Tag - Rockwool

Growing With Rockwool Plugs

Why We Love Rockwool Plugs

Why We Love Rockwool

Rockwool is one of favorite ways of growing anything. Rockwool originally started out in commercial growing applications, specifically with hydroponic growers. However, in recent years as home hydroponic and growing has become more popular we are seeing more and more people using Rockwool plugs.

So what is Rockwool?

Rockwool is exactly what it sounds like. Rockwool is made by taking molten rock/sand and spinning it, similar to when you make cotton candy. The end result is a dense wool like product that is inert, has no mineral, and is great at soaking up water and remaining saturated, but not too saturated.

Rockwool comes in a variety of sizes, ranging in small plugs perfect for starting seeds and propagating cuttings, all the way up large slabs which can be used for larger plants.

Why is Rockwool such a great product to use?

Rockwool is dummy proof and unlike using soil, Rockwool is almost impossible to over saturate thus increasing your chances of seed germination and reducing your chances of root rot.

Further to the above, Rockwool is super cheap and if you really wanted to you can even re-use your Rockwool plugs after your harvest.

The only downfall about Rockwool plugs is the need for frequent nutrient applications. Rockwool has no major nutrients in comparison to seed starting soil or potting mix which usually has slow releasing nutrients for up to 6 months.

How to use Rockwool

  1. Soak your Rockwool plugs for 10 to 20 min. Before you use your Rockwool plugs or slabs you will want to give them a good cleaning. This is not mandatory, but, is a good practice.
  2. Once your Rockwool plugs are cleaned place them in a hydroponic grow cup or in your growing bed. Note: I prefer to use expanded clay pellets for my growing bed.
  3. Insert your seeds or cuttings into your Rockwool plugs.
  4. Watering should be done every 4 hours, but this is dependent on the type of plants you are growing as well as other conditions such as temperature. The rule of thumb is to ensure that your grow beds water limit is slightly below the bottom of your Rockwool plug. This will ensure that the Rockwool does not wick water upwards and remain soaked 24/7.

If you choose not to grow hydroponically, you can also use your Rockwool plugs as seed and cutting starters. As long as you keep the Rockwool moist, you can fully root cuttings and start seeds. A few weeks after germination, you can place the plugs directly into a garden or soil filled container. The Rockwool is porous enough that the roots of your growing plants will slowly punch through it and into the soil.

If you ever grow lettuce you should use Rockwool plugs. You can thank us latter!  I have never had so much success growing lettuce until I stared using Rockwool plugs.

If you have any questions about this post or about using Rockwool growing products feel free to leave them in the comment section below.


Choosing The Right Cannabis Grow Medium

If you want higher yielding plants, one thing often overlooked is the type and quality of your grow medium. Choosing the right type of grow medium can have a huge effect on the health of your plants and their yields. In this article we are going to go over some great grow medium options that are both cost effective, and work very well for all plat types.

Coco Coir

Coco coir is a very common type of grow medium used for multiple types of growing applications. Coco coir is an organic and inert grow medium that is created from coconut husks. The ground coconut husks is great at retaining the perfect amount of moisture and can be used to grow establish plants, plants from cutting, and plants from seeds.

Coco coir can be used for hydroponics but is not the best option as the small fibers can clog your pumps. Coco coir is best suited for standard soil planting. What we recommend is planting your plants within the coco coir and then placing it within a well-draining soil and perlite mixture.


Rockwool has become more widely used over the past few years, and is an amazing grow medium that can be used for hydroponic growing and soil growing methods. Rockwool is made from rock. More specifically, Rockwool is made by taking molten silica based rock and spinning it. This is a rock version of cotton candy.

Rockwool is great because it is inert, it is strong, and it is very porous. These are all characteristics that you want in a great grow medium.

Rockwool comes in a variety of sizes and is reality cheap to purchase. Most growers will use the 1 inch Rockwool cubes for starting seeds, and larger cubes for cuttings and transplants.

Unlike coco coir, Rockwool can be used in hydroponic grow setups without the worry of damaging your pumps. Rockwool is best suited for flood and drain and drip hydroponics.

Expanded Clay

Expanded clay is another popular grow medium. This is very popular and can be used to grow almost anything. Expanded clay grow medium is comprised of small clay balls/pebbles that have been fired up in a kiln. The end result is a porous and light weight ball that sums up to be a great grow medium.

Expanded clay is best suited for use in expandable drip systems and deep water hydroponic systems. A great characteristic of expanded clay is that it is inert, and pH neutral. Expandable clay pellets can also be used in tandem with traditional soil growing methods. If you are growing in soil pots, simply cover the top of the pot with expanded clay pellets. The clay pellets will help retain moisture in the soil and prevent unnecessary water evaporation.

The above grow medium options are all great in their own way. If you have questions about our products, or need help with your grow setup, we are always happy to chat. Our team of grow experts can help you with any questions that you may have. Growing can be difficult, let us help!