Newly germinated seeds are a thrilling sight.

It’s a sign that new life has begun. But, still vulnerable, attentive care is required.

Here’s how to ensure your young seedlings thrive.

Getting the water just right

Seedlings need consistently moist soil. They should never be completely dried out. On the flip side, too moist soil can invite mold and bacteria, causing seedlings to rot.

It is a delicate dance. Two watering methods can help regulate water in the seedling’s early days:

1. Bottom watering: This method involves placing your seed tray in a tray of water, and allowing the seedlings to soak up moisture through the drainage holes.

2. Misting: Filling a spray bottle with water and misting the seedlings is a fine way to water them before they’re ready for a watering can. However, reserve this method for seedlings fully covered with soil or larger seeds. Tiny seeds like snapdragons that sit on the surface of the soil may be blown away by the mist!

In terms of how often to water, it varies by seed. It’s best to check on the seeds multiple times a day, and water when you can visibly see the soil beginning to dry.

The necessity of light

Some seeds will fare just fine on a table in front of your sunniest window. Others may require grow lights.

If growing seeds near a window, you may notice your seedlings getting a bit leggy. This is because they have to stretch a little farther to reach the light.

Try turning the tray 90 degrees throughout the day to even out the direction of the light. This prevents a tray of seedlings all leaning in one direction (if they do get a bit stretched, this video will help!)

Grow lights are mobile and relatively inexpensive (in Issue 06 I recommended these)—they help provide more even light to your seedlings. They’re also useful if growing seedlings that require long periods of light (like lisianthus, which require 16 hours of light a day!).

Grow lights also allow you to adjust the height of the light source. Keeping the light source about 2-4” above your seedlings helps reduce stretching and lanky plants, as the seeds do not need to reach for light.

Thinning seedlings

When sowing seeds, we often drop a few (at least 2) into each cell. It’s an easy way to hedge our bets, raising the likelihood of germination.

Inevitably, this leads to some cells having several seedlings. Once your seeds have a set or two of true leaves, it’s time to thin your seedlings.

It’s very tough to do. I feel it every time. But it’s necessary. Here’s why:

Multiple seedlings in one cell mean competition for resources, and a fraction of the nutrients they would receive if they were the only seedling. This creates weak and potentially unhealthy plants in the future.

To thin the seedlings, identify the strongest in the cell. That doesn’t mean the tallest—in fact it’s usually the more compact seedling. Snip the rest with scissors, until you have just one seedling growing in every cell.

To see this in action, watch me thin out my sweet pea seedlings!

Pinching

Pinching your seedlings is another tough love task of the gardener.

Once your seedling has 3-4 sets of true leaves, use scissors or your thumb and finger to pinch the top of the stem—just above a set of leaves.

This practice will encourage side shoots and create a stronger, bushier plant with even more flowers.

Most seedlings benefit from pinching, but especially basil, cosmos, dahlias, snapdragons, sweet peas and zinnias.

Potting up

Potting up means transplanting seedlings from their seed tray to a pot of their own, before being planted out in the garden.

This step isn’t necessary for all seedlings, but if your sprouts are getting too big for their trays, it helps to pot them up to avoid them becoming rootbound.

Wait until your seedlings have at least 2 sets of true leaves before potting up. If you prefer to wait it out, but notice your seedlings growing 2x the height of their tray (or notice they stop growing, indicating stunted growth)—you’ll have to pot them up.

If moving from a seed tray, 3-4” (9cm) pots are the ideal next container size.

📺 What I’m watching

This Beautiful Fantastic, a film by Simon Aboud. An Amelie-inspired, modern-day fairy tale. It’s whimsical and feel-good, if not a touch saccharine, and combines British gardens, libraries, fanciful tales and magical realism—all my favorite things.

👩🏻‍🌾 Seeds I’m sowing

Dahlia seeds! I’ve grown a big bed of dahlias for several years, and I always start from tubers (the dahlia equivalent of bulbs, they look like a clump of potatoes). But dahlias, like any flower, can be grown from seed as well—and I’m giving it a try this year. The interesting thing about dahlia seeds is that you don’t quite know what the flower will look like. Tubers ensure an exact copy of the parent flower, but seeds could take on any number of characteristics. So it’s a fun surprise!

🌸 Flower I’m admiring

My snakehead fritillaria are on the verge of blooming. Every morning I run outside to see if today is the day they reveal their checkered, seemingly pensive flower heads. I think the pattern spread across their petals is one of the most unique in all the flower world.

Did you plant any seedlings? How are they growing? Here for all of your successes and not-so-successes! 👀☕🌱

xx

Courtney