How to sow in a seed tray?

Sowing in a seed tray is a simple and inexpensive technique that allows you to both get a head start on your vegetable garden season and multiply your favourite seedlings in large numbers at minimal cost. Here, step by step, are the stages to ensure successful sowing in a seed tray.

When to sow in a seed tray?

Sowing in seed trays generally spreads from mid-January until early April. After this, temperatures will become high enough to sow directly in your greenhouse without this additional protection.

Essential equipment

You will need to acquire (aside from the container and its light-permitting lid):

• Homemade or special sowing compost of very high quality
• 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 with water
• Seeds

How to sow in a seed tray?

• Start by placing a layer of gravel or broken terracotta at the bottom of your container. This layer prevents water stagnation which could cause your seeds to rot.
• Fill your tray with compost to a few mm from the edge of your container.
• Level and lightly firm the compost using a wooden board. Your seedbed is now ready to receive your seeds.
• 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 as they may struggle to emerge from your growing medium.

• Use a sieve and lightly dust your seeds with fine compost. You should essentially "hide" them with compost without burying them. Some gardeners simply use a thin layer of vermiculite.
• Level again and water using a spray bottle so the seeds remain evenly distributed.

• Place your seed tray in a living area at around 20°C with good light. However, avoid direct sunlight on your tray as temperatures could rise to 60°C or more and destroy your seeds or young plants!

• As soon as your seedlings emerge, place them in full light (but without direct sunlight) and remove the lid.

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