Biodegradable Containers in Hydroponics (Are They Better?)
When I started my hydroponic journey, I explored using biodegradable containers instead of the usual plastic-based net pots. It was interesting, I am telling you. But, did it work better? This is the question that I will be answering today.
In general, biodegradable containers are more suitable to use during early plant stages. They are not recommended for use with mature plants in the hydroponic system. The benefits of using biodegradable hydroponic containers include eco-friendliness. However, there are cons as well, including the potential spread of fungal diseases.
Indeed, every product has its advantages and disadvantages. For biodegradable containers, knowing these will help you decide whether or not to use them in your hydroponic garden. Today, I will help you with that! Let’s move forward.
Why are Biodegradable Containers Used in Hydroponics?
Biodegradable containers such as pots, trays, and pipes are used in hydroponics because 1) they are environmentally friendly, 2) ideal for growing and selling organic produce, and 3) they can be transformed into compost when they break down after harvest.
1. Environmentally Friendly
Biodegradable containers are made of natural materials such as paper, coir, grain husks which are held together by starch-based binders. All of these raw materials can be decomposed back into soil and be a source of nutrients for plants once again.
2. Marketing as Organic
Using biodegradable hydroponic containers is wise, from a marketing aspect. It can make more people aware that your products are completely organic.
It has been a culture that when people hear biodegradable, they automatically associate that with being organic and environmentally friendly. That is the concept being taken advantage of when using biodegradable containers.
3. Compost Ready
Another aspect considered by growers is the technical side. Biodegradable containers can also be added to your garden soil, or growing medium, as it decomposes and adds carbon.
How does that happen? Is it practical to do that? These two questions will be answered at the end of this article.
Which Parts of a Hydroponic System Can Be Biodegradable?
Using biodegradable growing pots and trays is recommended when growing from seed to the seedling stage. In contrast, using biodegradable net cups and pipes in a hydroponic system is not recommended.
Biodegradable Growing Pots and Trays are Recommended
Biodegradable growing pots and trays are commercially available and are best to use during the early stages of seedling growth.
Several pots and trays made of paper, like the ones below, are available on Amazon.
When using these products, the manufacturer always recommended not to overwater, as this can disintegrate and destroy the biodegradable growing pots and trays.
This encapsulates the reason why these products are only viable to use from the seed to seedling stages. Why? Because during these times, the plants are not yet incorporated into the hydroponic system. Thus, you can control the amount of water being provided to your plants.
If we contrast the early stages to the late stages, your veggies and herbs after the seedling stage are already transplanted and suspended in water all the time. Thus, using a paper-based container for the developmental and reproductive stages is impractical.
Biodegradable Net Cups are Not Recommended
It is impractical to use biodegradable net cups in hydroponics. This is because an organic wet surface is a favorable environment for molds and microorganisms to proliferate.
Some gardeners use the same grow pots pertained above as hydroponics net cups for nutrient film technique (NFT). They use these biodegradable pots to take advantage of being able to use the “organically produced” label for marketing.
The brown-colored pots are made from natural fibers and have the same function as the plastic hydroponic net cups in nutrient film technique. Using this product, the roots of the plants are expected to grow through the porous pot wall.
Through the growing time, the fibrous root system will wrap across the biodegradable net cup, thereby making the pot itself a valuable part of the plant.
Biodegradable Pipes are Not Recommended
It is possible to create biodegradable hydroponic pipes from bamboo, but it is not highly recommended for a long period of time. This is because it may carry plant diseases and can be a breeding ground for harmful microorganisms like fungi and bacteria.
One way to make it, as illustrated in the figure above, is to fix a series of bamboo together with spaces in between them that will contain your net cups (Option A). Another way is to drill a hole into the bamboo that can fit a net cup of your choice (Option B).
This is absolutely a creative, and environmentally friendly option. However, we also need to consider different factors that can affect plant growth and development.
The next sections enumerate the advantages and disadvantages of utilizing biodegradable containers in hydroponic gardening.
4 Pros of Using Biodegradable Hydroponic Containers
Using biodegradable containers in hydroponics is 1) a cheaper option, 2) environmentally friendly, 3) easier to use when transplanting, and 4) can be transformed into compost.
1. Cheaper Option
Biodegradable pots on Amazon cost less than 20 USD for a 100-piece pack, while plastic net cups reach 30 USD or more for the same quantity and size.
If you browse on Amazon, there are available 100-, or even 120-piece sets of biodegradable grow pots with prices ranging from 16 to 20 USD. These are usually 2, 3, or 4 inches in diameter.
In comparison with the plastic net cups, let us use the 3-inch diameter size. Plastic net cups of this size cost 16 USD for 50 pieces—that is two times more expensive than the biodegradable ones!
2. Environmentally Friendly
Using biodegradable products lessen one’s plastic consumption, thereby helping the environment.
Using biodegradable growing trays or pots is eco-friendly as it is made from paper, or in some cases peat. These materials decompose and nutrients are eventually absorbed by soil and used by plants.
However, I personally recommend using these for household or small-scale gardening only, and not for large-scale gardening. This will make more sense moving forward.
In the case of bamboo pipes for nutrient film technique (NFT) in hydroponics, I can say that this is really an ecological and sustainable alternative for small-scale gardening. But as I mentioned a while back, it is not advisable for long-term and large-scale food production due to possible proliferation of diseases.
3. Easier Transplanting
During transplanting, the gardener can just tear the biodegradable pot and transfer the plant easily.
