Starting plants from seed isn't hard, and it is so satisfying to see those tender shoots emerge from the soil! Here's a little primer to get you growing your own in no time.
Annuals and vegetables are the easiest to grow. Some perennials can be grown from seed, but it is a little harder to get the seeds to germinate, and it can take a couple of years for the plants to reach flowering size.
You'll have better success starting some plants from seed directly in your garden. This may be because the seeds germinate quickly, so they don't need a head start indoors, or because the seedlings don't transplant well. Zinnias are an example of a plant that doesn't like to be disturbed once seeds have germinated. It may take Zinnias longer to get going in your garden, but you'll have much stronger and longer blooming plants if you sow them directly. Some vegetables also prefer to be started right in your veggie patch, and the seed packet usually will give you a hint, as there won't be a date for starting indoors.
When starting seeds indoors, be patient! If you start too early, your seedlings will be ready to be transplanted into the garden before our last frost date, and while you wait for that date to arrive, they will become leggy and overgrown. For your records, the average last frost date for Ottawa is around May 8th, depending on the source. Keep in mind though that this can vary. Every seed packet has a recommended planting time. It is usually best to pick a date in the later range in the Ottawa climate. For example, if the packet says sow indoors in March, wait until the end of March, or if the packet says sow four to six weeks before last frost date, wait until four weeks before the frost date.
To start seeds indoors, you'll need containers to grow your seedlings in and a growing medium. You can use any kind of container as long as it has holes in the bottom for drainage, and shallow is usually best. If you are reusing containers, make sure they are clean. If you like things neat and tidy, you'll probably prefer to buy a propagating kit, which includes cell packs, a tray to hold them, and a clear plastic lid. To avoid any confusion once seedlings emerge, label as you sow. All seedlings look suspiciously alike at the beginning! Fresh, sterile seed-starting mix is the perfect growing medium. You'll have to moisten it before you are planning to sow. Follow package directions for best results.
Be patient when waiting to sow seeds directly in the garden as well. Some seeds will not germinate until the soil reaches a certain temperature, and if we have a cool, wet early spring, your seeds will just rot in the ground.
Watch your water
Maintain moisture levels to help seeds germinate and keep seedlings healthy and strong. If starting seeds indoors, once they are sown, water lightly and cover to keep moisture in, with the dome if using a propagation kit or with plastic wrap if reusing another sort of container. As soon as you see signs of germination, uncover your seedlings. Only water your seedlings when the soil looks dry, and do so with the finest spray you can. Overwatering, especially if air circulation is not ideal, can lead to the development of fungal diseases that can kill your seedlings.
Check your light quality
Although a bright window may work, you'll have better success with grow lights or cool fluorescent tubes. Keep seedlings about eight to 10 centimetres from your light source or they will become too spindly as they reach for the light. Use an automatic timer set for 16 hours on, eight hours off. If you don't have access to an artificial light source, choose a sunny window and remember to rotate your containers a quarter turn daily to make sure plants keep growing upwards. You can also gently brush the tops of your seedlings with your hand from time to time to stimulate stronger growth.
You can start feeding your seedlings once they have two sets of true leaves. The first leaves that emerge don't count, these are seed leaves or cotyledons. Start with a weekly feeding of a balanced, water-soluble fertilizer (20-20-20) at half the strength recommended on the package, and eventually work up to full-strength after a few weeks.
Plants grown indoors will need to be acclimatized to garden conditions before they can be planted out. This process is called hardening off, and it is critical to the survival of your seedlings. Begin hardening off 7 to 10 days before you intend to transplant your seedlings into the garden. After the last frost date, set your seedlings outside in a shady, sheltered spot, initially for four hours or so, moving them back indoors at night. Gradually increase the time they spend outside until you are leaving them out all day, then begin moving them into increasingly sunnier and windier areas. Once your seedlings are hardened off, they are ready to be transplanted!