Beginner's Cannabis Grow Guide

If you're unsure of where to begin, you may want to skim this guide. Having an idea of which space you'd like to use and how much light you want is important.

1. SPACE

The first step is finding an appropriate space. Even a small closet can grow enough for personal use, but you need to be able to control the temperature of the area. Plants thrive between 70-90 degrees fahrenheit, and temperatures outside that range (either at the top of the plant or at the bottom of the roots) can slow growth substantially.

The next most important concern in selecting a grow space is lightproofing; even a very small amount of outside lighting during a plant’s dark period will alter its hormone production and prevent flowering in non-autoflower strains.

2. LIGHT

How much power your light uses correlates with how much it can potentially grow. Ignore claims about equivalence and search for the true wattage of the light. In order to determine how much light you need, keep in mind that you may exceed your allowed 10oz with even a single 600w light. 

HPS - High Pressure Sodium - Traditional bulbs with reflector hoods, HPS have been the standard for many years. They are cheap to buy and fairly power efficient, but the bulbs must be replaced regularly, and the extreme heat they radiate down at the plants must be dealt with. 

MH - Metal Halide lights are  traditionally used for their lighting spectrum in vegetative growth or as a supplement to HPS lighting. Generally speaking a small grow won’t see a use for these bulbs.

LED - Light Emitting Diode - LEDs have dropped in cost and improved in efficiency to such a degree it’s hard to recommend anything else for a small personal grow. High end brands do sport great performance, but at an inappropriate price. A new grower will be well served by much cheaper reputable brands that can be found online.

Fluorescent - encompassing CFL bulbs as well as T5 fixtures, fluorescent lighting can be used throughout a grow. However, due to the poor penetration of the light, it is generally considered to not be worthwhile for use on flowering plants. T5 High Output fixtures are often used for clones (be sure to get 5-6000k kelvin [color spectrum] bulbs) or small vegetative areas but if you’re looking for a single light for your grow they offer no advantages over LED lighting.

3. MEDIUM

While the method and medium you choose for your grow does not have as huge impact as your light on potential yields, it will dictate how much work, attention, and care is required for upkeep of your plants. Additionally, the acidity (or alkalinity, which are measured as PH) of the water / nutrient solution must be tested and controlled, and different mediums require a different PH.

Soil

Any medium that’s biologically active is considered soil. The plant gets its nutrients from beneficial bacteria and fungi in the soil (sometimes called ‘bennies’) which break down minerals in the soil to a form the plant can use.

‘Super Soil’ is a term for a soil mix made to contain all the necessary ingredients for plant growth to be broken down by the microbes in your soil over time. With a store-bought soil, your plant may exhaust the soil after a month or two, so be aware that you may want to supplement by top-dressing with earthworm castings or by using compost tea.

Be aware that if you purchase soil that has been stored outside you run a major risk of taking home fungus gnats or worse with you.

Soil growth requires a water (and rootzone) PH of 6.5 to 7.

Soil tends to hold a lot of water, and most growers add perlite when necessary to improve drainage.

Hydroponics

This term covers any method in which the substrate does not interact biologically with the plant. The water itself is considered to be the medium, and the plants drink soluble nutrients directly from the water. Instead of beneficial bacteria breaking down the soil components to feed the plant, we use an inert (or nearly inert) media and put everything the plant needs into the water ourselves - in the form of soluble nutrients. 

The simplest method is to run a hydroponic setup In a Pot/bucket. The plant will hang onto whatever substrate you choose and will grow roots just as though it were in soil. Perhaps the most popular medium for this approach is coco (coco coir) which is made from coconut husks.

Ebb and Flow is done with multiple plants in permeable containers on a large tray which is filled up with water and subsequently drained.

Instead of using a pot and a substrate that mimics soil, hydroponic growth can occur with the plant’s roots submerged in water. Keeping the roots continually submerged is called Deep Water Culture (DWC). DWC can be done with each plant in its own bucket separately, or multiple can be plumbed together with bulkhead fittings and tubing (or even multiple plants in a larger container) with a separate reservoir to allow you to put the nutrients in and test the water with ease. 

Nutrient Film Technique (NFT) runs water over the roots through a channel, which is the setup you see them building a couple times on Trailer Park Boys.

Aerating the water for all of these methods is very simple, but there are many methods. UnderCurrent (UC) aeration uses water flow between multiple buckets and a reservoir - just like a river - to aerate the water. You can also design your system with waterfalls or flooms for aeration, or using pumps with venturi fittings. In a reservoir of standing water, an air stone will often be the best option.

Hydroponic pH

Required pH depends on the media, but a common example is pure coco which should be kept roughly between 5.8 and 6.4. 

One of the main concerns of any method utilizing a reservoir will be keeping the pH stable over time. Even using a root zone conditioner (I recommend Dutch Master's Zone or simple diluted bleach) you should expect that your PH will rise outside of acceptable bounds over the course of as little as 1-2 days depending on conditions. A new grower should be prepared to test reservoir pH daily. 

4. PICK YOUR PLANT

Seeds sprout easily when cared for properly, but germination time varies significantly. Nearly every strain is available for purchase online through a seed bank. Locally, some grow stores offer seeds as ‘gifts’ with a purchase, but both methods of acquisition are legal grey areas; purchase at your own risk.

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A clone is simply a cutting from an existing plant. Cuttings, when planted correctly, grow their own roots. A cutting will be genetically identical to its ‘parent’ and thus you have at least some guarantee of its genetic success/vigor. Additionally, even a small clone is the equivalent of about a week of growth from seed. Unfortunately, taking a clone from someone else incurs the risk of bringing pathogens with it - use caution.

Regular seeds have a 50/50 chance of being male or female. Male plants produce pollen sacs instead of flowers, and will fertilize any female plants nearby so that they create seeds (seed production drastically reduces bud production). Gender of the seeds can take about a month of growth to determine, and generally male plants are thrown out.

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Feminized seeds tend to be more expensive, but will always produce a female plant. Generally speaking, fears of hermaphroditism of feminized seeds are unfounded. It can happen, but is usually a grower mistake and not a defect of the seed. In nearly all scenarios, you will want to purchase your seeds feminized.

Autoflower strains are bred with a third variety of cannabis called Ruderalis. Because of this they generally have lower THC contents, but some of the best strains are becoming competitive with photoperiod strains. They will start to flower after a month or so, regardless of the hours of light and darkness. Because of this, their maximum potential size and yield can be limited.

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Any strain that does not explicitly state that it’s an autoflowering strain will flower according to its ‘photo’ (light) ‘period’ (schedule). Approximately 12 hours of consecutive darkness per day will trigger your plant’s hormones to shift from vegetative growth to flowering. Photoperiod strains can be cloned effectively while autoflowers cannot.