Container gardening refers to the gardening practice of cultivating plants in pots, tubs, or other containers instead of directly in the ground or in raised beds.

Container gardening allows for food, flower, and herb production in locations where traditional gardens are not possible or accessible, including patios, balconies, decks, and sites with poor soil quality. They are a great option for renters, individuals with limited mobility, gardeners seeking to extend the growing season, and beginner gardeners looking to start their gardening practice gradually.

Here are our top tips for having a successful growing season in containers:

Varieties we recommend:

• Tomatoes: Look for determinate tomato varieties like ‘Celebrity’, ‘Early Girl’, or ‘Patio Princess’. These varieties are known for their ability to produce early, compact fruit even in fluctuating temperatures.
• Herbs: Herbs like rosemary, thyme, sage, and oregano are resilient and can tolerate a wide range of temperatures. They’re also versatile in the kitchen and add flavor to your dishes year-round.
• Lettuce and Leafy Greens: Varieties such as ‘Buttercrunch’, ‘Red Leaf’, and ‘Romaine’ lettuce, as well as spinach, kale, and Swiss chard, are cold-hardy and can withstand temperature fluctuations in Denver’s climate. Leafy greens can all be replanted in late summer for a fall harvest.
• Peppers: Opt for compact pepper varieties like ‘Jalapeno’, ‘Sweet Banana’, or ‘Mini Bell’ peppers, which are well-suited for containers and can handle temperature changes better than larger varieties.
• Radishes: Radishes are quick-growing and can tolerate cooler temperatures, making them ideal for early spring and late fall planting in Denver. Varieties like ‘Cherry Belle’ or ‘French Breakfast’ are popular choices for container gardening.
• Zucchini and Summer Squash: Choose bush varieties of zucchini and summer squash, such as ‘Black Beauty’ or ‘Yellow Crookneck’, which take up less space and are more resilient to temperature fluctuations than sprawling varieties.
• Marigolds: Marigolds are hardy annual flowers that add a pop of color to your container garden. Varieties like ‘French Marigold’ or ‘Signet Marigold’ are heat-tolerant and can thrive in Denver’s climate.

Experiment with a variety of plants to create visual interest and maximize productivity in your container garden. Mix and match different colors, textures, heights, and growth habits to create dynamic container compositions that are as beautiful as they are productive.

Plan for seasonal changes by selecting plants that offer year-round interest or swapping out plants with the changing seasons. Consider cool-season vegetables and annual flowers for spring and fall, and heat-tolerant plants for summer. Rotate crops regularly to prevent soil depletion and pest buildup.

Adding compost to a potting mix for container gardens is also quite beneficial. Compost adds valuable organic matter to the soil, which improves soil structure, increases water retention, and enhances nutrient availability for plants. It also introduces beneficial microorganisms that contribute to soil health and plant growth.

Planting Your Container Garden:

Before planting, fill containers with potting mix, leaving space at the top for watering. Add water to your mix in the pots so that the soil is well-moistened (but not soaking wet) before planting. Plant seeds or seedlings at the appropriate depth, following specific planting instructions for each plant. Water newly planted containers at the root of the plant to settle the soil and establish good root contact.

Arrange plants in containers with consideration for aesthetics and functionality. Place taller plants in the center or rear of containers, with trailing or cascading plants along the edges to soften the edges and create visual interest. Experiment with different planting schemes, such as symmetrical, asymmetrical, or layered arrangements, to find a style that suits your space.

Provide adequate spacing between plants to allow for proper airflow, sunlight penetration, and root development. Avoid overcrowding containers, as this can lead to competition for resources and increased risk of disease. Consider using companion planting techniques to maximize space and naturally repel pests, such as planting marigolds to deter aphids or basil to repel mosquitoes.

Caring for Your Container Garden:

Proper watering is crucial for ensuring healthy container gardens. To maintain optimal soil moisture levels, it’s essential to monitor the soil regularly. You can check the soil moisture by inserting your finger into the soil; if the top inch feels dry or no soil sticks to your finger, it’s time to water. When watering, ensure thorough saturation at the root level rather than watering from above, as this minimizes the risk of fungal diseases by preventing excess moisture on the foliage. Be aware that soil in containers may need daily watering to maintain moisture levels optimum for healthy growth.

In addition to proper watering, incorporating compost into the soil is beneficial for container plants. Compost enriches the soil with essential nutrients, improves soil structure, and promotes healthy microbial activity. Throughout the growing season, periodically add a layer of fresh compost to the top of the soil. Lightly mix the compost into the top layer of soil, ensuring it is evenly distributed. This practice replenishes nutrients and organic matter, providing ongoing nourishment for your plants.

After adding compost, consider applying a layer of mulch such as straw, leaves, or other green matter. Mulch helps retain moisture in the soil, regulates soil temperature, suppresses weeds, and reduces evaporation. Together with compost, mulch creates a favorable environment for plant growth, promoting healthy root development and overall plant vigor.
Prune plants as needed to maintain shape, control size, and remove dead or diseased growth. Deadhead spent flowers regularly to encourage continued blooming and prevent seed production. Use sharp, sterilized pruners or scissors to make precise cuts and minimize damage to plants.

As the season progresses, monitor plants for signs of pests and diseases and take appropriate action to control infestations. Effective organic pest control methods include hand-picking pests, spraying with insecticidal soap, and introducing beneficial insects like ladybugs and lacewings that prey upon pest insects. Practice good sanitation by regularly removing debris and fallen leaves from containers to reduce the risk of fungal diseases and pest buildup.

Throughout the winter months, periodically check the moisture level of the soil in your containers. While plants are dormant, they require less water, but it’s essential to prevent the soil from completely drying out. Water sparingly during dry periods to keep the soil slightly moist but not waterlogged.

As winter comes to an end, start planning for the next growing season. Consider which plants you want to grow, assess the condition of your containers and soil, and prepare any necessary amendments or repairs. By taking proactive steps to care for your container gardens during the winter months, you set the stage for a successful and bountiful garden in the spring.