As a gardener, I can attest to this. Transplanting is stressful not only for the plant but also for us. This is because we must be extra careful in handling the roots of our seedlings. Remember that any wound or root destruction can be a point of entry for plant disease.
Considering this, using a pot that can easily be torn apart lightens the pressure on our shoulders a little!
4. Can Be Transformed Into Compost
Paper is a rich source of carbon. Thus, incorporating it on the soil and letting it decompose for approximately 3 years will add this essential macronutrient.
This is applicable for farms or gardens that are not focused on hydroponics.
You can turn old and used biodegradable hydroponic containers into compost. Add them to your compost mix along with nitrogen, phosphorus, and potassium-rich biodegradable sources such as dried leaves, burned cucumber skins, and banana peelings, respectively.
Learn more about compost in our article loam soil and compost: differences you need to know.
4 Cons of Using Biodegradable Hydroponic Containers
Using biodegradable containers in hydroponics also has disadvantages namely: 1) they are not profitable in the long run, 2) they can’t survive continuous water pressure, 3) could cause algae bloom, and 4) increase disease incidence and transfer.
1. Not Profitable in the Long Run
Buying biodegradable net cups will consume a portion of costs every growing season.
Unlike plastic net cups, using biodegradable growing cups will entail more cost once a set of them breaks. Let me explain this in a scenario.
For instance, you are trying to grow lettuce at the moment. Three weeks back, you sowed the lettuce seeds in 10 paper pots. So this week, they must be big enough and ready for transplant.
So to easily transplant the lettuce, you need to tear the paper pots. It is a successful transplant. Afterward, you find yourself with bits of paper and decide to turn them into compost. They should be decomposed after 3 years.
After this, you go straight to a garden store, and buy another set of biodegradable growing pots.
See? This method will take money out of your hand every growing season. This is the reason why I recommend using biodegradable trays and pots for small-scale gardening, and not for large-scale production. Plastic growing pots and trays can last for years—even longer than the time it will take these paper containers to decompose!
2. Can’t Survive Continuous Water Pressure
Paper-based products are not suitable for hydroponic systems with flowing water such as nutrient film technique (NFT) and ebb and flow systems.
When paper is continuously struck with a water gun, ninety to a hundred percent of the time, it will break apart. The same goes with the biodegradable net cup scenario.
Remember that in hydroponics, water is always present. So continuous water flow or contact with the paper pots will absolutely destroy them.
Learn more about nutrient film technique in our article on horizontal vs vertical NFT hydroponics.
3. Possible Algae Bloom
Algae grows in a place where it has access to light, water, and nutrition. Hydroponic containers made of paper, being a source of carbon, partnered with flowing water, is conducive for algal growth.
Let us face it. Algae is really a big problem in hydroponics. The best thing we can do is to control for the factors that lead to its development—light, water, and nutrients.
Below is a video showing how to prevent algae infestation in your hydroponic unit.
4. Heighten Disease Incidence and Transfer
Molds can develop along the surface of biodegradable pots and can be transferred to the plant, and spread in the hydroponic system.
One of the problems I noticed when I used biodegradable pots is the emergence of molds after several watering. This happens when your plant is not in the hydroponic system yet.
Most of the time, plants are grown in little pots or growing trays first, before putting them in a hydroponic system. You will only transplant them once they are already mature enough or after developing 2-3 leaves.
The molds that develop during the early phase, even in the pot itself, are considered disease risks. Even when you remove the paper pot, if the mold has made its way to the plant’s roots, it can still infect the plant and prevent healthy growth.
Remember, this is the case for most plant fungal diseases.
But when plastic grow pots are used, you can easily reuse them after proper disinfection using hydrogen peroxide or bleach.
What is the best plastic for hydroponics?
Plastic #2 (high-density polyethylene) and plastic #5 (polypropylene) are the best plastics to use in hydroponics. They are food-safe options. Check the recycling number of net cups, growing trays, or reservoirs. Moreover, bottles and jugs are plastic #2, while yogurt containers are plastic #5.
Do you need food-grade buckets for hydroponics?
Checking for a food-grade hydroponic bucket is the best choice. Choosing food-grade plastic containers for hydroponics can help gardeners avoid possible Bisphenol A (BPA) contamination. In hot temperatures, BPA can leach into the hydroponic water and can accumulate in the plant’s roots. Dietary intake of BPA can cause serious health issues.
Summary of Are Biodegradable Containers Advisable in Hydroponics
Biodegradable containers are best to use from sowing to seedling stage. They are not advisable for use during the growing and reproductive stage of the plants cultivated in hydroponic systems.
Alternative biodegradable options are available for growing trays/pots, net cups, and even pipes. However, only the usage of biodegradable growing trays and pots during early developmental stages is recommended.
Using biodegradable containers in hydroponics is cheaper, eco-friendly for small-scale gardening, easier to use, and compost ready. On the downside, it is not profitable in the long run; biodegradable containers can’t survive continuous water pressure; and using them poses risk of algae bloom, disease incidence and transfer.
- “A Suspended Net-Pot, Non-Circulating Hydroponic Method for Commercial Production of Leafy, Romaine, and Semi-Head Lettuce” by Kratky, B.A. in University of Hawaii at Manoa
- “Evaluating Biodegradable Containers as Alternatives to Plastic Pots” by Conneway, R.L. in West Virginia University
- “Is Polypropylene a Safe Plastic to Use in Your Home?” by Stanborough, R.J. on Healthline