Seed Starting – Tips and Techniques (Part III)

Some of my starts after seven days

It’s been a week since I’ve written about seed starting basics and hopefully you’ve enjoyed some successful growing endeavors and seeds have begun to sprout!  If so, you probably noticed some seeds germinating in a few days while others taking a week or more.  What to do when seedlings have emerged?  In this post I’ll share some tips about what to do at this point.  In fact, you’re in the home stretch…

First thing is to remove the plastic or plastic dome you covered the seeds with when first setting them in the growing station.   Do this once a good amount of seedlings have emerged, usually 7-10 days after planting. Remember once the plastic has been removed the humidity controlled environment is also gone.  So now maintaining consistent moisture will be up to you. Don’t fret about this, just be mindful and check seedlings a couple of times a day and water accordingly. Bottom watering (pouring water into the tray holding your containers) works well at this point but remember to barely fill the bottom of the tray. Do not allow the seeds to sit in water so the soil is soggy.  If you get too much water in the tray, wait 15 minutes and whatever is not absorbed get rid of.  Too much moisture will create fungus.

I also like to mist seedlings with the spray bottle by lightly spraying them from above.  It is best to mist from above so the young plants do not get knocked over from a strong side spray. Keep the seedlings in the growing station when not watering and run the lights 12-16 hours everyday.  Keep the soil heat mat on as well to a maintain a constant soil temperature around 60-70.

First Leaves:  The first two leaves that appear as your seedlings sprout will typically be round in shape and are not considered true leaves. They are called cotyledons and are the result of the seed germination process.  The next set of leaves to appear are true leaves and it is a good idea to do any thinning that may be required before or right after the first true leaves appear.

Thinning: If you have several seeds that have popped up  in one small container you must thin them.  As hard as it is to destroy something you just put so much time and care into creating… you must do it. To start, select the strongest seedling (or two if you must) to be the primary inhabitant of the container/cell.  For all of the rest take scissors and simply snip them at the soil line.  Use this technique instead of trying to pull the young seedlings from the container because it will not disturb the soil line or tender roots of the seedling you have chosen to keep.

Fertilizing:  You can begin fertilizing now.  Use an organic, water-soluble fertilizer diluted to half-strength once a week. Seedlings need to develop strong roots therefore picking a fertilizer that is high in phosphate works best.  When looking at fertilizer options note that the middle number represents the amount of available phosphate.  One popular well-known choice is fish emulsion.  It has the right amount of phosphate and nitrogen giving your seedlings everything they need.  I mix the recommended amount (divided in half, 50% strength)  into my spray bottle and use it to mist from above and bottom water once a week.  For all other watering I use plain water.

Special Note: This year I really wanted to try a mixture recommended by Willi Galloway of of half fish emulsion and half liquid seaweed as my dilute fertilizer but I was not able to find liquid seaweed in my area.  If you come across liquid seaweed give it a try along with the fish emulsion.

Growing: Time to be patient, yet attentive and let the seedlings grow.  As they grow, move the lights up (or lower seed tray) so the tops of the plants are just 1-2 inches from the lights.  This helps the plants grow strong instead of long.  You do not want them to “stretch” to the light.  Now is a good time to place a small fan nearby for air circulation and to strengthen the stems.  Set the fan near the seedlings so a gentle breeze is moving over them.  Remember, not too strong or it could knock them over. Continue bottom watering daily, checking soil moisture and fertilizing every other week.  This should be the routine for the next 3-4 weeks.

Transplanting or Potting-up: Assuming your seedlings have grown beautifully, it is time to transplant or ‘pot-up’ during the fifth/sixth week.  If you are going to transplant directly outside you will want to go through the “hardening off” process (explained below) first.  If it is still too early to plant outside find a slightly larger container (usually around 4 inches) to ‘pot-up’ the seedlings.  To start, fill the slightly larger container with moist seed starting mix.  Use a pencil to make a medium size hole in the center of the pot.

If the seedling is in a plastic pot/cell loosen the soil by gently pressing on the sides of the container.  Now simply lift the seedling BY ITS LEAVES, NOT THE FRAGILE STEM and gently remove it from the original container. Next, place it in the new hole and push soil around the stem.  Water gently.  It is important to remember to handle seedlings by their leaves not stems.  The stems are very fragile and if they break your plant is gone!

If your seedlings are in peat containers carefully remove the sides of the peat container by gently tearing it away from the seedling.  Now same as before, place the seedling into the new hole, push soil around the stem and water gently.  Seedlings will not grow through peat containers quickly and they could become rootbound so that is why it is important to remove the sides of the peat container.  This lets the young roots grow into the new soil.

Special Note: If some of the seedlings are a little “leggy” you can try placing them slightly deeper in the new container and then pushing a bit more soil around the stems to give them more support.

Hardening Off: Once the soil has warmed and the temps are adequate and semi-stable prepare your plants to move outside.  This is called “hardening off” and is a method for slowly exposing indoor plants to the outdoors. Start by moving the plants to a shaded, wind-protected area for a few hours during the day but bringing them inside at night.  Slowly, over the next few days increase their exposure to sun, wind/breeze but keep bringing them inside at night.  After about a week leave the seedlings outside at night (not if temps are going to drop significantly) and now they are ready to plant in your garden.

Whew! You’ve done it and should have some beautiful fruits of your labor! Enjoy!

Check out some updated photos of my seedlings here.  They are either being “hardened off” or “potted up” at this time which is week five of seed starting.