Veranstalter / Organizers:
Messe Berlin Website
Datum der Veranstaltung:
17-26 Jan 2025
International Green Week
17-26 Jan 2025

Fascinating world of plants

Dr David Spencer is a plant biologist and science journalist. He wants to convince society of the fascination of the plant world. To this end, he runs the YouTube channel "Krautnah".

What is your favourite crop?

The potato. It is a crop that gives Germany its identity. And it provides lots of vital calories. It actually comes from South America. When you go there, you realise how many different varieties there actually are. Even more than here. The potato is also very clever.

What do you mean?

It can happen that a potato turns green when it comes into the light of day. This is to protect itself from being nibbled by insects, fungi or other bio-organisms. The green colouring is due to the fact that it produces solanine, a toxic substance. Most of the solanine is found in the potato skin. It is therefore advisable to peel potatoes before eating them.

Do plants and humans have anything in common?

Yes, they have a similar metabolism and, like humans, plants are dependent on nutrients, water and sunlight. If you look at the historical development of plants, it all started with algae. Thousands of years ago, single-celled algae swam like nomads through the primordial ocean, always in search of the perfect light and nutrient conditions. Then they settled down and formed societies with fungi and bacteria in order to survive in the primeval, very rocky world. Or consider cabbage varieties such as red and green cabbage: they are all based on one and the same species, but are nevertheless very diverse in their varieties. This individuality is no different in humans. In any case, humans can learn a lot from plants.

Now you're talking about the superpowers of plants.

What do you mean by that?

On the one hand, plants such as potatoes can defend themselves and drive away their predators by producing defence substances. On the other hand, some plants create illusions. Fruits containing capsaicin, such as chillies or pimientos, make people believe they are in pain when they eat them, so that they feel hot and start to sweat. In reality, however, this is not the case at all, but only takes place in the mind. Mint, for example, triggers the opposite effect when eaten, namely a sensation of cold. The third superpower is the regulation of our own water balance. Herbs such as sage can control their moisture content by preventing evaporation through a layer of wax on their leaves. And there are great climate and soil protectors such as beans and peas. They belong to the legume family and form a symbiotic relationship with bacteria. Nodule bacteria form nodules on the roots of the legumes in which they live. They bind the nitrogen in the air and supply the plants with it.

Speaking of growing. We are now also growing tropical fruits. A positive development?

Chickpeas, melons and sweet potatoes thrive wonderfully in our soil. The question is whether these products will also be accepted by consumers. In any case, our soil and climate are not the problem. I think that food grown in Germany is just as tasty as its relatives from southern countries. Especially because they are harvested here when they are ripe. Imported produce, on the other hand, only ripens during transport.

Honestly, is it possible without pesticides?

We have built up an agricultural system that is designed to provide us with a varied, high-quality diet, preferably without the use of additives. Our society is used to full shelves. But what happens if a harvest threatens to fail due to fungal infestation or disease? In that case, plant protection products must be used. Just as we take antibiotics in certain cases and are glad that we have these medicines.

Our society is used to full shelves

Is it possible to keep plants fit?

In principle, there are many prophylactic measures that require a reduced use of plant protection products or even make them superfluous. These include keeping the soil healthy with all its diverse inhabitants and an intelligent sequence of catch crops. A field should not lie fallow. Plants such as clover add value to the soil and strengthen the humus layer. Farmers who do not turn their soil counteract erosion, which can occur during heavy rainfall. Modern and digital machines also help farmers to cultivate their land in a regenerative way. I believe that if science worked more closely with agriculture, all sides could be even more inspired.

Do you have an example of such inspiration?

Pure crops don't always have to be planted. Mixed crops have many advantages. In southern Europe, olive trees are currently being attacked by a bacterium that is transmitted by insects such as cicadas. Olive growers are trying to plant marigolds between the rows of trees. Insects do not like the scent of the so-called marigold. Beans and potatoes would go well together here, as the solanine in potatoes repels animals that would otherwise nibble on the beans. The challenge, however, is to harvest both plants efficiently.

Is organic farming the solution?

It is politically desirable that we practise more organic farming. But it is a misconception that no plant protection measures are used there. Cereals, for example, can be infested by fungi. This is not harmful to health, but it does contaminate the harvest. This is why organic farmers spray copper preparations. The copper remains in the soil and is not broken down. For me, plant breeding plays an important role because it creates resistance to fungi and plant diseases.

Which plant breeding invention particularly impresses you?

Gregor Mendel has achieved outstanding things. His rules from 1866 are still valid and form the basis of modern plant breeding. Today we know which genes are responsible for what. With new genetic engineering methods, we can increase the resistance of our plants so that fewer and fewer pesticides are needed. Unfortunately, some politicians make us believe that we do not need these methods, but that is only because they have built their careers on these theories. The new genetic engineering is no more risky than the genetic interventions we made centuries ago.

One final wish

I think it would be good if we could continue to breed plants that can be used in a variety of ways. Rapeseed, for example. The plant can be turned into cooking oil, animal feed and biofuel at the same time.

End credits:

"You can find this interview and other exciting stories about people in agriculture on the website and in the magazine Stadt.Land.Wissen of our cooperation partner Forum Moderne Landwirtschaft: Magazin - Moderne Landwirtschaft (

David Spencer sits on the ground in his greenhouse

The plant whisperer - David Spencer researches plants and talks about them. Copyright: David Spencer.

Author:Daniela Breitschaft

Regional, Organic