How to Properly Distance Cannabis Plants in a Grow Room

The reasons for growing your own cannabis are numerous. There’s the price, the fun of seeing how your favorite plant develops, and the sense of satisfaction as you consume cannabis flower that you cultivated and harvested with your own two hands. As you’re looking around your available grow room space with visions of blooming buds dancing before your eyes, there is one question that you should be considering: “How far apart should I space my weed plants?”

There are a couple of major factors that you need to consider when it comes to how to distance weed plants — as well as growing in general — which we will delve into below.

What is the size of the grow room space that you’re working with? Depending on the cannabis strain that you’re planning to plant and raise, the grow room space you’ll need per plant could be anywhere from one to three square feet. This of course all depends on the set up of your lighting, your ventilation, and your pots, but we’ll cover that below.

The main thing you want to avoid is overcrowding. Your plants will branch out towards each other as they grow trying to reach their friends (or hog all the available light). When those branches start rubbing their leaves together they become especially humid and lose their ability to transpire efficiently. This can spread mold among your plants, as well as thrips, spider mites, and other problems. This can become especially problematic when combined with insufficient humidity and temperature controls as well as poor ventilation or air flow.

When considering how far to distance your weed plants, you’ll need to figure out your available grow room space and how many plants you’re looking to grow at one time. Keep in mind that when you’re distancing your weed plants, generally you want at least a six inches to a foot of room between the branches. How far apart your weed plants are will vary, but this guideline gives the plants plenty of distance apart and gives you room to maneuver as you care for and harvest your little cannabis friends. You can space your plants closer than this, as long as they are not touching, but at least half a foot is a good rule of thumb for distancing weed plants in your grow room space. 

As a general rule, the larger the grow container, the larger your plant will become. While you’ll start with ½ liter pots for any seedlings, you’ll need to figure out the average plant height of the strain you’re growing in order to decide on which pot to use from there. This of course will also vary if you’re growing a shorter, bushier indica or a taller, thinner sativa.

Square pots can be used to more effectively conserve space in your grow. photo credit

If you’re only looking to grow a shorter plant that maxes out at two feet, you’ll need about a gallon sized pot. If you’re growing anything larger than that, you’ll need to start with a two to five gallon pot. As a pro-tip, while circular pots are more widely used and widely available (especially if you’re looking at a paint bucket set up), square pots will help you conserve space. 

Your lighting set up in your grow room space will also have a big impact on how far apart your weed plants are, since your goal is to get as much of that artificial sun on every part of your plants as possible. The first thing to watch out for with your grow room lighting is what type of reflectors or hoods are on the appliance. If the hood is at too narrow of an angle, the bulbs are too deep set in the frame, or the reflective material is cheap, you’re losing a lot of available light while simultaneously wasting a lot of energy.

What you’re aiming for with the right reflector or hood is a range of 16 to 22 square feet of well-lit space per 1000-watt bulb. If you’re using a high quality, double ended bulb, you can get over a third more light intensity than a conventional HID bulb, but you’ll need to hang them higher due to the excess heat. With a quality double-ended bulb you can get a maximum of 27 square feet of usable lighting space.

Lighting plays a big role in how you should plan on spacing your plants. photo credit

If you’ve correctly distanced your weed plants, there should be enough direct light shining through the canopy to illuminate most of the plant’s leaves.

The light should be able to shine through from the top to the bottom of each cannabis plant’s perimeter, as well as on all sides. If a majority of the plant is being shaded, it will harm the plant’s development. This will lead to less potent trichomes and less buds being grown overall, and can stunt your plant’s growth or leave it vulnerable to disease. If you find some of your plants are stuck in the shade, it’s time to separate your plants even further from each other.

For every 1000 watt bulb, you should also have at least one foot-tall oscillating fan to increase airflow through your grow room space. You should see a slight breeze that moves the leaves and branches on all parts of your plants, from the crown to the base. If there are some plants stuck in an area of stagnant air, you’ll need to distance your weed plants further. Still air hanging above or around your plants can harm them by making the leaves too humid.

There’s no real hard and fast equation on how far apart your weed plants should be in your grow room space. Each plant is shaped differently, each strain has its own needs, and each room that you grow in comes with its own dimensions. However, making sure that your plants are spaced far enough apart so that they don’t touch is the point to start from when it comes to home growing.

It's important to remember that each plant is different with its own specific needs. photo credit

Once your weed plants are distanced, then it’s time to look at the other important factors mentioned above in your grow room space. Buy grow containers that will fit your room, adjust your plants so that they’re getting enough light on all sides, and be sure that there is enough room for a gentle but steady airflow throughout each plant from top to bottom. Once you meet all these requirements to keep every cannabis plant in your grow happy and healthy, that is your ideal distance to space your plants.

How much space should be between cannabis plants?

Generally you want at least a six inches to a foot of room between the branches. You can space your plants closer than this, as long as they are not touching, but at least half a foot is a good rule of thumb.

Can plants be too close to each other?

Yes. If two plants’ branches are touching, it can disrupt airflow between them and lead to excess moisture. This can cause mold to grow. Damage to branches can also cause plants to herm out, and when branches touch it can also spread pests.

How much space is needed for a grow room?

Depending on the cannabis strain that you’re growing, the space you’ll need per plant could be anywhere from one to three square feet, depending on the set up of your lighting, your ventilation, and your pots.

Do you have any tips for new growers looking to start their first round of plants? Share them in the comments below.

Photo Credit: micripper (license)