Cultivation Corner with Olivia Sobelman: Why professionals love indoor winter gardens

Pros, Cons, and Things to Know

Humidity

Winter is the easiest time to grow indoors. The humidity is lower outdoors which can help keep the humidity lower and under control in your indoor environment. A dehumidifier might still be necessary if you are running a room that isn’t bringing in air or moving air into separate rooms. Ideally, your room should be lower than 50% humidity. The lower the better to protect against powdery mildew and Botrytis.

Heating and Cooling

You should not need to run an air conditioner during the winter. Whereas in the summer, they are important to have even with smaller grows, in the winter you can simply bring cold air in from outside to cool your room. In a sense, the world is your A/C. You can turn your lights onto their highest setting, you can run more lights with fewer issues, and you can get much denser buds during the winter months. There are affordable temperature control sensors that can turn your fans on and off automatically to cool the room to the temperature that you choose. Some fans come with the sensor built-in, but that is a very easy option for those that don’t.

You can heat your room if necessary using a radiator-style heater. Pay attention to the style of heaters that you use. If they are anything other than a radiator style they may be more dangerous or be the style that emits an orange glow as the coils heat up, this can cause a form of light that can lead to light leak style hermaphroditism in your plants.

CO2

Carbon Dioxide is the Oxygen of plants. It’s common knowledge, but adding it is not incredibly common practice among all growers. It is considered an advanced growing technique, but not because it is difficult, simply because it typically requires a larger grow area to implement the CO2 effectively. I’ve met very advanced growers over the years that were successfully growing without the addition of CO2, but I did talk a lot of them into it just through the process of trading ideas and knowledge with them. I took a lot away from the conversations that I later implemented into my grow. That being said, they have used CO2 ever since and have never gone back. Of all the products and marketing that exist in the industry, most claim to add 10-20% yield to your plants. It is true for maybe a handful of them, but CO2 will actually add 20% to your yield if run between 1000-1600 ppm.

You can run CO2 burners in the winter that will effectively distribute CO2 into your environment. This is not the same method as filling CO2 Canisters which is less effective and costly to refill. Any Co2 is better than none, but burners are Ideal. They burn propane or natural gas, adding heat to your room and the byproduct of burning gas is Co2. Winter is the perfect time to run CO2 using this method.

Light Cycles

In the summer a common way to mitigate heat is to turn your lights on at night so that you aren’t running the lights during the heat of the day. During the winter you can run your lights in the daytime, spend more time with your plants, and actually be able to sleep at night. It also cuts down on the likelihood that you will have light leaks in your room because the sun will be shining when your lights are shining and they will be off at the same time that it turns dark outside. This is especially important and convenient if you are running a fan to bring in cold air from outside, light leaks can come in through this system as well as through window A/C Units. It is important to monitor and take note of how cold your room gets during the dark hours. On especially cold nights you could actually have issues with your room getting too cold. Adding a heater might be necessary at times.

Watering

Water temperature can be tricky this time of year. If you are running straight from a spigot into a reservoir and then immediately watering, you run the risk of using too cold of water. The plants respond to this by becoming shocked and refusing to uptake any of the water. They will mimic having a nutrient lockout and become an array of unhealthy colors ranging from purple to yellow and a handful of colors in between. Aquarium heaters that maintain 60-70 °F water may be necessary to keep your water at the right temperature for plant uptake.

Like Clockwork, clones may become slower to root at the start of winter. This can have everything to do with the colder temps keeping your humidity low and keeping your water/rooting plugs too cold. It can be a normal temperature in your room and your floor can still be too cold to successfully clone or germinate seeds. Placing your cloning chamber on a shelf or adding a heating mat underneath are both easy fixes for finicky babies.

Plant Health

The winter is a growers’ best opportunity to create the perfect environment for optimal plant health. You can control your temperature to the exact degree which in turn, can allow a plant to grow incredibly dense buds. Much like people, plants grow bushier and buds grow denser as a way of bundling up in colder climates. They do this to maintain their preferred internal temperature. Adversely, plants become lanky and airy in the summer to allow airflow to pass through the plant as a way of cooling itself down.

You can keep your pest problem down because they aren’t pouring in from outdoors and they multiply much slower when your room is below 80 °F.

You can achieve purple buds easier as your nighttime temperatures drop into the 50 °F range. Strains that have the propensity to turn purple via their genetics will turn purple without much temperature manipulation. The plants that are genetically predisposed to turn purple because they have adapted to growing in colder climates. Most of these have ancestors from the Hindu Kush Mountain ranges and typically tend to be Indica Dominant. They turn purple to attract the sunlight necessary for health and heat. If the planet was further from the sun then all plants would be purple instead of green to attract enough sun to photosynthesize. The unhealthy purpling is often accompanied by yellowing leaves and deep purpling stems, this is indicative of a potassium/phosphorous deficiency (more common during the flowering phase), or a nutrient lockout that could stem from too cold of water or too much salt build up in your root zone.

Winter gardens are the best kind for any indoor grower. You aren’t fighting an uphill battle with heat and pests, and you get to still have some greenery in your life during the cold winter months. It’s therapeutic in that way. Those who haven’t begun to grow indoors, I know I can speak for most people when I recommend that you give it a try this winter. These are the months where you can set a light in a tent, without spending extra money on inline fans and costly air conditioning units. With a good oscillating fan, most hobby or personal growers can produce great cannabis with just the bare minimum of equipment.

For those of you already growing, we would love to see your progress! Join the friendly, supportive, and helpful cannabis community on our Facebook group Grow Depot Presents: Cannabis Cup Quality. Happy growing everyone!