How to plant seeds in punnets

Oct 1, 2020 | Gardening tips, Planting guides

  • Use seed raising mix if possible. Seed raising mix does not contain nutrients, is finer than other soils, and is designed specifically for seed raising.
  • If you cannot access seed raising mix, use potting mix.
  • Do not use garden soil as it compacts around the seed.
  • Fill punnets 3/4 full with soil then firm it down with your knuckles, water, sprinkle seed onto the damp firm bed, cover with 1cm soil, and water again.
  • Keep punnet damp to prevent small seeds drying out. Use a fine spray from a spray bottle.
  • Water gently with a watering can once the seed has germinated.
  • Avoid heavy watering or a strong spray as this washes the seeds out of the punnets. The soil surface should remain undisturbed.
  • For pumpkin seeds and other large flat seeds, insert them vertically rather than horizontally (flat) to prevent water pooling on their surfaces and causing them to rot.
  • If using old punnets, scrub them out, rinse, then soak for one hour in 90% water 10% vinegar (any kind) to kill pathogens from the old soil. This prevents ‘damping off’ fungal disease which will kill seedlings.
  • When seedlings have four leaves, prick them out and plant them in seed trays in potting mix until big enough to plant in the garden. Generally you can fit 20 seedlings in a seed tray. Potting mix contains the nutrients that seedlings need to thrive.
Written by Robin Gale-Baker.