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Pythium | Plant-Magic

Pythium- The hydroponic plague

Pythium is a big problem when growing using hydroponic methods, especially when the summer approaches and grow room temperatures rise. But what is it, what causes it and how can it be stopped?

Pythium infection of a rockwool cube in an NFT hydroponic tank

Pythium infection of a rockwool cube in an NFT hydroponic tank…


What is Pythium?

Pythium is name of a family of fungus-like microorganisms (recently re-classified as plant parasites), but commonly called water moulds. Pythium plays a big part in the condition damping off, which kills seedling in cool, damp or high humidity conditions (hence the name damping off). This is because the spores require surface water to travel which, in field crops means the damaged caused is often localised to areas of poor drainage. In hydroponics however, the flow of nutrient solution acts as a perfect delivery system for the Pythium spores to spread. The natural capillaries in soil and coir act as a filter to the spores, reducing the spread, but the bare roots in hydroponic provide easy access. 

As the spores travel via water, the first tissue it meets is often the root system. This leads to Pythium-induced root rot, which starts by reducing the vigour of the plant, causes wilting and yellowing (and other signs of deficiencies) of the leaves and the roots turn from white, to brown. As the roots become further infected, they turn darker brown, appear slimy and begin to decay and die. With the death of the roots, the plant also dies, but not before allowing Pythium to produce millions of spores to spread the infection.

Two big problems with Pythium are that it is able to survive on decaying plant matter for a long time after the plant has died. This means that unless everything is completely cleaned and a strict hygiene regimen is followed, the infection will remain in your grow room. Secondly, Pythium is unspecific in the types of hosts it attacks, this means that it will infect a wide variety of different types of plants, and rotating crop types won’t avoid the dormant spores in the grow room.


How do I stop Pythium?

There are a few ways to prevent or minimise the impact of Pythium. With seedling, avoid sowing them too close together, as this reduces air movement, leading to the humid conditions that cause damping off. The standard advice for any grow room is important i.e. keeping good airflow, controlling humidity to between 40-60% and maintaining good hygiene practises. Pythium is often a secondary infection; this means that it usually attacks a plant when it’s been damaged or is suffering with non-ideal growing conditions. So just by keeping your grow room ventilated and your plants healthy you can reduce the chances of a Pythium infection.

Because Pythium is such a big problem for people and companies growing hydroponically, there are plenty of products out there that claim to stop Pythium from damaging your crop. You can use UV light or peroxide based products, but these can be expensive and detrimental to your crop, as there is a fine line between killing Pythium and killing your plants. Another avenue of approach is the array of liquid based sterilizers often utilising chlorine. While these products can work, the effectiveness of them is directly related to their age as their shelf life is limited. Chlorine is a volatile element, and in liquid solution it evaporates off. Due to the danger of using strong solutions of chlorine, companies selling these products have to use low concentrations to allow them to sell to the public. This means that the little chlorine that is in the product to begin with, is being lost all the time. When you finally pick up a bottle sat on the shelf of your local grow shop, there’s often no way of knowing how old it is, and whether it will be effective. Here at Plant Magic we have a different approach with our product Pyth Tabz.


What are Pyth Tabz?

Plant Magic Pyth Tabz are a strip of 10 highly concentrated chlorine-based tablets that have been specially formulated and have gone through thousands of hours of testing to allow all growers in hydroponics to have clean and sterile tanks free of Pythium and other water-borne diseases. Not only will a single tablet sterilise 120 litres of water, but it will continue to sterilise it for up to a week! This means that if you have two 60ltr tanks (e.g. GT604s), then you could sterilise both tanks for up to a week by dissolving a single Pyth Tab in 1ltr of water and pouring half of the solution into each tank. Pyth Tabz come in strips of 10 tablets, 2 for the two weeks of vegetative growth and 8 for the eight weeks of flowering/fruiting. Pyth Tabz are also effective against a multitude of biological contaminants including bacteria, viruses and other type of fungi. Unfortunately this means that they cannot be used alongside any beneficial bacteria or fungi such as mycorrhizae.

A strip of Plant Magic Pyth Tabz

Pyth Tabz


The main advantage with Pyth Tabz is that they use a solid, tableted form of chlorine, alongside other sterilisers in a hermetically sealed foil strip. This form of chlorine will not be released until it makes contact with water. This allows for a much more stable product with a longer guaranteed shelf life, so when you open up the sealed pack you know that it works every time.


Our Blog: Hydroponic Tips & Tricks

Whether you are an expert who already has a thriving crop of healthy plants, or you are trying to grow your very first hydroponic yield, we can help you to grow the strong and healthy crops you have always wanted.

Here at Plant Magic Plus, our team of gardening experts work very hard behind the scenes to provide you with the high quality nutrients, additives and growing media that will help you to get the most out of your growing plants.

But we understand that successful horticulture is about more than just having good quality chemicals, nutrients or fetilisers, that's why we have written this blog to provide you with the insights, tips and techniques you will need to give your garden that extra magic touch.

From helpful advice about watering your plants in soil and a guide to magnesium nutrients, to top tips about growing hydroponic vegetables and a comprehensive overview of microbes, we’ve got everything covered.


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