Mar 242011
 March 24, 2011

What Is The Best Soil For Growing Cannabis?

Marijuana growers need to make many different decisions when they are planning out how to grow their plants. Besides deciding whether to grow indoors or outdoors, indoor growers need to choose whether to use soil or a hydroponics system for their indoor setup. In case you haven’t used hydroponics before and are willing to dedicate the money to it, it can be a very practical option to choose.

Generally speaking, newer growers decide to grow their plants in soil at first. Taking this step allows them to get a feel for the undertaking of growing marijuana plants without risking huge amounts of money and extra time spent researching. Either route can be useful, but in this article we will cover information for people who want to grow their marijuana plants in a soil-based system.

Growing marijuana in soil

marijuana soilMarijuana roots extend deeply into the soil as they hunt for the best sources of water and nutrients. This is why indoor growing requires a different technique that will compensate for this lack of space. To put it simply, the root systems of indoor marijuana plants need to be smaller. The water and nutrients come from the grower rather than natural sources in wild soil, so root systems should be able to thrive without extending out too far.

The main thing you need to worry about with root systems is that the temperature stays relatively warm – around 68 degrees Fahrenheit. You will also want to check that there is plenty of water and oxygen throughout the soil. Make sure to download my free marijuana grow bible at this link here for more growing tips.

marijuana soilPros and cons of soil growing

Irrigation is more easily done in soil because mistakes are more easily made with hydroponic systems. Fertilization is also simpler, if only because people have been growing plants in soil for thousands of years, meaning there is tons of information and advice out there. Soil types can make a big difference in the taste of the resulting marijuana, which is an added bonus.

Soil isn’t perfect, however. It requires lots of space and weighs a lot, making things rather difficult for people growing indoors. Pests and insects are more likely to be found in soil as well, not to mention the fact that some people simply don’t have the “feel” required for growing any plants in soil. Read the article ‘How To Grow Marijuana Hydroponically‘ if you don’t want to grow in soil.

marijuana soilMarijuana soil container size

The size of your plants’ containers will alter the size of your plant’s root system. If the roots have more space, they will fill out their space even more quickly – making growth easier. Problems occur when the plant outgrows its container.

Regular sized marijuana seedlings will do well in a container that is 10x10x10 centimeters until it reaches the height of between 25 and 35 centimeters. At that point, you will need to transplant it to a container that is two times the size of the first one (15x15x20 centimeters). When the plant surpasses the 80-centimeter mark, you will need to transplant it to a container that holds 10-12 liters. The container size keeps increasing as the plant exceeds the 1-meter mark, and so on.

marijuana soilMarijuana soil nutrients

Soil already has lots of nutrients naturally, since it is made up of organic materials. Materials like rotting vegetables and animal manure cannot be placed directly on your plants as fertilizers – they need to be broken down additionally before they are able to be absorbed by the plants’ roots. Worms and insects are useful “tools” when breaking down these materials, as is rain. Water dissolves these and other materials allowing them to be absorbed by the marijuana roots.

While these things happen easily and naturally in the wild, it is not so in indoor growing systems. That is why beginning with soil that is rich in nutrients (as well as sterilizing it before planting) is so important for indoor growers. The best way to sterilize soil is to use heat, which is not 100% effective but will help ensure the safety of your plants nonetheless.

Download my free marijuana grow bible and learn how to increase nutrient absorption

Nutrient-rich potting soil mix can be found at your local garden center, and it can also be made on your own. Oxygen, a lukewarm environment (approximately 20 degrees Celsius), plenty of water, a balanced pH value, and lots of nutrients will create an environment that encourages healthy growth in any marijuana plants.

As an indoor grower, you will have to be especially aware of what your soil needs to contain. The pH value, humidity, and nutrients will make a bigger difference than you might expect, so keep tabs on these things. Additionally, if your soil doesn’t retain water well, plants won’t have time to “drink” as much as they need to. Too much water retention, however, can encourage fungal growth, which would lead to devastating root damage. Use vermiculite, sphagnum moss, turf, or perlite to alter the retention of your soil.

marijuana soilMake marijuana soil yourself

Soil is pretty easy to mix, as long as you pay attention to the ratios. These ratios also will change according to which stage of life your marijuana plants are in. Early stages of life, for instance, require balanced amounts of turf, perlite, and worm meal. Vegetative and flowering stages need balanced amounts of turf, worm meal, and compost instead.

To decrease a too-high level of compost, simply add chalk. You can also use liquid fertilizers as a way to add nutrients to your soil, and they can be made yourself. Just be sure that the liquid is homogenous and has equally balanced nutrients, thus preventing it from “burning” your plants. For nervous beginners, a store-bought option is probably your safest choice.

Watering marijuana soil

Watering in soil can be difficult because it varies according to the soil type and environment. Hot environments need more water while cool environments require less. Water works to move necessary nutrients and minerals to the roots, where they are then transported to the rest of the plant. Water also works to cool down plants when they are too warm and to keep the structure in line. Perhaps most important of all, water is a necessary ingredient for the process of photosynthesis to successfully be carried out. As a general rule of thumb, simply water until the soil is moist but not wet to the touch, unless you want fungi to grow and harm your marijuana plant’s roots.

 

About Robert Bergman

Robert Bergman is a master marijuana grower. Robert Bergman is the author of 'Marijuana Plant Care' and 'The Marijuana Grow Bible'.
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  • Dave

    Do you need to ph the feed when growing in bio bizz all mix ????

  • Tracey

    something has changed i have lots of leaf growth in last stages of bloom ? same feed same conditions any advice?