Different hydroponic growing media are used by farmers depending on the type of hydroponic system used or their individual requirements. Hydroponics involves growing plants without soil. A nutrient-rich water solution is instead used to provide plants with the nutrients that they need.
Hydroponics is very popular nowadays because of its ease of use and management. It is one of the best indoor urban farming systems used in modern agriculture and most commercial urban farms.
Soil is used in traditional agriculture to provide support and act as a substrate upon which plants grow and receive their nourishment.
However, in hydroponic growing, nutrient-rich solutions are used to provide nutrients and different growing media are used to act as a substrate that supports the plants and also help in delivering nutrients and oxygen to their roots.
The media can be supplied in slabs, blocks, and plugs or in a bulk form from which the farmer can pick and fill on growing trays, buckets or bags in which the plants are grown.
Whichever media that you choose, your choice will depend on;
Contents
1.The types of plants that you are growing.
Larger plants may require stronger intact media like gravel that can fully support their stems and plants roots compared to smaller plants like micro greens which have smaller roots.
2. The cost of the media
Depending on the region where the farmer comes from, the media should be very affordable and readily available. Breaking even from a hydroponic farm usually comes at a later date so it’s always important to keep the startup costs minimal and not too overwhelming.
3. The type of hydroponic system that you are using.
Different growing media work best with different hydroponic systems, for example, perlite is very ideal for wicking systems while gravel is good for flood systems because it doesn’t absorb water.
4. The water holding capacity of the media.
For hydroponic systems that aren’t in continuous flow like the flood and drain system, it’s always good to have media that has a higher water holding capacity to hold water long enough for the plant roots to absorb nutrients from it.
5. The durability of the media
The media should be long lasting and reusable i.e. not used just for a single growing cycle. This helps to curbs expenses
6. The air holding capacity of the media
The media should be able to provide good aeration to the plants’ roots.
7. The nutrient exchange capacity of the media.
The media should be able to hold and at the same time release nutrients to plants. If the media can’t release nutrients to plants from the aqueous solution, then they won’t be able to grow well.
8. Clean and contaminant free
The media should be clean and free from pathogens and contaminants and at the same time, it should not support their growth and replication.
9. Ease of maintenance
The media should be easy to clean, flush or sterilize
10. The needs of the farmer.
Some farmers may want to use organic growing media while others may prefer inorganic media.
These are the best growing media used in hydroponics
1. ROCK WOOL
Rock wool are cotton candy like fibers made from coke, limestone and volcanic rock. It is made available in plugs, blocks or slabs.
Pros
- Provides very good aeration to plant roots
- Very durable and long lasting
- Very good water retention
Cons
- Prone to very high PH
- Non- biodegradable
2. PERLITE
Made from volcanic rock, perlite is amongst the most commonly used hydroponic growing media. It is best for wicking hydroponic systems. It can also be used in aeroponics and drip hydroponic systems
It is made available in different grades from fine to coarse to support growing at all stages; seedling to adult plant.
Pros
- Provides good aeration for plant roots
- It is very light weight and porous
- Can be reused
- It has very good wicking abilities
Cons
- Poor water retention capacity
4. VERMICULITE
Pros
- Light weight
- Good water holding capacity
- Good cation exchange capacity
Cons
- Can suffocate plants since it can hold much water
5. EXPANDED CLAY PEBBLES
Expanded clay pebbles are made by heating clay in kilns at high temperatures. They are available in sizes ranging from 1- 18 mm. They are also called grow rocks.
This is best for drip or ebb and flow hydroponic systems.
Pros
- Provide good support to plants
- Provide good drainage and aeration because of their porosity
- Last relatively longer before they breakdown
- have neutral PH
- they are relatively cheap
Cons
- Poor water retention because of their porosity
- Breakdown from the particles can clog pipes and the drainage system
- They need to be rewashed and treated before reuse since the nutrients can clog on them along with some pathogens from the previous growing season.
- They are heavy and require a very strong support system if they are to be used to grow crops.
6. FOAM
This is majorly used to grow seedlings in nursery beds. It is also called phenolic/ peat or floral foam.
Pros
- Offers good water retention and aeration
- Can be reusable
- Some are biodegradable
7.COCO AIR
This is made from coconut husks and is a byproduct of the coconut industry. It is also known as coco peat/ ultra-peat/ coco tektite is mostly sold in blocks or slabs.
Pros
- Very durable and can be recycled
- Good water retention capacity between irrigation cycles
- Biodegradable
- Has anti-fungal properties
Cons
- Can contain high salt levels. Purchase only coco air with low salt levels.
8. GRAVEL
This is most commonly used in drip and flood systems because it cannot absorb water
Pros
- Very cheap and readily available
- Offers good drainage
- Offers very good support to plants
- Very easy to clean
Cons
- Very heavy
- Cannot retain water
9. Sand
Pros
- Very cheap and readily available
- Good water retention and root aeration
Cons
- Heavy and needs a very strong system for support
10. Pumice
Pros
- Very cheap and readily available
- Good water retention and root aeration
Cons
- Heavy and needs a very strong system for support
Bottomline
Hydroponic growing media are very many and after having read this post, you’ll be able to decide which the right choice for your system is and plant growing needs. Other hydroponic media used include; rice hulls, and sawdust. These also have their advantages and disadvantages.
Choice of the right growing media will determine and affect the growth of your plants, the management and the type of system that you are going to use for your hydroponic farm.