You don’t have to wait until spring to plan your vegetable garden! Despite the dreary weather, now is a great time to start preparing your vegetable seeds in the comfort of your home. You probably have a few questions: When is the right time to plant my seeds indoors? What gardening materials do I need to use? How do I grow healthy seedlings? Don’t worry — we have the answers to all your questions regarding indoor sowing!
When is the right time to plant my seeds indoors?
March is generally the perfect month to start planting vegetable seeds indoors. Nonetheless, the exact dates vary from seedling to seedling. Simply check the back of each seed package for details or refer to the vegetable planting schedule recommended by the Montréal Botanical Garden.
Keep in mind that it’s always better to start your indoors seeds later than sooner. Young, vigorous plants that are ready to grow are healthier than older plants that may be declining.
How to grow healthy vegetable seeds: the 9-step method
1. Choose the right soil:
Select a light soil that is specially formulated for seedlings and shoots. AgroMix® for seedlings and shoots is approved for organic culture, making it the perfect choice! This peat-based soil mix is enriched with coconut fibre, which helps to keep it moist—an essential condition for ensuring fast and healthy seed germination. Furthermore, the natural fertilizer in the soil mix will provide adequate additional nutritional elements to support plant growth after transplanting.
2. Moisten the soil:
Use a large plastic container to moisten the quantity of soil you will need to fill your small plant pots. Add more water using a watering can and stir the soil until it is thoroughly moistened.
3. Fill your plant pots:
Fill your plant pots up to 1.5 cm (½ in.) below their edges and gently smooth the soil with your fingers. Seeding trays are available at your local garden centre, or simply use recycled household containers (from yogurt, apple sauce, etc.). Wash them thoroughly and pierce the bottom with a nail for drainage.
4. Plant your seeds:
Place one seed on the surface of the soil at the centre of each container and gently cover it with soil (3 times its thickness). Avoid pushing the vegetable seeds too far below the surface. Pressing gently once should do the trick! The smaller the seed, the less soil is required on top.
5. Cover your seed starting tray with a clear dome:
Place the containers on a large tray to collect excess water and cover the tray with a clear dome. The perfect temperature for indoor seed germination is between 21°C and 24°C for most vegetables (25°C and 30°C for tomatoes, peppers and eggplant).
Mist once daily to keep the soil moist during germination. Ideally, use a spray bottle because it is perfect for gentle watering and will not disturb the seeds. It is very important for the soil to stay moist but not soaked. If there are water droplets on the dome, remove it momentarily to allow the excess moisture to evaporate and prevent your vegetable seeds from sinking (your young plants could otherwise become dislodged and collapse).
7. Remove the dome, lower the temperature and add light:
Once the cotyledons (first 2 leaves) appear, which may take between 3 days to 3 weeks depending on the species, remove the dome and lower the temperature by a few degrees (22°C during the day and 18°C at night). Overheating combined with insufficient light will inevitably produce weak, limp plants. Seedlings need 12 to 14 hours of light per day to gain strength and vitality. Natural light in March is insufficient, so you will have to use extra lighting.
This involves moving the seedlings into bigger pots to give them more room to grow. Transplanting triggers the development of secondary roots, which help the plant solidly anchor in the soil. A seedling can be transplanted once it has two real leaves in addition to the two cotyledons. Waiting longer will cause the roots to get tangled and it will be difficult to transplant them without damaging them—your seedling growth will also be affected. Water the seedlings before transplanting them. Use a small stick to gently loosen them in the soil. Hold them by the leaves (not by the stem) and separate each plant from the cluster. Replant them in a large crate or in pots, cover with soil to the first leaves on the stem, and gently water.
In a few weeks, your seedlings will be ready to plant outdoors. We recommend allowing 7 to 10 days for acclimatization during which time you can gradually expose them to outdoor conditions. If the temperature suddenly dips, shelter your plants indoors for the night. Once the temperature rises and there is no risk of further frost, it’s time to officially transplant them outdoors!
Everyone benefits from indoor seed planting!
Planting your own vegetables is easy and fun! It’s a great activity to enjoy with children. Your entire family will be proud, and you’ll quickly discover how economical it is when you harvest the “vegetables” of your labour at the end of summer!
I hope we have provided all the answers to your questions on how to start growing your vegetable seeds indoors.
On your mark, get set… sow!
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