Zinnias are a popular choice for those looking to add a pop of color to their garden. They are not only easy to grow in various soil types, but they also work great as border flowers and can be used as a backdrop for other plants in your landscape. Additionally, they look adorable in patio containers that can be moved around to follow the sun or accent seating areas. If you want to try growing zinnias in pots, we’ve got you covered with some helpful tips! Here are 11 simple things you can do to ensure your zinnias thrive in containers.
Starting zinnias from seed is an easy task because of their size and high germination rate. Zinnia seeds are relatively large, and most varieties offer a high germination rate, making it a simple decision to start them from seed. You can begin the process either indoors using cells or directly sow them into your desired container. If you choose to direct-sow them, ensure that you space them according to your pot size, burying them about a half-inch below the soil surface. It’s essential not to start them earlier than six weeks before the last possible spring frost to allow them enough time to mature before planting outside but not so long that they become root-bound or stressed. Seeds will germinate within 5-7 days when the soil temperature ranges between 74-80°, and the process can be quicker when heat mats are used. It’s crucial to water the seeds well but avoid fully saturating the soil. Don’t transplant zinnias into outside soil until temperatures consistently reach over 60° to reduce the risk of transplant shock.
Experts advise buying seeds from trustworthy suppliers to ensure quality. If you’re new to growing zinnias in pots, try ‘Benary’s Giant Blend’ – a foolproof favorite that showcases all of Benary’s colors so you can choose your favorites for next season. Keep in mind that these stems can grow tall, so make sure your container is the right size and offers support with enough space. For a more compact option, the award-winning ‘Profusion’ series is a bushier and colorful choice that will turn heads. The ‘Cactus Zinnia Flower’ offers a unique look and adds visual interest to your front stoop or back patio. Additionally, the new ‘Double Zahara™ Brilliant Mix’ is a mum-like zinnia that is bred for powdery mildew resistance. No matter what variety you choose, always buy seeds from a reputable source.
Select a soil mixture that is rich in nutrients and drains well. To enhance moisture retention, incorporate absorbent materials such as vermiculite or peat moss. To provide additional nutrients to your potted zinnias, it’s beneficial to mix in well-aged manure or compost. Zinnias are moderate feeders and spend a significant amount of time in the ground, making this an excellent way to promote healthy growth.
There are numerous options available for planting zinnias in containers, and gardeners today have more options than just window boxes or ceramic pots. To grow zinnias in pots successfully, you need the right container. There are several favorites that I recommend, including grow bags, which are becoming increasingly popular due to their built-in drainage material, mobility, and durability. The water drains out easily, making it nearly impossible to overwater. Most bags in the market have handles, making it easy to move your potted plants around or indoors during inclement weather.
Another excellent option is permanent raised beds, which are a gardener’s new best friend. I use them on our farm to keep herbs like mint and oregano from spreading, but they’re also ideal for annual flowers. Raised beds provide increased soil health, improved drainage, a clean look, and less bending over when harvesting. Hanging baskets add dimension and height to any garden display. Consider growing a shorter cultivar along with something that will hang over the sides to add a little drama.
Classic ceramic pots still work well for growing zinnias and add some sophistication to any patio or outdoor landscape. BPA-free plastic pots with a bottom-watering tray are perfect if you have to leave your plants to fend for themselves for a few days. Here’s a pro tip: if you want your patio arrangements to look intentional and pleasing to the eye, group pots in odd numbers of three or more to add a harmonious look to your outdoor living space.
Zinnias can flourish in different settings, including partial shade, making them ideal for pot placements or borders around your yard. While they prefer full sun, it’s best to protect them from strong winds. Zinnias are great for border wall plantings or as a lovely addition to small flower plots. Additionally, when potted, they can be displayed on your front porch, back patio, or even in garden beds. Don’t hesitate to move them around occasionally for some fun and variety!
