I have a 400 watt mh/hps light in a 2x4x5 tent. Assuming all other aspects are perfect what kinda of yeild can I expect from say 3 autoflowers? I know strain matters a ton but im just looking for a general idea as I am growing multiple strains. Thanks for any info
It depends heavily on strain, but with autos in a 2x4, expect somewhere around 150-200g for a first attempt. I know it doesn't sound like much, but Average for autos seems to be between 200-300g per sq metre, unless you get a large yielding strain, but even then the yields seem to be around 300-500g max per m², your just growing less plants at a time. From my small experience, 4 Oz per 2x2 seems to be a good goal for beginners, but most of them have been running 250w hps or 150w LEDs.
It's more about space and strain rather than number of plants. This is my gorilla glue #2/fat monkey auto at day 46 (second week of flower) in a 100x50 tent. It's a big strain, usually around 90-130cm. It has around 6 weeks left, and is already 14" from lights with only an inch left to raise in a 6ft tent. Make sure you check strains for heigh and light requirements, as I clearly didn't and got a tall and large auto strain. This has been heavily defoliated as well from the 2nd node down on every cola (8 main branches), so 32 shoots have been removed.
Fella i got the seeds with had two, each in 60x60 tents with 250w HID. They pulled 115 and 143g with a fair bit of popcorn from each. His GDP's in the same tents were half the size, only vegged for 3 weeks and put out 62 and 90g due to differing defoliation and training.