Transplanting Tomatoes in Pots: Caring for New Container Tomato Plants Properly

Tomatoes are native to Central and South America and thrive in warm, moist conditions. To grow them from seed requires at least 110 days of sunny, hot weather — a luxury we don’t always have in North America in some gardening zones.

American gardeners in the cooler zones have long used transplants to grow tomatoes. Small seedlings, purchased from a nursery or grown in your own home, are a reliable way to grow a bumper crop of tomatoes. Yet transplanting tomatoes isn’t without its risks. Tomato plants are prone to transplant shock, which can stunt growth, cause the leaves to yellow, or even kill the plant.

Many gardeners grow tomatoes in pots when short on space. This is a great strategy, but tomatoes transplanted into pots tend to suffer more transplant shock than those planted directly in the ground. If you’re growing tomatoes in pots, you’ll need to take a little extra care to ensure healthy plants. Read on to learn the secrets of transplanting tomatoes successfully:

Transplanting Tomatoes in Containers:

• Choose plants carefully. Your tomato crop is only as healthy as the transplant you start with. Buy your plants at a reputable nursery or garden center that offers a guarantee on its plants. Choose tomato plants with bright green leaves, sturdy stalks, and thick, straight stems. The ideal transplant is less than six inches tall and as broad as it is high.
  
  Avoid those that are leggy or spindly, as well as large plants already bearing fruit. Select seedlings in cell packs or individual containers rather than flats, as their roots will suffer less transplant shock. Ensure the plants are free of insects and visible signs of disease for a healthier start. Disease-resistant cultivars are especially important if you live in a humid climate prone to plant diseases.
  
• Buy small plants over larger ones. In recent years, nurseries, grocery stores and even warehouse stores have offered large potted plants that are already bearing fruit. These are fine if you’re planning to keep the plant in its original pot. However, if you hope to transplant the tomato into a larger pot or directly in your garden, choose plants less than 12 inches high. Smaller plants, ideally less than 6 inches tall and as broad as they are high, will experience less transplant shock and quickly catch up with the larger plants. If you’re transplanting seedlings you’ve grown at home, transplant them when they stand 4 to 8 inches high.
  
• Wait for the weather to warm. Containers don’t provide the same insulation as the ground so if you’re transplanting tomatoes into pots, wait until daytime temperatures remain above 70 degrees Fahrenheit. If temperatures dip after you plant your tomatoes, bring them indoors or cover them with a plastic cloche.
  
• Choose the right size container.  Tomato plants have a fairly wide root system so it’s important to pick a container big enough to contain the roots. When selecting a container, think about the size of the tomato cultivar you’re growing. Compact bush types need a minimum container size of 5 gallons. Sprawling heirloom types may need a 15 gallon container. Related: Growing Tomatoes in 5 gallon Buckets and Top Tomato Varieties for Small Spaces
  
• Don’t skimp on the soil. It’s tempting to use regular garden soil in your containers, but don’t do it! Garden soil is too heavy for containers and quickly becomes compacted so plant roots don’t get enough oxygen. Garden soil may also contain plant diseases and pathogens. Instead, opt for a high-quality potting soil that contains compost or vermiculite.
  
• Harden off the plants. Hardening off may seem like an unnecessary extra step, but it really does help transplants acclimate better. Set your transplants in a shaded area outdoors for two to three days before you plant them. Continue to water them as usual. They’ve come from a protected indoor environment and need time to adjust to changes in wind, moisture and air temperature. Garden center plants are often stored outdoors and are already hardened off.
  
• Plant a bit deeper. Place the transplant in the pot so the first leaves are covered or almost covered. This practice has been shown to promote strong root development and overall growth. Some gardeners also remove any flowers from the plant, which diverts energy to building a strong root system.
  
• Baby your transplant. After transplanting, pay extra attention to your plants for the first week or two. Apply a transplanting fertilizer if you like and make sure the soil doesn’t dry out. Keep the pots in a place protected from drying winds or excessive heat. Until the roots begin growing again, your transplants are very vulnerable to damage.
  
• Water Immediately: After placing the transplant in the container, water it thoroughly to help settle the soil and minimize transplant shock. A gentle soaking ensures the roots are well-hydrated and can begin to establish themselves.
  
• Maintain Moisture: Keep the soil consistently moist during the initial weeks after transplanting. Avoid overwatering or letting the soil dry out, as this can stress the plant and hinder its growth.
  
• Gradual Sunlight Exposure: Place the transplanted tomatoes in a partially shaded area for a few days, then gradually expose them to more sunlight. This process helps the plants acclimate to their new environment and reduces stress.
  
• Protect from Temperature Extremes: Monitor temperatures closely during the early transplanting stage, and bring the plants indoors or cover them at night if temperatures drop significantly to prevent damage.
  
• Timely Fertilization: Apply the first dose of fertilizer about 1-2 weeks after transplanting, using a balanced fertilizer designed for tomatoes. This provides essential nutrients for root establishment and healthy growth.
  
• Ideal Container Placement: Choose a location for the container that offers adequate sunlight, protection from strong winds, and stable temperatures. This will create a nurturing environment for the newly transplanted tomato plants during their initial stage of growth.

Other Tomato Container Growing Resources:

Vegetable Gardening in Containers from Texas A&M University

Vegetable Gardening in Containers from Colorado State University Extension