How to deal with sunflowers in winter
As a typical tropical plant, the maintenance management of sunflowers in winter is directly related to the quality of flowering next year. When the temperature continues to be below 10℃, the plant will enter a semi-dormant state, at which time the root activity decreases and the lignification of the branches decreases, and carelessness may cause frost damage. This article explains the core techniques for overwintering sunflower maintenance from three dimensions: environmental regulation, water and fertilizer management, and plant pruning.
Key points of environmental regulation
Accurate temperature control
In the northern regions, the plants need to be moved indoors before the first frost, maintaining a nighttime temperature of ≥8℃. It is recommended to use a double-layer insulation method: the inner layer using a transparent plastic bag to cover the plant (ventilated for 2 hours daily), and the outer layer hanging an insulation curtain 30cm away from the pot. In the southern regions, the pot can be placed on a south-facing enclosed balcony, and a heater can be used to assist with heating when the nighttime temperature is below 5℃.
Scientific light management
In winter, ensure 4 hours of direct sunlight daily, and use the rotating pot method to evenly expose the plant to light. During consecutive rainy and cloudy days, turn on the full-spectrum plant growth light for 3-4 hours daily, keeping the light 40-50cm away to avoid burns.
Key points of water and fertilizer management
Advanced water control techniques
Use the 'three-observation method' to determine the watering time: observe the potting soil (dry to 3cm), observe the leaves (slightly wilted), and observe the weather (continuous sunny days). Water in the morning 10-11 o'clock using 25℃ warm water, slowly pouring it along the edge of the pot, controlling the amount of water to 1/3 of summer.
Necessary analysis of fertilizer cessation
Completely stop fertilizing from the beginning of winter to the start of spring, focusing on removing any remaining fertilizer from the pot surface. When the temperature stabilizes above 15℃ in the spring, first apply a 1000-fold liquid of brassinolactone to wake up the roots, and then start the normal fertilizing program after 7 days.
Plant pruning standards
Control of pruning timing
Perform a heavy cut around the time of the minor snow season, leaving 3-5 nodes (about 8-10cm) on the main branches. Use a pruning shear that has been disinfected with alcohol, making a 45-degree oblique cut and applying healing ointment. After pruning, place the plant in a well-ventilated area and pause watering for 3 days to promote wound healing.
Solution for diseased branches
For branches that have turned yellow from frost damage, cut down 2 additional nodes until healthy green pith is exposed. After each use, the pruning tool needs to be disinfected with 75% alcohol to avoid cross-contamination.
Through a management strategy that links temperature, light, water, nutrition, and pruning in five dimensions, the survival rate of sunflowers overwintering can reach over 95%. After the Guyu season the following year, when the new buds have grown to 3cm, the plants can be gradually moved outdoors for routine maintenance, laying the foundation for a blooming summer.