Is soil improvement always necessary?
Is soil improvement always necessary?
About organic matter, compost, leaf mould, peat, sand and fertilisation.
We have been farming on our dry, poor Veluwe sandy soil for over forty years. A hundred years ago, it was still heathland with drifting sand. In those forty years, we have gained a great deal of experience in improving the soil and making it more moisture-retentive. Of course, it is important to find out in advance whether this is actually necessary, and opinions on this vary considerably. Roughly speaking, there are three approaches: doing nothing, impoverishing the soil by adding a layer of sand, and the classic soil or planting hole improvement.
Not doing anything to improve the soil sounds very appealing, of course. Every now and then you read stories (including from fellow growers) that plants have to fend for themselves. Only then will they become strong. In our experience, this only works with very specific plants, such as those in a prairie garden. Moreover, you have to limit your choice to the strongest species that are suitable for a particular soil type. With a little help in the beginning (they are like babies), you can have much more variety and the plants will eventually thrive.
In recent years, there has been a trend towards impoverishing the soil. This sometimes goes so far that a layer of sharp sand about 20 cm thick is spread over the ground. This was started by the Swede Peter Korn, and it is very interesting to read more about it. We sell his book, Peter Korn's Garden, Giving Plants What They Want, here at the nursery. In it, you can read all about his famous sand beds. We have created a few sand beds here at the nursery and will see how the plants behave in them. However, no matter how you look at it, raising your garden by 20 cm with sand is quite an undertaking, usually requiring the subsoil to be dug out first. Moreover, it is difficult to stimulate soil life in such a mineral sand layer.
We are of the old school and firmly believe that soil improvement is beneficial in almost all cases. Walahfrid Strabo (808-849), abbot of the monastery of Reichenau, wrote centuries ago: "The earth does not refuse to produce healthy and natural fruits and vegetables for us. But on one condition: that we are not trapped in a sluggish laziness and do not think, out of some foolish conceit, that all gardening is something inferior. Moreover, we must not be afraid of getting our hands dirty or calloused from daily contact with tools. Let us also not forget to give our earth a full wheelbarrow of manure in the heat and dust." At that time, people mainly grew food crops that needed more manure, but ornamental plants also need a little extra in the beginning to take root properly. Gardening, and certainly planting crops, is an artificial sensation for plants. A plant grown in a pot that has to find its way in whatever garden situation it ends up in. This could be a garden in a new housing estate with dead, sprayed soil, without any structure, or an old border or (boxwood) hedge that has been dug up and where the soil is completely exhausted. We cannot emphasise this enough: do not skimp on organic material! It is the engine of the soil and ensures that there is enough soil life and that it remains active! The organic matter is broken down by the soil life, creating humus. Soil rich in organic matter retains more moisture and binds nutrients.
By organic matter, we do not mean that bag of dried cow manure pellets, because that does not do any good. We mean compost, leaf mould or farmyard manure. Peat is also an organic matter, but we should no longer use it. This is because we need to treat the peat bogs that we still have left with greater care. Peat now comes entirely from Russia and the Baltic states. Transporting it here consumes a lot of energy. Furthermore, it has no natural nutrients, which must therefore always be added artificially (usually in the form of artificial fertiliser). Finally, and this is often forgotten, peat contains a lot of CO2 stored. Whether you burn it as peat blocks in the stove or use it ground up in the garden where it decomposes, it produces a lot of CO2 free.
Adding organic material is important for both new gardens and existing plantings. We still see people wanting to work compost into existing plantings. Don't dig it in, but apply a 2-3 cm thick layer of mulch (covering layer) between the plants in early spring or late autumn. We always do this early in the season, after we have cut back the perennials and preferably while the bulbs are still in the ground. We leave the leaves that fell last autumn where they are and sprinkle a thin layer of compost or leaf mould over them. The advantage is that it does not blow away and decomposes more quickly. This way, you will have hardly any weeds and you will get a loose, crumbly top layer, full of soil life. If you think the plants need some extra fertiliser, sprinkle the fertiliser granules first and then the compost.
Even in a new garden, it is advisable not to work the compost into the soil. Allow 3-5 m3 per 100 m2. This means a layer of 3-5 cm. You can work it into the top layer with a pitchfork, but do not go deeper than 10 cm.
It would be going too far to discuss home composting of organic waste in detail in this chapter. But it is incomprehensible when you see wheelie bins full of leaves standing by the roadside in autumn. It really is black gold for the garden!
We often hear stories that the leaves won't decompose, but if you compost them properly, it's actually very simple: Make two compartments out of chicken wire measuring approximately one metre by one metre. Collect the leaves in damp, rainy weather with a rake! Dry leaves blown together with a leaf blower in dry weather decompose very poorly. By raking them together while damp, you also collect some of the topsoil and humus particles, which contain a lot of soil life. Throw about 20 cm of leaves into the compartment and sprinkle with a thin layer of soil (or even better: old compost). Repeat this a few times and press down firmly each time so that it becomes a solid mass. This will cause the leaves to ferment (just like with Bokashi). After six months, grab the grabber and throw the material into the adjacent bin. If there are clumps of leaves, break them up and mix them together. This time, do this without trampling, so that oxygen can get in. Now the composting process begins and the soil life starts to develop. Turn the mixture over again after about three months and, in most cases, you will have good leaf mould a year and a half after collecting the leaves. If this takes too long or you don't have access to fallen leaves, we sell leaf mould here at the nursery.