If you want to develop turnips with great roots you will want to opt for low-nitrogen fertilizers such as 5-10-10 NPK as opposed to higher nitrogen fertilizers that, while they feed the leafy tops of the turnip, will reduce the root yield. As I prepare for planting, I usually apply compost tea and switch to bone meal for the bulking phase to boost phosphorus levels in the soil.
Organic Options
- Compost tea: Mix 1 part compost to 5 parts water. Apply at planting
- Bone meal: 1 tbsp per plant for phosphorus. Work into soil pre-planting
- Fish emulsion: Dilute 1:4. Use every 3 weeks for greens
Synthetic Choices
- 5-10-10 granules: Apply 1 cup per 10 sq ft. Water deeply after
- Slow-release pellets: Reduce leaching in sandy soils. Apply once
- Avoid 10-10-10 blends, excess nitrogen harms root formation
Use fertilizer 3 weeks after germination, when it appears that root swelling has occurred. You want to side-dress along the row, but make sure the granules are kept 2 inches away from the stems. I would say to test your soil every year since too much phosphorus can block important micronutrient uptake. With my dirt being clay, I simply skip a bone meal and switch to rock phosphate to produce a more balanced growth pattern.
Excessively fertilizer-treated turnips display symptoms of burned leaf edges and cracked roots. Upon the occurrence of nitrogen burns, flush the soil with water. For container plants, use one-half of the recommended rate. In any case of fertilizing, pair with a regular watering schedule of 1 inch per week to prevent salt accumulation. Always harvest greens first, as this allows the plant to repurpose energy to grow roots.
Read the full article: How to Grow Turnips: A Step-by-Step Planting Guide
