How to Label Sown Seeds and Plants in the Garden

When I first started growing plants from seed, I wanted to do everything as naturally as possible. I chose cardboard seed trays and beautiful wooden plant labels because they looked both attractive and environmentally friendly.

After my first growing season, however, I realised that not everything that looks natural is suitable for seed starting or long-term use in a damp environment. The cardboard trays began to develop mould and break down, while the writing on the wooden labels gradually disappeared.

I would therefore like to share my experience and explain which seed-starting containers, plant labels and markers work best.

Why do cardboard seed trays begin to decompose and develop mould?

In spring, cardboard seed trays and fibre pots can be found in almost every garden centre and supermarket. They create the impression that seeds are being grown in an especially natural and environmentally friendly way, but they have several disadvantages in practice.

Cardboard seed trays are usually made from compressed plant or paper fibres. Because they are biodegradable, they gradually begin to break down when exposed to moisture, warmth and microorganisms. In other words, the tray can start composting before the seedlings are ready to be transplanted.

Seeds require consistent moisture during germination. At first, the growing medium is usually moistened from above, while established seedlings are often watered from below. Cardboard absorbs this water and may remain damp for a long time.

If there is insufficient air circulation between the trays, the moisture cannot evaporate properly. A warm room, constant moisture and organic cardboard fibres create favourable conditions for mould to develop.

The problem can become worse due to:

• Overwatering
• Water remaining in the tray for too long
• Seed trays being placed too close together
• Insufficient air circulation
• An excessively wet growing medium

The cardboard gradually becomes soft, loses its shape and begins to break down. White or grey mould may appear on the surface, sometimes accompanied by an unpleasant smell.

Mould on a seed tray does not necessarily mean that the plant itself is already diseased. However, it indicates a persistently damp environment and insufficient airflow. These conditions may also encourage root damage and seedling diseases, including damping off.

Cardboard also absorbs some of the water intended for the growing medium. The outer edges of the cells may dry quickly, while the bottom remains wet for much longer. This makes moisture levels more difficult to control and can result in uneven watering.

Which seed-starting containers should you choose?

A more practical option is to use durable seed trays and pots that can be:

• Thoroughly washed
• Disinfected
• Dried
• Reused for several years

Over time, this may be both more convenient and more environmentally responsible than buying new single-use containers every spring.

Reusable seed trays also make it easier to manage moisture levels. They do not absorb water, lose their shape or begin to decompose while the seedlings are still growing.

Why can wooden plant labels be unreliable?

Natural wooden labels may initially seem like an attractive solution. However, they do not always last well in a consistently damp environment.

When a wooden label is written on with an ordinary felt-tip pen or an unsuitable marker, the writing may bleed during watering or gradually fade. After a few weeks, it can become impossible to identify which variety was sown in each tray.

When exposed to constant moisture, untreated wooden labels may:

• Change colour
• Warp
• Begin to break down
• Develop mould
• Become difficult to read

This is especially common in warm seed-starting areas where moisture, warmth and limited airflow occur together.

Wooden labels can, of course, be used for short-term or decorative purposes. However, if you need dependable labelling throughout the seedling stage or the entire growing season, a water-resistant and reusable solution is a better choice.

How should sown seeds be labelled?

Label your seeds immediately after sowing. Even if you believe you will remember every variety, young seedlings can be almost impossible to distinguish from one another after a few weeks.

For reliable plant labelling, I recommend using:

• Water-resistant, reusable plant labels
• A high-quality permanent garden marker
• Durable seed trays and pots

Our reusable white plant labels are made from durable, water-resistant plastic. They can be used in seed trays, pots and greenhouses, and later moved into the garden.

Each label has a small hanging hole, allowing it to be attached to plant supports, pots, shrubs or young trees. At the end of the season, the labels can be cleaned and reused.

For clear writing that will not wash away or bleed when exposed to moisture, use the waterproof Lumocolor® garden marker, designed specifically for writing on plant labels.

What information should you write on a plant label?

At a minimum, write:

• The plant name
• The variety name
• The sowing date

If you grow many different varieties, you can also include:

• Flower colour
• Seed batch number
• Seed supplier
• Planned bed or growing location
• Expected transplanting date

For example:

Zinnia ‘Oklahoma Salmon’ – 15 March

Write clearly and use letters large enough to read easily. Very long variety names can be shortened, but use a consistent system of abbreviations throughout your garden.

How should plants be labelled after transplanting?

When seedlings are transplanted, their labels can be moved into the garden with them. It is best to place the labels in the beds at the time of planting.

Even if you think you will remember where every variety has been planted, several plants may look almost identical after a few weeks. It is particularly easy to confuse different varieties of zinnias, snapdragons, dahlias, tulips and other plants of the same species.

If several plants of the same variety are growing in one bed, place a label at the beginning of the row. If you grow individual plants or want to maintain accurate variety records, label each planting group separately.

A garden label can include:

• The plant and variety name
• The year of planting
• Flower colour
• The plant’s source
• Any other information important to you

If you want the labels to remain outdoors for several seasons, choose durable labels and a waterproof marker. At the end of the season, they can be collected, cleaned and stored for the following year.

Environmentally friendly does not always mean disposable

Sometimes a durable item that can be reused for many years is more environmentally responsible than a product that appears natural but lasts for only a short time.

Reusable seed trays, pots and plant labels reduce waste while solving several practical problems. The containers do not decompose during the growing period, the labels remain legible in damp conditions, and you do not need to purchase everything again each spring.

Reliable, durable garden equipment is a small investment that makes sowing, growing seedlings and working in the garden considerably easier.