One gallon black and white panda poly grow bags work great for the vegetative growth period of most "indoor" cannabis plants. If you're starting cannabis seedlings in 16oz red party cups then a one-gallon grow bag is logically the next step up when the seedlings have established roots and grown enough to warrant a transplant. There are strong arguments for not stressing plants out too much with too many transplants, but there are also strong arguments for limiting the number of ways you could screw up. One-gallon black and white panda poly grow bags are just the right size for most cannabis plants during their early vegetative stage.
Complimentary to Grow Room Design
Black and white panda poly plastic grow bags are designed to complement the environment of most indoor grow rooms. Generally speaking, everything inside an indoor grow room should be white for maximizing the amount of light being reflected. It's why grow lights have reflective hoods and the walls are white. Anything reflecting light to the leaves of the plants is helping them grow - grow bags don't need to be an exception to the rule. The black-colored interior draws the light in the direction of the pots (i.e. at the plants) and the white exterior color reflects the light that misses.
Benefits for Plant Root Growth
The round shape of the pot lets roots wrap easier. When a plant's roots hit the edges of a container they need to find a new place to go and grow. It's really weird if they hit a right-angle at the corner of a square pot - nature doesn't make 90-degree turns. With round black and white panda poly grow bags the roots will never run into a corner. Instead of hitting a wall and getting lost, confused, or stuck, they'll twist and turn and grow until they're too big for the pot. In reality, it's not a huge difference, but cannabis growers know any time you can prevent unnecessary plant-stress that it's going to be better for the grow.
Simplified Transplanting and Repotting
Plast poly grow bag manufacturers might be in cahoots. Okay, so they're probably not in cahoots, but all the black and white panda plastic poly grow bags seem to be in harmony when it comes to sizes and height increments. The round design, straight sides, and complementary height and width of poly grow bags make removing and transplanting cannabis plants a breeze. It's super simple to grab a small tree by it's stalk, pull it out of the bag, and pop it into a new hole in a larger poly bag - whereas, transplanting into different shaped or different height containers may cause issues (e.g. most fabric air pots are shorter than poly grow bags, so it's hard to go from even a one-gallon poly bag into any size fabric planter because you can't recover the top soil without overflowing the shorter container).
Long-Lasting and Reusable Plant Containers
One-gallon poly grow bags are large enough to contain a cannabis plant through an entire 12-14 week grow. You can grow the plant from vegetative all the way through bloom to harvest. Some more vigorously growing strains may become root-bound - especially if you're extending the vegetation phase for any reason (like Low-Stress-Training a plant), but for most average 12-14 week grow-cycles one-gallons is enough room. Cannabis plants tend to fill the space you give them and it's a good idea to give roots room to grow for the entire grow, but if space or grow medium is in short supply then these work great to solve spatial issues too.
Plant Containers for Growing Cannabis
One-gallon black and white panda poly grow bags work great for growing cannabis plants. The round shape and straight size are an optimal growing space. The colors contribute to a higher-efficiency growing environment. They're affordable, easily replaceable, and have long life spans. You can re-use poly bags grow after grow. These bags make transplanting more fool-proof and offer plenty of room for a full-grow cycle if transplanting is not your jam.