Serious root volume for long vegetative periods and big single-plant grows. At this size, the medium holds more water and more nutrients, so a plant can go longer between feeds and ride out a missed watering. Suits a 5x5 tent running one or two plants, or a patio grow outdoors.
For long vegetative periods and large single plants
Twenty gallons is the size for growers vegging eight weeks or more, for anyone running one or two large plants instead of four small ones, and for outdoor container growing where the plant is expected to reach something close to its full size. On a four week veg with four plants to a tent it is simply harder to move and no more productive, and ten gallons is the better fit.
A bigger buffer between waterings
Seventy-eight litres of medium holds a great deal more available water than thirty-seven, which stretches the interval between waterings and means a missed day does no damage. That buffer is the main argument for the size, and it is what makes this bag suit growers who are away from the tent for several days at a time. The same buffer works for nutrient, so feed concentration swings are damped rather than hitting the roots directly.
78.5 litres, or roughly 2.8 cubic feet
Plan on one and a half 50 litre bags of mix per pot. At this volume the cost of filling starts to matter, and mixing a base medium with compost and amendments works out considerably cheaper than buying finished potting mix by the bag.
A practical outdoor size for a patio or balcony
Where a plant cannot go into the ground, twenty gallons is enough for a full outdoor season. Fabric drains heavy rain instead of holding it, and moisture evaporating through the walls keeps the root zone cooler than a black plastic pot standing in direct sun. Raise the bag off any hard surface so run-off escapes freely.
Serious root volume for long vegetative periods and big single-plant grows. At this size the medium holds more water and more nutrient, so a plant can go longer between feeds and rides out a missed watering. Suits a 5x5 tent running one or two plants, or a patio grow outdoors.
