You’re excited to start growing plants in containers. But you’re hesitating because you don’t know if the space is sufficient and how many plants you can grow.

On average, you can grow 2 medium plants per square foot in a container garden. You can grow 4-6 small plants per square foot in a container garden. You can grow several types of plants together in the same container to make efficient use of the space.

I’ve written the exact steps you can use to figure out the space you have and the number of container plants you can grow.

I conducted a poll with some of my fellow gardeners who are already growing a lot of plants in containers. And I was surprised to see that a lot of them had more than 20 plants growing in their container garden. Seems they have made pretty efficient use of their growing space.

75% of the gardeners were growing 20+ plants in their container garden as can be seen below.

Consider the average size of the container

The first thing we need to agree on is the average size of the containers you will use. Containers come in various shapes and sizes and this is not an exact science.

You could use containers such as pots, planters, grow bags, boxes, paint cans, barrels, buckets, or tubs. So the size will vary a lot based on what you pick.

But you can understand in a general way how much space a specifically sized container would take. Knowing this will help you plan better how many plants you can grow.

I’ve created a table below that will help you get this idea about how deep and wide a container will be based on its volume.

Container SizeDiameter (inches)Height (inches)
1 Gallon86
2 Gallon87
3 Gallon11.88
5 Gallon1410
7 Gallon1412
10 Gallon1813
15 Gallon2014
20 Gallon2115
30 Gallon2616
45 Gallon2718

Find out the space you have for your container garden

Now that you know how much space a particular sized container will take, you need to find out how much space you have for placing them.

You may have some space in your patio, balcony, or windowsill. You can get a rough idea of the area you have to place your container plants.

Take a measuring tape and measure the length and width of the space you intend to use. The length will help you understand how many containers you can place. The width will help you understand how many rows of containers you can place.

For example, the length and width of my apartment balcony are:

  • Length = 4 feet (48 inches)
  • Width = 2 feet (24 inches)

Figure out space the containers will take

Now you can find out how many containers you can place on your apartment balcony based on the area of the balcony and the diameter of the container.

Suppose I want to place 5-gallon containers on my apartment balcony. I would be able to place three such containers in a single row. I can find this out by using the below calculations. Note that the results are rounded to the lowest value.

Number of 5-gallon containers per row = Balcony Length (48) / Container width (14) = 3

Number of rows = Balcony Width (24) / Container width (14) = 1

I recommend you keep a space of at least 1-2 inches between the containers in each row. I would also suggest you keep 1 feet distance between the rows.

This will make it easier to move around the plants and take care of any issues or maintain your container garden.

If you add smaller containers like 1-gallon or 2-gallon then you can place more containers per row of your garden. If you add larger containers than 5-gallons you will have to reduce the number of rows and plants you’re growing.

How to grow more plants in your container garden

The above calculations will just give you an approximate idea of how many containers you can place assuming you’re growing one plant per container. But you can make more efficient use of your space and grow more plants.

Grow more plants in one container

The simplest solution is to grow more plants in a single container. You can pick a 5-gallon or 10-gallon container and grow several plants in them.

You will need to keep some space between the plants to ensure they don’t compete with each other for nutrients and resources. You can find the spacing requirements of each plant on the seed packets, seedling tags, or on the Internet.

You can also make use of companion planting to grow several plants together so they don’t interfere with each other. For example, you could plant garlic bulbs deep in the container that take several months to grow. You can plant spinach in the same container as it will grow on the surface and mature in just a few weeks.

Grow plants vertically to optimize space

The other way to optimize space is to grow your plants vertically. You can use hanging planters or baskets to grow multiple layers of plants.

You can use planters that can hang on the railing of the balcony. You can even use plant stands that can hold multiple pots in a vertical position.

If you are growing vining plants, you can grow them vertically giving them support with a trellis, stake, or some existing support structure present in your patio or apartment balcony.