Container Gardening Secrets: Ideas to Inspiration (2024)

Container gardening is only limited by the size of the container and your imagination. The right pot, with the right soil, placed in the right place can grow anything from a micro-farm of seasonal vegetables to your favourite specimen tree.

PRINCIPLES OF CONTAINER GARDENINGWHAT CAN YOU GROW?COMMON CONTAINER PLANTSCHOOSING THE RIGHT CONTAINERACHIEVING THE BEST SOILFEEDING YOUR PLANTS CARE AFTER PLANTINGWHAT MIGHT GO WRONG

Why container gardening?

Container gardens allow anyone with a little bit of space and sunshine to garden almost anywhere and may even lead to an addiction of colourful pots and quirky vessels on your deck or patio. The impact of colourful glazed pots or the whimsical effect of a repurposed washtub lends a personalized aesthetic to landscapes like your own signature.

There are endless choices available to begin your container garden. Cedar boxes, railing baskets, large resin pots, half barrels, storage totes, fish tanks, and even the kitchen sink can be used to grow vegetables in as long as you abide by a few fundamental principles when choosing.

Principles of container gardening

Pair plants with a vessel that accommodates their growing root system.
Provide a soil mixture appropriate for plant choice.
Ensure drainage will be adequate for the variety chosen.

Thanks to their size, container gardens are much more manageable than growing in a ground-level bed. They also allow for greater control of the growing conditions. You can address soil structure, fertilizer, and water needs of specific plants and you can position containers so they are receiving the appropriate sunlight for each variety.

Placing containers in ideal locations will save water and lead to healthier plants that can fight off pests more readily. Used functionally to grow produce in a small space or as an accoutrement to the landscape, container gardens have many benefits to offer.

What can you grow in a container?

There are so many plants that will grow successfully in containers the simpler question may be what can’t you grow? To begin, research the needs of your favorite varieties to determine the space you will need for the root system and the type of soil you will use to ensure a thriving plant.

In the list below you will find a list of the conventional container plants. This serves as a general guide to the pot size and the right soil combination for each. Note that the pot sizes listed are the minimum requirements. Some plants will have to be repotted into larger containers or else they’ll become root bound.

Common Container Gardening Plants and Their Needs

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How to choose the right container

The beauty of the pot is generally how we choose containers, but this is secondary to the function of the pot. Aesthetics and garden design aside, choosing the right container should be determined by the size of the plant/root ball you want to grow and the material the container is made from.

Size of plant/root ball

Plants like vegetables that mature over one season, trees with large root balls, or multiple plantings in a container can become root bound very quickly, causing the container to dry out fast. Avoid an exercise in frustration with a little bit of education on how big a space each will need.

For annual hanging baskets, a good rule of thumb is one plant per inch of basket diameter. For example, 12 plants per 12-inch basket.
For bigger plants like geraniums, herbs, and strawberries, use only four plants per 12-inch basket. Planters or large pots are more suitable for multiple plantings of more abundant vegetables, perennials, trees, or shrubs.
For window boxes, plant two plants for every 12 inches of length. Generally window boxes should be at least 8 inches wide and 8 inches deep to provide enough depth for root growth.

Container material

The container material is also a factor to consider when choosing your vessel. Some of the most common options are highlighted below.

Plastic or resin is lightweight, inexpensive, and durable. But these materials can also become over saturated, causing root disease. It’s also worth noting that the standard black plastic or resin pot absorbs more heat, so if you are putting a container in a hot, sunny location, choose a lighter colour instead.
Terra cotta or clay pots are a popular option for those who live in wetter coastal climates. Terra cotta pots dry much quicker than plastic (and smaller pots dry out more quickly than larger ones), which helps control associated moisture diseases. A downside is that they are heavy, breakable, and need to be emptied or protected in locations that freeze in the winter.
Glazed clay pots offer a wide range of colour and size providing significant impact in any space. However, like the plastic or resin, clay pots can become saturated with water causing root disease and also need to be emptied or protected in winter.
Eco pots or fibre pots have a high porosity and breathe well, which promotes healthy root growth, particularly for vegetables. These pots can be made from coconut coir, pressed paper or other grain husks, each with its own life span. A primary benefit being that these pots will degrade naturally with little impact on the environment by contributing to the landfill at the end of their lifespan.
Wood is the most common planter material for raised beds or planter boxes. Mostly constructed with cedar, wood is beautiful, easy to build and can be made to any size or shape. One of the disadvantages for those who live on the coast is that wood can rot, making it more attractive to the pill bug which also likes to feed on plant material.
Glass or plastic terrariums are meant to provide a moist, humid environment for tropicals and a beautifully unique way to create a lush environment in a small space. The terrarium can be created using an old aquarium, a large vase or clear bottle. Given that drainage cannot be added, over-saturation can be an issue encouraging rot and gnats. Ensure that the base of the vessel has a sufficient layer of coarse gravel and a thin layer of charcoal to alleviate these potential problems.
Uncommon vessels like metal buckets, washtubs, old boots, boats, baskets, sinks, bathtubs and even toilets can be used to personalise your landscape. With the addition of holes for water drainage, transforming these non-conventional containers to a planter requires little else.

