What is a soft landing system

Low-calcium or soft water for the plants

After I didn't have any indoor plants for a few years, only plants that you can stand on the balcony in summer or that only bloom in summer like oleanders or fuchsias, I treated myself to two indoor plants again because they looked so beautiful: One Kumquat and an orange tree (or miniature trees, because they are only about 50 cm high). Of course, I also found out how to care for the plants, and that brought me to today's topic, because you often find the advice that you should water the plants with rainwater or lime-free water.

It's actually quite simple, but to make sure that it is enough for at least one article, I'll dig out a little. All of the water we extract ultimately comes from the rain. Either you collect rainwater directly or it seeps into the ground there it passes the upper layers of the earth, collects in streams or it penetrates deeper and is blocked by a layer of clay at some point. On the way there, it can loosen minerals that are present in the soil or in the rock. The organic substances that are present in the humus layer and can easily be dissolved are soon bound again in the rock layer due to their high chemical affinity. It looks a little different with the minerals that come from the bedrock itself.

Lime - a little introduction to chemistry

Most rocks give off hardly any minerals, including granites and basalts, the most common rocks. Water from such sources, including some prominent brands such as Volvic, Apollinaris or Selters, are therefore very poor in minerals. The situation is different with limestone, which is mostly sedimentary rock. The Swabian Alb is a typical representative of this rock. It consists of the remains of lime-forming algae from the Jurassic, which have been compressed over millions of years. The algae separated the lime from the sea water and it dissolves again just as easily as it was separated. Even normal water easily dissolves lime from the rock; if it is acidic, the dissolving power increases significantly. The Alb is therefore covered by a karst and cave system, the crevices and caves were detached from the rock over thousands of years. Even if limestone is not present on the surface, it can still be present in the bedrock, for example in the Neckar Valley, where I live.

In addition to the lime (chemical calcium carbonate) in the water, there is also magnesium lime (magnesium carbonate), which is also water-soluble, but a little heavier, as well as the water-soluble sulfates of these elements such as calcium sulfate (occurs e.g. in gypsum) or magnesium sulfate (Epsom salt), but these are Rocks less common.

Lime dissolves as calcium carbonate, the carbonate reacts with the water and forms hydrogen carbonate:

CaCO3 + H2O → Approx2+ + 2 HCO3-

The most important point at this point is that the dissolved carbonic acid in the water is unstable. It is actually gaseous. They can be driven out by heat:

HCO3- + Heat → CO2 + OH-

It'll be OH- Ions are formed, the water becomes alkaline. Water with a high content of hardness therefore also tastes slightly alkaline, so slightly like soap.

Now we come to the plants. Plants grow in soil that consists of crushed rock and decomposition products from organic material, such as rotting leaves. Above all, these breakdown products are important. They form the humus and when they break down, organic acids, the humic acids, are formed. They ensure that normal soil reacts slightly acidic. If the rotting takes place in the absence of air, so that the humic acids are not oxidized, the pH value can even drop significantly. This is the case, for example, in bogs, which is why peat is extracted for potting soil. Plants that grow in bogs or similar environments therefore need soil with a very low pH value. They are used to this and cannot cope with normal garden soil. Most plants like a slightly acidic pH. Plants that grow in dry areas or on calcareous soil are adapted to the high pH value. In dry terrain, the pH value is often high because the soil hardly contains any humus.

What happens now if calcareous water penetrates normal garden soil? Now this contains H due to the humic acids+-Ions, so it's angry. The H+-Ions now split the hydrogen carbonate:

HCO3- + 2 H.+ → H2O + CO2

The resulting carbon dioxide is a gas and escapes from the solution, so that no reverse reaction is possible. If you pour this water regularly, the pH value inevitably increases. For the plants, the consequence of the low pH value is that at this pH value many metal ions from the clay stones dissolve and can only be absorbed by the plants in this way. If these metals are missing, the plants are undersupplied and the plants suffer, for example brown leaves. In the case of bog plants such as azaleas or rhododendrons, for example, iron is only available when the pH value is low. If the pH value rises sharply, soluble minerals such as aluminum, which is poisonous for many plants, can also be dissolved in the basic.

This is why peat is so popular as a potting soil. Bog plants need it, otherwise they will not grow properly. Here you have to exchange the whole earth. But even with normal plants it has the welcome effect that it acts as a buffer, since it is much more acidic than normal soil, the pH value will not rise until this acid capacity is used up. With many plants that are only kept in the pot for one season, this is usually completely sufficient.

So what is the solution for a permanent plant?

Now these can usually not be repotted regularly and the whole soil replaced, because larger plants then usually have rooted through the whole ball. The general solution is then to use lime-free water to pour. If you live in an area where the drinking water is "soft" (less than 7 degrees German hardness, inquiries from the local waterworks) you are off the hook, you can take it for watering. Others have to evade, or at least use soft water from time to time. If you can collect rainwater, then this is extremely suitable, because it has not yet come into contact with the ground and does not contain any lime. However, you need a lot of water, especially in summer, and rain is rare.

