Should You Use Fillers in the Bottoms of Container Plantings?

Should You Use Fillers in the Bottoms of Container Plantings?

Container Plants

Garden practices evolve and old habits die hard!

One such debunked garden habit is adding rocks or gravel to the bottoms of pots and planters in an effort to improve drainage. However, this practice has been shown to be more problematic because of the collection of stagnant water and pushes the saturated water table layer up; increasing the risk of root rot.

Proper drainage is a life-or-death necessity for plants, both in the ground and especially in containers! Ensuring your plant's roots have enough moisture, without having them sit in water can sometimes be a tightrope walk, but with practice and observation, you can quickly catch onto how to properly care for your potted pets.

Here is what you should be aware of when it comes to your plant's root system health!

Damage Caused By Poor Drainage

damaged plant

Plant roots actually need well-drained soil that provides oxygen and good aeration to prevent rot and bad bacteria from attacking them. Gravity pulls the moisture down while capillary action wicks moisture back up as the top layers of soil dries out.

When moisture becomes trapped due to the lack of, clogged drainage holes, or too much moisture with nowhere to go, you end up with swampy, bogged-down soil. Soggy soil creates anaerobic conditions and literally smothers the feeder roots, preventing plants from taking up moisture and nutrients - quickly leading to death.

Stagnant water leads to increased bacteria and fungal growth that kills roots and higher moisture leads to less oxygenation.

half dead plant

Plants with root rot will look as if they are wilting since water can no longer be absorbed at the root level. A novice gardener's knee-jerk reaction is the obvious ... Water more! But just exacerbates the problem. This is especially true for houseplants and plants in containers.

Landscaping plants and trees can be just as poorly affected as well. Whether it is due to poor soil, soil compaction, heavy clay, or just a high water table.

Poor soil conditions and improper watering methods, both in the ground and in containers, are among the leading causes of plant death and plants not establishing in their new sites, often leaving gardeners scratching their heads.

The Problems With Gravel As Drainage

When water sinks to the bottom of a pot, it collects and creates a type of water table or ‘perched’ water level. Soil types with faster drainage have lower perched water tables and absorbent soil has higher.

no gravel drainage

This is where using gravel or another type of extra coarse-sized medium as a method to help with drainage can become problematic. These materials reduce the volume of soil in the container and therefore push the perched water levels higher, resulting in the container's water table rising to smother the roots.

A reduced soil volume due to the use of gravel or coarse substrate also reduces the amount of room for plant roots to grow in and draw nutrients from.

The gravel also adds to the weight of your planters, making it difficult to move your plants around.

Benefits of Gravel In Pots

While some filler materials will help with container weight and allow you to use less soil. One alternative is to use filler materials in the bottom of the larger or deep pot, then place your potted plant (without any filler in that pot) on top of that filler material.

Pink potted flowers

In windy areas and outdoor planters that can be knocked or blown over, you can also use chunks of broken clay/ceramic, bricks, or cut-up logs in the larger container, so long as they don’t block the drainage holes.

Caring For A Waterlogged Plant

It is best to remove a plant that is waterlogged from its container, remove all the soil and wash it away from the root system gently. It is important not to let the roots dry out completely before you can repot them.

Remove any damaged, mushy, or dead roots carefully. Then repot in a cleaned, sanitized container with fresh moist soil, being sure to firmly pack it around the roots. Water sparingly until the plant recovers.

Proper Moisture Requirements


Nature Hills recommends the ‘Finger Test Method’ when watering and checking soil moisture.

Because of their contained environment, container plants need frequent water checks as the water needs will change depending on the pot size and the climate they are being grown in. Once the surface of the soil is dry to the touch, it is recommended to water thoroughly, let the excess drain out the bottom, and discard it.

This will greatly vary throughout the year and the interior environment of your home.

Back off on how much water you add to the soil since plants are typically not blooming, there are lower light levels in the winter, reduced growth during the cooler months or even go through a dormant period.

Proper Drainage For Containers

Proper Drainage For Containers

The first step in maintaining the health of your container plantings and potted plants is ensuring the container has good drainage holes in the bottom or sides of the pot.

Next, ensure you are using clean potting soil or other potting medium that supports both good moisture retention and drainage.

It can be a tightrope walk to find the happy medium, but the type of plant will dictate what kind of soil you use.

Fast-draining dry soil (best for Succulents, Cacti, and other Xeric plants), or more compost and organic matter to hold moisture for most plants.

  • 1 part clean garden soil (sterile if for indoors)
  • 1 part peat moss
  • 1 part perlite/vermiculite/coarse sand (not beach sand or play sand)
  • Coarse bark chips for Orchids and other Ephiphites
  • Moisture retention granules for full sun year-round planters
  • Other additions include manure, coconut coir and compost
  • A layer of arborist mulch over the soil surface
  • Water gardens can use soil, clay balls, or perlite or pumice stones

*Avoid using gravel in the bottom of the pot as these can actually block the drainage holes and hold moisture above the gravel.

  1. Add a tray large enough to catch any water that drains for indoor plants (this keeps your carpet/floor cleaner). But pour out any water accumulating after it's finished draining to stop the soil from sitting in water.
  2. If you’re concerned about soil seeping from the container bottom, cover the hole with a folded paper towel, newspaper, coco fiber liners (like what they use in hanging baskets), or a coffee filter.
  3. Add potting soil to the new container.
  4. Spread the plant roots, placing them on the soil. Make sure it’s centered and upright. Fill with soil and water well to settle in and remove excess air pockets.
  5. Continue to water using the ‘Finger Test’ method.


No More Wet Feet!

Waterlogged roots are a death sentence for your container plants, so just a few simple tactics will keep your plants happy and healthy!

If your plant is drying out very quickly, it is time to repot in a planter the next size up. If your plant is consistently soggy and not using enough water, then either your plant is too small for that sized pot or you have a drainage situation.

Plant root system types and pot sizes and shapes have quite an effect on your soil drainage as well! Shallow-rooted plants do best in shallow pots while plants with larger roots or taproots need taller/narrower plants. Match your pot size and shape with the types of root systems your plants have, so some research will be needed when choosing plants.

You’re in luck because Nature Hills' expert customer service team is here to help!

Happy Planting!

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