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How Many Plants in a Grow Tent / Grow Room?

How Many Plants in a Grow Tent / Grow Room?

 Getting a good yield is about growing the right number and right size plants.

Don’t cram too many plants into your tent. You won’t get a bigger yield by overcrowding plants. Instead, you’re likely to stunt growth and dent your yield.

Often you can get just as much yield - or even more - from fewer, bigger plants.

So how many plants should you grow in a tent or room?

The exact number of plants depends on many factors, including:

  • The size of your plants
  • Your growing system (the shape of pots, space between pots, size of pots, etc)
  • Your grow lights
  • The rest of the equipment in your tent

However, the main thing to do is leave enough space around plants for lateral growth. You don’t just want plants to grow tall – you want them to be big and bushy.

As a rough guide, you’re best off aiming for 1 – 4 plants per square metre.


Hint

Some people allow their plants to become too big during vegetative growth, and fail to leave room for any growth in flowering. By the end of the veg period, plants should be around half their final size. With that in mind, keep the veg period relatively short if you can only accommodate small plants.

If you want to let them develop but haven’t got space for the extra growth, you’re going to need a bigger room or tent.

Tent Guide

You can grow more smaller plants, or fewer larger plants. Here’s what we recommend for our main tent sizes:

Tent Guide
  Number of Plants
75cm x 75cm  1 – 2 plants
100cm x 100cm 1 – 3 plants
120cm x 120cm (XL) 1 – 4 plants
100cm x 150cm  1 – 4 plants
120cm x 240cm (XXL) 2 – 8 plants
150cm x 150cm 2 – 6 plants
150cm x 200cm 2 – 8 plants
150cm x 300cm 4 – 12 plants
100cm x 300cm 3 – 9 plants
200cm x 200cm 4 – 12 plants
200cm x 300cm 4 – 16 plants
240cm x 240cm 4 – 16 plants
360cm x 240cm 6 – 24 plants
300cm x 300cm 6 – 24 plants
600cm x 300cm 12 – 48 plants

If your tent size isn’t on this list, you just need to do a bit of maths:

Step 1

Work out how much floor space you have.

Multiply your tent's L x W (length x width)

e.g. a 3m x 3m x 2m tent has 3 x 3 = 9 sq.m of floor space.

Step 2

Work out:

(floor space) x (number of plants you want to grow per sq.m)

(e.g. a 9 sq.m x 3 plants = 18 pot system)

Remember – we recommend 1 – 4 plants per sq. m.

Maximise Floor Space

There are a few different ways to maximise the available floor space you have:

Maximise Floor SpaceMaximise Floor Space

1.     Use Expando Tent Supports

If space is tight in your tent, try Expando Tent Supports.

They keep your tent canvas taut and enlarge your growing space by up to 30cm (depending on the tightness of your canvas). That’s 7.5cm per wall.

They fit tents that:

  • Are 1m or bigger
  • Have 16mm - 28mm poles
  • Have gaps between tent poles of 1m - 1.5m
Taller TentTaller Tent

2.     Use a taller tent & low-profile system

Some growers find they are unable to allow plants to grow to their full potential because as plants grow, they get too close to their light source (which they're unable to move due to lack of headroom). When this happens, they cut their vegetative cycle short and flip to flowering earlier.

To prevent this from happening, consider using a taller 2.2m or 2.4m grow tent (you may need a more powerful light as a result) and/or low-profile system. Doing this will allow you to keep a safe gap between your grow lights and canopy.

If you find that your plants have filled out your floor space, prune plants so that they can grow taller without growing too big and bushy for your tent.  

Ultimately, you just have more space in your tent for plant mass.

Picking a system

Picking a growing systemPicking a growing system

Remember to pick your growing system carefully for your tent. It’s not just about matching the number of pots to the number of plants you want to grow – you need to make sure the system physically fits into your tent.

Modular systems – like RhizoSystems - tend to be quite flexible. You have more choice over how you connect and where you position pots. For instance, you can have fewer long lines, or more shorter lines. This means you can match your system to the shape of your tent.

Other systems are a bit more rigid. For instance, NFT systems are just the size and shape that they are. You don’t have the flexibility to change your layout, unless using multiples in a larger tent.

What Size Pots?

Once you know how many plants you’re going to grow, if you’re using a pot-based system, you need to pick the right number of pots and the right size pots.

Generally, you should use 50 – 60L of growing media per 1 – 1.2m2 of space in your tent.

50 – 60L will fill:

  • 6 x 8L pots
  • 4 x 12L pots
  • 2 x 30L pots
  • 1 x 56L pot

So if you decided you wanted to grow 4 plants in a 120cm x 120cm area, you would need 4 x 12L pots.

We recommend

We always recommend using RhizoPots, which are made from fabric. They allow air to contact root tips and ‘air prune’ roots. When this happens, rather than simply growing forwards, towards the edge of pots, roots start branching and producing secondary and tertiary roots.

Overall, you end up with a denser root network that's spread more evenly through the media, giving plants access to the nutrients and water in the central space. You also get more root tips for extra uptake.

Dan
Dan
About the author

Dan's the man behind our marketing. He makes the newsletters, emails, catalogue and shop displays happen!

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