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How to Start Seeds Indoors

Starting your own seeds is so rewarding! Some of the benefits include getting a jump start on the season, choosing from a wider selection of varieties, filling up your garden with more plants for less money, and having your hands in the dirt in the dead of winter.


  • Seeds
  • Soilless mix
  • Plug flats and/or cell inserts
  • Trays
  • Domes
  • Labels
  • Shop-light setup
  • Liquid Seaweed and Fish Emulsion
  • Mycorrhizal Fungi Inoculant, optional
  • Fine Vermiculite, optional
  • Heat mat, optional
  • Thermostat, optional


  • Before planting, read the back of seed packet for special considerations (germination rate, depth, temperature, light, etc.).
  • Moisten soilless mix so that it's damp but not sopping wet. When you squeeze it, it should retain its shape, but not drip, and break apart easily when poked. Mix in Mycorrhizal Fungi Inoculant at this time (optional).
  • Fill plug flat or cell inserts with soilless mix. Once full, pick up and tap on the table/ground to settle the mix in. You can use something long and flat, like a wooden stake, to skim extra dirt off the top if necessary.
  • While the soilless mix settles in, add your label(s).
  • If seeds are larger, poke a hole in each cell. In general, plant seeds twice as deep as they are big. Super-small seeds can be sown right on the surface.
  • Cover with soilless mix or a dusting of fine vermiculite.
  • Fill an empty tray with water and set the plug fat or cell insert in the tray, so the cells can soak up water from the bottom. Remove once evenly moist (half hour or so).
  • Place in an empty tray and cover with a humidity dome.
  • Place tray in warm room that stays above 65F or on a heat mat with the thermostat set to 70F (or recommended temperature on seed packet).
  • Check seeds daily, opening domes to prevent too much moisture. If soilless mix dries out, repeat bottom watering.
  • Once 75% seeds have sprouted, remove dome from tray and remove tray from heat mat (if using). Place under shop lights set on a timer for 14–16 hours per day. Lights should be directly over the seedlings, just a couple inches above them. Raise the lights as the seedlings grow so they maintain this distance.
  • Check seedlings daily, they can dry out quick! Water when necessary but avoid over-watering (media should not be soggy).
  • As seedlings grow, they benefit from a boost of nutrients. According to the label instructions, add the recommended amount of fish/seaweed emulsion to your watering can, and drench seedlings.
  • Once seedlings begin to outgrow their trays, either pot them up or plant them outside (if the weather allows). Before planting outside, seedlings should be "hardened off" in order to acclimate to outdoor weather conditions and avoid transplant shock. Set trays outdoors, starting with smaller increments and increasing time as you go. Pay attention to weather conditions and keep in mind that the soilless media will dry out quicker than when inside in mild conditions.
  • Once weather allows, transplant seedlings in their final spot, watering in deeply and nurtured for the first few weeks as they establish.


While the general materials are listed above, you can grab our exact list of seed starting supplies here (it's free!).
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