Whichever container material you use, drainage is key in how successful you will be. Standing water or excessive moisture for plants that don’t love wet feet invites diseases, fungus and pests, which will negatively impact your plants. Ensure you have adequate drainage for the plants that you choose. If drainage holes aren’t present or more drainage is necessary, add holes or a layer of coarse gravel at the bottom of the pot to allow moisture to be released.

How do you prepare the soil in your containers?

Preparing your container to plant is simple but requires a little more than filling the pot with potting soil and adding plants. Soil is the bed for your plant and the foundation on which the plant depends to grow. It is the medium in which the plants gain access to moisture, nutrients and oxygen. Not all plants require the same soil, so it’s important to know the soil combination each requires and the function of each material.

Organic matter (OM) is a dual purpose medium made up of varying sized chunks of material offering porosity to aerate the soil as well as acting like a sponge to hold onto water in the tiny particles of material. The most common organic matter chosen for containers would be peat or coconut coir. Both will help your containers retain moisture.
Compost is a type of OM that offers the same benefits as well as being rich in nutrients. Compost is generally derived from rotted plant material or manures processed by worms.
Sand is a fine, granular rock material that contributes to drainage in the container. Every container should have a bit, but too much can dry out a pot too quickly.
Loam is equal parts clay, silt and sand which gives the benefits of each with few of the disadvantages of each material.

Most often you will fill your containers with seedlings or starts, but you can also seed directly into containers. Sowing direct into containers requires a seeding medium on the top 3” of container soil.

Easy to create, add a 3:1 ratio of peat: vermiculite as the base for your seeds. Water well before seeding and follow up daily with watering to prevent seeds from drying out.

Related:

6 Tips for Building Soil for Raised Garden Beds and Planters
Raised Garden Beds: Soil Depth requirements

Feeding your potted garden

A new container filled with sterile soil or potting mix does not have many nutrients to feed the young plants. Adding food during the soil mixing stage is essential to give them what they need in their first month of growing.

One cup of organic fertilizer mix of 5-3-4, plus a 1/2 cup of bone meal per 10 gallons of soil mixed throughout the pot, will ensure an excellent start for your plants.

All-purpose organic fertilizer provides nutrients for potted plants.

For annuals, throughout the growing season, use 1/4 cup of the same organic fertilizer sprinkled weekly onto the soil surface or an all-purpose liquid fertilizer. Liquid fish emulsion is one helpful choice.

Compost Tea Recipe:

Add 2 cups well-rotted compost or worm castings to a 3-gallon bucket of water. Stir vigorously and allow to stand overnight. After 12 hours, stir vigorously again then let particles settle. Pour tea mixture into containers. The remaining sludge can be reused to make another batch of tea or added directly to a container. For more information, read The Best Compost Tea Recipes to Help Your Plants Thrive.

How to choose plants for containers and small space gardens

A visit to the garden centre to purchase starts or plants can be overwhelming if you don’t have a plan before you get there. There are so many options, so it’s easy to get distracted. As you would with your landscape, prepare your design ahead of your shopping trip, so you know exactly what you are looking for. Here are some insights to make the decision process a little easier.

Vegetables are not just limited to the landscape and beds. In fact, some thrive in potted conditions as you can provide exactly the right combination of conditions they are looking for. The top ten choices for your container garden are: tomatoes, peppers, squash, beans, lettuce, bok choi, radishes, spinach, peas and carrots.

Herbs love the confines of a container, especially the Mediterranean varieties. Rosemary, oregano, thyme, parsley and anything in the mint family will do well in a container filled with well-drained soil placed in a sunny location. Furthermore, a container will prevent some of the more aggressive varieties like those of the mint family from spreading into areas you don’t want them.

Perennials and shrubs planted in eye-catching containers make very attractive additions to a landscape. Ornamental grasses do as well. Keep in mind that plants should be sized to the pots and the pots sized to space. If foliage is the element, choose ornate pots for an ideal focal point. If plants produce many flowers, a more subtle container is in order. Also consider if the container will be a focal point or an accent to an entrance. The selection of perennials and shrubs are more specific, so it’s essential to do some research before choosing. A good horticulturist at your local nursery will be your best resource for the your location.

