Seed Starting Prep

Years ago, Seed2Need bought a case of 400 smooth sided, sturdy 4” pots that we use for seed starting. We use smooth sided rather than embossed pots because they are easier to clean. Of course, any size pot will do. Just make sure that there are plenty of holes in the bottom of the pot to provide good drainage.

seedsMaterials Needed

  1. enough plastic pots to start the number of seedlings needed.  Also plant a little extra to allow for poor germination. We use 4″ pots and plant 25 seeds per pot.
  2. plastic cafeteria trays – these are relatively inexpensive and they can be purchased from businesses that sell restaurant supplies.
  3. 1 or more grow light sets
  4. germination mix
  5. course vermiculite
  6. seed
  7. waterproof labels
  8. bamboo skewers or tweezers to position seeds in the pot
  9. small cups to hold the seed.

First, remove any loose labels, thoroughly wash the pots in soapy water and then sterilize them by soaking them in a 10% bleach solution. Drain the pots but do not wash off the bleach solution. Let the pots air dry.

Next, label your pots based on the number of pots needed of each seed variety (refer to your planting plans). I recommend using Avery 5520 waterproof labels. They are 1” x 2 5/8” and they can be printed on a computer. Waterproof labels hold up better inside the wet environment of a greenhouse and they are easier to remove when you wash the pots. Paper labels seldom come off in one piece and the paper dissolves leaving the adhesive on the pot.

Finally, fill the pots with propagation mix. Propagation mix is a lighter mix than potting soil so it drains better. Leave approximately 1/2” at the top of each pot for the seed and vermiculite.

Washing and sterilizing 400 pots and filling the posts with propagation mix is a time-consuming and back breaking task. I suggest recruiting the help of 3-4 volunteers.

Planting the Seed

  • Plant a 5×5 matrix of seed in each 4” pot. The seeds end up being about ½” apart. Do not cover the seed with propagation mix.  Instead, cover the seed with a thin layer of coarse vermiculite. Vermiculite helps keep the stems dry, it keeps the seed in place and it helps prevent damp-off disease.
  • The number of seeds planted in each pot (25) and the total number of pots should consider the number of seedlings needed and the expected germination rate. Also allow for seedlings that will be sold or donated to other projects.
  • We use an expected germination rate of 69% and also plant extra pots of seed in case they are needed. Place the pots on the cafeteria trays, water lightly and put the trays under the grow lights keeping the lights about 2”-3” above the seeds or plants.
  • Set the timer so the grow lights stay on for 8-12 hours each day. Adjust the height of the grow lights as necessary.
  • Water lightly every day.



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