The key to success or failure in growing potted flowers lies in the potting soil

Classification, selection and blending of potting soil for potted flowers?

The roots of flowers planted in the ground can spread freely in the soil without restriction; as long as the soil layer is deep, with good aeration and water permeability, not too acidic or too alkaline, and with a certain level of fertility, they can be grown well. For potted flowers, because root growth is restricted by the pot and the soil area is small, the quality of the potting soil becomes the key factor determining success or failure in cultivation. Nationwide, the soil materials that can be used to mix potting soil for potted flowers are roughly the following ten kinds:

1.

For garden soil, it is best to dig up the surface sandy soil of vegetable plots or plots where leguminous crops have been grown; they have relatively high fertility and good granular structure, and are one of the main raw materials for mixing potting soil for potted flowers. However, it cannot be used alone to grow potted flowers, otherwise the surface soil tends to harden after drying, and after watering the aeration and water permeability are poor. Garden soil in the north tends to be alkaline, while in the south it tends to be acidic, so it must be mixed with other soil materials.

2.

River sand and fine wind-blown sand. River sand is alluvial soil from riverbeds, with relatively coarse particles; fine wind-blown sand is aeolian soil from sandy wastelands, with relatively fine particles. Neither contains organic matter or other impurities, is fairly clean, and reacts neutrally. They can be used directly to grow cacti and succulents, or used for cuttings; fine wind-blown sand can also be used directly to grow annual and biennial herbaceous flowers and bulbous flowers. Mixing them into potting soil helps aeration and water permeability. When used alone in pots to grow flowers, because they lack fertility, although they can keep the plants alive, growth is poor.

3.

Peat soil, also called turf soil, is formed from ancient plants carbonized under the action of peat decomposition. Because the times of formation differ, it is further divided into brown peat and black peat. The former formed over a shorter period, and plant remnants can still be seen; it is brown, soft in texture, light in weight, and reacts slightly acidic. The latter formed over a longer period, is mostly found in the lower layers of mining sites, is black or blackish brown, appears in clod form, contains relatively abundant minerals, reacts neutrally, and is poorer in quality. When mixing potting soil for potted flowers, it is best to use brown peat. Peat soil has relatively good water retention, water permeability and aeration, and can be used to change the physical structure of other soil materials. Brown peat can also be ground into powder and used directly to grow acid-loving soil flowers such as orchids, rhododendrons, camellias, Michelia alba and gardenias. However, because it lacks fertility, after use additional topdressing is needed to make the plants grow vigorously. Peat soil also contains a plant growth hormone called humic acid. When taking cuttings of flowering shrubs, it is extremely beneficial for stimulating the cut surface to produce callus tissue and take root. Therefore, it is often mixed with river sand or fine wind-blown sand and used as a cutting medium.

4.

Coal soot ash. Under the large chimneys of heating boilers, a large amount of granular coal soot ash often accumulates, and we can make good use of this waste. When mixing potting soil, use it to replace river

sand or fine wind-blown sand; it not only greatly reduces the weight of the potting soil, but also keeps the potting soil loose at all times. Coal soot ash also contains various trace elements such as iron, sulfur, calcium and magnesium, some of which are soluble in water and can be absorbed and used by flowers.

5.

Pine needle soil. Under pine forests in mountainous areas, fallen branches and leaves decompose and rot over many years, forming a thick layer of pine needle soil. It is grayish brown; it has a certain fertility, its aeration and water permeability are very good, and it reacts strongly acidic. Adding it to potting soil can neutralize the alkalinity in northern soil, so it is a good soil material for mixing acidic potting soil.

6.

Turf soil. When growing flowers in the northwest region and Inner Mongolia, a layer of turf 5 to 8 cm thick can be dug from natural pastures and grasslands. Stack the turf layer by layer with the grass roots facing upward, let it ferment and rot for two years, then crush it and sieve it before use. Turf soil is quite rich in fertility and contains a large amount of mineral nutrients, and reacts alkaline. It is a good material for potted Chinese roses, chrysanthemums, dahlias and deciduous bulbous flowers.

7 .

Swamp soil. Use the surface soil at the edges of ponds or on dried-up swampland; it can be used directly to grow evergreen and semi-evergreen flowering shrubs. To improve their aeration and water permeability,

it is best to mix in fine wind-blown sand or coal soot ash. It reacts neutrally, contains abundant humus and minerals, and has relatively strong fertility.

8.

Leaf mold. Every year after autumn, collect large amounts of fallen leaves of willow or other broadleaf trees, then gather them in layers with garden soil; the volume of leaves should account for more than half the volume of the garden

soil. Water it thoroughly. After composting through one winter, open the soil pile in early summer the following year; the rotting leaves, on contact with fresh air, will quickly break down into powder. After turning it over 2 to 3 times to mix the rotting leaves and garden soil evenly, sieve out the dead branches and it is ready for use. Leaf mold contains a large amount of organic matter, is loose and fertile, has good aeration and water permeability, and reacts weakly alkaline. It is a good soil material for growing Chinese roses, chrysanthemums, dahlias and various herbaceous flowers in the north. Apart from willow leaves, the fallen leaves of other broadleaf trees need a longer composting time.

9..

Mountain soil. Mountain soil in South China and Southwest China is mostly reddish brown, called red mountain soil, and reacts strongly acidic, suitable for growing camellias, rhododendrons, orchids, Michelia alba, etc. Mountain soil in Central China and East China is mostly grayish brown, called black mountain soil, and reacts weakly acidic, suitable for growing osmanthus, gardenias, jasmine, Michelia figo, etc. When digging, soil from the mountain base is best; it is the surface soil of mountain ridges washed down by rain, relatively fertile and fully weathered, but stones must be sieved out.

10.

When growing potted flowers in the Jiangnan region, pond mud or river mud can be collected, locally called mud cement. After drying them thoroughly in the sun, break them into small pieces about 1 cm across, and they can be used directly in pots to grow flowers. The main roots of flowering shrubs mostly grow between the mud pieces, where aeration and water permeability are very good, which benefits root respiration, while the fibrous roots penetrate into the moist mud pieces to absorb nutrients. Pond mud is relatively fertile, and the mud pieces do not easily break down when exposed to water, so its quality is higher. River mud contains more sand, and the mud pieces easily break down, become compacted and harden when exposed to water, and its fertility is also poorer.

In landscaping, some of the above ten soil materials can be used alone, while others must be combined with one another to make up for each other's shortcomings, blended according to the different requirements of various flowers for soil acidity and alkalinity and their degree of moisture tolerance. One should also use local materials on the premise of reducing production costs, so as to achieve twice the result with half the effort.