TL;DR: Algae is a natural part of hydroponics. Our silicone net cups are your best defence. They block light from hitting your growing medium, stopping algae before it starts.
Why it happens
Algae occurs naturally when light comes into contact with nutrient-rich water. In a hydroponic system, any exposed opening on your lid where light can reach the water below creates the right conditions for algae to grow.
This is not a sign something has gone wrong. It is simply biology doing what biology does.
What it can do to your plants
Algae itself will not directly harm your plants, but the conditions it creates can cause problems. It competes for the nutrients and oxygen in your reservoir, and the excess moisture it introduces around the base of your seedling can cause stem wilting over time. Catching it early makes it much easier to manage.
The best prevention: our silicone net cups
Our proprietary antibacterial silicone net cups are specifically engineered to solve this problem. Unlike hard plastic cups, the opaque silicone blocks light from reaching the rockwool cube and the nutrient water beneath it, cutting off the conditions algae need to grow.
Make sure your net cups are seated firmly. Any gap that allows light through an open hole in the lid is an invitation for algae.
Managing algae if it is already there
Hold a gentle stream Spray of water pressure about 1cm from the surface of the affected medium to physically dislodge and rinse away the algae. Repeat until the surface is clear, then check that all openings on your lid are properly sealed.
If you are using our Greenhouse propagation system to sprout your seeds, you can germinate with minimal or no nutrients until your seedlings are established, then transfer the rockwool cube directly into your main system. This reduces the available food source for algae during the most vulnerable early stage.
If you are still seeing persistent algae growth after trying these steps, reach out to our team and we will help you get on top of it.