What is the Soil Used for Autoflowers?

Over the past few years, Autoflowers have become one of the easiest and fastest ways to cultivate cannabis. Irrespective of whether you are a first-time grower or have been growing cannabis for years, these seeds can help you produce a heavy harvest in a mere ten to eleven weeks. If you plan to use Autoflower seeds, you need to know about the best soil for it for optimized results.

In this post, we will help you learn about the same. So, if you are on the lookout for an answer to “what is the soil used for Autoflowers,” you can be in the right place. Let us not waste any further time, and quickly get started on what the best soil for Autoflowers is and how you can prepare this soil. Let the scrolling begin!

Also Read: How to prepare soil for planting flowers?

Which is the Best Soil for Autoflowers?

For many Autoflower growers, an easy answer to “What soil is best for Autoflowers,” is the soil that has an organic foundation. Such soil is usually rich in mineral nutrients, and due to this, they deliver excellent results. Also, since the soil is organic, all the nutrients in it are slow-release. These can simplify a lot for you.

With slow-release organic nutrients, you do not have to worry about nutrient overdose or depletion for a significant amount of time. In the past years, if you have ever experienced crop burning due to nutrient toxicity in the case of Autoflowers, organic soil is the best option for you. That being said, organic soil is not the only soil medium you can choose.

When it comes to the soil type that is the best for Autoflowers, no single soil mix can be called so. You will need a variety of ingredients for it to be the best. Typically, if you have good-quality Autoflower seeds, you do not have to worry much. They can thrive across a wide range of soil conditions, and even in hydroponic (soil-free) conditions.

So, we suggest that you do not get too hung up on defining the best soil for Autoflowers. Instead, there are certain basic soil requirements that you need to keep in mind. They are:

With all these three characteristics present in a soil type, your Autoflower seeds are sure to thrive and become healthy plants.

How to Prepare Soil for Autoflower Seeds?

How to Prepare Soil for Autoflower Seeds?

Next, let us find out – “how do you prepare the soil for Autoflowering cannabis seeds?” When it comes to Autoflowering cannabis seeds, they should have the toughness to grow in a variety of soil types. Instead of finding a particular blend for their soil, look for some characteristics that the soil type should have.

For instance, the soil needs to be aerated to enable the plant roots to thrive in an oxygenated medium. Then, it should be able to provide enough moisture to cannabis without creating excessively wet root zones. It means that an ideal soil mix should also be able to drain freely. And most of all, it should be nutrient-rich. Here are some key soil substrates that you can use to prepare the soil for Autoflowering cannabis seeds:

  • Coco Fiber

This is a natural fibrous material that comes from coconut husks. Be it home growers or licensed professional growers it is widely used by all for cannabis cultivation. This fiber has a free-draining nature and offers natural aeration. These two key factors make it an excellent growing option for Autoflowers. 

In order to use Coco fiber, you can simply add it to your soil. You can either use 1:1 of soil and coco fiber ratio. Alternatively, it is also okay to 10-20% of coco fiber in the soil. With this, you are sure to have a soil type that is lighter, more aerated, and provides better drainage for fast plant growth. 

While coco fiber has all these advantages, it has some cons too. This natural soil substrate has very little nutritional value to offer to your plants. It simply means that if you are using it, you also need to ensure that you provide the soil with all vital nutrients.


  • Biochar

The next soil substrate you can use is biochar. For those who are not aware, it is nothing but any organic material that is carbonized (turned into carbon) under high temperatures. Generally, these temperatures are between 300°C to 1000°C. Furthermore, this process of turning organic materials into carbon (pyrolysis) is done in the presence of no or very little oxygen.

During the process, all the natural bio-oils, gasses, and other materials are removed. All that remains is a solid residue – biochar. It has 80% elemental carbon and is often added to soil blends. Adding it can neutralize excessive soil acidity to improve plant health. It is believed that the soil substrate can provide nutrients and water retention in sandy soils too.

