A seed is a marvel of nature. It is composed of a hard outer shell, an embryo, and food.
As seeds age, they are less likely to germinate. Some seeds are good for one year, such as parsnip or onion. Some, such as cucumber, beets, radish, squash, tomato, or Swiss chard, and the brassica family, last for four or five years. The rest last for about three years. You can test your seeds by placing 10 on a wet paper towel. Once they sprout, count the percentage sprouted. If the percentage is 50 per cent, simply plant twice as many.
You will need potting soil, seed-starting potting soil, compost, vermiculite, pots or containers, and potting trays with clear plastic covers, all available from your local garden market. I use a mixture of sifted compost, potting soil, vermiculite, and a one-inch topping of seed starting soil. The mixture is loose, with lots of air pockets. Plants need oxygen to grow and before a plant has leaves, it must get oxygen from the soil.
In each two-by-two-inch plastic pot, plant four seeds and place them in a tray with a clear plastic cover. Set the tray set on risers over a heating vent; the heat helps the seeds to germinate or sprout. Before they germinate, keep the topsoil moist using a spritzer. Remove the clear plastic top once the plants have sprouted to avoid dampening off.
Once they have germinated and have their first true leaves, transplant all but one into two-by-two-inch pots.
Water as required, preferably from the bottom. Do not let the soil get dry, but do not overwater.
Plants need light. Seedlings grown by a window receive an inadequate amount of light and become weak and spindly. Therefore, grow lights are essential when starting seedlings indoors. The benefits include stronger stems, better health of the seedlings, and a larger yield of the transplants.
Plants are categorized into high-light plants, such as tomatoes, peppers, and perennials, and low-light plants, such as herbs and leafy greens, such as lettuce. High-light plants can absorb more light than low-light plants. The recommended distance from light bulb to plant is six inches for high-light plants and 12 inches for low-light plants.
If our weather pattern was stable in Alberta, I could definitely say when to start my seedlings, but it isn’t, so I refer to the long-range weather reports. I have found the following approximate best times for the various seedlings:
- March 1: Brussels sprouts, and annual flowers such as pansy, lobelia and petunia;
- March 15: Onions from seed. I don’t separate the onion seedlings into separate pots, but separate and plant them outside as early as possible;
- April 1: Brassicia — broccoli, cabbage, cauliflower, kale, rutabaga, and turnip;
- April 1: more of your favourite flowers.
- Your favourite herbs in six-inch pots; some will stay in the pot that you bring in in the fall, some to be transplanted into the garden.
- April 6: peppers;
- April 10-15: tomatoes;
- End of April, holly hock, and more annual flowers to replace the early ones that have started flowering.
Transplant the brassica family and onions in early May. Transplant other seedlings from the middle to the end of May when the threat of frost is over. Be prepared to cover transplanted seedlings if frost is forecast.
To adapt to outdoor conditions, harden off the seedlings. Start with a couple hours in an outdoor shaded area and gradually increase to up to a week in broad sunlight. If you don’t, they may get sunburned and their growth will be set back. Bring them in each night.
Most seedlings are exceptionally resilient. To transplant, remove them from the seedling container and quickly plop them into a well-watered hole and tamp the soil gently around the root. Water to move the soil around the roots. For peppers and tomatoes, add some bone meal and egg shells to prevent blossom-end rot.
