Turnip plants can be planted in containers, although several modifications must be made when planting in containers instead of in a garden bed. Follow these steps to successfully grow turnip plants in pots or planters.
Step 1 - Choose a Container
The right container should give your turnip plant enough room to grow and while it helps to drain water and maintain the correct temperature. The depth of your container should be double the depth of your plant room. A 12-inch container should provide a turnip plant with plenty of room to grow.
Transplanting is difficult on turnip plants, so it is best to plant them in a container for the remainder of their life. Make sure your container has plenty of holes on the bottom to help with draining. For best results, turnip plants should be kept below 75 degrees Fahrenheit. To help keep the soil cool, use a lighter-colored container that will reflect light.
Step 2 - Prepare the Container and Soil
Line the bottom of your container with a couple layers of newspaper, so soil won't leak out through the drainage hole. Placing a couple inches of gravel on the bottom of your container will help the soil from getting to soggy. If possible, purchase a compost-enriched potting soil instead of using garden soil to insure that your soil is disease-free. Your soil should have plenty of sand for good drainage and have a pH level of around 6.5. Fill with soil to within a couple inches of the top.
Step 3 - Plant Turnip Seeds
Most turnip plants will be ready for harvest within 35 to 60 days after planting. When planting in containers, it easier to maintain the correct temperature (between 55 and 75 degrees), so you can plant more flexibly. It is important that turnips get plenty of sunlight, so planting in the spring or late summer is generally the best time.
Sow seeds ½-inch from the top. Plant 2 to 3 seeds in the middle of the container about 1 inch apart. After 2 weeks, they should be about 3 inches high. Pull out the smaller seedlings, allowing just one to grow to maturity.
Step 4 - Feed and Water Generously
Since a turnip in a container doesn't have the ability to reach out as far to get nutrients from the soil, it is important to lightly fertilize every couple of weeks. If you are growing mainly for the greens, use a nitrogen-rich fertilizer. If growing for the roots, use a potassium-rich fertilizer. Fertilize at half strength every couple weeks. To keep the turnip root from getting tough and woody, water generously, never allowing the soil to dry out completely.
Step 5 - Harvest Turnips
Harvest greens by cutting off when they reach 4 to 6 inches high. The greens should grow back several times. Harvest the turnips roots when they are about 3 inches in diameter. It is better to harvest turnip roots too soon than too late, as they are more tender and tasty when young.