From Seeds to Garden Transplants – Part 2 of 5

by David Marshall – Halton Master Gardener

Last month I wrote about preparing your grow light set up for starting seeds indoors, and this month we will discuss planting your seeds and caring for them up to the planting in the garden time.

First, you’ll need your supplies. They can be found at seed houses like William Dam, nurseries, hardware stores, and even dollar stores.

  • a bag of soil-less seeding and potting mix (a mixture of peat moss, vermiculite and perlite)
  • seed flats (10 inch by 20 inch, as many as you need for your light set up)
  • cell packs (3” x 5”, 12 per flat)
  • transparent cover for seed flats (to retain moisture until the seeds germinate)
  • a spray bottle for misting the young seedlings.
  • a timer set to 16 hours.
  • a transplant tool to move the seedlings for ‘growing on’, four to a pack. I use a tongue depressor sharpened to ¼ inch wide at one end, or you can use a popsicle stick or a teaspoon handle.
  • a balanced soluble general purpose fertilizer.
  • flower or vegetable seeds of your choice.
  • cell packs for transplanting (4 cells to a pack, enough to fill your 10” x 20” flat)
Starter seed flat with transparent moisture retention lid.

Many vegetable seeds are sown directly in the garden, but the following are best started indoors:

  • Broccoli, cabbage, cauliflower, Brussel sprouts, cucumbers, squash, zucchini, leeks, tomatoes, peppers, and beans (optional for an earlier crop) and onions if grown from seed

Seeds can vary in size from like dust, to as big as coconuts and can take from two days to two years to germinate (but usually only two to three weeks) and seed packs can contain anything from five to five hundred, so study the back of the pack before you buy. If you are starting out with just a two-flat set up you will end up with about a hundred finished plants so you can probably grow as many vegetable plants as you wish. If you’re growing flowers, however, decide how many of each variety you actually want and buy your seeds accordingly. Some seeds need light to germinate, some need darkness, but most don’t care. Be guided by the instructions on the seed packet and observe the seed coverage stated. Do not cover fine seeds too deeply because they often do not have sufficient vigour to push up through heavy cover.


Let’s get started:

  • Soil-less mixes are hard to wet initially, so put some in a large container, add water and stir it around until it is evenly moist, but not overly wet. Let it stand for a couple of hours until the water is absorbed and stir again, adding more water if necessary.
  • Fill the cell packs to the rim and press the mix down about 3/8 inch with the bottom of a cell pack.
  • Sprinkle the seed evenly onto the surface. A good way is to put the seed onto a folded piece of paper and hold it over the cell pack, tapping the paper gently and moving it around so that the seeds fall off individually. If the seed is very fine, mix it with a bit of sugar.
  • Cover the seed to the specified depth and press the mix down gently. If the seeds don’t need to be covered with soil (again, refer to package instructions), just press the seed into the mix.
  • Water the pack gently and place under the lights with the transparent cover.
Wet the soil-less mix such that
it forms a bit of a ball when
you squeeze it but still
crumbles when you let go.

Different varieties germinate and grow at different rates so you cannot plant everything at once. Work back from your local first frost free date and add the longest time shown on the seed packet — they are always a bit optimistic! Mist the seeds if the surface dries out. Once the seedlings grow a bit, you may have to water from the bottom to avoid flattening them. Place the packs in about half an inch of tepid water until it absorbs and feels heavy – 5 to 10 minutes. The soil-less mix has an initial charge of fertilizer but about two weeks after germination, start fertilizing with a general purpose soluble fertilizer at one-quarter of the recommended strength, weekly.

When the seedlings are about an inch tall and can be handled, they are ready to be transplanted four to a cell pack. Use your transplanting tool to gently loosen a group of seedlings, make a hole in the new cell pack and lifting a seedling by a leaf – never the stem — drop it into the hole and firm the mix around it. As the seedlings get larger, increase to half strength, fertilizer weekly. Now you need to care for them patiently until it is time to move them out and prepare them for planting in the garden. We’ll deal with that next month!

Contact me if you have any questions. It is easier to do than to describe. David Marshall

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