How To Fill A Seed Tray

Starting seeds in a tray instead of sowing them directly into the ground has several advantages, especially for delicate or slow-growing plants. Seed trays provide a controlled environment, protecting young seedlings from harsh weather, pests, and competition with weeds. They also allow for better germination rates, as the compost in trays is finely textured and free from large debris, making it easier for seeds to sprout.

Starting in trays can also help to maximise space—you can grow many seedlings in a small area and transplant them into the garden once they are strong enough. This method is particularly useful in early spring when outdoor soil is still too cold for germination. By using seed trays, you give your plants a head start, leading to healthier, more resilient seedlings when they finally move to the garden.

Our Seed Compost Recipe

For nearly all our seed starting we opt for a peat-free multipurpose compost and mix in perlite and grit.

6 parts ‘multi-purpose’ compost

1 part perlite/grit

How to Prepare a Seed Tray for Sowing

Getting your seed tray ready properly gives your seeds the best chance to sprout and grow strong.

1. Fill the Tray with Compost

Use a good-quality seed compost mix to fill your seed tray. To remove air pockets, give the tray a gentle tap on the table or lightly press the compost down with your fingers. Be careful not to press too hard—seeds need air to germinate!

2. Level the Surface

Check for any sunken spots where air pockets may have collapsed, and top them up with compost. Then, lightly scrape your hand or a flat tool across the top to remove extra compost. This prevents overfilling and stops seeds from getting washed away when you water.

3. Even Out the Compost

Making sure the compost is evenly spread in each cell helps with consistent watering. If some areas are too compacted or too loose, seeds may not grow as well.