Location
The elm is not an indoor plant, so it should be kept outside for most of the year. Place it in a well-lit area, but in the shade, as it doesn’t like direct sunlight, especially during the summer. For better effect, the bonsai should be positioned separately. Choose a spot where the miniature tree can stand out and won’t be “overshadowed” by other objects. First and foremost, the bonsai should be placed in a way that allows the observer to clearly view the most visually appealing side of the plant.
Watering
Bonsai requires regular and meticulous watering.
In nature, a tree's roots grow deep into the soil. If there’s a period without rain, deep roots enable the plant to access the water and nutrients it needs. In confined conditions, bonsai has no way to independently direct its roots to grow in the necessary direction. Bonsai grows in a very small amount of soil, making it much more dependent on watering than a tree growing in the wild.
It’s also important to note that during hot summer days, water movement and evaporation through the leaves help regulate the plant's temperature and protect it from overheating. As long as the soil is moist, the plant can continue to develop normally even under very high temperatures. A lack of water, however, can cause the plant to dry out.
It’s also important to note that during hot summer days, the movement of water and its subsequent evaporation through the leaves help regulate the plant's temperature, protecting it from overheating. As long as the soil is moist, the plant can continue to develop normally even under very high temperatures.
Watering quantity and frequency
The frequency of watering bonsai depends on environmental conditions, soil in the container, and the type of plant. Bonsai should be watered not at strictly defined intervals, but as needed. For example, in late spring and summer, watering once a day might not be sufficient. There’s also a misconception that watering during hot parts of the day is harmful to the plant. In summer, it may even be necessary to water bonsai during sunny periods of the day. So, don’t follow a rigid schedule, such as “the bonsai must be watered once a day in the evening.”
Elm bonsai requires less moisture, but allowing the soil to dry out completely, even for one day, can often result in the plant wilting. Be sure to check the soil condition daily and water when needed. First, observe the moss. It’s easy to notice when its surface is dry, as it changes color. Use regular tap water for watering. Make sure that the soil is thoroughly moistened after watering; otherwise, only the surface might get wet while the deeper layers remain dry.
In spring and summer, the plant requires more water than in late autumn or winter. In winter, it may be sufficient to water the plant only once a month throughout the season (do not water bonsai during freezing periods).
It’s also important to consider the time of day when watering bonsai. In late spring and summer, when temperatures are high, it’s best to water in such a way that the soil in the container remains moist overnight. Water in the evening, after sunset. If you water only in the morning or midday, the soil will dry out quickly, leaving the plant in dry soil throughout the night. In autumn, when the sun is no longer as intense, you can water the bonsai at any time of the day. As for overwatering, when the soil is constantly wet around the roots, the oxygen levels in the soil decrease. This can lead to the deterioration of fine roots. Damaged roots begin to rot, and if this process isn’t stopped, a significant portion of the root system will eventually decay. As a result, the tree weakens, and if the situation isn’t corrected, it will die. Therefore, after thoroughly watering the bonsai, allow the soil to gradually dry out before watering again. Excessive soil moisture can also result from continuous rain. However, even a week of uninterrupted rain won’t harm the plant. What’s dangerous is when the soil remains saturated with water continuously throughout an entire season.
There is another mistake that often happens during watering. In summer, after a brief rain, only the surface of the soil in the container gets wet, while the deeper layers remain dry. If you're not sure that the soil is thoroughly moistened, water the bonsai as usual. In this case, excessive watering will not cause harm.
Bonsai care in winter
In winter, trees enter a state of dormancy, and their active growth temporarily halts until spring. This dormant period is just as vital for a plant's survival as the active growth phase. Therefore, bringing bonsai indoors during winter solely to prevent it from "getting too cold" is harmful to the plant. Of course, bringing it inside for 1-2 days for decoration will not harm it. But if it stays in warmth all winter, it will inevitably dry out.
In the conditions of Tbilisi, bonsai does not require any special conditions for wintering. However, if the temperature stays very low throughout the day (below -10°C), it is essential to protect the plant from freezing, especially the roots. Bonsai roots are not deeply embedded in the soil, so they can freeze. During this period, it may be necessary to temporarily place the plant somewhere where there is no severe frost.
Protection of Bonsai in Summer
At temperatures above 30°C, if no special measures are taken to protect the bonsai, it can be damaged or even dry out. How well the plant withstands extreme heat depends on the species' heat tolerance and the duration of the high temperature during the day.
