Brilliant glass trick for March: How to make chives grow rapidly

In many gardens, late winter still looks rather bleak. The beds are damp, the nights are cold, and yet keen home gardeners are already itching to get started. This is where a surprisingly simple tip comes in: with nothing more than an ordinary glass jar, you can build a mini greenhouse that helps chives, parsley and other tough herbs grow much faster in March - with no high-tech kit, electricity or expensive specialist equipment.

How the glass trick really works in March

The idea sounds almost too straightforward to be true: place a glass upside down over a young plant like a bell. That is all there is to it. Even so, it relies on a small physical effect that large greenhouses also use to good advantage.

The glass creates a sheltered microclimate: warmer, damper and stiller, which is ideal for early herbs in March.

As soon as sunlight hits the glass, the air inside warms up far more than the air around it. At the same time, moisture evaporates from the soil, condenses on the glass wall and drips back down again. The result is a warm, humid environment that encourages the plants to put on growth earlier than they otherwise would.

• The air under the glass stays warm for longer, even after sunset.
• Wind and cold draughts cannot reach the tender shoots.
• The soil dries out more slowly because the moisture is trapped inside the glass.

It is important to remove the glass as soon as the weather turns reliably milder in spring or once the herbs reach the underside of the glass. Otherwise, the interior can become too hot and the plants may quite literally scorch.

If you want to improve the effect, choose a clear jar that is clean and free from cracks. It should be large enough to give the plant room to grow, but not so small that the leaves touch the sides too quickly. On very bright days, a brief lift of the glass can also help prevent excess condensation and keep the young herbs healthy.

Which herbs benefit most?

This trick is especially suitable for herbs that are hardy and send up new growth from the ground each year. In other words, plants that stay in the garden anyway and are not killed off completely by frost.

Chives – the ideal candidate for a glass cloche

Chives are among the first herbs to reappear in late winter. Their slender hollow stems push through the soil early, but they are very vulnerable during cold nights. Under a glass, chives grow:

• upwards more quickly,