Leggy seedlings can be a common problem when growing plants from seed. They develop long, thin, weak stems rather than short, sturdy growth. There are three main things to watch for.

Give seedlings enough space

If seeds are sown too closely together and you get a good germination rate, the young seedlings can quickly become overcrowded and start competing for space and light.

Sow seeds thinly and allow enough room between them where possible. If too many seedlings emerge together, thin them out early so the remaining plants have room to develop.

Increase light once seedlings emerge

Insufficient light is another common cause of leggy seedlings. When young plants stretch towards a light source, they can develop long, weak stems. This is known as etiolation.

Once seedlings emerge, remove any cover from the seed tray and move them into a bright position with plenty of natural light. Rotate trays regularly if seedlings are leaning towards the light so they grow more evenly.

Prick out overcrowded seedlings

“Pricking out” is the gardening term for carefully transplanting young seedlings from their seed tray into a larger tray or individual small pots.

Once seedlings are large enough to handle, pricking them out gives their roots and foliage more room to develop and helps produce stronger, healthier young plants. Handle seedlings carefully by their leaves rather than their delicate stems when moving them.

Keep Daltons Premium Seed Mix evenly moist while seedlings are young, but avoid overwatering.

Harden seedlings off before planting

Before planting seedlings outside, gradually harden them off over 10–14 days.

Start by placing them outdoors in a warm, sheltered position for a short period each day, then gradually increase the amount of time they spend outside. This helps young plants adjust to outdoor temperatures, wind and sunlight before they are planted into the garden.