I had set up a polytunnel consisting of 2 raised bed of 20ft x 4ft. I have planted some bell pepper, Indian chili, eggplant, melons, beans and some root vegetables. The plants are around a month old. Q1. What are the precautionary steps I should be looking at for disease controls? Which bio-pesticides, bio-agents and at what stages? Q2. When can I start micro nutrients (liquid sea weed extract) and what's the time frequency for next spray? Q3. What's the ideal temperature and humidity I should be maintaining inside polytunnel? Q4. Any source or guide for homemade bio-pesticides? Sorry for too many questions but I am very keen and enthusiastic to learn from experts. Thanks. Regards, Suresh.
Vegetables on Raised Beds
Certified GKH Gardening Expert
I will answer your questions the best I can.
Q1: Biopesticides include both products derived from bacteria and fungi, and products derived from plants. Most are targeted at specific diseases or pests, which you can look into if any specific diseases or pests appear on your plants. Here are some guides:
Other biopesticides can be used for prevention, including extracts of neem, garlic, thyme, Reynoutria, and other plants. Adding mycorrhizae (fungi that are symbiotic with plant roots) to the soil or dusted onto the seeds or roots at planting time can also improve plant resistance to diseases, and also help them absorb nutrients. I am not sure if all these products are available in your region, but some of them can be made at home.
Q2. Seaweed extract can be added 2 weeks after germination. After that, follow the instructions on the product label. These articles explain more about adding nutrients:
Q3. It is important to make sure the temperature does not go too high in hot/sunny seasons or too low in cold seasons, by providing ventilation as needed. A wide range of temperatures and humidities can be tolerable, but avoiding large swings will help keep plants healthy. This website is about high tunnels, but most of the advice applies:
Q4. Here are a few ideas:
Also look into Integrated Pest Management techniques, which include biopesticides and other measures to prevent pest problems: