Fill a pot halfway with soil and position the ugli fruit seedling so the first leaves start near the lip of the pot. Finish filling the pot with soil surrounding the root system of the plant, leaving 1 to 4 inches open below the lip for easy watering. Press the soil around the plant until it is packed firmly to keep the seedling in place.
Place the pot in an outdoor location that receives sunlight for most of the day, with partial shade. Avoiding constant sunlight will help your ugli fruit plant adjust to different seasons and will prevent it from growing too rapidly so it cannot be kept in a container.
Wait until the top inch of the soil in the pot is dry before each watering. Gradually fill the container with water and allow excess to drain from the bottom.
Monitor the color of your plant’s leaves. If they do not appear dark green, the tree may be malnourished. Purchase a water-soluble fertilizer at any home and garden store and apply it based on the instructions of the specific brand in relation to the size of your pot.
Remove the top third of the ugli fruit tree during the winter months to cause the plant to grow bushy and produce many branches. Pruning the top of the tree during the cold season will not interrupt the production of fruit.