Biochar is also claimed to enhance drainage and aeration along with providing a habitat for beneficial soil microbes. That being said, some of the biochar types can have a heavily alkaline effect on your soil, and this kind of soil is not ideal for Cannabis. Therefore, make sure to check the soil pH range once you use this.

  • Perlite

This white and granular substance is made from expanded volcanic glass. It is not just ideal to be used in Autoflower soil mix but for mostly all plant types. This natural soil amendment can help you improve the drainage of the soil. Alongside proper drainage, it also helps in water retention by withholding the amount of water needed by your plants.

You can readily add 10-20% of perlite to the soil mix you prepare for Autoflower seeds. In case you feel that the soil you are using is a little heavy, Perlite should be your go-to solution for aeration and drainage. That being said, while using Perlite, you need to keep in mind that it can harm you if not handled with care.

The dust from it can cause lung as well as eye irritation in humans. As for the plants, if you use too much of it, your soil medium can drain moisture away too quickly. Further, if you simply add it to the top layer of soil, it can blow away easily with strong wind. While you use Perlite make sure to keep all these things in mind.

  • Vermiculite

Like Perlite, Vermiculite is another natural soil mix ingredient that is highly beneficial. This organic mineral is a mix of Iron (Fe), Aluminum (Al), and Magnesium (Mg) silicates. When heated in a hot furnace, this expands and forms a product that can hold water well. Thus, it is a great amendment to use for your soil if you wish to retain moisture whilst increasing aeration for your soil.

When it comes to the pH range of this natural mineral, it is close to neutral. Due to this pH range, it can hold a high level of water. Using it in the soil mix will ensure that the Autoflower roots stay moist for longer as it takes a long time to dry. Furthermore, this substance is super easy to use and mix in any soil blend.

While Vermiculite is great for plants, not all gardeners like it. Some believe that it is a non-sustainable resource, and is more expensive than other soil additives. If that is not an issue for you, Vermiculite might be suitable for you. Just make sure not to use it too much or it can make the Autoflower soil blend a little too wet. This can harm the plant and even encourage fungal growth.


What is the Best Soil mix for Autoflowers?

Now, with so many different additive options that you can use to make your Autoflower soil mix more effective, how does one find the perfect composition? If you like the idea of slow-release nutrition that can cover all the plant’s requirements, supplement your soil with organic nutrients like Bio Tabs. 

These will take care of your plants for a long time – from Autoflowering cannabis seed to harvest. You can use a large aerated container for mixing these into the soil and simply add water. Another soil mix that you can choose is a 1:1 blend of coco fiber and light-mix soil. This is typically designed for more root aeration but little nutrition.

If you use such a soil mix, keep in mind that you will have to add your own nutrition to the soil. For it, you can use anything ranging from bottled mineral nutrients to slow-release organics. All in all, the best soil for Autoflowers may be anything that you mix up yourself or even buy at a store. It should only meet up all the requirements of the plant needed to grow and develop.

In case, you are on the lookout for a typical basic homemade Autoflower soil, you can make it easily yourself. It is inexpensive and only needs a few ingredients. A simple recipe is mixing 80% supermarket soil, 10% coco fiber, and 10% perlite. You can mix these in a large bucket, and use them as a foundation for your Autoflower seeds to grow.

The quantity we have mentioned here is, of course, not fixed. You can easily adjust these ratios as per your needs. For instance, if you are aiming for a lighter soil mix, you can always add more than 10% coco fiber. Further, be it biochar, bat guano, seaweed, dolomite, worm castings, or fish/blood/bone nutrients, you can add whatever you want to the mix for more advanced growth.

Can you Plant Autoflowers directly in the Soil?

Next, let us look for an answer to: “can you plant Autoflowers directly in the soil, and how much soil does an Autoflower seed need for it? Firstly, you can easily plant Autoflower seeds directly in the soil. Doing so is very simple as you only have to put the seeds around 10 mm below the surface of the soil. While doing so, you also need to ensure that the soil and its surface are moist.

