Should I drop my seedlings to separate them? 4 horticulturist-recommended ways to separate seedlings safely to avoid killing them, and what to never do

I have recently seen gardeners on social media showing a gardening ‘hack’ of dropping clumps of seedlings to separate them for potting up. Can this ever be a sensible way to handle young plants and what other less risky options exist to separate seedlings?

Let’s start with the issue. Seedlings are very delicate and dropping clumps of them, even if not from a great height, risks damaging their fragile stems and roots. It appears many gardeners agree, as many responses to the videos were people saying they would be scared attempting to separate seedlings this way.

Why take the gamble when there are other safer ways to separate seedlings that don’t risk damaging the delicate stems? Here I showcase four methods to use when transplanting seedlings that pose less danger to your precious seedlings.

How to separate seedlings without killing them

I worked as a professional horticulturist for many years and have grown thousands of flowers, vegetables, and herbs from seed each year for the gardens. As budgets were tight, we started most plants by sowing and germinating seeds indoors.

As well as sowing seeds indoors, much time was spent pricking out and potting up seedlings to grow them on before planting them outside into flower beds or vegetable gardens.

I found some methods worked better than others to separate seedlings and the following four ways certainly do less damage than dropping trays of plants.

1. Use a fork

A kitchen fork is the best garden tool for separating seedlings. Its prongs are ideal for scooping seedlings from trays and lifting them with soil around the roots. The fork also helps to untangle roots as you gently lift the seedlings from the compost.

Hold the seedlings in one hand by the true leaves and carefully get the fork’s prongs underneath the seedling. Then gently lift the seedling from underneath to pull it out of the soil.

An alternative tool to a fork is a transplanting tool with v-shaped tines. It is also possible to separate seedlings with a spoon, though a spoon does not allow for the delicate touch like a fork.

2. Use a wooden plant label

A wooden plant label, a wooden popsicle stick, or a chopstick can also be used. You may have wooden accessories around the potting shed if you are trying to sow seeds without using any plastic and they can gently separate seedlings.

Place the tip of the label or stick into the soil next to a seedling and use it to gently level it out of the compost - taking care to only hold the seedling by a leaf and not damage the delicate stem. If more than one seedling comes out, lay the two on a flat surface and ease the roots apart by hand or with your tool.

Sticks or labels can also be used to make holes in the compost to place the seedlings into.

3. Put them in water

Placing a ball of entwined seedlings into a bowl of lukewarm water for 5-10 minutes can cause them to start separating. Gently swirling them in the water can also give them an extra helping hand to split apart.

With this method, the water will remove most of the soil from the roots. While this helps to separate seedlings, it does mean that you need to be extra careful not to damage the bare roots during transplanting.

4. Loosen roots with a pencil

Any stubborn seedlings that remain entwined, even after being lifted from the soil, can be gently prised apart with a pencil or toothpick. This requires a careful touch to avoid damaging the stems or roots of each seedling.

How diligently you try to separate every seedling may depend on how successful your sowing is - you may have more than enough plants and sacrifice a few seedlings to the compost heap rather than painstakingly prise apart roots.

FAQs

How long can seedlings stay in trays?

Seedlings should be transplanted from trays around 4-6 weeks from sowing the seeds. Any rate of development will depend on the type of plant and the level of heat and light seedlings will get, but they want to be transplanted once they get their first set of true leaves.

The longer seedlings remain in trays, the more they will get tangled up as they compete for water and nutrients in the soil. Potting up at the right time makes pricking out easier and ensures your seedlings develop healthily.

Not all seedlings have to be separated, however, as you can successfully plant some vegetables in clumps without the need to thin or separate them.

Leeks, radishes, onions, arugula, and peas are all vegetables that can be planted in clumps. The resulting vegetables are often smaller than when planted individually, but it can be a useful way to save on propagating space and get harvests in smaller spaces.