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  • Writer's pictureJulia Watson

Growing from Seed - Part 2

We plant many of our seedlings in the parking strip in front of our house.


Are you ready? Do you have your seeds and seed trays? Did you remember to wet your soil mix so that it’s not dry and flyaway? OK then, let’s start by assembling those things in your workspace, and as long as you’re up, please go get a marker and some kind of labeling material, like painter’s tape, Popsicle sticks or small plastic garden markers.

If you’re a beginner, I strongly recommend using a standard 72-cell seed starting tray. These are available at most nurseries, and they have three parts: a bottom tray to hold excess water, the seed cells (usually in 4 separate parts) and a clear plastic lid. Take everything apart and start by filling the seed cells with your damp soil mix. Pack it into the cells, poking it down gently so you don’t have huge air gaps but not so much that the soil is solid. When all the cells are filled, get your labeling system ready – that can be a piece of tape on each row, a Popsicle stick stuck into the last cell of a row, or a garden marker in every row or the whole tray. Whatever your label type, mark it with the seed name and date of seeding.

Now open up those seed packets. Notice how different each plant’s seeds are. Zinnia seeds are long and dark; cosmo seeds look similar. Sunflower seeds are familiar to all of us, as are beans. In the last post I gave you a list of easy seeds, and none of them look very strange, but there are flowers that make different kinds of seeds. Poppies and snapdragons make seeds as tiny as grains of sand; nasturtium seeds are large and wrinkled.

The package will tell you the recommended depth for that seed. Add seeds to each cell and cover to whatever depth is recommended for that flower. It’s never much, and some seeds shouldn’t be covered at all – simply pressed into the soil surface.

Put the seed cells into the bottom tray, then add water to the bottom tray. Water will be drawn up into the seed cells since they have drainage holes at the bottom. This method of bottom watering is best for seed starting, and during the entire process you’ll be repeating this step as needed, adding water to the bottom tray instead of watering from the top.

Start Growing!

When your tray had been seeded and watered, place the clear cover on it and put it under the lights. I said in the previous post that you need lights on a timer, hung about 4-6” above your seed trays. We use a schedule of 12 hours on, 12 hours off for all the seeds we grow. There are MANY videos on the internet about how to set up lights and timers, so I won’t cover that subject except to say this: don’t believe anyone who says you need expensive lights with special wavelengths. Home Depot or Lowe’s shop lights are just fine, so keep it simple.

There’s one more thing that’s helpful but not absolutely needed, and that’s a heat mat. Some growers always use one to get seeds started. It does speed up germination, but you’ll need to watch that it doesn’t raise the overall temp in your growing tray over 75 – 80 degrees F.


Now you wait. Seeds can take up to 2 weeks to germinate in cool weather. Even after years of growing flowers, it’s still exciting to me to see green specks emerging from the soil! The first set of leaves you see are cotyledons and they won’t look like the plant’s mature leaves. The second leaves are called true leaves and they are a sign that your seedlings are off to a good start. When about half the seed cells have germinated, remove the clear cover and the heat mat (if you’re using one). Mold and fungi can start growing if you leave it on.

Now there’s more waiting, but also keep watch on watering. Don’t let the soil get waterlogged or dried out – you want it evenly moist. As the seedlings grow, you might need to re-position the lights to keep them 4 – 6” below the lights. If your seeds haven’t germinated after two and a half weeks, there’s something wrong and you’ll need to start over. But don’t be too discouraged – all gardeners have seed-starting failures at some point.

Hardening Off and Planting Outside

These are the last steps in seed starting. Hardening off means getting the baby plants used to being outdoors. You place the trays of seedlings outside during the day then bring them back inside during the night. If you’re having a snowstorm, driving rain or hail, then of course you won’t put your babies out, but other than that, let them get used to being outdoors. Do this for three days before planting outside.

Planting day is exciting, but just like sending children off to kindergarten, it can make you nervous. I’ve been growing for years and I still sometimes have worries about my seedlings, but I’ve learned that most plants are tough. I use a very small putty knife to plant seedlings – it’s straight and flat and works perfectly for getting the little plants out of their cells. Make a small hole in the outside bed and tuck in your seedling. Press it into the soil lightly, then go on to the next seedling. When the whole row or bed is planted, water them in well. At this step you want the soil to be very wet. Watch the soil moisture as the seedlings grow – add water if needed but don’t let them get waterlogged. One last thing on planting day - add Sluggo and bird netting after planting if you have snails or squirrels. When all seedlings have been planted and soaked with water, you’re done. Pat yourself on the back for a milestone in your gardening career!

Zinnias grown from seed

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