Homegrown: Basics of Growing Weed Indoors

Basic Gear for Growing Weed Indoors

Lights

Plants need light. Fortunately for us, horticultural lights have become fairly commoditized, especially LEDs. Lights that were well over a thousand dollars last year are now practically half that price. There are options available to the home grower for as little as $200-300. And if that’s too much, look around. Facebook Marketplace, Craigslist, eBay… there are a lot of unused lights out there. Fixtures that use bulbs are fine too. Just remember that they will use more electricity and generate more heat. Also, they don’t dim and require bulb replacement from time to time.

Beyond price, other considerations would be the quality of the fixture, what kind of warranty the manufacturer offers, and is the light the right shape for your space. As far as quality and warranty, let’s just say the devil is in the details. How long is the warranty and exactly what does it guarantee? LEDs, and especially cheap ones, will lose intensity over time. A good warranty will not only guarantee that the fixture will continue to perform but also will maintain a certain intensity.

As far as shape, pick a light that fits the shape of your space. You are looking to light every square foot of that space as evenly as possible so that your plants will perform as equally as possible. A rectangular fixture or even two smaller fixtures might make the most sense.

Each fixture has all sorts of information available about its spectrum, total output, electrical efficiency, etc. Don’t concern yourself with any of that for now. A good rule is at least 25 watts of power per square foot of grow space. 40W is the most commercial growers use, and they’re usually able to take advantage of higher light levels by adding CO2 to the environment. This isn’t something that I’d recommend for beginners or even intermediates.

Also, look for a light with a dimmer knob. Hanging that light with an inexpensive set of rope ratchets will give you the ability to raise and lower it easily, getting the light source closer or farther from the plant. There is a ton of latitude in this: just don’t hang a 100W light in a 4×4 grow tent and expect big returns. You’ll probably end up with tall plants and low yields.

Temperature

The next biggest concern is temperature. Generally, cannabis likes it warm. It thrives in daytime temperatures in the upper 70s and even higher for experienced growers. If your space can’t maintain overnight lows in the 60s and reach daytime temperatures of the mid-70s, consider adding a small space heater. Otherwise, your plants may grow slowly or even show signs of stress.

It’s also important that daytime temperatures don’t get too high. If you live in a warmer climate, or you opt to start a little bit larger grow that will be generating more heat from more equipment, your space can quickly get too hot and your plants will start to stress, especially if the humidity is too low.

Adding air conditioning to the space would be by far the largest expense you could consider at this point. As a beginner, I recommend scaling down the size of your grow so that you can handle any heat issues with ventilation instead.

An inline exhaust fan can cost under $100 and with the addition of a $30 fan speed controller, you can exhaust air from your space at a controllable rate. These fans will mount inside tents with ease. Usually, I’ve been able to do it with zip ties. If you are in an open room, it’ll probably turn into a little project.

Humidity

The next thing you’ll need to consider is relative humidity, or RH. It’s called relative because as air temperature increases, that air is capable of holding more water. So, for example, if you increase the temperature of a space without adding more moisture, the relative humidity will go down. If you decrease the temperature, the humidity will go up. Generally, cannabis likes it a bit on the humid side. It can thrive in humidities of 70% or more.

Unfortunately, so can mold and other fungi. If the humidity allows, those fungi will find a food source in your room and start to grow. Certain types of fungi will even grow on your plants. Nothing will ruin your day faster than realizing that a beautiful flower that you’ve just grown has succumbed to mold. I’ve been there. So, as a beginner, I suggest that you just plan on doing your best to keep your humidity between 50 – 55%

Plants transpire, or essentially sweat, all day, adding moisture to the room. So, at some point, you may have to start dehumidifying the space to keep the humidity in check. If you are in a more humid climate, maybe sooner than later. Again, you may be able to control this humidity with ventilation.

If you need to add a dehumidifier, most consumer models will suffice. A good rule to remember is water in = water out. You may need to remove as much water from the air as you use to water your plants.

Understand that dehumidifiers are not only an added expense but will also add considerably more heat to your space and take up some real estate. If you’re growing in a tent, you may consider dehumidifying the outer room and adjusting the ventilation through your tent to achieve the proper balance of temperature and humidity.

Low humidity can be potentially stressful to the plant. Do your best to keep the RH above 50%. If you live in a more arid climate or have low humidity in the winter months, you may also need to add a small humidifier. Fortunately, there are many affordable options available. Just be aware if you are buying one that calls for only filtered water or requires the regular changing of a filter.