For indoor growers we recommend around 10-gallons+ of soil volume per plant. (5-gallons+ for autos)
For outdoor growers we recommend around 40-gallons+ of soil volume per plant.
A question we get often is, “Can I use a smaller 5-gallon container? Or maybe even a 3-gallon container and still only add water to harvest?” The short answer is yes you can – but to a point. So, we wanted to dive into this subject a bit and explain in more detail why we suggest 10-gallon+ containers, so that you can make the best decision for your garden.
First off, this is a great question because in some cases using larger containers will reduce the amount of plants someone can grow in their gardening space. Smaller containers are also very common when using auto flowering seed variety's, were water soluble synthetic nutrient gardeners typically use containers in the 1-5gallon size range. Other reasons for wanting to use less soil volume may include cost, space to mix soil, living situations etc. We fully understand this and want to help you make the most informed decisions for your garden and how to get the most from it.
With Soil Charge Packs one reason to use larger soil volumes are because you will use this same soil over and over, so invest once and go for it. Simply think of the amount of money you will save on future harvests from not buying soil over and over again each harvest. With Soil Charge Packs after you harvest, you will cut the plant down and then put a new plant right into the same soil and continue on with the Topdressing of Soil Charge Packs every 21-30 days and adding water to another harvest - after harvest – after harvest – after harvest. So, you may as well start off with good sized containers (or larger) from the beginning.
You can get away with smaller sized containers - if they are smaller sized plants. You see, in this natural and organic style of growing all of the nutrients and minerals the plant needs will be physically in your soil, and also on the top layer when top dressed. There are no instant “shots” of nutrients from water soluble synthetic nutrients. So, the more soil volume the better, as it will make it easier on your living soil to provide anything the plants needs and requests from the soil at any moment in time – at any stage of growth. If you have a plant that is too large for its container then it will be growing faster than the living soil can provide for, simply from lack of soil volume. Picture a 6-foot tall plant inside a 1-gallon container – it’s not going to grow to its genetic potential.
More soil volume gives the worms and microbiology more space, this will only be a benefit to your garden. If a plant gets badly root bound then they can run out of nutrients near harvest because they will have run completely out of soil to access nutrients. Then on the flip side, small plants can be grown even in small 1-gallon containers all the way to harvest just fine in some situations. Again, it all just depends on the size of plants to figure out what size container you can get away with. This will all come with experience, so our 10-gallons of soil volume is a great starting point indoors and 40-gallons+ outdoors. You can use more or less soil volume from there as you experiment.
A rule of thumb to remember when trying to decide on container size is that you can’t use to much soil, but you can use to little. As the old saying goes, “The bigger the roots – the bigger the fruits.” It's true – go ahead and give it a go and see what you think.
Raised beds instead of containers are excellent as plants typically have access to a larger volume of soil to grow into. But containers vs raised beds is another subject that we will discuss later.
Stay tuned, and happy growing!