Depends on the medium your growing in. In coco coir i always got away with the third lower in pot size...sometimes even half. Ive found that coco coir packs a rootball big and fast. It also thrives on frequent feedings. A smaller pot compared to soil or peat based soilless mixes helps the coir dry out faster hence more feeds. A drip system on a timer helps if you do t want to feed manually. But regular soil or soiless...go with the above suggestions.