The seedling chamber

 Filling the trays is a step that must be well done to preserve as much as possible the air retention capacity of the soil. We favor thus greatly the root development of the plant. Here is how we do it:

The first step is to moisten the mix until it is tacky On stage before that we can form a ball that is held). If he is not wet enough, we add water to it and brew it again with the shovel until satisfaction.

The multi-cells are then filled up to the rim and the excess soil is removed with a stick or brush. The uniform filing is important, because the less full cells dry out more quickly, which complicates watering. The soil of the cells by lifting the trays to a height of about 6 centimeters and letting them fall.

After sowing, we cover the seeds with a thin layer of dry potting soil, which will prevent them from dry too quickly in case of lack of water. At the end, the trays should be filled to 5/6 of their capacity, to save free space for water retention.

Finally, the last step is to properly arrange the trays sown in the nursery. It is therefore important to group those who have the same number of cells, to promote uniform watering.

The seedling chamber

Certain crops such as tomatoes, leeks, onions, or other vegetables that we want to produce early must be started as soon as spring arrives to be harvested early in the season. Since heating a greenhouse for a period of the very cold month involves heating costs considerably, it is better to start seedlings inside the house in a place already heated where you can handle potting soil, water and spread out on multi-cell trays. Such space is commonly called a "room to seedlings ”and there are several ways to create them a. Here are the main factors to consider counts when planning:

The main purpose of a seedbed is to manage perfectly the parameter's growth. The average temperature to aim for plant growth is 18 ° C to 23 ° C during the day and 18 ° C at night. In our room at seedlings, it is electric baseboard heaters that maintain the desired temperature, but other heating systems are also good, provided that the heat is not diffused directly on the seedlings. The relative humidity in this room should be between 60% and 90%, which a simple system mist controlled by a timer (e.g .: 10 seconds / 20 minutes) allows easily. The Seedling chamber should be covered with polythene to allow heat and humidity to stay there. Adding a small fan will prevent the formation of stagnant air, favorable to the development of fungal diseases.

As the photoperiod in March and April is too short for optimal growth plants, it is necessary to provide additional lighting which will allow the seedlings to receive 14 to 16 hours of light per day. To achieve this, several solutions are possible, but the most simple and economical is to install fluorescent tubes above the trays. Furthermore, you will need to equip yourself with a Cool White fluorescent and a fluorescent Warm White (red waves for bathrooms) to offer a light spectrum complete to plants. To prevent seedlings do not wilt, the height of the tubes should be adjustable and placed about 10 centimeters from the head plants that grow.

Finally, to ensure better lifting of seeds (most vegetables require emergence temperature higher than that of growth), you can equip your sowing chamber with mat heaters that are plugged into a 110-volt outlet. With these mats, the floor temperature is maintained day and night at optimum germination heat (about 25 ° C). Contrary to popular belief, seedlings do not benefit from the dark to germinate better. On the other hand, soil moisture is essential and this is the reason why, in addition to watering them frequently, we cover our trays with a small piece of floating blanket.


A seed chamber is ideal for starting a small part of its domestic production, but when it grows and other seedlings add to the load, you have to move to a larger space. For the needs of a garden market gardener, setting up an outdoor greenhouse dedicated to the production of transplants is essential. This implies significant investments in terms of infrastructure and heating and ventilation.

When we planned the nursery for Jardins de la Grelinette, it was obvious that it was more advantageous to install it temporarily in a greenhouse housing crops during the season rather than permanently in another greenhouse erected only for the production of transplants. Like we don't need a nursery that on a seasonal basis, we were indeed judging that it was better to preserve the versatility of our installation. In addition, the optimal heating required for the growth of transplants can be used to grow early crops in the ground. This way of doing things roughly meets these two objectives.

At the end of winter, we establish the nursery in our large tomato greenhouse that we divide in half with a piece of polythene. This film is fixed to the greenhouse poles using clamps and move easily to allow us to expand heated space as our seedling production increases. As we will only use part of the greenhouse for the total needs from the nursery, the remaining space is sown with mesclun, radishes, and other early vegetables we want to harvest for our first market. The layout of the nursery takes, at most, half a day's work: this consists of spreading a ground-cover geotextile (to prevent weeds do not take root) before installing tables at removable seedlings.

During the spring, when temperatures outside heat up and part of the seedlings interiors are transplanted into our tunnels and under shelters in the gardens, we are redeveloping the nursery to reserve a section for tomatoes ready to continue growing in the ground. The polythene is then removed and the greenhouse heats tomatoes, transplants, and early vegetables. When the dangers of ground frost have passed, the nursery is moved outside. In our climate, this is usually produced in late May or early June. Shortly after, the early crops are harvested and the rest of the tomato plants are quickly planted on the ground over the entire space of the greenhouse.

All of this involves a lot of manipulation and requires some planning, but Ultimately, this scalable way of operating the nursery allows us to make optimal use of and multiple of the heated pace. Considering the price of fuels, such a puzzle is well worth it.