In hydroponics DWC (Deep Water Culture) systems, a net pot is a specially designed container that holds the plant in place and provides support for the root system while allowing it to be exposed to nutrient-rich water. In soil grows you generally want to scale the size of the pot to match the size of your plant but that’s not the case with hydroponics and net pots. In hydroponics the net pot is not the limiting factor since the plants grow through the pot. The real limit is the size of the container where the roots reside..

The net pot is typically made of plastic or other similar materials and features several holes on the sides and bottom, allowing the roots to grow freely and absorb nutrients from the surrounding water.

The main purpose of the net pot in DWC hydroponics is to allow the plant to be suspended above the nutrient solution, keeping the roots constantly exposed to oxygen-rich water.

When choosing a net pot the size of the net pot is not going to limit the size of the mature plant since the roots grow through the pot not in it. There are still a few factors to consider

1. How much space do I have in my system? This one is fairly obvious. You cant put a 6 inch net pot in a mason jar. If your system is based on a 4 inch pvc pipe, using 3 inch pots with a flat brim isnt going to work.
2. Will the net pot support your plant? Consider what your plant is going to be exposed to as it grows. There will be times when it’s bumped, blown by the wind, etc. A wider pot can provide a stable base for shorter plants. Tall plants are going to need additional support regardless of your net pot choices.
3. I like to have a diverse set of plants in my planters. I might plant cucumbers and lettuce in the same container. If all of my plants use the same net pots it makes things really simple. Everything is planted in the same size pot, If one plant dies I know that any other plant will fit in it’s spot.
4. If you use net pots that are bigger than your starter medium (rockwool) you will need something to fill in the space with something. The most common filler is expanded clay pellets but gravel works too.

I personally have found that 2 inch net pots are ideal for me. I have grown some super big tomatoes without any problems related to the size of the net pot. I offer all of my plants supporting trellis so the pot really doesn’t have to support the plant from tipping over. When building the planter a two inch hole is pretty easy and safe to cut with a hole saw. Finally I start my seeds in 1.5 inch rockwool cubes and those square cubes fit really nicely inside the 2 inch pots without any extra filler.

Net pots are not particularly expensive and they are made of plastic so they can be used year after year.