How to Prepare Flower Pots for Planting

Don't start planting until your pots are ready to do their job. Make sure your containers are well prepared, draining properly and protected from the elements so they'll be easier to maintain. Here's everything you need to know.

Most ceramic pots are made with drainage holes so that excess water can drain away (if it can’t, plants will rot). Some plastic (shown here) and most non-traditional containers do not have drainage holes. When a pot doesn’t have holes, you will need to make some. This is easily accomplished with a drill and an appropriate bit.

This plastic pot did not come with pre-drilled holes. In this instance, the pot is very large so we’re using a 1/2” drill bit to produce five evenly spaced holes in the container base. Choose a hole diameter and number of holes that will allow water to drain freely. The type of pot you’re trying to drill will dictate the type of drill bit you need. For most plastic containers, a regular twist drill bit is fine. For terra cotta and un-glazed ceramics, you’ll want to use a masonry bit, and for hard-glazed containers, you’ll need a glass/tile drill bit.

To help water drain freely, place broken terra-cotta pots (crocks), Styrofoam chips, or large pebbles in the base of the pot. Alternatively, you can use a layer of fine mesh with gravel on top. This prevents drainage holes from becoming blocked and soil from being flushed out.

Any pot will be heavy when filled with soil, and even heavier after being watered. To reduce weight, fill the bottom third with Styrofoam or large pieces of plastic like the water jug shown above. Note that this applies only to pots with annuals or plants that don’t have long, extensive roots.

All pots, including those left in the garden or stacked up in the garage, must be cleaned immediately before use. This applies even if the pots were stored under cover and cleaned before being put away. Undisturbed pots can be breeding grounds for pests and diseases, larvae and baby slugs. Additionally, if your pots housed any diseased plants during the previous season, it might be necessary to use a mild, biodegradable dish soap to clean them out. Avoid using harsh or toxic chemicals to clean your pots, especially if you plan on growing any edibles in your containers.

Clay pots that have not been completely glazed on the inside are vulnerable to frost damage. This is because they are porous, and when water seeps into them and then expands as it turns to ice, the pot cracks. To prevent this, line pots that you want to sit outside all year with heavy-duty plastic. Always buy more plastic liner than you think you need. Push it well down into the pot, and use a pair of scissors to cut out drainage holes in the bottom. Then place a layer of pebbles or stones in the base, and fill up with potting mix, the weight of which will push the liner further down. Finally, trim away the excess liner flush with the top of the container. Lining terra-cotta pots in this way also prevents salts in the soil and water from leaching through the clay and discoloring your container.

Next to proper watering and drainage, soil is the next most important factor in the success of a potted plant. Soil mixes that have been formulated for containers are typically labeled as potting mix or potting soil. Mixes labeled garden soil or topsoil are too dense for use in containers and can lead to root rot in your plants. The potting mix on the left is a potting soil sample with peat moss and vermiculite added to the mix to lighten the soil, increase aeration and aid moisture retention. The soil on the right is a sample from the ground and contains rocks, roots, and other debris that add weight to the container and can introduce disease, pests and rot.

It can be a nightmare trying to move large, filled, heavy pots unless you have help, and even then you are in danger of hurting your back and dropping the container. The best solution is to transport your containers on a sturdy dolly. To avoid lifting a filled pot, place it on the dolly before planting, and move to its final destination. The dolly can also double as a pot stand, eliminating the need to lift the heavy container and allowing water to drain away efficiently.