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How to Start Seeds

How to Start Seeds

Orange Flesh Tendersweet Watermelon, Chocolate Stripes Tomato, German Butterball Potato… Do these sound good or what?  These varieties and thousands of others can only be found in seed catalogs.  If you want to grow the most delicious fruits and veggies imaginable, seed starting is the way to go.  You’ll be amazed and delighted by the range of plants available.  I order most of my seeds from Baker Creek Heirloom Seeds and reviewed my 3 favorite seed catalogs here:  If you’re ready to take the plunge, here are some guidelines to help get you started.  It’s a straight forward process and you’ll be well rewarded in the end!

How to Start Seeds Indoors

Starting seeds indoors gives you a head start on the growing season.  This is particularly helpful for short growing seasons and for seeds that are difficult to grow.  The best plants to start indoors are those that can handle root disturbance and that benefit from a prolonged growing season.  Some common examples include broccoli, cabbage, eggplant, onions, peppers and tomatoes.  However, not all plants like to be transplanted.  Most root vegetables and some others such as beans and peas are best planted directly in the garden.  Refer to your seed packet for growing instructions and google your specific plant for additional information.


  • Lots of containers make a good choice for seed starting.  I like plastic seedling flats because they’re easy to find, flexible and inexpensive.
  • Other options include peat pots, styrofoam or wooden flats.  Just make sure that they’re at least 2-3 inches deep and that they have drainage holes.

Soil/Growing Medium

  • Some people advocate for soil-less seed starting (usually a mix of vermiculite and peat moss) because it reduces the likelihood of insects and disease.  However soil-less mixtures contain very few nutrients and require fertilizer after your plants germinate.
  • I prefer starting my seeds in the same soil I use in the garden: 1 part vermiculite, 1 part peat moss and 1 part compost.  I already have it on hand for my garden, the compost eliminates the need for fertilizer and I haven’t had any issues with insects or disease.


  • Germination location: Seeds don’t need light until they sprout, so their germination location can be different from their growing location.  This is important because germinating seeds usually require higher temperatures than the seedlings themselves.  Most germinating seeds like temperatures in the mid to upper 70’s.  Most seeds will eventually sprout in cooler temperatures but they’ll take significantly longer.  I plant my seeds in little seedling flats, give them a good spritz of water and slip the entire tray into a large ziploc bag.  I put the bag someplace warm like our bedroom or above the refrigerator until the seeds sprout.
  • Growing location: Once your seeds germinate they’ll need a strong light source.  If you have a very sunny, south facing window (at least 8 hours of sunlight/day) that will do the trick.  Otherwise you’ll need to buy or make a cool spectrum grow light to provide adequate light for your seedlings.  You can find these online and at many gardening/home improvement stores but it will run you about $100.  Alternately you can make your own for a fraction of the cost.  Here are instructions for the grow light we made this year for just $30:  In this phase most seeds prefer temperatures in the sixties, although they can usually tolerate from from about 50-75 degrees.

Planting Dates

  • Planting timelines are based on frost dates so first you’ll need to determine the last frost date for your area.  Here’s a nifty site that lets you look up frost dates by zip code:
  • Next refer to your seed packet for the recommended seed starting time – it’s usually listed as a specific number of weeks before or after the last frost.  Apply this guideline to the last frost date in your area to determine your specific planting dates.  Some plants benefit from a month or more indoors while others get root bound after only a couple weeks and need to be transplanted quickly.  Refer to your seed packet and do a google search for additional information.
  • I make an Excel spreadsheet to organize my seed starting dates.  The spreadsheet includes the name of the plant, the indoor seed starting date and the outdoor transplanting date.  Then I sort  it  by date to make sure I stay on track.


  • Fill your containers in layers and spray each layer with water to make sure it’s moist throughout.  Fill the containers nearly full – within 1/4 inch or so of the top.
  • A rule of thumb is to plant seeds twice as deep as the seed itself.  Small seeds can be sown right on the surface of the soil with a very fine layer of soil spread on top.   If you’re using high quality seeds, you’ll only need to plant a couple seeds per cell because  a high percentage of them will sprout.  If the seeds are big I usually plant 1 or 2 per cell.  If they’re small, I plant a small pinch of around 3 seeds.  Refer to the instructions on your seed packet for any additional instructions.
  • After you’ve planted your seeds give them a gentle spraying or dribble of water to embed the seeds in the soil.  Place the tray in a Ziploc bag, labeled with the plant name(s) and date planted.  During the germination phase seeds don’t need light but they do need warmth.  Place them somewhere warm (ideally around 75 degrees) and check on them every day or so to see if they’ve sprouted.
  • When you see sprouts, take the tray out of the bag and place under your grow light.  Most seedlings do best 60-70 degree temperatures.  Make sure you don’t got below 50 or above 75.  Place your seedlings 2-3 inches from the light source and keep the light on for 14-16 hours a day.  If your seedlings start to look tall and leggy, they probably aren’t getting enough light – move them closer to the light source or keep the light on a little longer.

Care Instructions

  • Watering: Maintain moist, but not wet soil.  I gently water my seedlings every morning (as needed) and let the soil dry slightly in between waterings.  When they’re really little I water with a spray bottle but that gets annoying so I switch to a small watering can after a couple weeks.
  • Thinning: If too many seedlings sprout, you’ll need to thin them out.  You don’t want their roots interfering with each other, so thin each cell to 1 or maybe 2 seedlings.  Wait until the soil is relatively dry then grasp the plants by their leaves and gently pull/wiggle out.  If you’re careful not to crush the stem, they can often be repotted successfully – just plant them in a new cell a tiny bit deeper than they were previously growing.
  • Hardening Off: A week or so before you transplant outdoors begin introducing your seedlings to the great outdoors.  Start them off easy by bringing them outside for an hour or so on a nice day and placing them somewhere sheltered like a porch.  Gradually increase the amount of time outside and the amount of exposure they get.  Usually by day three they can be out for 1/2 a day and by the end of the week they can be out for the whole day.  But avoid extremes of heat, cold and wind.
  • Fertilizing: I use a high quality compost made from dozens of ingredients which eliminates the need for fertilizer.  However, I do occasionally apply some all natural additives for an extra level of insurance.  Once the seedling are a few weeks old I give them a half strength dose of kelp extract and/or fish emulsion and repeat every 2-4 weeks.  If you use good compost this step is totally optional.


  • The best days to transplant are cloudy and overcast.  Drizzle or light rain are also good.  Avoid days that are overly hot, cold or windy.  Wait until the late afternoon so that your seedlings have some time to recover before being exposed to the midday sun.
  • Water  your garden soil that morning so that it is moist throughout but doesn’t have any sitting water.  Use your hands or shovel to loosen any soil that is compacted.
  • Dig your holes slightly larger and deeper than the size of the root balls (about twice as deep if you’re planting tomatoes).
  • Unpot each seedling by turning the pot upside down and slipping it out into your hand.  If the seedling is stuck or if you’re working with attached cells that can’t be turned upside down, use a spoon to gently scoop out the entire root ball. It’s okay if you have to rip some small roots, especially if they’ve become root bound.  Just keep it as intact as you can and avoid pulling the plant by its stem.
  • Place your seedling in the hole, fill in any gaps with soil and tamp down the surrounding soil gently but firmly.
  • Water each seedling well and make sure they stay moist until they are well established (usually 1-2 weeks).

Photo Credit: Seed Fingers , a photo by furtwangl on Flickr.

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