Avoid These Container Gardening Mistakes

If your container plants are drying out or have rotting roots, you may have made one of these common container gardening mistakes.


“The Anxious Gardener’s Book of Answers” by Teri Dunn Chace identifies the 100 most common gardening mistakes and gives you the information you need so that you’ll never make them. Or, if you’ve already goofed, it tells you how to fix the mistake.

Courtesy Timber Press

Content Tools

Your garden is supposed to be fun — a place to relax in and recharge your batteries, a source of beauty and pleasure. But all too often, things go wrong. Those expensive tulip bulbs you planted last fall never came up. Your lilac doesn’t bloom. The lawn looks terrible. And worst of all, you don’t know what to do about it. The Anxious Gardener’s Book of Answers (Timber Press, 2012) contains great gardening advice to help you solve virtually any gardening challenge. In this excerpt from the chapter “Containers,” author Terri Dunn Chace provides tips for avoiding common container gardening mistakes. 

Not watering plants enough

In some places, especially hot, windy, sunny locations, plants in containers can suck up all the available moisture in their potting soil and start to wilt in a single day, or even in a matter of hours. If another day (or two) passes, you may not be able to revive a display.

You might think that plants in containers dry out alarmingly quickly because their root systems aren’t huge or able to avail themselves of extensive or deep-ground moisture in hard times, like plants in the garden can. But there’s another reason: their root systems are very nearly exposed, as a thin layer of plastic or clay is all that protects them from the elements.

The right way to do it: First, be wary of clay pots, which wick away moisture from roots. Try planting in a slightly smaller plastic pot and nesting it within a clay or ceramic one. Lightly mulching the soil-mix surface has the same benefits as mulching out in the garden proper—it helps hold in moisture and moderates soil-temperature fluctuations (you can use a thin layer of bark mulch or even pea gravel). Buy a potting mix that includes moisture-absorbing coconut hulls, or try moisture-holding gel or gel beads (follow the label directions or this material will lead to slimy soil mix).

There are some nifty watering gadgets available, including gauges that warn you when moisture is getting low by changing color, and ingenious self-watering pots.

If I goofed, can I fix it? Bring on the water the moment you notice a potted plant in distress. If you are lucky and your display is resilient, the plants will recover. They may shed a few flowers, buds, or leaves, but will ultimately forgive and generate new ones. Bear in mind, though, that putting any plant through repeated cycles of drying out and soaking can be stressful. For most plants, a regular, steady supply of moisture, with no wilting episodes, is much better for their health and appearance.

Filling a pot so it’s too heavy to move

You have an ambitious plan. You find a big, handsome pot and add a plant or ensemble of plants, and it looks great. You set up on the patio, near the hose, or someplace where it’s comfortable to do this work and clean up afterward. Work all finished, you straighten up, admire the results proudly—and find you can’t even lift the creation off the ground. It may not even be a matter of having a bad back. The display is simply too heavy.

The right way to do it: Do the work on-site. Take the container to its intended location and spend a few moments making sure it is secure and level and can be viewed from an attractive angle. Only then should you fill it. Granted, doing the project this way can be inconvenient. The spot might be far from a water source, and you need to soak the creation well not only on planting day, but regularly thereafter. Tote along a watering can. The soil mix, drainage stones, and potted plants you mean to transplant into the display can make a mess as you put it all together. Bring a tarp, which you can gather up when you’re done, drag away, and shake or hose off as needed.

If I goofed, can I fix it? The worst-case scenario is undoing all your work and starting over. Easier possible solutions include moving the unwieldy container with a few strong helpers, using a dolly, or maneuvering the plant onto a board or tarp and dragging it to its destination.

Using a large container for a small plant

It seems like a savvy gardening tactic to put a small plant into a large pot, windowbox, urn, or planter, as you are allowing for future growth. And unlike in the yard, you generally don’t have to worry about weeds moving in and crowding out the plant. However, this sensible-sounding plan can and does go awry when the small plant really is a small or slow-growing customer destined never to get very large. The result looks bad because the plant is overwhelmed by its surroundings—a classic example is a dwarf conifer plunked into a half-barrel container. Additionally, a small plant can dry out quickly, as water has to disperse throughout the entire pot.

The right way to do it: Whenever you are pairing a plant and a container, aim for compatible size. A small pot-grown plant doesn’t have to contend with competition from weeds or encroachment by garden plants, so it should be free to reach mature size. The key is knowing what that size is going to be.

A widely acknowledged design principle is to keep the ultimate plant-to-pot ratio at about 1:1. Put that cute dwarf conifer in a smaller container that will accommodate its root system but also be a fair and even match for its height and girth.

If I goofed, can I fix it? Transplant the little plant into a smaller home. You can do this at almost any time, even in the heat of summer, if after the move you pamper the plant with a bit of sheltering shade and plenty of water until it settles in, at which time you can return it to the intended spot and adjust its care as needed.

Alternatively, you can add some supporting-player plants to the container. If you wish to retain your original vision of it being the star of the pot, just add shorter or sprawling plants around it. If your star has flowers, choose foliage plants.

Using a container without a drainage hole

It’s a sad fact that some attractive or appealing containers lack drainage holes in the bottom to let out excess water. This is true of fun found containers, like vintage teapots, but it is unfortunately a common problem even with pots clearly being sold for planting (what were they thinking?). If excess water cannot get out of the bottom, sogginess results. Roots are deprived of oxygen and will rot.

The right way to do it: You don’t have to forgo the beautiful ceramic pot or the charming kettle as a home for a plant display; you just have to be sure drainage is provided for. It may be possible to poke or drill holes in the bottom, depending on what the item is made of and whether you have a tool that can do this (note that drilling holes in a flat-bottomed clay pot can lead to the container breaking into pieces). If you can’t create holes, there are two other solutions.

First, try nesting a somewhat smaller plastic pot with drainage holes inside the larger decorative pot. Take care not to overwater, as excess will drain into the larger container and create standing water. Alternatively, line the bottom of an undrained container with a layer of small rocks or pebbles (some gardeners use Styrofoam packing peanuts, but these break down eventually). This creates an area where excess water can flow and, hopefully, wick back up into the soil mix above as needed. A drainage layer helps prevent the plants in the pot from experiencing incessant wet feet; that is, drowning in standing water or drenched mix. This tack is not ideal, but certainly it’s better than no drainage provision.

If I goofed, can I fix it? Yes. Carefully remove the plant or plants and cover the root system(s) with a damp cloth to prevent them from drying out while you work. Scoop out all the soil mix and rinse out the container. At this point, you can either poke or drill drainage holes in the bottom or line the bottom. Return the soil mix to the pot, replant, and water.

Read more: Read another excerpt from The Anxious Gardener's Book of Answers in Gardening Advice: Avoid Pitfalls With These Garden Design Tips.

This excerpt has been reprinted with permission from The Anxious Gardener’s Book of Answers, published by Timber Press, 2012.