Coco Peat / Coco Coir

Coco coir is quickly becoming a favorite among hydroponic gardeners. It’s made from ground up coconut husks and represents a giant leap in hydroponic growing media. Rockwool has all of the benefits of most growing media, with some pretty serious downsides. The ground up coco coir will act as a great hormone rich and fungus free medium for our plants.

In the same way that it helps the coconut to germinate, it will help all of our seeds and seedlings to start strong. Coco coir has a great air to water ratio, so we don’t have to worry about drowning our roots. Best of all, it’s completely renewable. Coconut husks would generally go to waste or be composted if they weren’t used in hydroponic applications. Here, we’re taking what was once a waste product and re-purposing it to grow more plants!

Benefits

• Usually organic
• Sustainable
• Compactable (buy compressed, expand at home…saves money on shipping)

Downsides

• Holds a lot of water and may drown plants

Expanded Clay Pellets

Arguably one of the most popular media to use in days past has been hydroton expanded clay pellets. As their name suggests, these are made by expanding clay to form round balls of porous material. The best part about them is the fact that they release almost no nutrients into the water stream and are pH neutral. In addition, their spherical shape and porousness help to ensure a good oxygen/water

balance so as not to overly dry or drown the roots. The only two downsides to using hydroton pellets has been their weight and their draining ability. In certain hydroponic systems, like ebb and flow, filling up an entire flood table full of hydroton is going to leave you with a very heavy system. They also drain and dry out very fast because there is much more space between each pellet than other hydroponic growing media. They can be used to great effect to line the bottom of an growing tray, when draining is an issue. Other than these two disadvantages, hydroton pellets are a great, re-usable media to use!​

Benefits

• Reusable
• pH Neutral
• Do not compact

Downsides

• Heavy
• Drain and dry very fast, roots may dry out
• Strip mined (environmental concerns)

Perlite

Perlite is something that many traditional soil gardeners already recognize. It’s a soil-free growing medium that has helped to add aeration to soil mixes for years. It’s created by air-puffing volcanic glass to create an extremely light and porous material. It has one of the best oxygen retention levels of all growing media because of how porous it is.

Its weight can be a downside in certain hydroponic systems where water interacts directly with the growing media, causing it to shift around and wash away. Because of this, perlite is rarely ever used alone – typically it is mixed with coco coir, soil, or vermiculite.

Benefits

• Lightweight
• High oxygen retention level

Downsides

• Too lightweight for certain hydroponic systems
• Strip mined (environmental concerns)
• Potential particle inhalation danger

Pumice

Pumice is formed when hot lava mixes with water and hardens, resulting in a porous and abrasive stone perfect for sloughing away dry skin. To use a pumice stone, soften the calloused skin in warm water, wet the stone, then gently rub the stone over the area using circular motions until you remove the dead skin. In addition to its primary purpose exfoliating skin, you can also use pumice to remove hair, remove pills from fabric, and even clean your toilet.

Benefits

• Lightweight
• High oxygen retention level

Downsides

• Too lightweight for some hydroponic systems if bought as small pieces

Gravel

This is the same material that is used in aquariums. As long as it is washed, you can use any type of gravel. Relatively cheap and easy to clean. A great DIY starter media if you’re short on cash!
Gravel supplies plenty of air to the roots but doesn’t retain water, which means roots can dry out quickly. Its weight makes it difficult to handle, but it does have the advantage of not breaking down in structure and can be reused.

Gravel can easily be reused as long as it is washed and sterilized between crops. Also use heat, steam, bleach or hydrogen peroxide for cleaning.

Benefits

• Very inexpensive
• Easy to clean
• Drains well

Downsides

• Heavy
• Plant roots may dry out
• Not suitable for certain hydroponic systems

Vermiculite

Vermiculite very similar to Perlite. It’s a mineral that is heated until it expands into pebbles. It retains more water than perlite and can wick (draw) water and nutrients upwards. Often used in combination with other types of media to create a highly customized media for specific hydroponic applications.

The ground up coco coir will act as a great hormone rich and fungus free medium for our plants. In the same way that it helps the coconut to germinate, it will help all of our seeds and seedlings to start strong. Coco coir has a great air to water ratio, so we don’t have to worry about drowning our roots. Best of all, it’s completely renewable. Coconut husks would generally go to waste or be composted if they weren’t used in hydroponic applications. Here, we’re taking what was once a waste product and re-purposing it to grow more plants!

Benefits

• Water retention

Downsides

• Hard to find
• Expensive
• Can hold too much water