When you transplant tomato seedlings you need to partially bury them in the soil. This encourages more roots to form which make the plant stronger and more resilient against wind, drought, pests and diseases.

Handle the seedlings gently by their leaves and never by their stem. If you damage the stem it cannot be fixed and your plant will die.

Choose the Right Container

Ideally, you want to plant tomato seedlings in containers that have good drainage and that will retain moisture. Fabric, terra-cotta, and plastic are all good choices. Avoid using wooden or metal containers that tend to hold too much heat, which can damage the roots and stems of your plants.

Generally, garden soil is too dense for container gardening, and it increases the likelihood of disease-causing pathogens. Instead, use a high-quality bagged or homemade potting soil that’s light and fluffy and rich in organic matter like peat moss, shredded bark, vermiculite, and compost.

While prevailing potting practice is to keep the level of soil the same when transplanting, you should bury your tomato plants more deeply than you did their previous home. Burying the lower parts of their stems encourages them to produce new roots along the buried sections, making them more resilient and able to support themselves as they grow. You should also group the containers together, which will provide shade to the root zones and help protect them from harsh sunlight that can burn leaves and make them prone to disease.

Prepare the Soil

Tomato plants are heavy feeders and need good quality soil. Dig a hole that is slightly larger than the root ball, and add compost or other organic material to the bottom of the hole before planting. It’s also a good time to add mulch, especially if the garden isn’t yet covered with leafy debris.

Before digging, gently remove each seedling from its container and pinch off any early flowers or suckers with your fingers or clean scissors. It might seem counterintuitive, but this will help the plant focus on settling into its new home rather than using energy to produce seed and flowers.

Tomato seedlings need plenty of water, particularly at the time of transplanting. Water them slowly and deeply each morning until they’re acclimated to outdoor conditions (check our article on watering tomatoes for more information). It helps to add a trellis, cage, or stake to the tomato plant at this stage too. This prevents the plants from becoming too densely packed, which can inhibit airflow and encourage disease.

Bury the Seedlings

Once the tomato plants are planted, gently sink the stems deeper into the soil than you did in their container. This helps tomatoes tolerate drought and improves root establishment and wind resistance. It also encourages tomato plants to develop adventitious roots along any part of the stem, which are important for disease prevention.

Planting tomato seedlings with buried stems also prevents them from producing flowers at this early stage, which could rob the plant of vital energy and encourage it to focus on fruit production. This also prevents the development of a long list of diseases that prey on tomato plants, including blights and other fungal pathogens.

When transplanting tomato plants, dig a hole larger than the nursery pot and fill it with premium quality potting soil or well-amended native soil for raised beds. Avoid tamping down the soil, as this can compact it and reduce the oxygen content, which inhibits root growth. A few pinches of soil on each transplant can help you remove the plant without damaging it, and a strip of cardboard or an old paper towel tube prevents cutworms from chewing off tomato plants at ground level.

Water and Fertilize

Once your tomato plants have been transplanted and settled in, it’s time to water them thoroughly. It is also a good time to mulch the tomatoes (see our article on mulching to learn how). Mulching helps retain moisture and discourages fungal diseases.

Remember to plant your tomato seedlings deeply – sink the stem right up to its lowest leaves. This seems counterintuitive, but it is very important. Tomato plants produce adventitious roots all along their stems, and burying the plants promotes a more robust root system.

Water gently and deeply each morning for the first few days that your plants are in their new home. Be careful to avoid splashing water on the leaves, which can encourage fungal disease. When your plants are established, water them regularly using a deep watering technique, and fertilize weekly with a liquid fertilizer diluted to half strength. Be sure to follow the instructions on the label of your particular fertilizer.