How to treat a polycarbonate greenhouse in autumn after harvest from diseases and spider mites? - briefly
After the harvest, clear all plant residues, wash the polycarbonate panels with a mild detergent, then treat the surfaces with a copper‑based fungicide and a neem‑oil acaricide to eradicate remaining pathogens and spider mites. Finally, seal the greenhouse, maintain ventilation, and store any equipment in a dry, frost‑free area until spring.
How to treat a polycarbonate greenhouse in autumn after harvest from diseases and spider mites? - in detail
Post‑harvest maintenance of a polycarbonate greenhouse in autumn requires a systematic approach to eliminate residual pathogens and suppress spider‑mite populations before winter dormancy.
First, remove all plant debris, fallen leaves, and fruit remnants. Dispose of material in sealed bags or burn it, preventing inoculum sources from persisting. Clean the interior surfaces with a high‑pressure water jet, then scrub frames and support structures with a mild detergent solution to eliminate dust and organic films that can harbor spores.
Second, apply a broad‑spectrum fungicide approved for polycarbonate structures. Choose a product with a systemic component (e.g., a phosphite‑based formulation) to penetrate residual mycelium, and a contact component (e.g., a copper‑based spray) for surface protection. Follow label‑specified dilution rates, covering all horizontal and vertical surfaces, including roof panels, vents, and gutters. Allow the coating to dry completely before sealing the greenhouse.
Third, implement an acaricide regimen targeting spider mites. Opt for a horticultural oil or a neem‑based product that penetrates mite shelters without damaging the polycarbonate coating. Apply at the recommended interval (generally every 7‑10 days) until populations fall below economic thresholds. Rotate active ingredients to prevent resistance development.
Fourth, enhance ventilation to reduce humidity, a key factor in fungal proliferation. Open roof vents and side panels during warm, dry days, and use exhaust fans to circulate air. Install hygrometers to monitor relative humidity, maintaining levels below 70 % whenever possible.
Fifth, treat the growing medium. Remove old substrate, sterilize containers in a pressure cooker (121 °C for 30 minutes), and replace with fresh, disease‑free soil or a well‑balanced soilless mix. Incorporate beneficial microbes (e.g., Trichoderma spp.) to outcompete pathogenic fungi and encourage a healthy microbiome.
Sixth, inspect structural seals and joints for cracks or gaps. Seal any openings with a UV‑stable silicone caulk to prevent entry of overwintering insects and moisture ingress. Replace damaged polycarbonate panels, as cracks can harbor spores and mites.
Finally, document all treatments, dates, and observations in a maintenance log. This record supports future decision‑making, ensuring that each seasonal cycle builds on verified control measures and reduces the risk of recurring infestations.