Indoor Grow Media
There are many ways you can grow plants indoors beyond using just soil. Let’s discover these methods together to see what works for growing food indoors.
Soil
Earth’s soil is quite simple and cool. Our insect and worm buddies have curated it from earth’s fallen debris. They also, allow oxygen and water to get deep into the soil for root growth and plant food. All of this activity is continually happening under our feet every day in the outdoor world. The result is called topsoil and its perfect for plant growth. It’s rich with all of the nutrients that plants need, and it’s made up of the castings of worms (yeah, worm poop)and other goodies from insects. I won’t be focusing on the nutrients in this discussion, but trust me, we will have much to discuss on this topic in later posts.
Since our insect and worm friends are so heavily involved in this process, unfortunately, we DON’T want this in our indoor farms. Why? Well, the simple answer is don’t bring insects into your home as some of the more hungry species will destroy your plants. We grow indoors to avoid this problem. So, how exactly do we solve this problem?
Indoor Farm Potting Mix Soil
Just a visit to pretty much any hardware/ gardening store will reveal the plethora of options for plants when it comes to soil. We are looking for a specific indoor potting mix. Read the label on your potting mix to be sure it’s intended for indoor plants. We want potting mix here and not potting soil. There is a difference. Potting mixes often have aerators in them called perlite (the little white chunks) that will make the mix lighter. Aeration allows the plant to breathe and for water to drain through. If your potting mix is still too heavy or dense, you can add some vermiculite to lighten it up a bit. Vermiculite is remarkable because it does well at holding water in more dry conditions. More on this a little later.
Composting
If you compost in your home, this could be another great option. Several companies are targeting indoor plant growers with their composting products. It would also do us a massive favor in reducing the waste coming from your home. In my house, we are on a mission to become zero waste. It’s something that takes a bit of work, but worth it in the end. Compost makes an excellent soil for your plants to grow in. There are even new compost computers that will do this automatically for you. Companies like Whirlpool’s WLabs have designed products like “Zera, the food recycler” and have peeked my geeky interest. I’ll try these guys out and let you all know how it goes. But I am excited about this as it would be more of a natural process for my indoor plants. I will be posting more on this topic later as well.
Those Cool Soil-less Options
Beyond potting mix and compost, you can get into the world of Hydroponics discussed more here in my “The Indoor Growing Methods” article. I’m a massive advocate of hydroponics and will speak mainly on this topic on IFL. It has led to many innovations including alternative options for indoor soil like sand, different wood residues, sugar waste called bagasse and many others. There are several folks out there experimenting with what plants can grow in, and there are quite a few. However, I want to focus on the most popular here for learning purposes. Feel free to see what researchers have discovered that works for our plant friends.
Stone Wool
Stonewool, or often called Rockwool, is very popular in hydroponics. Composed primarily of granite and limestone, which is superheated and melted, then it is spun into small threads like cotton candy. It usually comes in cube form from 1.5 inches and will allow you to re-pot or replant all of the way up into a whopping 8"x 8"x 8" cube called “Big Mama,” by Grodan. A cube of that size would be useful for growing dwarf fruit trees. Rockwool loves water so you need to ensure you don’t let it become completely saturated as it will choke your roots and lead to root rot. Otherwise, these cubes are very easy to use and are highly recommended for starting your seeds.
Coco Coir
Coco is made of coconut husks, and it’s fantastic! Someone turned this often discarded gift into an indoor farm miracle. It degrades very slowly and doesn’t add any unwanted nutrients to your grow. Aeration is available for your roots. You can get this in different varieties, large or dense. All of which your plants will undoubtedly love.
Perlite
Perlite is a volcanic siliceous mineral like stone wool, but it is made and acts a bit differently. This growing medium is crushed and then heated until vaporization into a light powdery substance. Lightness and uniformity make perlite very useful for increasing aeration and drainage to your plants. Perlite also floats during watering, but many indoor growers have had success with this product.
Clay pellets
Clay that is super-heated to create a porous texture. It’s heavy enough to provide support for your plants but still lightweight. It will get the nutrient solution to the root systems of your plants very well. Clay pellets are one of the most popular growing media used for hydroponics, and it’s pretty easy to find in hydroponics stores.
Vermiculite
Vermiculite is a mineral also produced by heating. It becomes these plate-like particles and has a very high water holding capacity and aids in aeration and drainage. Vermiculite has excellent ability to supply potassium and magnesium to your plants. Although vermiculite is less durable than sand and perlite, its chemical and physical properties do very well for indoor farming.
Now, Let’s Get Growing
These are just a few of the many possibilities of grow media for indoor farming. I personally love Rockwool or Coco but feel free to experiment with different types of media for different plants. I also supplement my Rockwool grow by using vermiculite above my seeds when sowing. It seems to allow the seeds what they need in moisture and nutrients to sprout. Grodan is a leader in the Rockwool space, and I highly recommend their products. I have used them through countless grows. Get growing and happy harvest.
