How big should my holes be? New Grower lol

I want a very good yield from my plants. Just wondering on how big the whole should be ? I read the roots grow more horizontally than they do vertically so i was thinking maybe 2 feet deep and 4 feet wide? What do you guys think is best for maximum yield ? (Dont tell me 10 ft holes lol)

4x2 will be good....last year i dug about 18'' wide and 18'' deep and got over a pound per plant. the roots grew into the natve soil.

This year i dug 3ft wide and 3feet deep, so i expect more.

DAM! i dont think i will be able to get that much, im just gonna use compost with perlite and idk what else should use (CHEAP suggestions?) and i might put mulch on the top, i herd that helps with moisture control also..

The bigger the hole,the bigger the plant.
The bigger the plant, the bigger the harvest.
That is the general idea. But there are alot more factors involved in growing big yielding plants.

i have a few seeds planted but the problem is that the soil is 30cm deep the hole area is 7 square meters thats no problem , im wondering if the roots will grow on sides ok . a few are already showing up

They don't necessarily need to be deep.I've had 13 foot tall by 10 foot around in an18" deep x 48" wide x 36" raised bed above native soil.If it has good soil to grow in,the roots will out grow the hole and grow into the native soil.

i mean under my 30 cm soil i have concrete only ... i forgot to mention that

Much love guys! Ill dig my holes until I get to high to dig (hoping around 2 feet deep and 3-4 wide )