Key Technical Points and Methods of Soilless Cultivation of Flowers Explained
1 Introduction
The method of cultivating plants without soil by using nutrient solutions and other facilities is called soilless cultivation. Soilless cultivation of flowers is safe and hygienic, pollution-free, and of high quality; growth is easy to control, production can follow market demand, and growth is not limited by soil or water conditions. In recent years, soilless cultivation of flowers has developed rapidly in China, and soilless cultivated flowers will become widespread in households, public places, and private rooftop gardens. However, some problems also exist in actual production, such as a small number of pest and disease occurrences, and unbalanced plant uptake due to the amount of inorganic salts in the nutrient solution. This article focuses on summarizing the feasibility basis for soilless cultivation of flowers and several issues that should be noted in soilless cultivation of flowers, in order to exchange ideas.
2 Overview of Soilless Cultivation of Flowers
2.1 Advantages and Disadvantages of Soilless Cultivation of Flowers
It overcomes the traditional method of soil cultivation and breaks free from certain limitations of natural conditions. It makes full use of space and is not limited by geographical location. The flower yield per unit area is high, and the quality standards of the flowers are consistent, making it suitable for large-scale commercial cut flower production. It removes places where pathogens and insect eggs lurk and overwinter, thereby reducing the occurrence of pests and diseases. Compared with soil cultivation, nutrient utilization rate is higher, reducing losses by 30% to 40%. Not using soil cultivation reduces labor procedures and lowers labor intensity. The entire production process requires automated control, enabling flower production to move toward modernization, standardization, and commercialization. This lays the foundation for modern agriculture. However, soilless cultivation of flowers is highly specialized, requires a relatively large one-time investment, and has high costs.
2.2 Development Trends of Soilless Cultivation of Flowers
From the trend of flower consumption, temporary flowers such as those used for conferences and gifts are mainly fresh cut flowers, accounting for 80% of this type of flower consumption, while more permanent flowers such as indoor decoration and home flower growing are mainly potted flowers and bonsai. Flower grades tend to favor precious varieties, emphasis on safety and hygiene, small and lightweight forms, and diverse styles. This trend brings opportunities for the development of soilless cultivation of flowers.
3 Basis for Soilless Cultivation of Flowers
Nutrient solutions can replace soil in providing various nutrients needed for plant growth. Many natural and processed inorganic or organic materials are lightweight, non-toxic, odorless, and dust-free, and can be used to replace soil in supporting plants. The application of computers in soilless cultivation can automatically control the concentration, pH, and dosage of nutrient solutions, as well as temperature, humidity, and light, making cultivation management simple, automated, and scientific. The emergence of some new industrial products such as rock wool and foam plastics has provided excellent substrates for soilless cultivation. The laws of some countries restrict the import of plants with soil, which has also promoted the development of soilless cultivation in ornamental plant exporting countries. The emergence of soilless cultivation has brought fundamental changes to ornamental plant cultivation. Soilless cultivation also has many problems, such as a small number of pest and disease occurrences, unbalanced plant uptake due to the amount of inorganic salts in the nutrient solution, and cost reduction, all of which require further research to promote the development of soilless cultivation technology.
4 Key Technical Points of Soilless Cultivation of Flowers
4.1 Selection of Substrates
4.1.1 Adaptability of the Root System
One of the advantages of soilless substrates is that they can create the optimal environmental conditions required for plant root growth, namely the optimal water-air ratio. Aerial roots and fleshy roots need good aeration, and at the same time need to maintain humidity around the root system of more than 80%, or even 100% water vapor. Thick and strong root systems require more than 80% and good aeration.
4.1.2 Practicality
The low bulk density of the substrate is considered for the convenience of transporting soilless cultivated flowers. Preferred substrates include ceramsite, vermiculite, perlite, rock wool, sawdust, urea-formaldehyde, and peat, as well as mixed substrates of these. Using substrates such as sand, gravel, and furnace slag, which are abundant in source and low in price, at production bases can greatly reduce costs.
4.1.3 Economy
From a comprehensive economic perspective, choosing ceramsite, perlite, and the like in flower cultivation is more economical and cost-effective, and with slight treatment they can also be reused.
4.2 Preparation of Nutrient Solutions
Like substrates, nutrient solutions are the core part of soilless cultivation. Among nutrient solution formulas, the one studied by American plant nutritionist Hoagland is the most famous and has been widely used around the world. In Japan, a balanced nutrient solution known as the Garden Test Formula has also been widely used.
4.2.1 Preparation Procedure of Nutrient Solutions
When preparing nutrient solutions, never use metal containers, and even more so never store them in metal containers; use ceramic, enamel, plastic, and glass vessels. During preparation, first use a small amount of warm water at 50°C to dissolve each type of inorganic salt separately, then pour them one by one into water that amounts to 75% of the designated volume according to the order in the formula, stirring while pouring, and finally add water to the full amount. When adjusting the pH value, first dilute the acid or alkali, add it drop by drop into the nutrient solution, and test continuously at the same time. Note that the acid should be poured into the water.
4.2.2 Selection and Use of Nutrient Solutions
When using nutrient solutions in soilless cultivation, on the one hand the content of some elements will decrease due to plant uptake, and on the other hand the concentration will increase due to evaporation of the water in the solution itself. Therefore, when flowers are growing normally, when the nutrient solution decreases, it is only necessary to add new water and not to replenish the nutrient solution.
When adding supplemental nutrient solution to hydroponic troughs or large-area soilless cultivation substrates, it should be poured in separately from different locations, and the distance between each injection point should not exceed 3 m. For fast-growing 1- to 2-year-old herbaceous flowers, perennial flowers, and bulbous flowers, the stock solution can be used during the peak growth stage. Later, as growth gradually decreases, a 1:1 dilution or dilutions at other ratios may be used as appropriate.