The impact of heat on deciduous trees is easy to notice. The plant cools down through the evaporation of water from the leaves. During high temperatures, the plant loses water quickly. If the bonsai does not receive enough water, leaf temperature can reach critical levels. Leaf wilting is the first sign of water shortage. In extreme heat, the plant may prematurely enter dormancy, shedding leaves starting with the inner and lower ones. Direct sunlight can heat the soil, potentially damaging roots. Coniferous plants, however, do not show such "signals" and require extra care in summer.
Bonsai can tolerate very high temperatures if normal conditions for its functions are maintained. There are several simple methods to protect the bonsai from extreme heat. Avoid direct midday sunlight or use shading. Do not place the bonsai on surfaces that get very hot from the sun, such as stone, concrete, or metal. Try to increase humidity around the bonsai by spraying it more often or watering the area around it. Ensure that the soil in the container does not dry out completely. Watering at midday is another way to cool the roots.
Fertilizer
For normal growth and development, in addition to carbon (C), hydrogen (H), and oxygen (O) which the plant takes from air and water, it is essential for the plant to take macro and microelements from the soil. Macro-elements include: nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg). It also requires various microelements in very small doses: iron (Fe), copper (Cu), zinc (Zn), molybdenum (Mo), boron (B), manganese (Mn), sodium (Na), and other elements. Each of these elements is vital for the plant's existence. This is especially true for macro-elements. An excess or deficiency of each has a noticeable impact on plant growth. For example, nitrogen is required for regulating growth, leaves, and fruiting. A deficiency in nitrogen is quickly noticeable by slowed growth. Excess nitrogen causes the prolonged growth of new shoots. Adding nitrogen-rich fertilizers does not occur in the second half of the growing season. Phosphorus helps plant development, root growth, and increases resistance to drought and frost. Potassium ensures the plant's resilience to stress (extremely high or low temperatures, excessive or insufficient moisture). The optimal amount of potassium enhances the plant’s ability to overwinter and resist fungal and bacterial diseases. Calcium is necessary for the normal exchange of substances in the plant. Due to limited soil in the container, nutrients quickly deplete. Therefore, regular addition of fertilizer containing all these elements is as essential as watering. Without additional nutrition, the plant develops weakly, leaves and needles discolor, and it becomes more susceptible to diseases.
Bonsai can be fed with both organic and mineral fertilizers, but they should not be mixed and added together. There are fertilizers specifically designed for bonsais, which contain all the necessary elements. Such fertilizers can be either liquid or solid, in granular form. Liquid fertilizer dissolves in water in a specific dose, and the resulting solution is used to water the plant. The plant absorbs liquid fertilizer quickly, so it is added to conifers once every 3 weeks. Granular fertilizers have a longer-lasting effect. Such fertilizer is either mixed into the soil or placed on top of the soil in a small container. With each watering, a certain amount dissolves in water and gradually feeds the bonsai. Special bonsai fertilizer can be ordered online.
If you are unable to find such fertilizer, you can use a combined fertilizer available in gardening or flower shops. Usually, such fertilizers contain all the elements necessary for plants. For bonsais, it is preferable to use one that dissolves well in water. This type of fertilizer is more convenient to use. The packaging always lists the composition in percentages (NPK) and how much water it should be dissolved in. When adding fertilizer, be very cautious and determine the correct dose, because an excess amount can cause the plant to dry out. It is recommended that the fertilizer contains NPK-10-10-10 and microelements.
Usually, the addition of fertilizer begins early in spring, starting from March, and ends in the fall, by the end of September.
You can purchase the fertilizer "Kristaloni 20-20-20" from Samtho Kimia. Dissolve 1 teaspoon in 1.5 liters of water.
Spraying water
Water spraying is essential for both deciduous and coniferous plants. Start spraying when warm weather begins in the spring and continue until the leaf-dropping period starts. In summer, spraying daily is recommended, but of course, there is no need to spray on rainy days.
Spray water while watering the Bonsai.
Some water-soluble fertilizers are also intended for foliar spraying. This helps the development of vibrant, healthy leaves, and prevents them from getting sick easily. There are also foliar fertilizers in liquid form, which have a very positive effect when sprayed. If necessary, spray with water-diluted fertilizer or foliar feed once a week, or at the same interval as you apply the fertilizer to the soil.
Disease and pests.
Like all plants, bonsai can get diseases and pests. Therefore, it is better to carry out prophylactic treatments once a month from spring to autumn. Dissolve Ridomil Gold, Strobistar, and Aktellik in water according to the required dosage and spray. Never treat bonsai in a closed space.
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