Methods for Overseeing Rhododendrons in the North during Summer
Today, I will elaborate on common knowledge of flower cultivation, focusing on the experience with rhododendrons, specifically the methods for caring for rhododendrons in the north during summer. Below is a detailed introduction.
Due to the impact of temperature, sunlight, humidity, and other conditions in the northern regions, rhododendrons have to endure certain challenges during the summer. If not properly managed, they may accumulate multiple diseases, leading to defoliation and eventual death. So, how can we ensure they safely pass through the hot summer? The following points should be primarily considered:
I. Ventilation
In the north, rhododendrons spend the winter in greenhouses. As spring arrives and temperatures rise, by the beginning of April, indoor temperatures can reach about 28°C during the day. This is when ventilation should start, otherwise, it may lead to incurable diseases, especially defoliation. One can initially open a few vents at the top back of the greenhouse and gradually increase them as temperatures rise. When external night temperatures do not drop below 10°C, the entire plastic film can be removed, leaving only the shading net.
II. Shading
In late March, the sunlight in the north is already strong, and leaves near the plastic front can be burned, turning red-brown. It is essential to cover them with a shading net at this time. Open it in the morning and evening, and cover it during midday when sunlight is strong. Gradually increase the shading time, and there is no need to shade during cloudy or rainy days. This shading net can be laid over the greenhouse framework and secured with tension lines. By the end of May, two layers of shading nets can be used to achieve over 75% light blockage during the summer. This net can be fixed in the air with thin iron wires parallel to the ground, providing both shading and improved ventilation, making the environment inside the net cooler.
III. Watering
With the arrival of spring, the water requirement of rhododendrons gradually increases. By mid-April, they can be watered once a day on sunny days, with individual attention. By mid-May, they can be watered once a day and sprayed once. After June, in addition to daily thorough watering, frequent spraying is necessary to increase humidity and reduce temperature, keeping it between 15°C to 25°C, and relative humidity around 70%. Since the plastic film has been removed, there is generally no risk of disease due to excessive watering and lack of ventilation. This is an excellent environment for rhododendron growth in the summer.
The above three points are the main conditions. Others include avoiding over-dense placement, ensuring no standing water in the pots, applying a fertilizer solution every half month, and adding a ferrous sulfate solution once in between, with a concentration of 3% to 5%. This can be applied as a foliar spray or root irrigation. Additionally, a mixture of 1000 times the concentration of mitacloprid and 500 times the concentration of chlorothalonil, sprayed every 20 days, can ensure the plant is robust and disease-free. With such care, there is no need to worry about rhododendrons safely surviving the summer!
That is a specific introduction to the methods for caring for rhododendrons in the north during the summer. I hope you will enjoy it!