Nursery sowing is a strategic stage in the success of any vegetable crop, just as important as field cultivation. In fact, 50% of a crop's success depends on the nursery phase: the first 30 days in the nursery are as important as the following 120 days in the field. Proper management during the early stages of growth allows growers to produce uniform, vigorous seedlings that are ready for transplanting under the best possible conditions. At Smarties.bio, we believe that crop quality begins with germination. For this reason, successful nursery sowing requires careful attention to every detail, from selecting the right growing medium to controlling temperature and humidity.
Why Choose Nursery Sowing?
Growing seedlings in a nursery offers numerous advantages over direct field sowing:
- Greater control over environmental conditions.
- Higher germination rates.
- Uniform seedling development.
- Reduced losses during the early stages of growth.
- Accurate transplant scheduling.
- Improved weed management.
Careful nursery management also produces healthier and more resilient seedlings, ultimately improving crop performance and yield.
Choosing Containers and Growing Media
For effective sowing, it is recommended to use plug trays or seedling trays specifically designed for nursery production. The use of new trays is always recommended. If previously used trays are employed, thorough cleaning and disinfection are essential to prevent plant health issues. Likewise, it is important to choose a growing medium specifically formulated for vegetable crops, avoiding excessively light, long-fibre peat substrates that are better suited to ornamental plant production. The substrate should be uniform and capable of providing proper root aeration. A clean and well-managed nursery environment is the first step towards producing high-quality seedlings.
Temperature and Humidity: Key Factors for Germination
During germination, temperature control plays a crucial role. For chicory and radicchio, optimal germination occurs at temperatures between 25°C and 28°C (77–82°F). These conditions should be maintained until seedling emergence while ensuring consistent moisture levels in the growing medium. It is also important to avoid:
- Temperatures above 35°C (95°F).
- Temperatures below 24°C (75°F).
- Waterlogging, which can promote root rot.
For lettuce, germination temperatures above 20°C (68°F) should be avoided, with 15°C (59°F) being the ideal temperature. Proper irrigation should keep the growing medium consistently moist without becoming saturated, ensuring the right balance between water and oxygen.
Early Growth Stages
After germination, young seedlings require stable conditions to develop a healthy root system and balanced vegetative growth. During this stage, it is important to monitor regularly for aphids, thrips, caterpillars (Lepidoptera), and other insect pests, especially during the warmer months of the year. Timely intervention helps preserve seedling quality and promotes healthy, consistent growth.
When to Transplant
One of the most common mistakes is delaying transplanting for too long. Seedlings are generally ready for transplanting when they reach the 4–5 true leaf stage. For chicory and radicchio crops, this usually occurs after 20–25 days for summer sowings and up to 30 days during cooler periods. It is essential to avoid transplanting seedlings that are too old (more than 30 days after sowing) or stressed, as this may encourage premature bolting and compromise the final crop performance.
Practical Tips Before Transplanting
To minimize damage to both the root system and foliage, seedlings should be properly prepared a few days before being transferred to the field. Careful management during this stage promotes rapid establishment and enables young plants to resume growth quickly after transplanting. Ideal seedlings should have:
- A uniform green colour.
- A well-developed root system.
- No signs of pests or diseases.
- Balanced growth without being overgrown.
The blog posts, guides and technical insights available on our website fully reflect the philosophy behind our Seed&Service approach:"We sell you the seed and teach you how to grow it." Whether you are a professional grower or taking your first steps in vegetable cultivation, you will find practical information and valuable resources on our website to support you throughout every stage of the growing process and if you ever need personalised advice, do not hesitate to contact us. The Smarties.bio team is always available to help you identify the varieties and solutions that best meet your production needs.
Don't miss our guide to growing radicchio in the nursery.