This Pro Tip Will Save You Money on Your Container Garden
For large planters, use empty milk cartons or plastic bottles to fill extra space before putting in potting soil
Large container gardens have a big impact in yards and interior spaces — they bring bold foliage, colorful flowers and seasonal interest wherever they’re placed. However, large vessels swallow a lot of potting soil at planting time, making them expensive, heavy and cumbersome to move.
This spring, steal a trick from the pros by adding a lightweight filler material to the bottom of your large or medium containers. You’ll save money on soil, lighten containers and set up plants to thrive.
This spring, steal a trick from the pros by adding a lightweight filler material to the bottom of your large or medium containers. You’ll save money on soil, lighten containers and set up plants to thrive.
How to Fill Your Container
1. Select your container and make sure there are drainage holes (drill holes if needed).
2. Choose your plants and take note of the soil depth they need to thrive (see the recommended soil depths later in this article).
3. Gather your filler materials, screwing the caps on bottles or jars and closing the flaps of milk cartons so they don’t fill with water and soil.
4. Put the filler at the bottom of the container to fill up excess space, making sure no drainage holes are covered.
5. Cover the filler with fresh potting soil.
6. Plant your selected plants in the container, adding more potting soil around the root ball if needed.
7. Water the container well and continue watering as needed for the plant type.
1. Select your container and make sure there are drainage holes (drill holes if needed).
2. Choose your plants and take note of the soil depth they need to thrive (see the recommended soil depths later in this article).
3. Gather your filler materials, screwing the caps on bottles or jars and closing the flaps of milk cartons so they don’t fill with water and soil.
4. Put the filler at the bottom of the container to fill up excess space, making sure no drainage holes are covered.
5. Cover the filler with fresh potting soil.
6. Plant your selected plants in the container, adding more potting soil around the root ball if needed.
7. Water the container well and continue watering as needed for the plant type.
Best fillers. Using the following materials as fillers also keeps them out of the landfill.
- Empty milk cartons
- Empty plastic milk jugs
- Empty plastic bottles
- Empty nursery plant pots
- Plastic bags filled with packaging
- Expanded polystyrene packaging (including packing peanuts)
Soil depth. The quantity of soil you need in a container depends on the type of plant and how deep the roots grow.
- 12 inches for annuals
- 12 to 18 inches for perennials
- 18 inches to 2 feet for shrubs
- 2 to 3 feet for small trees
When to Use Filler
A container filler makes sense in a number of cases, including applications where shallow-rooting plants are growing in large containers like feed troughs, crates or old wine barrels, or when you want to reduce the weight of a large container on a balcony or rooftop garden. Deep window boxes planted with flowering annuals also can benefit from fillers placed at the bottom to reduce weight and help with moisture balance.
A container filler makes sense in a number of cases, including applications where shallow-rooting plants are growing in large containers like feed troughs, crates or old wine barrels, or when you want to reduce the weight of a large container on a balcony or rooftop garden. Deep window boxes planted with flowering annuals also can benefit from fillers placed at the bottom to reduce weight and help with moisture balance.
Skinny upright containers filled with smaller plants are another prime opportunity for using filler. For tall inverted cones, it can be helpful to put something heavier than empty soda bottles at the bottom to help balance the weight of the pot and keep it from tipping over. Try an overturned terra-cotta pot, if it fits.
See similar outdoor containers
See similar outdoor containers
Likewise, rectangular containers that are tall and skinny can benefit from having filler placed at the base to help reduce weight and balance soil moisture.
When to Avoid Filler
There are a handful of cases where it doesn’t make sense to take up any soil space with a filler material. As we already talked about, if your plant type needs the entire depth of soil provided by the container (see the recommended soil depths earlier in this article), skip the filler. Other cases where you should use the full amount of potting soil include smaller containers and shallow containers, particularly if they are placed in full sun where they might dry out quickly.
There are a handful of cases where it doesn’t make sense to take up any soil space with a filler material. As we already talked about, if your plant type needs the entire depth of soil provided by the container (see the recommended soil depths earlier in this article), skip the filler. Other cases where you should use the full amount of potting soil include smaller containers and shallow containers, particularly if they are placed in full sun where they might dry out quickly.
You also should skip the filler if larger veggie plants (among them tomatoes, squashes and eggplants) are growing in medium containers. Although you can get away with growing herbs and shallow-rooting crops like lettuce and radishes in medium containers with a bit of filler at the bottom, in general, you’ll want more soil for edibles.
Growing small trees in containers is another notable case where you want as much soil as possible. At least 2 feet of soil depth, more ideally 3 feet, will set up potted trees like olive, Japanese maple, magnolia, crabapple, citrus and others to thrive.
Tell us: Have you used fillers in containers? What other container garden hacks have you discovered? Share in the Comments below.
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Empty milk cartons or other lightweight fillers can be used to partially fill large or medium containers, cutting down on potting soil, lightening the weight of the container and creating a better growing environment for potted plants.
Although it may sound counterintuitive, reducing the amount of soil in a large container can actually enhance plants’ growth by helping to regulate soil moisture. A small plant placed in a deep container filled with soil can’t stretch its roots to the bottom to take up water. Excess water can collect at the bottom of the pot, forming a soggy base that creates an unhealthy growing environment.