Key Technical Points for Raising Hami Melon Seedlings and Planting in Autumn
1. Sowing
In the Shanghai region, raising Hami melon seedlings in autumn is best done at the end of July and the beginning of August, choosing high-yield, high-quality Hami melon varieties suitable for cultivation in the Shanghai region. First dry the Hami melon seeds in a constant-temperature chamber at 40°C for 24 hours, then keep the temperature constant at a high temperature of 70°C for dry-heat sterilization for 72 hours.
For seedling raising, use plug trays or nutrient pots, filled with sterilized seedling nutrient soil. You may use rice chaff : vermiculite : perlite : peat at 2:1:1:2, mixed with sterilized organic fertilizer. Sowing is best done in the evening. Before sowing, the seedling nutrient soil must be thoroughly watered with a 5000-fold dexon solution for sterilization. When sowing, poke a hole 1.5 cm to 2 cm deep in the seedling nutrient soil with your finger, sow 1 seed per hole, place the seed flat, and do not leave a gap underneath. After sowing, cover with nutrient soil and press lightly with your hand. After sowing, cover the surface of the seedbed with a shade net to lower the temperature.
2. Seedbed management
Under normal circumstances, open the greenhouse for ventilation. When more than half of the seeds have pushed through the soil, remove the shade net as soon as possible if the temperature permits, so the seedlings can receive light and to prevent leggy growth. At midday, when temperatures are high, still cover appropriately with a shade net for shading and cooling.
Watering is best done in the early morning. In the Shanghai region in autumn, temperatures are relatively high after 10 a.m., so before then ensure there are no water droplets on the seedlings. After emergence, control moisture to prevent damping-off and leggy growth of seedlings, following the principle of “dry and wet alternately”.
3. Pest and disease control
During the seedling stage, Hami melon is prone to damping-off, rhizoctonia rot and fusarium wilt. If a small number of diseased seedlings are found, remove them as soon as possible and spray 75% chlorothalonil wettable powder at 600-fold solution, or 64% oxadixyl mancozeb wettable powder at 500-fold solution, or 70% mancozeb wettable powder at 500-fold solution for timely control, generally spraying once every 7 to 10 days. Keep the greenhouse ventilated and exchange the air to reduce the relative humidity inside, so as not to create suitable conditions for disease occurrence.
Pests that are likely to occur in autumn in the Shanghai region include tobacco whitefly, melon aphid, American serpentine leafminer, melon borer, beet armyworm and red spider mite, etc. For tobacco whitefly control, use imidacloprid at 2000-fold solution; for melon aphid control, you may use 20% acetamiprid emulsifiable concentrate at 5000-fold solution (20 grams per mu); for American serpentine leafminer control, you may use 75% cyromazine at 2000-fold solution (7 to 10 grams per mu); for melon borer control, you may use 20% fenvalerate emulsion at 3500-fold solution (30 grams per mu); for beet armyworm control, you may use 2.5% lambda-cyhalothrin emulsifiable concentrate at 2000-fold solution (50 grams per mu); for red spider mite control, you may use 20% abamectin emulsifiable concentrate at 1000-fold solution (100 grams per mu). Pesticide application is generally carried out in the evening, when it is less likely to cause phytotoxicity, and the pesticide has a long duration of action and good control effect. Installing insect-proof nets and other insect-proof facilities around the greenhouse can effectively reduce seedling-stage pests.