Growing On

Average time to read: 2.7 minutes

You did it! Your seeds have germinated and now you have trays of teeny tiny seedlings. If you’re anything like us, you can’t help but gaze upon them with pride and delight. Clearly you did a great job at creating good conditions for germination. You’re a master germinator! But you’ll need to make some changes now that growth has begun.

This next phase is called growing on.

During germination, you know seeds must be kept moist and warm. However, when growth begins, those conditions which were perfect for germination spell trouble for growing on. That’s because a warm, humid environment is a breeding ground for bacteria, mold, mildew, and myriad other garden baddies. Check your seed packets! Chances are they’ll have instructions for germination, followed by a few lines beginning with, “Grow on at a cooler temperature…” etc.

Strawberry seedlings in the foreground with Echinacea in the background.

Temperature & humidity

To ensure your seedlings grow up big and strong, remove any clear plastic humidity domes and/or seed starting mats that were used during germination.

*It may be worth noting here that you will see us using taller plastic domes long after germination in some of our photos. These taller (7 inch) plastic domes have vents at the top and allow enough space and air circulation for proper development. We also remove the domes every morning and evening, allowing for a breeze to blow over the uncovered trays for thirty minutes to an hour at a time. We choose to do this because our grow station is often visited by a cat who enjoys pulling up young seedlings. You can do this too! The 7” domes are harder to find online but should be available from your local garden centre.

Air circulation

As for that breeze we just mentioned, don’t rely on the natural air circulation in your home because it won’t be sufficient. Keep a small fan nearby and use it to direct a light breeze over your grow station. This helps to prevent the kinds of issues that develop in humid, stagnant air. It also encourages stronger stem and stalk development which will serve your plants well when they are eventually moved outdoors.

Uncovered trays receiving a breeze from the nearby fan.

Light

Your seedlings also need light! Get them into a sunny south-facing window and/or under grow lights. When they are very small, you might want to consider propping them up so they are closer to the light. This is possible thanks to new LED grow lights, which don’t give off as much heat as the old ones. Double check yours to make sure they don’t scald your seedlings.

If your lights are on a timer, set it to 12-16 hours of light per day. Do not leave it on overnight; plants need rest just like you. If you don’t have a timer, just turn them on when you wake up and turn them off when you go to bed.

Watering

As your seedlings grow, they should be watered lightly and regularly. Pay close attention to trays that are in direct sunlight because they will dry out much faster than trays that are under grow lights. Always water in the morning, especially at this young stage. Watering at night when the temperature will naturally drop can stress your seedlings, possibly fatally.

Tiny Echinacea seedling.

Keep an eye on them

Young seedlings are fragile! Check on them every morning and every night to make sure they look ok and haven’t gotten too dry. If they start looking ill, don’t wait. Send a photo to a green-thumbed friend or head into your local garden centre with photos to chat with their knowledgeable staff. And don’t forget, Mother Nature is your boss in the garden. Sometimes your seeds will fail and you’ll never know what went wrong. That’s ok, it’s just part of gardening. If you’re lucky, you have enough wins to keep you going.

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