The most expensive option is to use soft water in the form of certain mineral water or distilled water. Distilled water is free of lime. Numerous mineral waters contain hardly any minerals, here you should pay attention to the lowest possible hydrogen carbonate and carbonate content. But be careful: Most mineral waters are called that because they also contain minerals and that is mostly dissolved lime.

The most practical option is to lower the pH value yourself or to increase the acidity of the soil. There are two ways to do this. One is to put some peat in the water and let it steep. It neutralizes the lime. This can be used several times, peat contains a lot of acid. The second option is to add acid yourself. A shot glass of vinegar (5% acid, 20 ml) lowers the hardness of 1 l of water by 2.If you have water with 10 degrees of German hardness and want to get into the soft area (7), it is enough to add 30 ml of vinegar to the water, or a 0.7 l bottle for 20 l irrigation water. In the end, if you take vinegar essence or cheap vinegar, it is much cheaper than buying water or demineralizing it. With vinegar essence with 25% acid, you need five times less vinegar because the acid is five times more concentrated. If the drinking water is not extremely calcareous, you do not have to constantly add acid, because because the hydrogen carbonate splits off carbon dioxide by itself, it is sufficient to neutralize part of the calcium. If you use this method you have to pour a lot and throw away the excess water. The background: This is how you neutralize the carbonic acid ions, but the calcium and magnesium ions are still present. But they are water-soluble. So if you water more than the plant needs, some of the calcium ions will remain in the excess water as calcium acetate. Alternatively, you can regularly soak the whole bale with soft water, rinsing out the calcium salts. For potted plants, the method is therefore not so ideal or only applicable if the plant only needs a bit of acidic soil, but not very acidic one (then you don't have to constantly acidify the irrigation water). However, it can be used well for plants in the garden, wherever the excess water can run off or where it is insured that it can be used. So you can water plants that need a bog bed or you can get blue flowers in hydrangeas due to the low pH value.

Water can also be descaled in an energy-intensive way by heating it, then some of the lime falls out and is deposited on the walls of the pot. It is just as expensive to decalcify the water yourself with ion exchangers, there are devices of this kind to produce tea water that should also be soft. It does not matter to the plants that these devices tend to germinate and that other metal ions are often released if they are used for too long. Here the filters are designed for the preparation of tea or coffee, so small amounts of water are very expensive.

Article last changed on 6.4.20616

Books from the author

So far, four books have been published by me on the subject of nutrition, food and food chemistry / law:

The book “What's in it?” Is for those looking for independent information on additives and food labeling. The book is divided into four parts. It starts with a compact introduction to the basics of nutrition. The content of the second part is a brief introduction to food labeling - how to read a list of ingredients. What information does it contain? This is supplemented by some further regulations for further information (EU labeling of geographical information, organic / eco-labels, etc.).

The largest of the four parts is a description of the technological effect, the purpose and the advantages - as well as known risks - of additives. The last part shows an example of 13 foods, how to read a list of ingredients and other information, what information can be derived from this before buying, which will help you to avoid bad purchases and which tricks manufacturers use to disguise or add additives To make the product look better than it is. In 2012 a new edition was published, expanded by 40 pages. On the one hand, it takes account of the changed laws (new additives have been included, regulations on light products are described) and, on the other hand, it contains a keyword index that many readers have asked for a quicker look-up.

It turns out that most of the readers bought the book because of the central part, which contains the additives. I also got feedback that a reference table would be very useful here. So in 2012 I went through this part and the section on food law again, adding the newly approved additives and new regulations, such as when advertising with nutritional information. Supplemented by a reference table, the two middle parts are now available as a separate book under the title "Additives and E-Numbers".

After losing more than 30 kg myself, but also had to find out how little many people know about nutrition or food, I set out to write a diet guide "of the other kind". It does not contain a magic bullet (albeit a lot of useful tips), but takes the approach that someone who is more successful with a diet who knows more about the basics of nutrition, what happens when losing weight and where dangers lurk. That's why I consciously called the book "This is not a diet guide: ... but an aid for losing weight". It is more of a book about the basics of nutrition, what a healthy diet looks like and how this knowledge can be put into practice in a diet. It is therefore also of interest to people who just want to find out more about healthy eating and are looking for tips to maintain their weight.

The book "What you always wanted to know about food and nutrition" is aimed at everyone who has one or two questions about food and nutrition, as well as who are interested in the subject and are looking for further information. While other authors also take up popular questions and often answer them in a few sentences and move on to the next question, I have limited myself to 220 questions, which I see more as a starting point for a topic, so the book also has 392 pages. So each question takes up 1-2 pages. They are grouped according to similar issues / food and these are again divided into four sections: two large ones on food and nutrition and two small ones on additives and food law / advertising. You can therefore read through the book from cover to cover and thus broaden your horizons, but you can also quickly look for an answer. I got a lot of positive feedback, mainly because the style is not sensational and wants to spread a dogma, but is enlightening.

You can get all of my books from bookstores (but only on order), but also from bookshops such as Amazon, Libri, Buecher.de and ITunes. You can also order the books directly from BOD.

You can find more about these books and others by the author on the subject of space travel on the Raumfahrtbucher.de website.

© of the text: Bernd Leitenberger. Any publication of this text in whole or in part may only take place with the consent of the author.