A biofilm is a community of bacteria, fungi or algae that attach to a surface and wrap themselves in a sticky matrix of their own polymers. In irrigation and hydroponic systems biofilms coat tubing, emitters, chillers, reservoir walls and roots. They are more resistant to disinfectants than free-floating microbes, and can protect pathogens such as Pythium.
In practice
Growers meet biofilm as "root slime": brown or tan gel on roots in deep water culture and recirculating systems, often with a sour smell, or as clogged drippers and slick lines. Not every biofilm is harmful; beneficial bacteria also form films on healthy roots. Trouble begins when warm, low-oxygen water lets harmful organisms dominate. Prevention is light-tight reservoirs, cool well-aerated solution, regular cleaning of lines between runs, and a consistent strategy: either a deliberate beneficial-microbe reservoir or a fully committed sterile one. GenetixBay prefers the beneficial route, since bacteria arrive regardless.
Don't confuse with
- Pythium root rot: a specific pathogen; slime is often a symptom of it, not the same thing.
- Algae: green growth where light reaches the water.
- Additive staining: brown colour without slime.
A chiller is a refrigeration unit that cools hydroponic nutrient solution, keeping it around 18-21 °C so it holds more oxygen and root pathogens are discouraged.A genus of oomycete water moulds, such as Pythium myriotylum and P. aphanidermatum, that cause brown, slimy root rot, especially in warm hydroponic systems.DWC (deep water culture) suspends a plant's roots in an aerated nutrient solution, typically in a bucket with a net pot lid and an air stone.A recirculating (closed) system returns drained nutrient solution to the reservoir to be reused, saving water and nutrients but needing more monitoring and sanitation.Drip irrigation delivers water or nutrient solution through tubing and emitters directly to each plant's medium, in measured amounts on a timer or controller.Pest and disease prevention by changing how the crop is grown, such as humidity, airflow, spacing, watering and cultivar choice, so pests and pathogens struggle to establish.A beneficial-microbe reservoir deliberately inoculates hydroponic solution with helpful bacteria and fungi so they occupy the root zone before pathogens can; GenetixBay prefers this approach.Decay of roots by pathogens such as Pythium, Fusarium, Rhizoctonia or Phytophthora, usually triggered by low oxygen, heat and waterlogging around the roots.Cleaning and disinfecting rooms, tools, containers, irrigation and people's clothing so that pests and pathogens are not carried from plant to plant or crop to crop.Stocky dark flies of the genus Scatella (family Ephydridae) that breed in algae on wet surfaces; mostly a nuisance and contamination issue rather than a root feeder.
