Soil Care in Autumn: What to Bear in Mind

The garden is slowly preparing for hibernation. The kitchen garden has been largely cleared, the fruit trees are going dormant and no longer need nutrients. Nevertheless, it makes sense to apply slow-acting fertilisers now – as a stockpile for the coming year. Read here what else you need to know about soil care in autumn.

Soil care in autumn: Slow-release fertiliser for the garden

In addition to compost, manure and lime can be applied in autumn and winter. But be careful: never apply both at the same time. Lime promotes the rapid decomposition of dung or manure. This means that nutrients are already lost in autumn and winter.

Do not apply lime on spec, but determine the soil pH beforehand. This can easily be done with a test kit from the garden centre. If the pH value is too low, liming will help. Phosphate lasts about two years in the soil and can also be applied in autumn.

The heavier the soil, the better it holds the nutrients. On clay soil, potassium also remains in the root zone of the crop for two years, on sand rather only for one year.

Soil care in autumn: compost

Two-year-old, well-rotted compost can be used anywhere in the garden in autumn. In addition to fertilising nutritive humus, it contains valuable permanent humus that improves the soil in the long term. It makes heavy soils light and crumbly, while light soils retain nutrients and water much longer.

Compost works slowly and over a longer period of time. That is why it is best applied in the vegetable garden between November and March as a basic fertiliser. Spread it on the unplanted beds. Do not undermine, because most of the roots will later be found in the top 20 centimetres of the topsoil.

If you want to grow strong crops such as head cabbage or pumpkins on the beds, give about five litres per square metre, otherwise three litres are quite sufficient. Compost from the current year that is only a few months old can also be used now, but: It will be largely decomposed on the bed within one growing season. During this decomposition, its nutrients are released. It therefore acts primarily as a fertiliser. Still coarse, unrotted components are sieved off and returned to the compost, where they decompose further. They are also suitable for mulching.

Turning compost

Compost from the previous year is now turned so that the upper layers go to the bottom and the outer layers go to the inside. In this way, an even and well-rotted humus is created in slatted composters and windrows until the coming autumn.

In closed composters made of plastic (thermal composters) there is no turning. Here, the finished compost is taken out of the flap provided at the bottom. New plant waste is continuously added to the top. This relatively young humus has above all a fertilising effect and is particularly suitable for soil care in autumn.

Only spread manure at the end of winter

What is often used as a swear word is actually a technical term: manure, or more precisely stable manure, contains straw or other remains of the bedding used in addition to the excrement of cattle, horses or other farm animals.

Manure, on the other hand, gave the fertiliser its name and contains only animal excrement. Both can be used fresh, but it is best to use it only at the end of winter on cold soil. By spring, it is then less acrid and does not burn the young roots. Better still, manure or dung is first composted for one to two years. This turns it into valuable compost.

Autumn fertilisation with dung or manure is not recommended. During the autumn months there is increased leaching of nutrients, which is why fertilisation is not efficient. More importantly, large amounts of nitrogen are released into the groundwater and harm the environment.

Soil care in autumn: green manuring

Autumn is the ideal time to give exhausted garden soil a cure. Green manuring loosens the soil through the targeted cultivation of certain plants, promotes microorganisms and supplies important nutrients. In this way, beds can recover between two heavily consuming vegetable crops, for example.

If the garden soil is very depleted, it makes sense to leave the green manure plants for a whole year. If you want to speed things up, you can sow fast-growing plants in autumn that will still grow plenty of leaf mass until winter (e.g. yellow mustard, yellow lupins or phacelia). Water the planting well and also water on dry days. In late autumn, mow the bed and work it into the soil or mulch it. Then wait at least three weeks until the next plants come into the bed, because the green manure must have decomposed sufficiently.

Digging up was yesterday

Digging up is part of soil care in autumn? This cannot be said without exception. Because even if you want to do something good for your beds, deep digging up messes things up. Soil consists of different layers, which differ in their composition and are also colonised by different soil organisms. In a healthy soil there are not only a few earthworms, but also fungi, bacteria, arachnids, nematodes and protozoa – billions of small organisms live in just one litre of soil.

And they are responsible for the decomposition of organic material, making nutrients available to the garden plants. Normally, these creatures are exactly where they belong. If, however, intensive digging brings the lower layer to the top and vice versa, these little helpers become irritated. Only very compacted and heavy clay soils really need to be dug up.

What you can do instead: Use a digging fork to ensure good aeration of the soil. This does not shift anything, but it does loosen the soil. In addition, every garden soil is happy to have a protective cover in winter. For example, a layer of mulch can be spread over shrubs that have been pulled in. This protects against drying out and insulates against the cold.