Using beneficial organisms in your orchid culture
A short introduction
For several years now, we have been introducing beneficial organisms to our growing media and mounted orchids with some amazing success and would like to share our experience with everyone.
Being a young orchid growing company that’s just starting, fungal and bacterial infections were something new to us and a recurring problem. But rather than spraying some nasty stuff like diluted Hydrogen peroxide or Physan20 for example (which, in hindsight, are terrible things to spray on your orchid roots and in your orchid medium), we wanted to have something more…nature-inspired let’s say. And so we started looking and asking around to the more adventurous types amongst our orchid acquaintances, until we regularly ended up discussing bacteria, mycorrhizae, parasitic fungi and other similar beneficial organisms.
Some of you might be skeptical when hearing about beneficial bacteria or pro-biotics, seeing it all as some mumbo-jumbo that just doesn’t weigh up to good old-fashioned chemical sprays.
Honestly, we were too at first. “You want me to ADD fungi to my orchids? As if I didn’t have enough trouble keeping the actual fungal infections under control…”
But backed up by some people more knowledgeable than us (there are plenty), we decided to try it out.
The good thing is, it literally can’t affect your orchids negatively using these organisms, not like trying out a new chemical that might burn your leaves out in a jiffy.
So why not give it a go?
Here’s the basis we’ve been using to understanding what fungi are, how they work, what they need to thrive and how best to fight them and avoid any nasty infections.
What are fungi?
Fungi are living organisms classified in their own kingdom that are different from plants in two ways: their cell walls are composed of chitin rather than cellulose (like plants) and they do not make their own food (like plants do through photosynthesis).
The important part here is the fact they do not make their own food. Meaning they need to get it from somewhere else. They get their food by decomposing matter or eating off their hosts as parasites.
Decomposing matter is not a bad thing, as breaking down organic matter releases carbon, nitrogen (a nutrient for your orchids) and oxygen into the soil and the atmosphere.
But, decomposing organic media become humus, a material not suited to orchid roots. Due to its structure, a decomposed medium as humus won’t allow enough oxygen to reach the roots. This will eventually lead to rot and your orchid will die.
Last thing: fungi reproduce through huge amounts of spores (a lot of zeroes) rather than pollen or fruits. As you can imagine, this means once you have a fungus around, it can spread at a phenomenal rate through your growing area.
How can fungi affect your orchids?
There are 2 types of fungi that are going to affect your orchids:
Pathogenic (disease-causing) fungi get inside your plants. They either make a hole in the ‘skin’ (epidermis) or they will grow through the ‘breathing-holes’ (stomata) and thus infect your plant. Once they’re inside, they release a poison that kills plant cells and absorb food from them. They might also act parasitically and steal nutrients from the living cells of your orchid.
The spores of these fungi can enter your orchid in different ways, from being airborne or living in the water and soil. Airborne spores will attack the leaves of the plant, creating dead (black) spots on your leaves or killing it completely. Other spores will end up in the water and soil and enter your orchid through its root system, blocking the water-conducting cells or killing the roots, which will end up killing your orchid as well.
An example of a pathogenic fungus is what is known as Black Rot:
This fungus causes black rot inside orchids, typically when there is plenty of water available for them. Their spores are capable of independent movement (zoospores) inside water and can thus enter your orchid if there is water sitting on top of the leaf for example. The next stage in their life cycle is developing their hyphae (tiny, thread-like filaments) rapidly through the affected areas of the leaf or other plant tissue. Once this has started, the spots will rapidly develop into brown and then black, spreading throughout the whole plant (and its neighbors) if left untreated.
Fungi competing with your orchids
Some fungi can be a problem for your orchids simply by existing in the growing medium.
A perfect example of this is the Snow Mold:
Snow mold is a water-repellent fungus that spreads through the growing medium. At a certain point, it will have spread throughout the whole medium, preventing water from reaching the orchid roots. So even by not feeding off the plant, it will damage your orchid and thrive off decaying matter inside the medium.
Introducing beneficial organisms to your growing medium
When we talk about beneficial organisms, we mean any organism that benefits the growing process of your plant. Insects, plants, bacteria, fungi, nematodes, etc. that will offer you (better) pest control, pollination and overall soil and plant health.
Generally speaking, the beneficial organisms we will discuss below will have the following results on your plants:
Increased drought tolerance
Improved stress resistance
More vigorous growth and more shoots per growth cycle
Healthier plants and boosted immune defences
Crowd out pathogens (thanks to a bacterial colony for example)
Trichoderma are parasitical fungi and will not only destroy unwanted organisms, but also induce and increase the host plants resistance to pathogens, mould and undesirable fungi, not only in the plants root system but throughout the structure of the plant.
Mycorrhizae will establish a symbiotic relationship with your orchids by producing hyphae (tiny microscopic filaments) that are incredibly long and they are able to transport valuable minerals such as Nitrogen, Phosphorous, Potassium and Trace elements back to the host plant. Because of their length they can obtain these nutrients from a volume which is vast when compared to the plant’s root system alone.
Bacteria help to create a healthy and highly nutritional environment for plant roots. For example, the nitrogen fixing bacteria B. polymyxa can take atmospheric nitrogen and convert it to ammonia which can be absorbed by the plant.
Other bacteria will break down and degrade waste organic materials that accumulate over a growing season. This not only releases valuable nutrients back in to the food web but means these potential sources of food don’t get taken advantage of by undesirables (think: things you're actually trying to get rid of, such as certain fungi) within the substrate.
Things to consider
If you’re a die-hard Hydrogen Peroxide or any other similar anti-bacterial or anti-fungal product, remember this will also affect the beneficial organisms (naturally present in your growing medium, or added) and kill them off in the worst-case scenario. It’s either the one or the other, but we would advise you to trust in nature and move away from those harsh products. We haven’t opened our bottle in over 2 years now, just to give you an idea.
Don’t expect this to be a short-term miracle product, resulting in instant blooming or leaf-spot removal (no product does that by the way). Consider this a long-term, well-balanced mix of organisms that will keep your plant healthy throughout its whole lifecycle.
These organisms do require a moist environment and will continue to live as long as conditions are right. A dry period will result in the fungi releasing spores for example or bacterial colonies to be reduced, but overall these organisms should take care of themselves.
How and when to use
We apply our organisms on a monthly basis in order to:
Replenish any affected colonies (due to a dry period for example)
Introduce the organisms in any new plant we have in the greenhouse
Generally, we would advise to introduce these organisms every time you have a new plant in your greenhouse or orchid collection. You can’t overdose, so a plant already containing these organisms won’t be bothered by a second dose shortly after. If you're a bit lazy or have a large number of plants to take care of, apply it on a monthly basis and you will be fine.
Are you interested in trying this out for yourself?
Beneficial organisms will be a great addition to your growing medium and will help you fight fungal and bacterial infections, offer you stronger, more resistant plants that display an overall more vigorous growth.
Check out our ideal mix of beneficial organisms, easily diluted in water to be used in spraying, watering, or even (semi-)hydroponics systems.