Tomato and Pepper seedlings require a head start in most parts of Canada.
When you live in a cool climate like we do, you have to pre-plant quite a few seeds early to give them a head start. My first two most common early-start plants are peppers (both hot and sweet) and tomatoes.
I typically start my tomatoes and peppers in a mix of compost and perlite. The compost provides plenty of nutrients for the young seedlings, while the perlite adds aeration to the compost so tender plants don’t suffer from root rot (or “damping off”). I start them in individual yogurt cups with holes in the bottoms. I find these useful because, once you remove the label, you can easily write directly on the container with a sharpie. If you want to make sure your seeds germinate before planting them, the baggie method is a great alternative for seed starting.
The cups are placed on heat mats, which help raise the temperature of the soil. Pepper seeds require heat to germinate. Tomatoes don’t need it, but it does help. Once the seedlings emerge from the soil, I move them to a tray, about an inch from the grow lights. Placing them close to the lights helps to produce bushier, more dense plants. I have a two shelf system set up under the lights, one slightly lower than the other. This is so that once the plants fill that inch and are about to brush against the lights, they can be moved to the lower level which gives them another inch to grow before they have to be moved again.
Having two different levels under the lights helps control how close the seedlings get to their light source.
Once they have outgrown their two inch space, all of the plants will be tall enough that I can move the lights up to allow for more growth. Once they have reached the maximum height of the lights from the top shelf, I start removing shelves and lowering the trays.
While they are in the greenhouse, the plants enjoy a 16-hour on, 8-hour off light cycle. While the lights don’t add much heat to the greenhouse, the heat mats do, providing the plants with a regular air temperature range of 18 – 26°C. Daily watering puts the humidity at around 60%.
One final note, the seedlings are exposed to a light wind simulation every few days. Nothing harsh, just a fan on a gentle breeze. Using this hardening-off method early on seedlings helps the plants grow strong stems, preparing them for the transplant into the ground in spring.
Peppers and tomatoes may need an early start, but the plants are known to produce great harvests and are well worth the effort.