Watering potted flowers requires care, and the techniques differ at each stage
Different species of flowers have different water requirements. For example, succulents such as cacti and ball cacti are fairly drought-tolerant and do not need much watering, while flowers such as umbrella plant (Cyperus alternifolius) and Christmas cactus (Schlumbergera) prefer a moist environment and need more watering. The same flower also has different water requirements at different growth stages: during the period of vigorous growth it needs a larger amount of water, so water a little more to promote growth; during flower bud differentiation, water a little less to promote bud differentiation.
Choosing the water quality for watering flowers
Natural water is divided into hard water and soft water. Hard water has a high content of mineral salts, and long-term watering with it will adversely affect flower growth. Soft water has a low content of mineral salts and is ideal water for watering flowers. Rainwater, river water and lake water have low hardness and can be used directly for watering, but groundwater such as spring water and well water has very high hardness and cannot be used directly to water flowers. Tap water, because it contains chlorine and other disinfecting substances, is also not suitable for direct use; it is best stored in open containers such as vats or ponds for 3~5 days, and used after the harmful substances in the water have evaporated and settled.
Watering the settling-in water well
The first watering after planting is called the settling-in water. The settling-in water must be given generously and thoroughly. Because the newly planted soil has not fully settled and there are many gaps in the soil, only after thorough watering can the soil and roots fully bond. Generally, after planting, water twice in a row: after the first watering has drained and water is seen flowing out of the drainage hole at the bottom of the pot, water again, so as to ensure the soil absorbs enough water and bonds closely with the roots.
When watering, most flowers are watered by spraying. This can both increase air humidity and wash dust off the leaf surface. However, for flowers with fuzzy leaves or those in bloom, do not spray water; instead, set the flower pot in a basin of water and let water seep in through the drainage hole at the bottom of the pot to keep the potting soil moist.
In summer, potted flowers respire vigorously and require good air permeability in the potting soil. Therefore, when the potting soil is not dry, generally do not water, so as to avoid excess water affecting air permeability, but once it is dry, water immediately and water thoroughly. In summer, potting soil often cracks due to excessive drying, so watering cannot be done all at once; otherwise the water will leak straight down through the cracks to the bottom of the pot while most of the potting soil remains very dry. After the first watering, wait a moment, and water again once the soil cracks have closed.
If you forget to water for several days and the plant becomes drought-stricken and wilted, do not rush to water heavily. First move the potted flower to a cool, ventilated place and spray the leaves with a watering can 2~3 times; after the leaves have recovered, water a small amount, and once the roots have regained their water-absorbing function, water thoroughly. Be cautious about watering in midsummer and deep winter
Water temperature has a direct effect on the physiological activity of flower roots. If the water temperature differs greatly from the soil temperature (by more than 5°C), watering will cause a sudden change in soil temperature that harms the roots, and instead affects the roots' absorption of water, causing physiological drought. Therefore, it is better to water when the water temperature is close to the soil temperature, and this should be paid even more attention in winter and summer. In winter, it is best to first store the water indoors for a while, or add a little warm water, to raise the water temperature to 15~20°C before watering. In summer, avoid watering under the blazing sun and during the high temperatures at noon.
Time for watering flowers
The time of watering should be chosen so that the water temperature and soil temperature are as close as possible. Under normal circumstances, when the difference between water temperature and soil temperature is within 5°C, watering flowers is relatively safe and will not damage the roots. As for the specific daily watering time, spring, summer, autumn and winter are all different.
In spring, autumn and winter, around 10 a.m. and after 4 p.m. are suitable times to water flowers. At noon in midsummer, the temperature is very high, and the temperature of the leaf surface of flowers can often reach as high as about 40°C; transpiration is strong, and water evaporates quickly at the same time, so the roots need to continuously absorb water to make up for the loss from leaf transpiration. If cold water is poured at this time, although water is added to the potting soil, the sudden drop in soil temperature stimulates the root hairs with low temperature, which immediately hinders the normal absorption of water. At this point, because the flower has no preparation whatsoever, the leaf stomata are not closed, and water loses the balance between supply and demand, causing the leaf cells to change from a turgid state to wilting, producing 'physiological drought' in the plant, with scorched leaves and, in severe cases, death of the whole plant.
This phenomenon is especially obvious in herbaceous flowers; for example, geranium, cypress vine and China aster most dread being watered with cold water at noon on hot days. Therefore, never water flowers at noon in the heat of summer. By the same reasoning, in winter, when the temperature difference between morning and evening is large, flowers should of course be watered at noon when the soil temperature and air temperature are relatively close. Many flower growers are in the habit of watering in the evening, mistakenly thinking this is best, but in fact it is the opposite; especially in winter or indoors, if watered at night, water dissipates slowly, which increases the humidity of the potting soil and the air and can easily lead to flowers being infected by disease and suffering cold damage.