkle the liquid fertilizer water used as a top dressing on the leaves.

  10. Fertilizing on sunny days is good; fertilizing is not suitable on rainy days or during the plum rain season.