How To Sow Seeds Using A Seedling Flat


Seedlings growing in seedling flats

Seedling flats or trays are a fabulous way to germinate seeds, grow healthy seedlings (without single-use plastic pots or punnets), and to use for succession planting to extend the harvest. They allow your plants to start out and thrive in a protected, nutritious, and microbe-rich soil to produce strong seedlings that are more likely to succeed.

A range of different seed types can be sown into the one flat. Ideally you plant what you want to grow for the season in one or as many flats as you need.

Flats allow you to easily move your seeds into environments that are not too cold or hot as conditions change and in sight to ensure they are kept moist.

The seedlings will not fully mature in the seedling flat - they are a tool for nurturing young seedlings to a size ready for plant out into garden beds or containers.


Seed Sowing Method

Seedling flats with popstick markers for seeds Sowing seeds into seedling flat   
  1. Make a list of the seeds you have and want to grow for the season.
  2. Write the name of each seed you are going to sow on a label eg. a pop stick or plant label.
  3. Fill your seedling flat with quality seed raising soil (such as Bioactive Cocopeat) that is full of life and diverse inputs to provide plants with what they need to grow strong and fight disease and pests. It needs to be a light, well drained soil as seeds need air and moisture to germinate. 
  4. If using, place a seed template on the edge of the flat. Our seed template creates an equidistant planting guide using a hexagonal shape.  It is not a necessity and you can ensure each seedling will have enough space by eye or other measuring methods.
  5. Place the labels to identify the seeds being planted in each row or in each flat.
  6. Use a seed dibber or pointy object to make shallow furrows or evenly-spaced indents to the depth needed for each seed. Seed sowing depth guidelines are; fine seeds are sown on the soil surface, sow other seeds 3 x the diameter of the seed, and if oblong between 1 to 3 times the length of the seed.
  7. If using, remove the template and gently put each seed to bed by filling the furrow or hole and gently pressing down the soil surface over the seeds.
  8. Moisten the soil with a misting nozzle or misting bottle - a bottle top sprinkler is a great, cheap, easy tool. Germinating seeds need constant moisture and will not germinate if they dry out.

Preparing seedling flats for sowing seeds Using template and seed dibber to plant equally distanced seeds Seedling flat ready to sow seeds


    Succession Planting

    When seedlings have grown to a decent size (approx. 10 - 20cm) transplant the seedlings using a transplanter trowel into your garden where they will grow to maturity.

    Growing in seadling flats

    Seedling flats are a great tool for succession planting where you purposefully transplant the same type of seedling into the garden a week or so apart so that they will mature and be ready for harvesting one after the other, this reduces the glut and increases the harvesting period.


    Other Uses and Benefits

    Using wooden seedling flats to grow your garden from seeds is a zero-waste way to garden!

    It allows us to avoid buying stacks of single-use plastic punnets and pots that often head straight to landfill. It feels amazing being able to grow our gardens consciously without detriment to the Earth. The flats are also compostable at the end of their life. See our article on Reducing Plastic Waste in The Garden for more tips!

    Furthermore, flats are great to grow microgreens in, they are handy for travellers and those on the move, they will last for many years and weather gracefully.

    Our seedling flats are made locally by the Vic Park Men's Shed and Rippa Woodturning

    Wishing you lots of happy sowing success and bumper crops!! 🌻

    Leave a comment

    All blog comments are checked prior to publishing
    You have successfully subscribed!