Encouraging bushier growth is possible by pinching back young plants before transplanting. While it may seem counterintuitive to do so, pinching back your zinnias can help them establish better, produce side shoots, and prepare for abundant and continuous blooms throughout the season. Studies have shown that certain cultivars respond to pinching back by becoming shorter and bushier with thicker stems, making them ideal for container gardening. Although cutting off seemingly healthy flowers may feel sacrilegious, you are actually investing in the future of your garden. Deadheading, or cutting back unwanted, misshapen, or wilted flowers, can also create more airflow and space for new blooms. By leaving at least two sets of intact leaves, you ensure future growth. This method not only cleans up your flower patch but also promotes new blooms within a week or so. With just a little pinching and cutting back, your zinnias can be revitalized and ready to bloom again!
To ensure the proper growth of your zinnias, it is advisable to provide them with about one inch of water per week, especially if you live in a sunny location. Although zinnias do not require much water, they love being in full sun and heat, so it’s essential to monitor their water levels to prevent them from drying out. When growing zinnias in pots, remember that their roots have no place to reach down to search for water, so they rely solely on you for care.
Water the base of the plants, preferably in the early morning instead of at night, allowing the plants to absorb the water and dry out during the day to prevent fungal disease from spreading in wet conditions. During hot spells, it is recommended to water the plants twice daily. To determine if your zinnias need watering, perform the finger test by checking if the soil feels dry about two inches down.
If you have many containers to water, consider laying a soaker hose over the top of them at the plant base for efficient, simultaneous watering. However, make sure to keep the leaves from getting saturated as this can increase disease pressure.
To prevent Japanese beetles from damaging your zinnias, you can use traps or soap water. While zinnias are easy to grow, they often attract pests like Japanese beetles. These bugs love munching on the leaves and flowers of zinnias. If you have used Japanese beetle traps before, try hanging one near your zinnias, but not directly next to them. The lure of the trap will hopefully divert the beetles away from your plants. Alternatively, keep a jar of soap water nearby and hand-pick the beetles each morning, dropping them into the jar. Then, dust the plants with diatomaceous earth to deter other beetles from landing on your plants. Spider mites and aphids may also be a problem, but they can usually be controlled by spraying your plants with insecticidal soap.
To maintain consistent blooming and ensure plant health, it’s recommended to fertilize your zinnias with a phosphorus-rich fertilizer on a monthly basis. When transplanting zinnias, mix in a tablespoon of bone meal into the top layer of soil to encourage a strong root system. For continuous blooming and overall plant health, monthly fertilization with a fertilizer that has higher levels of phosphorus than nitrogen is beneficial. Healthy plants are more resistant to disease and pests. However, it’s important to conduct soil testing before the planting season to determine the appropriate amount of fertilizer for your garden.
In warm and dry conditions, powdery mildew can thrive and cause damage to buds and leaves by forming grayish-white spots. It is crucial to be aware of the right conditions for disease formation and how to prevent it. Adequate airflow can be ensured by spacing out zinnias at least a foot apart. If you detect powdery mildew, use copper fungicide to prevent its spread and dispose of any diseased debris. Southern blight occurs during extended periods of wet weather and manifests as small reddish circles with light centers. Good airflow, properly spaced plants, debris-free gardens, and clean seed-starting supplies and tools can prevent it. Bacterial leaf spot symptoms include small, circular purple spots that appear after extended rainfall. Growers can use copper fungicide after rainy periods to prevent the fungus from spreading. To find disease-resistant zinnia varieties, use the search filter to show ‘Zahara’ and ‘Profusion’ series.
Zinnias are delicate and cannot survive in cold weather. They are highly sensitive to environmental stressors such as droughts and floods. If you grow them in cell trays, make sure not to let them become root-bound before transplanting them into their containers as this could cause transplant shock. Moreover, if you have chosen a double-bloom variety, they might revert back to single-blooms due to stress, which can be disappointing. Zinnias will die even after a light frost as they have zero tolerance for low temperatures. During the fall months, their growth and blooms will slow down as the temperature cools off. However, treating them well from the beginning will ensure an abundance of brilliance all summer long. Zinnias come in different sizes, colors, and shapes, making them a joy to grow each season. Remember to take preventative disease care measures and proper pruning to grow them exceptionally well in containers. Regardless of your space, whether it’s a big patio full of grow bags, a window box, or a raised metal bed, zinnias won’t disappoint. If you haven’t grown them before, consider adding them to your next season’s seed order and allow them to reseed themselves for an even more abundant crop the following year.