If you have sown several seeds into a seed tray, it is important to prick out the seedlings and transplant them, to give them enough space to grow healthily, and allow them to benefit from the extra feed in the fresh compost.
Prick out seedlings of flowers and vegetables once they have their first pair of true leaves – these are the first set of leaves that resemble the parent plant. Use a pencil or dibber to lever the roots of the seedling out of the compost, holding the seedling by the leaves, as these are replaceable, and never by the stem, which can be easily crushed. Transplant your seedlings into small pots or trays filled with peat-free multi-purpose compost. Use a pencil or dibber to make a hole in the compost and drop or spiral the seedling in so the surface of the compost comes up almost to the lowest leaves. Transplanting deeply will help keep your seedling securely in place. Gently firm the compost around the seedling.
Aim to transplant 12 seedlings into a half-sized seed tray. Use a dibber to mark out the spacing, with three plants across the width and four down the length of the tray. It is better to transplant large seedlings into their own individual pots. Once your seedlings are transplanted, water well using a watering can with a fine rose attachment, and place on a bright windowsill, in a greenhouse or in a propagator.
If you don’t prick out seedlings, they can succumb to a disease called damping off, causing them to collapse. It’s possible to avoid the need to prick out seedlings by sowing seeds singly in modular trays, but these take up more space in propagators or on windowsills.
Monty Don explains how to tell when to prick out seedlings, what to move them into, and how to lift these fragile plants without damaging them, in this video guide.
More advice on how to prick out seedlings:
- How to harden off plants
- How to grow tomatoes
- How to grow cosmos
- How to prevent damping off
- Tips for early seed sowing
- How to grow cut flowers from seed
Follow the advice in this easy guide to how to transplant seedlings, below:
You Will Need
- Seed dibber, pencil or another similar implement to lever out seedlings
- Seed tray or small pots
- Multi-purpose or bedding compost
- Watering can with rose attachment
- Plant label
Gently lift one seedling at a time using a dibber to lever out as many of the roots as possible. Always hold seedlings by a leaf, not the stem, as this is easily crushed, which would kill the seedling.
Transplant the seedlings to individual pots or new seed trays, which should be ready and waiting alongside. Filled with multi-purpose compost, the surface should be level and gently firmed.
Make a hole with the dibber and lower the seedling into it, almost to the base of the leaves. Firm it in carefully, ensuring the seedling is upright, well spaced from its neighbours and in a straight row.
Soak the newly transplanted seedlings using tepid water from a watering can with a fine rose, so as not to disturb them. Label with the plant’s name and place it on a greenhouse bench or a bright windowsill to grow on.
Caring for your seedlings
Place the seed tray in a warm, well-lit spot, keep the compost damp, and check plants regularly for aphids. As the seedlings grow, pinch out the tips of vigorous or leggy plants to make them bushier.