What is the best size pot for my room?

  • Thread starter Cannasurfer
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Hi all,

I am a long time lurker, and semi experienced grower. Historically, I've only hand watered, used Promix HPCC, 15 gallon smart pots, with the Aptus Nutrient "Extreme Feed" schedule under Gavita 1700e. Typically veg for 2 weeks in 1 gallon pots before transplanting to 15 gallon and vegging 6 more weeks before flipping, and yield thus far has pretty consistently been around 1.9 lb/light.

My property has a pole barn on it, so I am switching from my basement to the barn. The barn is much larger, with 12 ft ceilings. My flower room is about 600 sq ft and has 24 Gavita 1700e in it. to stay within my plant count, I have 24 plants going in that room, so basically each plant is under its own light, so I need the plants to get fairly large. I set up an automatic watering system to help with this, so I can deliver multiple smaller smaller feeding a day, as my day job keeps me fairly occupied. I am also planning on using 70/30 coco/perlite for the barn. I have a couple questions that I am hoping you fine people could help answer for me:
  1. Considering the auto watering and ceiling height, room size, grow medium etc, should I stick to 15 gallon pots? If I go up to 20 gallon pots, will I get much larger plants with the same veg time? Many people have told me they use 10 gallon pots for similar set ups, but I don't want my room or lights to go to waste. If I could throw 50-60 plants in there, I wouldnt be too worried,
  2. Aptus nutrients are way too expensive to use for the auto feed system, so I am thinking of switching to Athena's Pro Line. Has anyone had success with this lineup? Anyone make modifications to it that prove beneficial? I was thinking of still using Aptus' Fasilitor product in addition to the Athena lineup.


If I go up to 20 gallon pots, will I get much larger plants with the same veg time?

From Want bigger plants? Get to the root of the matter:

“They also looked at 65 independent studies across a wide range of species including tomato, corn, pine tree, cactus, wheat, and cotton plants, and found that all species reach larger sizes when grown in a bigger pot. On average, doubling pot size allowed plants to grow 43% larger.


To understand the pot size effect, the scientists looked at various aspects of the plants' growth. They found that the plants in smaller pots grew more slowly because of a decreased rate of photosynthesis. But, looking for causes for the decrease, the scientists ruled out limitations in water and nutrients and did not find any differences in the thickness of the leaves for plants in smaller pots. It is therefore unlikely that the plants use water and nutrient levels to sense the pot size, supporting the possibility that sensing happens another way, such as by the roots.”

You’ll get larger, though I wouldn’t count on much larger with a five gallon increase. Certainly it wouldn’t hurt. 😉


Like cannasurfer suggests...15 gallon fabric bags grow a nice healthy plant...anything bigger than that you may as well grow a tree outside in the ground let Mamma Nature takeover. I've been using 10 gallon bags for a few years now...no complaints, but a 15 gallon bag seems to have grow a bit bigger of a plant...or maybe it's all in my head...? Maybe not? lol
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