Autoflowers are an easy way of getting started growing cannabis indoors. They grow rather fast, don’t require a lot of maintenance, and they switch automatically from veg to flowering. The downside with autoflower type plants is that they are more sensitive to topping, pruning, and defoliating. This results in less maintenance but also less trained plants. Because we as growers can’t cut them as much as photo plants, autos usually grow taller and slankier. This means they occupy a smaller space than bushy photo (non-auto) plants.

The size of plants is determined by the strain, the size of the pot they grow in, and how well the grower takes care of the plants.
This means that the number of plants in a given area will vary a bit depending on the given grow conditions.
Assuming autoflower weed plants are grown in a large pots (4+ gallon, 15+ liters), are well fed with nutrients, given a lot of light, and the strain by nature grows wide and busy, four mature plants (two rows with two plants per row) will fit in a 3×3′ (90×90 cm) tent.
On the other hand, if the autoflower plants are grow in small pots (<3 gallon, 10 liter), given limited nutrients and light, and not cared for very well, they will be smaller in size and nine plants (three rows with three plants per row) can be squeezed into a 3×3′ tent.
Here we see a 2.5×2.5′ (80×80 cm) tent with two mature autoflower (Auto AK-47) plants:
There’s plenty of room around the plants and two more could easily have been fit into this 6.25 sq ft area.
A 3×3′ tent covers an area of 9 sq ft, which tells us that there’s enough rooms for 9 plants.
To summarize:
A 3×3′ tent will fit 4-9 auto flower plants. The quantity depends on how large the plants’ pots are and how well they are taken care of. Beginners growers who aren’t all that experienced with plant management will likely have plants covering a smaller area, which means more plants (9) can fit inside the 3×3′ space.
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