Annuals are the best for adding instant colour and flair to the landscape. In your designing stage consider the “thriller, spiller and filler” technique of planting, which incorporates multiple varieties in one pot—the thriller being the focal upright, the spiller to cascade over the pot and the filler to take up the spaces in between.

Thrillers – Alocasia esculenta, dahlia, cosmos, salvia, snapdragons.
Spillers – Lobelia, bacopa, nasturtiums, petunia, allysum
Fillers – Coleus, Heliotrope, Lantana, amaranth, violets, geraniums

Cacti and succulents are one of the easiest to grow in a container as they happily tolerate drier conditions, so terra cotta is one of the best containers to choose for this application. Succulents are also not limited in color, so consider a few of these varieties to plant singly or in a collection:

Echeveria
Opuntia
Crassula
Senecio
Sedum
Snake plant
Aloe vera

Containers can host multiple plants and types as long as you ensure they have the same moisture and food requirements and enough room to grow. A lovely combination for drier conditions would be African daisies mixed with sedum, senecio, and echeveria. If it is a shady area, you would like to make lush consider a combination of caladium, fuschia and ferns. If space is limited, but the food is your priority, mix greens with cucumber and a tomato plant in a half barrel to provide salad fixings for the summer. Abide by the rules, and you will be happy with the outcome.

Don’t forget to acclimatize your plants before planting. If starts are coming from a lovely warm greenhouse or nursery, they will need some time to adjust to the outdoor temperature. Bring them outside daily and inside at night to harden off and accustom to their new environment for a minimum of 3 days.

How to care for containers after planting

Once you have your containers planted, they will need a bit of care. Place containers in a location where they will receive adequate sunlight and temperature for the variety. Monitor the moisture and water as necessary.

Use a natural-based slow release fertilizer of 5-3-4 every week or water with a compost tea 2-3 times per week. Support peas, beans, wisteria and other vines with a trellis to give them the support and stake tomatoes and peppers before they fall over.

If plants are struggling to grow, they are susceptible to pests and diseases. Give them what they need and avoid the risk.

Things that might go wrong

Too much or too little moisture is the most common problem for container planting. This leads to stressed plants which lead to pests. Let your pots dry a bit between watering and only water until it runs out the bottom.

If the soil has become too dry and plants have wilted in full sun, add small amounts of water throughout a day until the soil is saturated again. Stressful conditions attract pests so do your best to avoid overcrowding or mixing non-like varieties. Pests like aphids and whitefly are the most common of culprits but if caught early can be controlled with a pure soap and water mixture. For more information, read our guide about Natural Garden Pest Control.

Container plants draw attention so you will want to keep up with deadheading, removing exhausted plants and cleaning up brown or tattered leaves. Varieties that have passed their prime should be replaced with something similar or something that will bloom in the near future. Remember to empty clay and terra cotta pots if you live in freezing climes and prune in the fall to put your perennials to bed.

Creative containers for a well-rounded garden

Adding containers to your garden or balcony design offers the opportunity to create seasonal themes, creative dimension or functional purpose. It is an inexpensive way to satisfy the gardener in you and provides an additional habitat for the beneficial bugs and birds that live in your landscape. Let your imagination guide you.

Insights, advice, suggestions, feedback and comments from experts

As an expert in container gardening, I can confidently say that container gardening is a versatile and exciting way to grow plants. With the right pot, soil, and placement, you can cultivate a wide range of plants, from seasonal vegetables to stunning specimen trees. In this article, we will explore the principles of container gardening, the types of plants you can grow, how to choose the right container, achieving optimal soil conditions, caring for your plants, and potential challenges you may encounter.

Container gardening offers a solution for those with limited space and access to sunlight, allowing you to garden almost anywhere. It can even become an addictive hobby, with colorful pots and unique vessels adorning your deck or patio. The aesthetic appeal of colorful glazed pots or repurposed washtubs adds a personalized touch to your landscape, like your own signature.

When starting your container garden, you have endless choices in terms of container options. Cedar boxes, railing baskets, large resin pots, half barrels, storage totes, fish tanks, and even the kitchen sink can be used, as long as you follow a few fundamental principles when choosing. These principles include pairing plants with vessels that can accommodate their root system and providing an appropriate soil mixture. It is crucial to ensure that the chosen container has adequate drainage for the specific plant variety.

