February and March is usually the time when people start their spring seedlings indoors. This way the plant seeds can sprout in warmer conditions and get a good start on life before being planted outside in the balcony container garden. About a month after starting your container plant seeds, they will be ready for planting.
You don’t need to purchase a seed-starting kit to start your plant seeds indoors – you can use an egg carton with drainage holes punched in the bottom (place the carton on a tray, plastic bag, etc., to catch any excess water).
It is not necessary to start all plant seeds indoors. You can toss some seeds directly into the container garden, and they will flourish. For example, wildflowers, sunflowers, poppies, columbine and other flowers do fine when planted directly into the container garden (at the correct time of year, of course). Some flowers that you should start indoors include petunias, marigolds, snapdragons, coleus, zinnias, etc. Some vegetables, such as tomatoes, peppers, lettuce and broccoli, will also do well if their seeds are started indoors.
Because each plant differs, research each individual container plant to find out how to plant them. If you’ve purchased seed packets from your local garden shop, you will find most of this information on the back of the packet. The seed packets should tell you when to plant, planting depth, germination time and spacing, but unfortunately not all packets will include this information. You may also need to warm, cool or soak the seeds before planting them in potting soil. Some seeds require some time in the fridge, and others need to be placed on a heating pad before they can sprout.
Before sowing the seeds, make sure your seeds are fresh (those that are more than a year old or those that have been kept in inappropriate conditions may not sprout). One planting technique is to wet a paper towel, fold it up and place it inside a Ziploc bag. Place 10 seeds or so on the paper towel and wait until they germinate. You can then plant the sprouted seeds in the seed-starting tray and not waste any space for seeds that will never sprout.
Sow seeds in a clean, well-drained plant container filled with seed-starting mix. Potting soil from the garden can be used, but it may introduce weeds or garden pest insects (sterilize dirt by baking it for two hours at 180 degrees). It is especially important to purchase new potting soil or sterilize old soil if you have had an outbreak of disease or fungus in earlier seasons. Make sure the potting soil reaches the top of the container, which will allow for airflow once the seeds sprout. Keep seeds evenly and continuously moist until the seeds germinate, then water normally (use warm or room-temperature water and not cold water). Keep lights about a foot above the seeds or keep the tray by a southern-facing window. If you are not using supplemental lighting in this indoor garden setup, rotate the tray so seedlings don’t grow in one direction toward the sunlight. Good air circulation and temperatures at about 65 to 72 degrees Fahrenheit will help the plant seeds sprout and stay healthy.
If needed, transplant the seedlings into individual plant containers once they’ve gotten several sets of their “true leaves,” (true leaves are leaves that will photosynthesize and that are more characteristic of the plant). Keep the plants inside, then plant them in the container garden after the last frost.
Starting seeds indoors gives your outdoor container garden a jump-start and allows you to enjoy your plants longer than if they are planted later in the season.