In order to keep the soil surface damp, you can use two methods. Firstly, you can use a transparent kitchen film and put it over the plant container. This will easily prevent the moisture from evaporation, and thereby, keep the surface moist. If you are not using a transparent kitchen film, simply mist the surface occasionally. Of course, do not overdo the misting.

In the case of a transparent kitchen film, you need to remove it once the Autoflower seeds germinate. Now, moving on to the quantity of soil that your Autoflower seeds may need, it depends on the kind of results you want. For instance, if you are not expecting a large plant or significant yields, even a one-liter container full of soil will work for you.

Alternatively, if you are a serious auto grower, you need to take a fifteen-liter container full of soil mix at a minimum. If you are looking for larger and more optimized results, choose a large quantity of soil. The bigger your container, the more cannabis yield you will have. If you have enough space, and can easily afford extra soil, a 30 to 50 liters container is the best fit for you.

How long do Autoflower seeds take to germinate in Soil?

After how much soil your Autoflower seeds will need to germinate, let us find out how long it takes for autos to germinate in the soil. Typically, most Autoflower seeds can germinate between four to seven days. In some cases, this period can take a couple of weeks, as well. If you wish to fasten the Autoflower germination process, we gave a perfect method for you.

If you are about the start the process of germinating your cannabis seeds, do not plant them directly in the soil. Instead, place them between two moist cotton pads. Make sure that these cotton pads are only damp and not soaking wet. Within a few days, you will notice that your Autoflower seeds have germinated. Once this happens, place the germinated seeds’ roots down in the soil.

Further, when it comes to the growth of Autoflower seeds, there are several things you need to know. For instance, how wet should soil be for Autoflowers? Ideally, you should water the soil medium in such a way that it is 60-70% dry. Apart from this, there are various other factors ranging from pot size and strain to temperature and nutrients that will be responsible for the growth of your Autoflowering Cannabis plants.


How to tell if your Autoflower Soil is Healthy or Unhealthy?

How to Tell If Your Autoflower Soil Is Healthy or Unhealthy?

By now, we are sure you know the answer to “what is the soil used for Autoflowers?” After this let us tell you how to find out if your soil is healthy or unhealthy. Irrespective of whether you prepare your own Autoflower soil mix or buy it from a store, you cannot visually determine if it is healthy. For it, you need to understand the composition of the soil you are using.

Along with it, you need to be aware of the signs of healthy soil. If your soil is healthy, you will notice that it is light, airy, free draining, and has an open texture. Further, this soil should also have all the nutrients in sufficient quantities. These should be able to sustain the plant from its germination stage to the cannabis harvest.

Further, the soil should always have beneficial bacteria. These are super crucial for the uptake of nutrients by the plant roots. Also, these continuously work to improve the Autoflower soil. When you make your own soil, you can always add important soil amendments to it. However, if you get your soil from a store, make sure that certain ingredients are present for Autoflower growth.

For instance, the soil mix must have an ingredient like coco fiber. This is to make sure that the mix is light in structure. It should also have other additives like vermiculite, cork, and perlite. You can also determine how healthy the soil is once the plants start growing. If they appear lush and have luxuriant green growth above ground, the soil is healthy. The same goes for the root. If it is healthy, your soil is working fine.

Final Thoughts

So, this is all the covers “what is the soil used for Autoflowers.” To sum up everything, we can say that there is probably no single soil mix that you can pinpoint for your Autoflowers. Instead, there are a variety of ingredients that can be added to the soil for the best growth of the plants. At the same time, always make sure to invest in quality Autoflowering Cannabis seeds as they come with solid genetics, and can even survive in adverse conditions. Also, while choosing a soil medium, make sure that it offers good drainage, proper aeration, and complete nutrition. Simply by taking care of this, you can experience solid plant growth and development.