Container gardens offer several advantages over ground-level beds. They are more manageable in terms of size, allowing for greater control over growing conditions. You can address specific soil structures, fertilization needs, and water requirements for each plant. By positioning containers in ideal locations, you can optimize sunlight exposure, leading to healthier plants that are more resistant to pests and diseases. Whether used for functional purposes or as an aesthetic addition to your landscape, container gardens have numerous benefits to offer.

When it comes to plant selection, the possibilities are virtually endless. Almost any plant can thrive in a container, as long as you understand its specific space and soil requirements. Researching the needs of your favorite plant varieties will help you determine the proper container size and soil combination. To make it easier for you, I have provided a list of common container gardening plants and their corresponding pot sizes and soil combinations in the article.

Choosing the right container involves considering both aesthetics and functionality. While the beauty of the pot is often the primary consideration, it is important to select a container that can accommodate the size of the plant's root ball. Additionally, the material of the container plays a role in its suitability for specific plants. Plastic or resin pots are lightweight and durable but can become saturated, potentially leading to root diseases. Terra cotta or clay pots are popular in wetter coastal climates due to their ability to dry quickly. Glazed clay pots offer a wide range of colors and sizes, adding significant impact to any space. Eco pots or fiber pots, made from materials like coconut coir or pressed paper, promote healthy root growth. Wood is commonly used for raised beds or planter boxes, but it can rot in coastal areas. Glass or plastic terrariums create a moist environment for tropical plants. Uncommon vessels like metal buckets, old boots, or even toilets can be used to personalize your landscape with a touch of creativity.

Regardless of the material, proper drainage is crucial for successful container gardening. Standing water or excessive moisture can invite diseases, fungus, and pests that harm your plants. Ensure that your containers have adequate drainage holes, or add holes or a layer of coarse gravel at the bottom to allow excess moisture to escape.

Preparing the soil for your containers is a simple but essential step. Soil serves as the foundation for your plants, providing access to moisture, nutrients, and oxygen. Different plants require different soil combinations, so it is important to understand the function of each material used. Organic matter, such as peat or coconut coir, promotes moisture retention in containers. Compost, rich in nutrients, can be incorporated into the soil mixture. Sand contributes to drainage, but too much can cause the soil to dry out too quickly. Loam, a combination of clay, silt, and sand, offers the benefits of each material without many disadvantages.

Feeding your plants in containers is crucial, as new containers filled with sterile soil may lack sufficient nutrients. Adding organic fertilizer during the soil mixing stage provides essential nourishment for the plants in their first month of growth. Throughout the growing season, you can continue to feed your plants with all-purpose organic fertilizers or use compost tea made from well-rotted compost or worm castings. Compost tea provides micronutrients and beneficial microbes to the soil, contributing to healthy plant growth.

When choosing plants for your containers, it is essential to have a plan in mind before visiting the garden center. Vegetables, herbs, perennials, shrubs, annuals, cacti, and succulents can all thrive in containers, as long as you provide the right conditions. The top ten choices for container gardening vegetables include tomatoes, peppers, squash, beans, lettuce, bok choy, radishes, spinach, peas, and carrots. Mediterranean herbs such as rosemary, thyme, oregano, and parsley do well in containers. Perennials, shrubs, and ornamental grasses planted in containers can add an attractive dimension to your landscape. Annuals are perfect for adding instant color, and you can use the "thriller, spiller, and filler" technique to create dynamic arrangements.

Caring for your containers after planting involves placing them in locations with adequate sunlight and temperature for the specific plant variety. Monitoring moisture levels and watering as needed is essential. Slow-release organic fertilizers or compost tea can provide the necessary nutrients throughout the growing season. Supporting climbing plants with trellises and staking tall plants like tomatoes and peppers will ensure they grow upright. Regular maintenance, such as deadheading, removing exhausted plants, and cleaning up leaves, is crucial for the health and appearance of your containers.

While container gardening offers many benefits, there are some challenges you may encounter. Over or under-watering is a common problem that can stress plants and attract pests. It is essential to allow the soil to dry out slightly between waterings and only water until it runs out of the bottom of the pot. Overcrowding or mixing non-like varieties can also lead to pest infestations. Aphids and whiteflies are common pests, but they can be controlled with a mixture of pure soap and water. Regular maintenance, such as removing faded plants and replacing them with new ones, will help keep your containers healthy and vibrant. In freezing climates, remember to empty clay and terra cotta pots to prevent cracking, and prune perennials in the fall to prepare them for winter.

Adding containers to your garden or balcony design offers endless possibilities for creativity. You can create seasonal themes, add dimension, or fulfill functional purposes. Container gardening is an inexpensive way to satisfy your gardening passion while providing an additional habitat for beneficial insects and birds. Let your imagination guide you as you embark on this exciting gardening journey.