Indoor planting of vegetables
Winter is not over, but gardeners are already starting to plan their vegetable gardens and some are looking forward to starting their indoor seedlings.
Indoor seedlings, for which vegetables?
The time it takes for a vegetable to grow from seed to maturity can vary depending on its category and origin. It will take a plant longer to produce a fruit, such as a bell pepper, than a leaf, such as a salad. A plant like the tomato, which is native to Mexico, will require more hours of sunlight to produce its fruit than a pea which is native to a temperate climate.
To produce a tomato, it takes about 100 days between 20°C and 25°C from sowing to harvest. Unfortunately for us, we do not have an average temperature of 23°C for 100 days in Quebec. Therefore, it will be necessary to extend this period of heat by sowing indoors. Some vegetables absolutely need to be sown indoors and others need to be sown outdoors. And finally for some, we have the choice depending on whether we want to grow vegetables earlier or not.
Here's a chart that can help us untangle all this:
When to plant indoors?
The most common mistake when planting indoors is to plant too early and end up with overgrown, wilting vegetables that cannot be planted outdoors because it is too cold. Transferring and planting your indoor seedlings outside should be done after the last frosts, depending on your region, and from the four-leaf stage, counting cotyledons. So you need to have your vegetables ready in time, but not too early.
It will be important to establish a planting schedule if you have several vegetables to plant. Count down from the date of the last frost, depending on your vegetables. You will generally find on your seed packets indications of the number of days or weeks to respect before planting. For example: you live in Laval (the last frost is around May 15) and the indications for planting are 6 weeks before the last frost, so your planting date for this vegetable will be around April 3. Allow a little less time if the room where you are sowing is well heated.
Material for indoor planting
- Seeds. It is better not to buy them too far in advance.
- Potting soil or substrate. Do not use soil from your garden. Substrates sold for seedlings in the garden center will be perfectly suitable, such as Fafard organic potting soil for seedlings or Promix potting soil for seedlings;
- Containers can be trays, pots for grouped sowing or individual sowing (peat cups, peat pellets, tray in individual cells);
- Labels. You must identify your seedlings. We have prepared a kit of 12 labels with a Sharpie;
- A bucket or large bowl;
- Transparent domes to cover seedling containers;
- A hand sprayer to keep your seedlings moist.
You can recycle various containers (milk carton bottoms, yogurt cups, etc.) It is important to wash them well with soap and to make holes in the bottom to avoid water accumulation.
Making the seedlings
Make your cake mix. Mix in a bucket your potting soil that is dry with water while mixing. Add the water gradually, avoiding excess water. When you squeeze the mixture in your hand, a small amount of excess water should run through your fingers, but no more.
Prepare your labels. Write the name of each variety and the sowing date in advance with a permanent marker on your labels.
Fill the containers. Fill your containers with the mixture, packing it down slightly. Level off your mixture to about 2 cm from the top edge. If you are sowing directly into individual containers, make a hole the recommended depth on the bag, place three seeds in the center of each container. For grouped sowing of small seeds in a tray, level off to within 2 cm of the rim. Open your bag, hold it horizontally over the substrate while moving gently from right to left to cover the surface of your tray as evenly as possible. Pack lightly with a wooden block and moisten with a spray bottle.
You can also do row planting. Draw lines with a pencil at the recommended distance and depth on the packet. Place the seeds one by one in the furrow at a distance of 1 cm, then cover the furrow with the substrate. Moisten with a spray bottle.
Plant an identified tag in front of your seedlings.
Cover the seedlings. Germination requires a constant humidity at the seed level, an availability of air and a generally high temperature. It is therefore important to cover your seedlings with plastic domes, glass or plastic film to maintain a good humidity and avoid drying out, until the seeds germinate.
Follow-up of the seedlings
Although seeds do not need light for germination, you can keep an artificial light (fluorescent lamp) at 15 cm from your seedlings to maintain a constant temperature. If you place your seedlings on the edge of a window, avoid exposing them in full sun to avoid having too important temperature variations.
After germination, remove domes, plastics or glass to avoid excess moisture and disease on your young seedlings. If you have the possibility, it is preferable to make the follow-up of your seedlings in a room which you frequent less possible to be able to lower or raise the temperature and the humidity in order to better control the growth of your seedlings.
Light becomes very important after germination. You can use artificial light or place your seedlings on a windowsill.
Monitoring watering is also tricky on your young seedlings. You can use an undrilled tray, put your seedling containers on the tray and pour about 2 cm of water into the tray. The containers will absorb the water without damaging the young foliage like a watering can would.
You can find all the seeds and seedling material on our website and in our garden center.
We will be publishing a column on outdoor planting in a few weeks. Until then, good luck with your indoor planting!
