Your Guide On The 7 Best Hydroponic Grow Mediums

Your Guide On The 7 Best Hydroponic Grow Mediums

There is no general answer to what is the best medium for hydroponics. It depends on what you are growing, your personal preference, and your system. The price and availability of the hydroponic medium also have to fit your needs.

If you’re wondering about which grow mediums are best to use, below is a comparison of some common, effective hydroponic mediums. This article will help you choose a suitable growing medium for your hydroponic needs.

hydroponic medium

Do You Need a Medium for Hydroponics?

Since growing plants hydroponically is done without soil, only nutrient solution, plant roots often need to be firmly held in place by a hydroponic medium. Additionally, the grow medium assists in delivering water, oxygen, and nutrients to plant roots.

1. Hydroton

Hydroton is growing rocks that have been proven to be very versatile hydroponic mediums. Surprisingly, they are not entirely rocks – they are an expansion of a clay product, and people often refer to them as expanded clay pebbles. Hydroton is the most popular growing medium used by hydroponic gardeners. It is common in many hydroponic systems,s but it works well with Deep Water Culture (DWC), Ebb and flow, and Drip systems. However, it is also a concern for systems that flood the root system because they can float, disturbing the plant roots.

Beneficial Characteristics:

Water retention and drainage

Hydroton is filled with tiny pores, making them the right amount of water and preventing overwatering by draining excess water.


Hydroton remains compact when used, and hence it renders continuous oxygen exchange, which helps keep the plant root healthy.

Neutral pH

Hydroponic gardening requires a growing medium that is not too basic or acidic. That is where hydroton thrives; it has a neutral Ph, so you won’t have to worry about unstable pH, which negatively impacts the plant’s health.


Clay pebbles are suitable for long-term use. However, after your growing season and you want to use them again, rinse them to make the pores clear.



Low water-holding capacity

Hydroton lacks good water-holding capacity. If the medium does not have a good water-holding capacity, the crops might go dry and wilt. Low water-holding capacity is not a big issue. Make sure to water your plants frequently.

Fairly expensive

Although clay pebbles are the first choice for many hydroponic gardeners because of their ease of use, they become quite expensive for large-scale growers.


Before being saturated, clay pebbles float and get stuck into drain lines and causing problems with pumps and plumbing.

2. Rockwool

This product has been used for many years of gardening, especially when starting plants. It is fibrous, but it is delivered as cubes after processing. Rockwool hydroponics is made of different elements and therefore has to be pH neutralized by soaking it in pH-balanced water before use. hydroponics

Beneficial Characteristics:

  • Rockwool is highly porous; hence it can efficiently absorb and retain large amounts of nutrients and water.
  • It is also reusable after harvests, although you have to repeat the pH balancing steps or sterilization.


  • The fibrous roots irritate the skin, lungs, and eyes because of their chemical composition, and it is often recommended to have safety gloves and a dust mask when handling the product.
  • The high pH in Rockwool may often shift, which calls for continuous monitoring of pH levels in your hydroponic system.

3. Perlite

It is light and retains oxygen which makes it have good aeration. However, it is poor water retention and is often used as an additive to garden soil. Perlite’s lightweight property makes it float and may cause blockage of drain pipes and pumps; hence it is not recommended on some systems that flood the roots. Perlite is also very inexpensive.

Beneficial Characteristics:

  • It provides good aeration to plant roots.
  • It can be reused after harvest.
  • Perlite can be mixed easily with other growing mediums.


  • It is not renewable
  • Requires frequent watering because it is deplorable at holding water.
  • It is harmful to your health, and it is recommended to pre-wet the product and wear safety clothing before handling it.

4. Pumice

It is a volcanic rock considered eco-friendly and works well with hydroponics. In addition, it can be mixed with other growing mediums and has proven to work well.

Beneficial Characteristics:

  • Eco-friendly as it is a naturally occurring product.
  • Good drainage helps the roots get air through the pore of the product.
  • Reusability since pumice is natural and has a long life. It has the added advantage of serving different crop seasons.


  • Pumice is not able to able to retain water for long; hence you need to water the system frequently.
  • It is not always readily available, making it a bit expensive.

5. Cocoa Peat

It is also known as coconut coir or fiber. Cocoa peat works best on small systems and with herbs, tomato, and pepper plants.

Beneficial Characteristics:

  • It is ideal for germinating seedlings.
  • Cocoa peat is porous and hence provides good aeration.
  • It retains nutrients and moisture for healthy roots.
  • It is organic, making it resistant to diseases.


  • It is plain with no nutrients that are valuable to plants. Normally, you must add a nutrient solution to your system.
  • It is rather expensive.
coco peat

6. Peat Moss

This product is top-rated in hydroponics and aeroponics. It is often used for seed germination in hydroponics. Peat moss has low acidity levels making pH monitoring easier.

Beneficial Characteristics:

  • It is mainly used because of its water-holding capacity, especially during seedlings.
  • Peat moss can hold soil nutrients.
  • It is bacteria-free because it is sterile.
  • It can last longer before starting to decompose.


  • With time, it decomposes and compresses, choking the plant roots. Mixing it with other growing media may help with this.
  • It is non-renewable.
  • Peat moss is relatively expensive.

7. Vermiculite

It is manufactured by combining materials and exposing them to high temperatures. It is sterile, pH neutral, moist, and non-toxic. It comes in many forms, so you have to read the properties of the type you choose to use.

Beneficial Characteristics:

  • It retains water and nutrients.
  • It has neutral pH that makes pH adjustment easy.


  • Its retention capacity can suffocate your plants by over-moistening them. Mixing it with other grow mediums is often a good idea.
  • It has poor drainage, which makes it unfit for some systems.

What is the Cheapest Growing Medium for Hydroponics?

Sand is readily available and plentiful for plants that don’t need a lot of nutrients. If you put in other factors like nutrient retention and aeration, it can cost you and be expensive. Consider other options discussed here like hydroton or rockwool, which have good retention and, in the long run, save you costs on water and nutrients.

Final Thoughts

Some growing mediums can be mixed at levels and still work well. With the help of growing medium properties discussed here, you can try it in your system. Make sure the hydroponic medium allows air and nutrients to your plant roots to achieve great results.

rockwool hydroponics