Containers are a fabulous way to add color, texture, fragrance and even tasty goodness to your client’s home, whether they’re intended for a balcony, patio or in a traditional suburban yard. A handy formula for creating container gardens has made the circuit for years now – the “Thriller-Filler-Spiller” design with a tall plant in the center, something full and colorful in between and a vine hanging over the edge. But don’t worry about following the rules. Anything goes with containers these days, so try something new this year. Keep in mind, though, the basics for a healthy container garden: Good soil, good drainage, good site selection – and the right plants – will make and keep container plantings beautiful and healthy throughout the season.

Begin with good design

Garden design is important because a container is a garden, albeit a small one, and it needs to blend and integrate into the surrounding area. Placement of containers could be on a porch, in a woodland area, in a vegetable garden or in a flowerbed. The container itself could be a focal point, or multiple containers could be used as a flowing connection between two garden areas, living spaces or as a guide to a business entrance.

Color themes are always popular, whether it is the tried and true red, white and blue or the cool, peaceful colors of silver, white and purple. Color combinations can set the mood for a garden container and invite people in to a peaceful, relaxing setting or grab their attention with eye-popping bold colors. Hot colors such as orange and red warm people up and stimulate their appetite. Cool colors such as blue, gray and green will keep them calm and relaxed. Container gardens are an easy way to introduce these colors into a living, working or even therapeutic area.

Large, dramatic containers planted with cool colors provide an elegant transition from concrete surface to the garden beyond.

Container basics

Choose the container based on where it will be situated. Consider the space available, how tall the plants will be (will a trellis or other support be needed?), whether a single container or multiple containers will be used, and most importantly: How much light will the container receive during the day? Full sun is needed for growing herbs, vegetables and many of the flowering plants. Full sun is defined as greater than six hours of direct sunlight a day, which is sometimes difficult to obtain with planters under overhangs and near buildings.

A cluster of similar containers creates a small, easy-to-maintain garden tableau.

Consider the planter as a piece of art, or simply as a functional holder for the plants, which will then become the work of art. Use whimsical planters for children’s areas. Match styles and colors to the d_cor of the home or building. Recycled containers are wonderful to use, but should be food-safe if you are growing herbs and vegetables. Metal containers are sometimes an issue due to potential lead, copper or zinc contamination. Lead is a problem for humans, but copper and zinc can create toxicity issues for the plants. Consider using a liner for metal containers.

Large containers that will be left outdoors all year round should be freeze resistant if your winters come with ice and snow. Many ceramic and concrete containers must be protected over the winter to keep from cracking.

Plants will grow in most anything as long as there is enough soil or soilless mix, and there is a drainage hole. Good drainage is the key to successful container gardening. Resist the temptation to use a container without drainage holes. Use “feet” or a plant tray turned upside down to keep the container up off the surface whether it’s soil, concrete, brick or decking material. Feet can be functional and fun, and should be promoted for use with container gardens. Pots can literally look like they have feet or claws, or the feet can simply be plastic pads or plastic triangular supports. With slight elevation, the pot will drain better, and there will be fewer problems with deck and patio staining.


Above, combining ornamentals with edibles saves space in a small residential setting. Below, use “feet” to keep the container up off the surface, whether it’s soil, concrete, brick or decking material.

What type of container?

The variety of container styles can be overwhelming, but what’s also important is the container’s composition.

  • Clay pots require a high frequency of watering, so they’re great for plants that like dry conditions. Clay is very porous, and salts – and sometimes algae – may build up on the exterior and rim of the pot. These containers also are heavy and breakable.
  • Plastic containers are easy to use and easy to keep clean, and they retain moisture better than clay pots. New styles look like terra cotta or glazed ceramic; and although an advantage is that they’re lightweight, this means they can turn over easily. Plastic is generally not breakable, however.
  • Ceramic, glazed pottery retains moisture longer than unglazed pots, so make sure there is a drainage hole. Some foreign imports may be contaminated with lead, either in the clay or in the glaze.
  • Metal is not recommended as a primary container for growing plants, as the metals can leach into the soil and cause toxicity problems. It’s advisable to use a liner or secondary pot within the metal container. Depending on the metal, rust may develop from frequent watering. For a “rustic” look, however, this can be a bonus.

