Choosing the best vegetable seedlings is essential for both large-scale agricultural businesses and small farmers. Typically sold in polystyrene cell containers, these seedlings represent the beginning of our garden, and it’s crucial to start off on the right foot. Planting poorly grown vegetable seedlings from the nursery can jeopardize the success of your cultivation.
In this article, we will understand the characteristics that vegetable seedlings should possess to make an informed and vigilant purchasing choice.
How Vegetable Seedlings Grow in the Nursery
Seedlings destined for professional or hobby horticulture are produced by specialized companies in the floriculture sector. They are typically grown in polystyrene containers with numerous cells. Sterilized materials, high-quality fine soil or peat, surface perlite, and seed placement machinery are used in their production.
Growth takes place in dedicated greenhouses, where temperature, humidity, and irrigation are continuously monitored. Some nurseries adhere to the principles of organic farming and primarily cater to certified organic farms. These are the nurseries you should look for when purchasing your seedlings. Unfortunately, most nurseries do not operate organically.
Assessing the Quality of Vegetable Seedlings
From an agronomic perspective, the quality of a vegetable seedling is judged based on its ability to establish itself after transplanting. Essentially, you evaluate how quickly it resumes vegetative activity after transplanting and its success rate in doing so. If there are many shortcomings after transplanting, it means the seedlings are of poor quality.
What Happens When We Transplant Seedlings to the Garden
At the time of transplanting, seedlings are moved from the greenhouse to the open air. In the greenhouse, as mentioned earlier, environmental conditions are stable and controlled, vastly different from those in open fields. The leaves of a seedling grown in a greenhouse transpire significantly. This condition intensifies when transitioning to open fields, especially during summer transplants, where high temperatures, low humidity, and wind create conditions distinct from those in greenhouses. This transition increases the need for water, which cannot be met by the existing root system, which is not fully developed yet. Therefore, the soil must be adequately moist and irrigated both before and after transplanting.
Transplant Stress
When a vegetable seedling is transplanted, it undergoes what’s known as transplant stress. In summary, this involves a temporary growth halt. However, if you’ve purchased good seedlings, an interruption in growth will be followed shortly by the rapid formation of new roots (establishment). These new roots must be capable of resuming vegetative activity by producing new leaves. When transplanting, it’s essential to ensure the root ball of the seedling adheres well to the garden soil without placing it too deep.
Differences Between Different Vegetable Species
Some crops respond better to transplanting than others. One such example is the tomato, a plant that can establish itself quickly, even under high-stress conditions. More challenging are cucurbitaceous plants (such as zucchini, cucumber, pumpkin, loofah…), which take longer to establish themselves.
Ideal Requirements of a Vegetable Seedling
To quickly overcome transplant stress, here are the requirements that nursery-purchased vegetable seedlings should meet:
- Good reserves of nutrients with tissues that are not overly watery and are robust;
- Efficient leaf apparatus from a photosynthetic perspective, with bright and uniform green color;
- Absence of yellow leaves;
- Sturdy stems and short internodes, capable of withstanding mechanical stress (transport, wind, etc);
- Wide and well-distributed root system;
- Roots developed in a balanced ratio with the above-ground part;
- Absence of bundled or tangled roots;
- Roots should not protrude from the bottom of the container and grow in the gaps or at the bottom;
- Evident formation of root hairs;
- White roots;
- Right age and absence of flowering.
The Importance of Buying Young Seedlings
A common mistake made by gardeners is purchasing vegetable seedlings that are too mature. It’s better to use seedlings at a young stage. But how can you tell if a seedling is young? Besides the absence of yellow leaves and overly developed roots, there should be no signs of flowering. Early flowering, before vegetative growth is well established, can significantly affect the final production. For instance, when buying tomato seedlings, you can easily check for flowering; just make sure there are no early blossoms. However, it’s more complicated for plants like cauliflower. In this case, the transition to the reproductive phase occurs in the field, when it’s too late, resulting in the premature formation of undersized and low-quality inflorescence. This phenomenon is called buttoning.
Mistakes Made by Nurseries Regarding Seedlings
The transition of plants from the vegetative phase to the reproductive phase can be induced by nursery practices gone wrong, such as thermal and/or nutritional stress or extended stays in the nursery. Other signs of “old” vegetable seedlings include: yellowing of cotyledons; root growth circling along the cell wall (root bound). In the latter case, after transplanting, the roots maintain the circular orientation, delaying plant establishment.
Preference for Nursery Seedlings Grown in Large Cells
A factor influencing the quality of seedlings for your garden is the size of the cell in which they were grown. For economic reasons, nurseries tend to use cell containers with many small holes. This situation is suitable for plants like lettuce, but it generally shortens the time the plant stays in the nursery. Consequently, seedlings in densely populated containers are more likely to be of lower quality. For cucurbitaceous plants, which are highly sensitive to transplant stress, cells with a diameter of no less than 5 or 6 cm are used.
Buying Seedlings from a Trusted Nursery
Navigating through all these technical parameters can be challenging for those who only want to choose seedlings for their garden. Ultimately, the quality of these seedlings depends not only on the work of the nursery but also on its honesty. It’s best to establish a trusting relationship with your nursery provider to avoid unpleasant surprises. After all, they supply your raw materials—the seedlings. As in any production process, trust in the various participants in the chain is essential. Be cautious when purchasing online, as buyers have virtually no control in such cases.
