Why are my kolrabi growing all leaves? No bulb for eating.

Why is my kohlrabi growing all leaves, no bulbs?

​Good morning.  Back to watering.  It looked like early we were to get some rain, but it didn’t happen. Now storms this afternoon see what happens.  Stay safe all.  And stay cool.
 
Australia family and friends for Thursday June 11 will have 96% chance of rain. With a high of 63F(17C).  I would think they would like that.  I will ask?  Stay warm, stay dry, stay safe.
 
Question asked about kohlrabi just growing leaves.  They thought they got the wrong seed, but this is what I found out.  Hope they follow me on this posting.  Several reasons so have to play detective which one it is. 
 
Why Kohlrabi May Grow Only Leaves
If your kohlrabi plant is producing only leaves and no swollen stem, it’s usually due to environmental stress, improper planting, or nutrient issues that prevent the plant from developing its characteristic edible stem.
Common causes:
Too much heat or drought – Kohlrabi is a cool-season crop that thrives in temperatures between about 7–24 °C (45–75 °F)  In hot, dry weather, especially in summer, plants may stop forming the swollen stem and focus energy on leaves instead. In hot climates, fall planting is recommended to avoid this.
Poor soil or nutrient deficiency – Kohlrabi has a high nitrogen requirement. If the soil lacks nitrogen or other nutrients, the plant may prioritize leaf growth over stem development. Ensure fertile, well-draining soil with organic matter added regularly.
Overcrowding or poor spacing – If plants are too close together, competition for light and nutrients can reduce stem formation. Kohlrabi should be spaced about 15 cm (6 in) apart
Pests or diseases – Insect damage (e.g., cabbage aphids, beet armyworm) or diseases (e.g., black rot, downy mildew) can stress the plant and halt stem growth
Harvesting too early or too late – If you pull the plant before the stem has fully formed, you may only get leaves. Conversely, if it’s left too long, the stem may become woody and fibrous
What to do:
Plant in cooler seasons (spring or fall) for best results.
Maintain consistent moisture and fertilize with a balanced, nitrogen-rich fertilizer
Keep plants well-spaced and free from weeds.
Inspect for pests and treat promptly.
If the plant is still young, it may recover with better conditions; if it’s mature and stressed, the leaves can still be eaten like other greens.
In short, kohlrabi without a stem is often a sign of heat stress, nutrient imbalance, or poor growing conditions rather than a genetic defect. Adjusting temperature, soil, and spacing should help the plant develop its edible stem.
Till next time this is Becky Litterer , Becky’s Greenhouse, Dougherty Iowa [email protected] 
641-794-3337  cell 641-903-9365  Beckysgreenhouse.com  Facebook Becky Kerndt Litterer or Becky’s Greenhouse