Vegetable seedlings indoors and under cover
Depending on the season and the heat requirements of each species, you should sow indoors (in boxes, terrines, or pots), under cover (under a frame, in a tunnel), or outdoors. Discover our tips for successful sowing under cover or indoors.
Some delicate species require a lot of heat to germinate well, and the seedlings cannot tolerate even the slightest frost. Therefore, sowing is carried out indoors, in a warm, well-lit room:
- in terrines or boxes for eggplants, tomatoes
- in pots for all fruit vegetables (eggplants, cucumbers, gherkins, zucchini, melons, watermelons, tomatoes, etc.).
In the South West and the South, it is possible to sow these species directly in the ground provided you wait until the soil is sufficiently warm.
Potted seedlings allow you to raise plants individually and transplant them well-rooted, with their root ball. Some biodegradable pots allow for direct transplanting with the pot, which will degrade in the soil.
Using a soil press can also be a good, economical alternative. The soil press allows you to create small clumps of seedling soil in which you place your seeds, no need for pots. Place the clumps on a tray with a base of water. You can plant the clumps directly in the ground, no more stress for the young root system of your plants.
For all small seeds it is better to choose the 17 mm clod press, it will allow the early start of crops on a small surface, ideal for vegetables to be transplanted several times (celery, cabbage, etc.). The mini-clods can be transplanted after 2-4 weeks into larger clods (50 mm) or in a pot.
For other seeds (tomatoes, eggplants, beans, etc.) it is better to use the 50 mm clod press.
Successful indoor sowing
- Get some seed compost which will be ideal for the development of your seedlings because it is very fine.
- Fill your boxes, terrines or pots with this potting soil then pack it down by hand, leaving a small space to sow your seeds.
Spread the seeds evenly over the surface and cover with a few millimeters of seed compost. Place 2 to 5 seeds per pot. 2 if the seeds are large; 3 to 5 if they are small (tomato, basil, eggplant, pepper).
Water your pots gently without soaking the soil.
Place your pots in a mini greenhouse and close the lid. Place the greenhouse on a windowsill in a bright location, ideally near a heater to facilitate germination.
It is also possible to cover the terrine with stretchable plastic film or a glass plate while the seedlings emerge.
Tip: To avoid sowing too densely, you can mix your small seeds with fine sand.
When the young plants are well grown, it is advisable to transplant them into pots before finally planting them in the ground.
Be careful, if your young seedlings stretch and soften, it is a sign of a lack of light. So place your pots closer to a light source.
To strengthen them before planting, you can dilute plant purines (special seed or nettle, for example) in the watering water. Spray your young seedlings every 10 days.
Successful sowing outdoors under cover (frame, tunnel)
It is possible to sow a large number of species early (beetroot, carrot, celery, cabbage, lettuce, turnip, pine nuts, peas, radishes, tomatoes, etc.), provided that they are well protected from the cold and that varieties suitable for early crops are chosen.
The frame is the most classic system. It consists of a box (wood, metal, brick) covered with a transparent plate (glass or plastic) that can be easily lifted (for ventilation and watering). It can also be used for transplanting plants grown in tubs or pots. It is a way to gradually harden them to outdoor conditions.
- Sow from the end of February in fine seed compost, without too much organic matter to avoid the risk of seedling burns and water without soaking the soil.
- Draw small furrows in the potting soil and place your seeds, cover with a few millimeters of seed compost, press down and water.
- When the weather is nice, open the window.
- If the nights are very cold you can cover your frame with a winter veil.
- Transplant the young plants into the ground in your garden when they are well developed.
The plastic tunnel is also used to protect seedlings and seedlings from the cold. It is less effective than the frame but easier to use because it can be installed over existing seedlings or in a designated area for seedlings in a nursery.
As with the frame, it is possible to lift the plastic film on one side to allow ventilation, prevent the development of rot and possible "heat strokes" on sunny days.
Well-protected seedlings: plasticulture
This technique, commonly used in market gardening, helps protect seedlings, speed up crops and thus enable vegetables to be harvested earlier.
It involves spreading a plastic film over the soil and seedlings to promote seed germination and plant growth. This film also serves as protection against insects and heavy rain.
