Why Can't Flowers Be Grown in Greenhouses?
In the cold winter season in the north, greenhouses are an important facility for protecting flowers from the cold. However, many horticulture enthusiasts have found that after moving their beloved orchids, roses, and other plants into greenhouses, they experience yellowing leaves and rotting roots and stems. This seemingly contradictory phenomenon hides special challenges of the greenhouse environment.
Dilemma of Survival in an Enclosed Space
Deadly Deficiency of Air Circulation
Although the fully enclosed structure of greenhouses significantly retains heat, it also completely blocks the exchange of natural air. Studies have shown that after 12 hours of closure, the concentration of carbon dioxide drops by 40%, while plant metabolic gases like ethylene accumulate to exceed standards. It is recommended to open the top windows for at least 2 hours daily, or install mini exhaust fans to maintain air circulation.
Double Crisis of Humidity Imbalance
The sealed environment formed by glass or plastic film keeps humidity at over 80% throughout the year, providing a breeding ground for fungal spores. Experimental data shows that at the same temperature, the incidence of powdery mildew in greenhouse environments is 3.8 times higher than in open-air environments. Using a dehumidifier for 2 hours at 10 a.m. can control humidity within the optimal range of 60%-70%.
Hidden Threat of Invisible Gases
Invisible Killer from Fertilizer Emissions
Nitrogen fertilizers like urea release ammonia in high temperatures, and at a concentration of 5ppm, orchid leaves will show brown spots within 72 hours. It is recommended to switch to slow-release fertilizers and use activated carbon absorbents, which can ensure nutrient supply and reduce gas hazards.
Chronic Poisoning from Equipment Emissions
Coal-burning equipment used for heating in winter produces carbon monoxide. When the concentration exceeds 0.2%, succulent plants will stop photosynthesis. Using electric heating membranes with a temperature control system can reduce harmful gas emissions by 90%.
Crisis of Ecological Chain Breakdown
Imbalance of Microbial Systems
The enclosed environment reduces beneficial bacteria in the soil by 83%, while pathogenic fungi like Fusarium increase by 4 times. Supplementing with EM agents and mixing in earthworm castings monthly can rebuild a healthy soil microecosystem.
Consecutive Reactions from Absence of Natural Predators
The greenhouse isolates beneficial insects like ladybugs and lacewings, leading to a fivefold increase in the reproduction rate of spider mites. Hanging yellow sticky traps along with biological control can establish a new ecological balance.
The emergence of smart greenhouse control systems and three-dimensional cultivation techniques provides new ways to solve these problems. By installing environmental sensors to monitor data in real-time and using automated ventilation equipment, modern horticulture can create an artificial ecosystem closer to nature. Choosing disease-resistant varieties like camellias and Monstera deliciosa and using soilless cultivation techniques can truly make greenhouses a paradise for plant growth.