Repotting Trichocereus seedlings from a group setting into 2-inch plastic containers is an important step in ensuring their continued growth and health. Here are the steps to follow when repotting Trichocereus seedlings:

1. Choose the Right Potting Mix: Trichocereus seedlings need a well-draining potting mix that contains equal parts of perlite, sand, and peat moss or a commercial cactus mix. This mix should provide enough aeration and drainage to prevent root rot while retaining enough moisture to promote healthy root growth.
2. Gather Supplies: You will need 2-inch plastic containers, a potting mix, a sharp knife or pruning shears, and a label to identify each seedling.
3. Prepare the Containers: Fill the containers with potting mix, leaving about 1/2 inch of space at the top for watering. Make sure the containers have drainage holes to allow excess water to drain away.
4. Remove the Seedlings from the Group Setting: Gently tease the seedlings out of the group setting, taking care not to damage the roots. If the seedlings are too tightly packed, use a sharp knife or pruning shears to cut apart the root systems. We like to use these rubber tipped tweezers from Amazon.
5. Plant the Seedlings: Place each seedling into its own container, making sure that the root system is fully covered with potting mix. Firm the mix around the roots to ensure good contact between the roots and the potting mix.
6. Label the Containers: Label each container with the seedling’s name or identifier to keep track of its progress and make sure it is getting the proper care.
7. Water the Seedlings: Water the seedlings immediately after planting. Make sure the water reaches the roots, but be careful not to over-water as this can lead to root rot. Allow the top inch of the soil to dry out between waterings.
8. Provide Adequate Light and Temperature: Trichocereus seedlings need bright, direct sunlight to thrive. Place the containers in a bright, warm location, but avoid exposing them to direct sunlight for extended periods as this may cause sunburn. Optimal temperatures for Trichocereus seedlings are between 70-85°F.
9. Monitor Growth and Health: Check the seedlings regularly for signs of pests, diseases, or other problems. Address any issues promptly to prevent further damage.
10. Transplanting to Larger Containers: As the seedlings grow, you may need to transplant them into larger containers. This should be done when the roots have become root-bound and are growing out of the drainage holes in the bottom of the containers.

By following these steps, you should be able to successfully repot Trichocereus seedlings from a group setting into 2-inch plastic containers. It is important to provide the seedlings with the right conditions, including proper watering, light, temperature, and nutrition, to ensure healthy growth and development. With proper care, your Trichocereus seedlings will grow into strong, healthy plants that will thrive for years to come.