You may have considered growing in an empty space and be wondering how many plants you could realistically fit in there. Making the best use out of free room requires a bit of methodical planning. There are a few adjustments and techniques we can use to maximise efficiency to get the highest possible yields, even in an individual square meter. We're here to show you how it's done.
How Many Plants Can I Grow In A Square Meter?
Getting the right amount of plants (or more importantly, buds) to fit perfectly in your grow space is determined by a few factors. From the space itself, to your pots and grow lights, there is plenty to consider before attempting to fill out the space with as many plants as possible.
For plants to grow efficiently in a limited space:
- Pots need to be large enough for the plants.
- Ample light distribution across canopy.
- Proper airflow around the whole grow area.
- Training to improve production and maximise space.
Your Grow Space
The first thing to do is measure your available area to see exactly the size you are going to be dealing with. For the purpose of this article we will be calculating the amount of plants based on a single square meter, if you hadn't guessed that already.
Obviously, the size of the area will a big deciding factor on how many plants your are going to be able to fit in a square meter. Most growers tend to use a grow tent for their indoor growing setup, usually measured in meters. Which tent you choose comes down to how big the indoor space is, how you plan to grow, as well as your harvest goals.
Depending on the technique and equipment used, an average between 1 - 16 plants can be grown in a square meter. If you want to grow only one plant, whether trained or untrained, then a single square meter is recommended. But if your focus is maximum efficiency and yields and you only have a square meter available, then you may want to add more plants with the intention to manipulate them or keep them small by flowering them early.
Strain Matters
It's common that one of the first things beginner growers think about is which strains they would like to grow.
The strain makes a big difference to the final size of a plant, and therefore will affect how many plants you are realistically going to fit into that square meter.
Some genetics do not mind being manipulated, while others need to spread out if they are to produce decent yields. For example, Indicas are usually short and bushy, unlike Sativas, which have a tendency to grow tall and branch out a fair amount. You may opt for genetically smaller plants if you are trying fit more plants into the space.
Consider growing one strain so you end up with plants that are more or less the same height. It becomes increasingly harder to manage space efficiently when all the plants are different shapes and sizes. Smaller plants may also not do as well as larger plants surrounding them.
Pots
The size of your pots not only determines how many plants you are going to be able to fit in the cultivation space, but how big the plants can grow. That being said, you need to make sure you don't add too many large pots otherwise your plants might not have enough space. The plants are much easier to manage if the pot fits the size of the plant. This is why many growers chose to transplant during different stages of growth.
There are many different kinds of container, usually available in a range of sizes. If you plan to fit more than one plant into your grow area, square pots are advised. Each pot needs some space around it as the plants tend to get wider than the diameter of the container.
To get a rough idea of pot size in relation to how many plants you could fit into a 1x1 meter space, you may use the following guide:
| Pot Size (litres) |
N° Plants/m2 |
| 3 |
25 |
| 5 |
18 |
| 11 |
9 |
| 15 |
5 |
| 18 |
2 |
| 21 |
1 |
Grow Lights
The more powerful your grow lights are, the more light is distributed across the grow space. A higher output light covers a larger area, meaning more plants can be grown. Depending on the design of the light and its output, the edges of the square meter may not receive the same amount of light as in the centre of the canopy. That means your light needs to be powerful enough so you can place it at the right height and each plant gets a fair share of the resources.
If you have lots of plants that do not receive enough light they are likely to deliver underwhelming harvests. Therefore, if is best to start with fewer plants if your light isn't powerful enough to cover the whole area.
A higher wattage leaves a larger light footprint:
| 150W |
0.6 x 0.6m |
| 250W |
0.8 x 0.8m |
| 400W |
1 x 1m |
| 600W |
1.2 x 1.2m |
| 1000W |
1.5 x 1.5m |
There are a few different types of light we can use to grow cannabis, however for this example we will be discussing the amount of plants you can grow under a standard HID light fixture. CFLs and LEDs can be used to grow but have different specifications. For HID lighting, growers can simply divide the wattage of the light by 75 to get an idea of how many plants they can grow:
- 150W (÷75) = 2 plants
- 250W (÷75) = 3 - 4 plants
- 400W (÷75) = 5 - 6 plants
- 600W (÷75) = 8 plants
- 1000W (÷75) = 13 - 14 plants
Wattage is not the only factor to consider when it comes to grow lighting. The type of light, as well as the lumens and spectrum are all important in determining the footprint. It is recommended you check this information with the manufacturer before purchasing any light.
Training Techniques
Growers looking to maximise yields in a small space will often choose to train their plants. You may decide you do not want to train your plants and leave them to grow naturally. In this case, each plant needs more space, both in height and width.
How you train cannabis plants determines how efficiently they use the available space:
Sea of Green (SOG) - This method involves growing lots of small plants in small pots. Plants are kept in vegetation for just one or two weeks before forcing them to flower. Results in an even spread of bud that covers more floor space instead of height. (4-16 plants/m2)
Low Stress Training (LST) - Plants can be manipulated by bending and tying branches to achieve a desired shape. Encouraging plants to grow outwards rather than upwards requires more floor area per plant. (1-4 plants/m2)
Screen of Green (ScrOG) - Involves setting up a netting over the plants, allowing a grower to control height and even out the canopy. Although a slightly more complicated training method, this is a great way to manage less plants and achieve big yields in a single square meter. (1-4 plants/m2)
Topping/FIMing - These are both high stress techniques that involve cutting the main shoot of a cannabis plant to limit height and increase yields. Topping and FIMing causes plants to bush out and develop multiple colas instead of focusing their energy on one main cola. (2-9 plants/m2)
Mainlining - Mainlining involves heavy manipulation of branches and leaves. Mainlining keeps plants very short but allows them to develop large colas. Plants can be topped and trained over and over, which tends to result in a wide structure that takes up a good amount of floor space. (1-4 plants/m2)
Dark Devil Auto by QuantumSkies From GrowDiaries
Conclusion
There is plenty to discuss on the subject of space efficiency, but it all comes down to the resources you have available and how you chose to grow. If your are still unsure about the amount of plants, it is best to start small and work your way up. Just remember to allocate enough floor space for each plant and provide the right amount of light before thinking about training techniques.
External References
Photometry and Photosynthesis: From Photometry to PPFD (Revised). - Ashdown, Ian. (2015).
The results of an experimental indoor hydroponic Cannabis growing study, using the 'Screen of Green' (ScrOG) method-Yield, tetrahydrocannabinol (THC) and DNA analysis. - Knight, Glenys & Hansen, Sean & Connor, Mark & Poulsen, Helen & McGovern, Catherine & Stacey, Janet. (2010).
This article was updated October 2020.
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