1. Choose the Right Container
Much like plants, containers have their own characteristics to take into account, including weight, sensitivity to weather changes, and appearance. You’ll also want to consider your budget, space, and style when choosing a container. Keep in mind that the larger the size, the less you’ll need to water, but whatever you choose, always make sure the container has holes in the bottom for drainage. Some common types of pots include the following.
Terra-Cotta: Versatile and inexpensive, terra-cotta containers are also called clay pots. You can find them plain or decorated in colorful glazes. The only downside to using terra-cotta is that it’s somewhat fragile. It will chip and crack if handled too roughly, and can be damaged by freezing temperatures (empty and store them indoors over winter in colder regions). Concrete: Concrete containers can take any type of weather. Be careful where you place concrete planters, since they’re extremely heavy and very difficult to move, especially once they’re filled with soil and plants. Wood: Pick a durable wood, like cedar or nontoxic treated pine. To help them last longer, brush all the surfaces with a clear waterproofing sealer labeled for use on outdoor wood. Metal: Galvanized tubs and buckets are great options for container gardens. However, beware when using a metal container because they will heat up quickly in the sun and cook your plants. To protect the plants, line the container with garden fabric and place it in a shady spot. Plastic, Fiberglass, or Resin: These types of containers can be made to look like just about any other type (but at a lower price and lighter weight). They aren’t as high quality and won’t last forever, but they can provide a certain look. Repurposed Containers: Choose old baskets, tin buckets, birdbaths, and watering containers to house your favorite plants. The thrifted look is stylish and rustic.
2. Select Color Schemes and Plant Combinations
Having a color theme for your container garden can help you select a good mix of plants. You can play off the color of your container, or focus on the flowers and foliage you plan to include. When combining plants in your containers, make sure they’ all need the same light levels and frequency of watering. Plant them in odd numbers and be sure to have at least one thriller, filler, and spiller plant. Combining these three types of plants adds interest and balance.
Thriller: These plants add height and a bold vertical element. Some options include plants chosen for foliage, ornamental grasses, or upright flowering plants. Thrillers typically go near the center of a container. Filler: Fillers tend to be more rounded or mounded and serve to make the container look full. These are generally placed in front of or around the thriller. In a long and narrow container like a window box, fillers are placed midway between the edge of the container and the thrillers. Spiller: Plants that hang over the edge of the container are considered spillers. If your container garden is going to be seen from all sides, be sure to place spillers all the way around.
3. Limit the Number of Plants You Use
Be careful not to overfill a container garden. If the plants are overcrowded, growth can be stunted both above and below the soil. To lessen the chances of overfilling a container, you will generally want to follow these plant to pot size ratios:
10" to 12" pot can hold 3-4 plants14" to 16" pot can hold 5-7 plants16" to 20" pot can hold 6-9 plants
4. Fill the Container with Potting Mix
Once you’ve selected your plants and a container, it’s time to get planting. Fill your container two-thirds full with an all-purpose potting mix. Don’t be tempted to use garden soil. It’s too heavy and won’t drain as well as it must in a container. If you have a really large planter and would like to use less potting mix, turn smaller empty containers upside down and place them on the bottom to take up some of the space. Then fill around them with potting mix until your container is two-thirds full. Test Garden Tip: Before filling your container, you can place a piece from a broken clay pot over the drainage hole to prevent the potting mix from draining out—but make sure the water can still drain. Never add a layer of rocks to the bottom because this actually makes it harder for water to drain out, rather than helping.
5. Place Plants in Your Container
When you’re ready to add plants, give their nursery containers a gentle squeeze around the sides to loosen the root ball enough until you can slide it out. Avoid tugging on the plant itself, which may damage it. Then, set your plants on the potting mix so that the top of their root balls are a couple of inches below the rim of your container. This will make it easier for you to water later. Fill in around your plants with more potting mix, making sure the stems are no deeper in soil than they were in their nursery containers. Use your hands to press down lightly on the mix to eliminate large air pockets.
6. Water in Your Plants
Water your container garden to help the soil settle in. Add more soil if needed so that all the roots are covered. Remember to keep the soil level a couple of inches below the rim of the container to prevent water and soil from spilling out. After that first watering, check back in a day or two to see if the first inch or so of soil is dry to the touch. If it’s dry, it’s time to water again. You’ll know you’ve given your container enough water when some runs out of the drainage hole (s). If you choose to use a saucer under the pot, make sure to keep it emptied since plant roots can rot when left sitting in the collected water.
