What to Put in the Bottoms of Flower Pots

Gravel

• Gravel is an inexpensive, readily available pot filler that provides weight at the bottom of top-heavy pots to keep them from tipping. Choose relatively coarse gravel, then cover it with landscape fabric or sphagnum moss to keep the soil from sifting between the stones. In pots with drainage holes, the result is faster, more efficient drainage.

Crushed Limestone

• Crushed limestone works much like gravel, but provides an alkaline environment for plants that do best in environments with a higher pH. Crushed limestone is also sometimes called road base.

Broken Pots

• Gardeners who use many clay pots can line their containers with broken or crushed terracotta from older containers. This material functions much like stone, but is considerably more absorbent. This property allows it to retain more moisture and can help keep plants from drying out. Broken terracotta can break down over time and may need to be replaced periodically.

Aluminum Cans

• The Ohio State University and the University of Illinois Extensions recommend using crushed aluminum cans in the bottoms of flower pots to reduce the amount of potting soil required. Cans won't break down and are relatively light, making them a good choice for very heavy pots.

Plastic Containers

• Crushed plastic containers, including milk jugs, beverage containers and old plastic flower pots, work much like aluminum cans. Some plastic is biodegradable, but most won't break down over time. The large air spaces in these crushed containers provide better drainage and a lighter pot.

Whole Pots

• Placing a whole plastic or terracotta flower pot upside down inside a larger one can help reduce the amount of soil required, while keeping the pot light. This works best in pots where the container is larger than strictly needed for the plant. Avoid using this technique for trees or deep-rooted plants. Whole pots are easy to recover and use again after the container has been emptied.

Pine Bark

• Pine bark is a lightweight, absorbent, acidic material suitable for use with plants that prefer a low-pH environment. This material holds moisture, and can help keep a pot from drying out. Use large pieces to maintain good drainage.

Polystyrene

• Polystyrene "peanuts" and other packing material make a lightweight addition to large pots. Like plastic and aluminum, they don't break down easily. Use relatively large pieces of polystyrene rather than small "beads," since small pieces provide fewer air voids. This material can blow around easily if exposed to the air. Work with it indoors or in a protected area.

Paper

• Crumpled paper is an inexpensive, lightweight addition to the bottom of flowerpots. Like other porous materials, it holds moisture. Use relatively stiff paper, and don't pack it into the pot, as this can cause drainage problems. Over time, crumpled paper tends to break down and compact. Replace it regularly to keep plants healthy.