Lars Lund

08 Sep 2020 14:34

It is cold in the greenhouse, but it is still full of life

It was a bit of a change to get into December. Luckily, I got my long-wanted and much-needed insulated plant hotel ready before the frost really set in. It's just a well-insulated shed with a few low-energy windows, a floor with thick rubber mats, made from old car tires, and a radiator that turns on when the temperature drops to minus five degrees. All that is needed is quite a bit of electricity, then it is almost a 64.5 square feet hotel so hot that the cold is kept out. And of course, the power comes from a solar cell panel. That is how it is these days.


The light is coming

It is still dark, and therefore a little artificial light is needed to make life even better for the hotel guests.

The research of finding just the right colour spectrum in artificial light is in full speed. The Swedish company, Venso Eco Solution, has, based on the new knowledge of different LED lights' colour spectra, developed an LED string that, according to the manufacturer gives the right light to plants.

This means that you can, for example, grow fresh herbs all year round. You can read more about the different options at www.plantfactory.se. Here is also a system of LED lights, where you grow herbs in aquaculture, that is, virtually only in water and without soil.

Herbs and the smell of glögg

My greenhouse has been a Christmas bazaar for the family's own creations throughout most of December. It has been really nice with fire in the tiled stove, fresh apple slices, hot glögg and the smell of spruce. Perhaps the best thing is that the herbs that usually are in pots but are in the ground this year have an aroma beyond compare.

A new black tomato sort

The harvest of tomatoes was at first not a big success for me this year. However, I had jumped the gun. I tried a lot of different sorts and many of them just needed a little more time than usual. In 2013, a new tomato emerged. It is almost black and is called 'Indigo Rose' Lycopersicon Esculentum.

The tomato was developed by a research team at the American University of Oregon, which especially works with developing tomato sorts with a high content of antioxidants. It is also the first tomato sort to be developed so that the fruits contain anthocyanins.

Anthocyanins are a large group of colourants, which appear in many shades of red and blue, and are considered to act as antioxidants. Thus, they contribute to the high nutritional value of berries and fruits. The many anthocyanins are one of the reasons why blueberries have been named as superfoods.

Tine Albinus, who sells the seeds, says that ‘Indigo Rose’ dates back to the 60s when two tomato growers - one from Bulgaria and one from the USA - crossed cultivated tomato sorts with wild sorts from Chile and the Galapagos Islands. Some wild tomatoes contain the wanted anthocyanins, while cultivated tomato sorts have so far had only the active pigment in the inedible leaves and stems.

At the University of Oregon, many generations of wild and cultivated tomatoes have been crossed, which in 2012 were presented as 'Indigo Rose'. ‘Indigo Rose’ suits the climate of the northwestern state of Oregon, and it is not that different from ours. Therefore, ‘Indigo Rose’ can be grown well in the open air, as long as it is warm, sunny and sheltered. The largest harvest is secured if grown in greenhouses. The plants of ‘Indigo Rose’ are generally healthy and resistant to pests.

Happy New Year also for the vine

While you wait for the new year, you can check your fig tree and your vine for scales. They can be squeezed with a nail, and it is fairly easy to get rid of them at this time of year. It is also before New Year that you cut your vine back a bit. All side shoots must be cut back so that there are only two to three buds and the new growth of the main stem itself is cut back one third.

Om Lars Lund

Lars Lund
Danish horticulturist and journalist
Lars Lund has for many years engaged in the garden and greenhouse. Lars has published many books about greenhouses, and he has participated in many Danish horticultural TV shows. He is a walking garden encyclopaedia, and he has answers for most basic cultivation questions – also the more ambitious ones.  

Get to know Lars Lund