How to sow in a seed tray?

Sowing in seed trays is a simple and inexpensive technique that allows you to both get a head start in your vegetable garden and multiply your favourite seedlings in large numbers at minimal cost. Here is a step-by-step guide to ensure successful sowing in seed trays.

When to sow in seed trays?

Sowing in seed trays generally takes place from mid-January until early April. After this period, temperatures will be warm enough to sow directly in your greenhouse without this additional protection.

Essential equipment

You will need to gather (apart from the container and its light-permeable lid):

• Homemade or high-quality seed compost
• Gravel or other drainage material to place at the bottom of the tray
• A sieve
• A rigid board to firm down your compost
• A watering can with a fine rose, a spray bottle or a saucer to soak your compost
• Seeds

How to sow in seed trays?

• Start by placing a layer of gravel or broken terracotta at the bottom of your container. This layer prevents waterlogging which could rot your seeds.
• Fill your tray with compost, leaving a few millimetres from the rim.
• Level and lightly firm the compost using a wooden board. Your seedbed is now ready for sowing.
• Sow in rows or broadcast depending on the space available (don't forget to label to avoid confusion!). As seeds sown in trays are very fine, take care not to bury them too deeply as they may struggle to emerge from the compost.

• Use a sieve to lightly dust your seeds with fine compost. The aim is to "hide" the seeds without burying them. Some gardeners simply use a thin layer of vermiculite.
• Smooth the surface again and water with a spray bottle to keep the seeds evenly distributed.

• Place your tray in a living space with temperatures around 20°C and good light. Avoid direct sunlight on your tray as temperatures could rise to 60°C or more, destroying your seeds or young seedlings!

• As soon as your seedlings emerge, place them in bright light (but not direct sunlight) and remove the lid.

Note: Due to the high density of seedlings in this propagation method, pricking out will be necessary very quickly at the cotyledon stage (seed leaves) using a pencil or smooth stick. This will allow you to lift the entire root system and avoid stressing your plants when transplanting into individual containers.