Large planters can add a dramatic touch to your outdoor or indoor spaces, but filling them entirely with potting soil can be surprisingly expensive. If you’re looking to pot larger plants without emptying your wallet, there are several clever and cost-effective ways to fill those big containers. Here’s how to cheaply fill a large planter while still ensuring your plants thrive.

The Problem with All Potting Soil in Large Planters

While potting soil is essential for providing the right nutrients and drainage for your plants, using it to fill an entire large planter has a few drawbacks:

• Cost: Potting soil can be a significant expense, especially when you need a large volume.
• Weight: A planter filled entirely with wet potting soil can become incredibly heavy and difficult to move.
• Drainage Issues (Potentially): While good potting soil drains well, a very deep column of it can sometimes lead to compaction and drainage problems at the bottom over time.

Smart and Affordable Filler Options

Instead of relying solely on potting soil, consider using these budget-friendly materials as filler in the bottom of your large planters:

• Plastic Bottles and Jugs: Clean, empty plastic water bottles, soda bottles, or milk jugs (with their lids on) are excellent lightweight fillers. They take up a lot of space without adding much weight and won’t decompose quickly.

• Aluminum Cans: Similar to plastic bottles, empty aluminum cans can be used as a lightweight base. You can crush them slightly to save space.

• Packing Peanuts (Polystyrene or Biodegradable): If you have a stash of packing peanuts from shipments, they can be a great way to fill space. Opt for biodegradable peanuts if you’re concerned about the environmental impact. Avoid using peanuts that dissolve in water if your planter will get very wet.

• Styrofoam Blocks or Pieces: Large pieces of styrofoam packaging or insulation foam can effectively fill the bottom of a large planter. Make sure they are broken down into manageable sizes.

• Wood Scraps, Branches, and Twigs: Untreated wood scraps, small branches, and twigs from your yard can be used as a natural filler. They will eventually decompose, adding some organic matter to the soil over time. Avoid using treated wood, as it can leach harmful chemicals.

• Leaves and Other Organic Matter: Dried leaves, grass clippings (untreated with pesticides), and other organic materials from your yard can be used as a base. These will also decompose and improve soil structure over time.

• Inverted Empty Plastic Nursery Pots: Place a few empty plastic nursery pots upside down at the bottom of your large planter. This creates air pockets and reduces the amount of soil needed.

• Gravel or Rocks (Use Sparingly): While gravel or rocks are often suggested for drainage, a thick layer at the bottom can actually hinder drainage by creating a perched water table. Use a thin layer (an inch or two at most) only if you suspect drainage issues with your chosen planter. For filling volume, other lighter options are generally better.

How to Fill Your Large Planter Cheaply: A Step-by-Step Guide

1. Ensure Drainage: Make sure your planter has adequate drainage holes. If not, consider drilling some (if the material allows).

2. Add a Layer of Filler: Place your chosen filler material at the bottom of the planter. The amount will depend on the size of the planter and how much you want to raise the planting level. Aim to fill about one-third to one-half of the planter’s volume with the filler. For plastic bottles or cans, you can fill them loosely. For wood scraps or leaves, pack them down a bit.

3. Consider a Barrier (Optional): If you’re using organic materials like leaves or wood, you can place a layer of landscape fabric or an old cloth over the filler before adding the potting soil. This can help prevent the organic matter from decomposing too quickly into the potting mix.

4. Add Potting Soil: Top the filler layer with a good quality potting soil. The depth of the potting soil layer will depend on the root depth requirements of the plants you intend to grow. Ensure there’s enough soil for the roots to establish and thrive.

5. Plant Your Flowers, Vegetables, or Shrubs: Plant your chosen plants as you normally would in the potting soil layer.

Important Considerations:

• Plant Type: Consider the root depth of your plants. Shallow-rooted plants won’t need as much potting soil depth as deep-rooted ones.
• Drainage: While using filler reduces soil volume, ensure you’re not compromising drainage. The filler should allow water to flow through to the drainage holes.
• Weight: Using lightweight fillers like plastic bottles or packing peanuts can significantly reduce the overall weight of the planter, making it easier to move.
• Decomposition: Organic fillers like leaves and wood will decompose over time, potentially causing the soil level to sink. You might need to add more potting soil in subsequent seasons.

Conclusion

Filling large planters doesn’t have to be an expensive endeavor. By using cost-effective filler materials in the bottom of your containers, you can significantly reduce the amount of potting soil needed, save money, and even make your planters lighter and easier to manage. With a little planning and creativity, you can create stunning displays of plants without breaking your budget.