Proper soil is critical

Container gardens grow fast and furiously when provided with the right soil environment. Go organic! Use a lot of organic matter in your soil or soilless mix to increase growth and help retain moisture in the pot. Happy roots produce happy plants, beautiful blooms and more fruit! Remember the container is a limited growth environment for plants; the soil mix will make the difference in their health.

Soilless potting mixes are generally organic, usually containing peat moss, compost and sometimes pine bark. In addition, they may have perlite or vermiculite added for drainage. Soil – real soil – adds a lot of weight to the mix, but it can certainly be included for outdoor container gardening. Adding soil to a soilless mix is great for large containers; just make sure it is clean, sterilized soil to reduce the risk of disease or insects. That additional weight in the pot may be very helpful as the summer progresses and your plants get taller and more top heavy. Extra weight also keeps containers from taking a walk late at night.

Consider choosing edibles

For a different twist on container gardening, surprise your customers with colorful, edible plants. Food production in pots can be as simple as a single tomato plant in a five-gallon bucket, but adding a touch of creativity to a single tomato plant could turn it into a “salsa garden of delight.” Try combining ‘Margherita’ tomato, ‘Chichimeca’ jalapeno pepper and a few plants of cilantro – perhaps the All-America Selection ‘Delfino’ – to spice up the container’s look as well as the taste.

Maybe a colorful salad container would be appreciated. Try ‘Garden Babies’ butterhead lettuce, ‘Sweetie Baby Romaine’, ‘Sea of Red’ lettuce, ‘Thumbelina’ carrot, and ‘Salad Bush’ cucumber for a one-pot salad that’s ready to harvest. Some vegetables are beautiful and healthy: An all-eggplant container that would also be a conversation starter could contain the All-America Selection winners ‘Hansel’, ‘Gretel’ and ‘Fairy Tale’.

Mix flowers in with vegetables, mix herbs with flowers, mix tropicals with foliage plants. The potential for container combinations is endless, as long as you mix and match plants based on size and location of your container, and the light and water needs of the plants.

Care of the container garden

Water is absolutely essential, and outdoor containers will require frequent watering as the summer progresses and the plants get bigger. Advise your clients to check containers daily to see if they are dry, and be sure to water thoroughly till water drains through the bottom of the pot. Do not let plants sit in water; water is needed, but good drainage is also essential!

For best results over the summer, incorporate into the soil mix a timed-release fertilizer for flowering plants – do this before planting. In addition, fertilize every two weeks with a balanced nutrient mix (for example, 10-10-10 or 20-20-20) or a fertilizer for flowering plants (such as 9-18-9 or 5-10-10). This may seem like a lot of work, and you may need to remind your customers that these plants are in a confined, limited resource pot and will grow quickly. In addition, with the regular and frequent watering that outdoor container gardens require, many nutrients will be leached out of the soil.

Gardening can be tricky for those new to this most popular hobby, but gardening in containers is an easy way to get them started. Once successful, they’ll keep coming back for more – more containers, more plants, more fertilizer and more education.

Thinking outside the pot

A simple but effective combination of cool blooms and bold foliage makes a welcoming statement.

Creativity comes out in individual container designs and groupings of containers when the limits are pushed. Overflowing containers can be dramatic, but may require a bit more care, a little more fertilizer and extra water.

  • Too many plants? Simply remove one or more as the season progresses.
  • Too few plants? Fill in with a bolder color or dramatic foliage. Be sure the plants that are added require the same care.
  • Just right? That’s the container that fills in, grows up and flows over using every square inch of space available.

Creativity also arises when containers are used as a true garden space. The basics of garden planning and design still apply:

  • Site selection and view
  • Available light
  • Soil type and drainage
  • Focal point
  • Color – cool, warm or hot
  • Texture
  • Fragrance
  • Size of the plants – height and spread

Containers are the perfect way to try new plants, new techniques and even new foods, without as much investment as that spent on a large flower or vegetable garden. Encourage the trend. Encourage clients to grow more, and encourage them to chronicle their adventures in container gardening through photographs and container “recipes.” Sharing these successes can boost their confidence – and your bottom line.

Patti Nagai, Ph.D., is horticulture educator for Racine County, University of Wisconsin Extension in Sturtevant, Wis., serving both consumers and producers of horticultural products. She trains Master Gardener volunteers and teaches the public about healthy garden practices. She can be reached at