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Container gardening can be a great way to grow if you’re limited to space or only have a patio. For most larger vegetables such as tomato or pepper plants you’ll need at least a 5-gallon container. So, the question is… how much soil for a 5-gallon pot?
How Much Soil for a 5 Gallon Pot
At the gardening centers you’ll find many shapes and sizes of 5-gallon pot. For our needs, we prefer to grow in 5-gallon buckets. They’re readily available and a consistent size, helpful if you’re using multiple buckets and need uniformity in a structure such as our outdoor hydroponic bucket planter.
No matter the shape of the container, a 5-gallon pot of any size will hold the same amount of soil. The amount of soil to fill a 5-gallon pot or bucket is approximately 0.7 cubic feet. If your soil comes in bags of 2 cu. ft. then you should be able to fill about three 5-gallon pots. This volume will also be the same whether using a soil mix or hydroponic mediums.
The volume mentioned above is factoring in all components of the soil mix. If you’re going to be mixing perlite, vermiculite, compost, etc. then you will use 0.7 cu. ft. of the final mix per 5-gallon pot or bucket. Mixing other components will also affect the weight but the average weight of pure soil could be as much as 40lbs per container so plan accordingly when considering a structure or stand to support the pots.
Container Soil Mix
When growing in containers it’s important that the soil has proper drainage but still retains the proper amount of moisture. We prefer to mix our own potting soil rather than purchasing it premixed, which can be a cost saver. Our mix is as follows:
- 1/3 Compost
- 1/3 Coconut coir *(or sphagnum moss)
- 1/3 Perlite
The compost is where your plants will get their nutrients. The coconut coir (or sphagnum moss) will help with moisture retention. Perlite provides drainage by keeping the soil from compacting. Throughout the season the compost will break down as it feeds the plants. As such you may need to supplement the plants with additional fertilizer mid-season. Optionally you can add a scoop of a balanced slow-release fertilizer into the potting soil before planting in the container. We prefer this organic fertilizer from Burpee.
If you have an odd sized container larger or smaller than 5-gallons or you don’t know the size of your container you can use this soil calculator to determine your needs.
*We recommend coconut coir over sphagnum moss for a couple reasons. Important to many, coconut coir is renewable unlike sphagnum moss. Coconut coir also has superior water retention properties and will not become hydrophobic (repel water) like sphagnum moss does if it completely dries out.