The nice thing about growing potatoes is that you can decide for yourself which variety you want to plant. Whether floury or waxy, red-skinned or yellow – there is a potato to suit every taste. In order for it to grow and thrive even without garden soil, a so-called planting bag is required. This is a stable, but air and water permeable bag made of solid plastic fabric, which is intended to enable private vegetable cultivation in the smallest of spaces. However, before you start growing, some precautions must be taken. We will explain what these are as follows.
First of all, it is important to know that you can only grow new potatoes from pre-germinated (old) seed potatoes. Accordingly, you should store your favorite variety in a dry, bright and cool (approx. 10 °C) place from mid-March at the latest – for example on a windowsill in the bedroom. To ensure that all sides receive equal exposure and ventilation, it is recommended to store the potatoes upright in an empty egg carton.
When planting, keep in mind: You should not plan more than four potatoes per planting bag so that they have enough space to grow. While the nightshade plants begin to sprout again, you can take care of the necessary drainage. Ideally, this consists of several components – such as expanded clay and plant substrate (i.e. soil, sand and mature compost). Alternatively, you can also mix vegetable soil with sand.
Before you put the pre-germinated potatoes in the planting bag, first roll it down until it is only 30 centimeters high. Then fill the bag with expanded clay, a maximum of five centimeters high, and layer the plant substrate on top, about 15 centimeters high. Distribute the four nightshades per bag evenly over the soil and cover the tubers completely. The plant bag is then watered well.
As soon as the plants have reached a height of around 30 centimeters, roll the bag up further and fill it again with fresh substrate (approx. 15 cm high). After two weeks at the latest, repeat the process again and then again 14 days later. This procedure is important because potato plants form new roots on their upper shoots – and thus additional tubers. And the more tubers, the bigger the harvest.
Although most plant bags are permeable to water, it can happen that waterlogging forms on the ground – which should be avoided at all costs. So that the excess liquid can drain away properly, it is recommended to cut several small drainage slots (maximum one to two centimeters long) in the bottom of the bag with a craft knife.
The plant bags should be completely rolled up after six weeks. The first nightshade plants can be harvested another six to eight weeks later. You can see whether you are really ready by looking at the integrated folding window on the bags. Another indication that the potatoes are ripe is the yellow, dried shoots (after the plants have flowered). So the longer you wait, the larger the tubers will become. However, you should remove all potatoes from the planting bag by autumn at the latest, before the first frost comes.
Another tip: Dark humic acid spots are likely to form under the plant bag. If you want to protect the floor on the balcony and terrace from this, place the bag on a waterproof film.
Source: My Beautiful Garden
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