Potting 101

How and Why to Properly Pot a Plant

Your plant can only be as good as its genes will allow. If you have gone to the trouble of acquiring great genetics, you will want to see your plant live up to its genetic potential. That means making all of its environmental variables supportive rather than challenging or harmful. Your variables are: Air, water, temperature, light and soil (or other medium). Scientific Soils has got you covered on the soil, but you need to meet us half way by using the product correctly. Here’s how you pot a plant to help it reach its maximum potential.

Potting soil needs to accomplish 4 things for the plant. 1. It needs to provide substrate for the plant’s roots so that the plant may stand upright; 2. It needs to allow for oxygen to get to the roots, i.e. the soil structure must be good; 3. It must remain moist while allowing excess water to drain; 4. It needs to provide nutritional support for the plant.

Let’s look at each of these 4 items separately. Item 1 is fairly straightforward–this is the purpose served in hydroponic applications by rock wool, net pots, expanded clay pellets, etc. The roots need something to grip.

Items 2 & 3 go together. Soil structure is perhaps the most commonly overlooked component of soil–one that beginners often get wrong or overlook entirely, but it is critical. A soil that is too fine will hold too much water and muck, choking off oxygen and allowing the proliferation of anaerobic bacteria. This will quickly make a plant sick and eventually kill it. A soil that is too coarse will not retain water or nutrient or provide much of an anchor for roots. Plants in soil that is too coarse will starve, tip over or dry out. It is important to note that the act of watering soil–that is, the water flooding the surface and then sinking down into the soil–draws air and oxygen down into the root zone, which is highly desirable. A soil that is just right, with a vigorously growing plant in it will require watering 2-3 times a week, replenishing the oxygen each time the water falls through the soil to the bottom of the pot. This is why it is especially important to have a layer of rock at the bottom of the pot to create a plenum or air space. You never want your soil sitting in a saucer full of water. With a few inches of rocks at the bottom, this cannot happen. (We like lava rock the best for this application.)

Item 4, nutritional support, is the most complex. It is also the area that most commonly frustrates new growers. There are 19 nutrients that a plant needs to reach its genetic potential. They are the primary macronutrients, nitrogen (N), phosphorus (P), and potassium (K); the secondary macronutrients, calcium (Ca), magnesium (Mg), sulfur (S), and silicon (Si); the micronutrients, chlorine (Cl), iron (Fe), boron (B), manganese (Mn), sodium (Na), zinc (Zn), copper (Cu), nickel (Ni), and molybdenum (Mo); and the nutrients the plant gets from the air or water, hydrogen (H), carbon (C), and oxygen (O) Nitrogen is present as dinitrogen (N2) in the atmosphere and is not available to plants in that form (though this is the source of all soil nitrogen), organic nitrogen (C-NH2, where C is a larger organic molecule) gets broken down in soil by the nitrogen cycle into the three useable forms, NH4 (ammonium nitrogen), NO2 (nitrite), and NO3 (nitrate), all of which are useable by the plant. Soil that is not getting enough atmospheric oxygen is a problem because the aerobic bacteria in your soil will take the oxygen they need from nitrate (NO3), creating NO and N2, both of which are gasses and which will escape from the pot and not be utilized by the plant. Proper potting procedure and a well-structured soil such as those offered by Scientific Soils is critical to your success. Scientific Soils has included the right kinds of bacteria, mycorhizzal fungi, and sources of nitrogen such that nitrogen cycling will begin immediately upon the addition of plant and water.

In addition to nitrogen, Scientific Soils products have been refined thoroughly over many generations such that every needed nutrient is present in sufficient quantity to take your plant through its entire life cycle, timed at approximately 90 days–30 days of veg and 60 days flowering. (There is some wiggle room in these number, so you need not worry if you go over or under these times. If you plan to grow much larger plants and go over, you need only to grow in a larger container with more soil.)

A high quality soil that is properly structured and has sufficient nutrition is the first hurdle, then you want to plant in a sufficiently large container for your objectives. Pot size really depends on the size of the plant you intend to grow and how long you intend its life cycle to be. We prefer a #8-10 nursery size for a 90-day grow (about 8 or so English gallons). Add to the bottom of the pot two inches of larger lava rock (pumice), then add Scientific Soils to an inch from the rim of the pot. You want to plant your plant to just above where the roots and the green stem meet. Neither more nor less depth is desirable, but it is better to err by going a bit deeper rather than not deep enough. That’s how you pot a plant properly and why. Happy growing!

Adding rock

Relative amounts

Ready to go!