Reasons and Solutions for Yellowing Leaves of Lupinus
Lupinus (Scientific name: Lupinus) is also known as lupine, and it is favored by horticulture enthusiasts for its unique spike inflorescence. However, yellowing leaves are a common problem that困扰s growers in practical maintenance. This article systematically analyzes the causes of yellowing leaves in lupines through four core dimensions of maintenance and provides professional solutions.
Environmental Changes Trigger Yellowing Leaves in Lupines
Adaptation障碍 in New Environment
The phenomenon of leaf fall and yellowing after transplantation is essentially a stress response of the plant. Data show that lupines need 7-15 days to adapt to a new environment, during which the metabolic rate can decrease by 30%-40%. It is recommended to use a progressive domestication method: maintain the original pot soil moisture for the first 3 days and gradually increase the duration of sunlight from the 4th day.
Temperature and Humidity Adjustment Techniques
Keep the daytime temperature at 20-25℃/nighttime at 15-18℃, and control the air humidity between 60%-70%. A thermometer and hygrometer can be used for real-time monitoring, and sunshade nets and humidification trays can be used to regulate the microenvironment.
Soil Imbalance Causes Yellowing Leaves in Lupines
pH Diagnosis Standard
By detecting with pH test paper, lupines grow best in acidic soil with a pH of 4.5-5.5. When pH > 6, the absorption rate of iron elements can be as high as 80%, and the leaves show reticulate yellowing. It is recommended to water with white vinegar water (1:50) every month to maintain an acidic environment.
Substrate Improvement Plan
Improvement formula: peat soil + perlite + decomposed leaf soil in a ratio of 5:3:2, and add 2g of sulfur powder per kilogram of substrate. Compacted soil can be loosened deeply with a horticultural three-tooth rake to improve aeration.
Abnormal Light Triggers Yellowing Leaves in Lupines
Light Intensity Threshold Management
In spring and winter, full sunlight (≥6 hours) is required, and in summer, 50%-60% shading is needed. When the light intensity > 80000Lux, leaf burn spots will appear within 48 hours. It is recommended to use a 60% aluminum foil sunshade net.
Supplemental Lighting System Configuration
For indoor maintenance, it is recommended to configure a full-spectrum plant light, keeping the light intensity at 30000-50000Lux, with a daily supplemental lighting duration not exceeding 4 hours and the lamp distance from the plant at least 40cm.
Water and Fertilizer Imbalance Causes Yellowing Leaves in Lupines
Scientific Irrigation Cycle
Use the dry-wet cycle method: water thoroughly when the top 3cm of soil is dry, 3-4 times/summer and 7-10 times/winter. Accumulated water for more than 24 hours will lead to root asphyxiation, and root rot will occur when the oxygen content is below 5mg/L.
Precise Fertilization Plan
Apply magic fertilizer (NPK 15-5-15) once a month during the growing period and top-dress with ferrous sulfate (0.2% solution) after flowering. Avoid using alkaline fertilizers such as plant ash, as an imbalance in the NPK ratio can cause leaf tip yellowing.
By establishing an environmental monitoring log, regularly testing the soil, and adjusting the light, temperature, water, and fertilizer systems scientifically, the yellowing leaf phenomenon of lupines can be effectively prevented. It is recommended that growers conduct a full plant health check every quarter, pay special attention to the growth status of new leaves, and adjust maintenance strategies in a timely manner to keep lupines green throughout the year.