Cactus care: Water & fertilize

Cacti (Cactaceae) are very popular ornamental plants. We give expert tips on what you need to consider when caring for and fertilizing prickly plants.

Cacti (Cactacea) are a family within the order of the carnation-like (Caryophyllales) and belong to the flowering plants (Magnoliopsida). In general, the cacti family includes more than 100 genera and over 1500 species. These numbers alone give an idea that cacti are much more diverse in terms of their morphology and physiology than you might think at first. There are tree-like species such as Pereskia grandifolia, but also very tiny species such as Blossfeldia liliputana. What they have in common, however, is that they are all based on the American continent. Here their occurrence extends from southern Canada to Argentina and Chile. They inhabit various habitats from tropical rainforests to dry deserts. What these very different habitats have in common: Seasonal water availability.

Cacti are among the succulents. They can store moisture in their tissues and survive even in severe drought. The thorns also minimize water evaporation and also protect against predators. Just as they can endure exhausting heat, hardy cacti also survive temperatures down to an almost unbelievable -20°C. Hardy species include, among others Chamaecereus silvestrii and Cylindropuntia imbricata. Not least because of these properties, cacti are considered the Spartans among ornamental plants. Put it in the sun, some water and nothing more can happen. But there are also a few points to consider when caring for cacti. Although the requirements vary between species, there are some tips and tricks for fertilizing and watering basically to be observed, so that the small green cactus on the balcony can also become a really big one can.

Water cacti properly

Cacti need water regularly, especially during the growth and flowering period in spring and summer. However, it should not be watered too often and waterlogging should be avoided at all costs, otherwise there is an increased risk of rot. The substrate should be (almost) completely dry before watering again.

Water the room cacti

In the case of indoor cacti, you can stimulate growth in the spring by showering them over. About a week later, the plants are watered more vigorously. A rule of thumb says: During the growing season from March to September, water thoroughly. You can easily check this by stuffing. Do not water again until the substrate is completely dry. Coasters, bowls or planters can hold excess water or be used to water from below. Another tried and tested method is the damming method: Here you place the pot with the cactus in a larger container with water so that the pot is completely submerged. As soon as no more air bubbles rise, take the cactus out of the water and put it back in its place after it has drained well.

Water cacti in the garden

If the cacti are in the garden, it is advisable to ensure an adequate water supply, especially in the spring months. In summer you should water fairly regularly. But only on sunny days after long periods of drought to avoid overwatering from subsequent rain. At the change of season, the watering rhythm is gradually reduced. In winter, special attention should be paid to watering. On the one hand, there is an increased risk that the soil will become waterlogged and fungal infections will spread. Additional rain protection should therefore be installed. On the other hand, a dry period in the winter months promotes the flowering of many types of cacti in the following year. However, this can only be implemented for potted plants that overwinter under a roof.

Fertilize cacti properly

It's a common misconception that cacti don't need fertilizing. On the contrary, there are few plants that are as dependent on fertilization as cacti. Deficiency symptoms often appear late and can then no longer be quickly remedied. Timely fertilization is therefore essential in order to be able to enjoy the plants for a long time.

Fertilize indoor cacti

For indoor cacti you should approx. start fertilizing four to six weeks after the first overspray in spring with a normal complete fertilizer dissolved in water. A liquid fertilizer like ours Plantura organic indoor and green plant fertilizer can be administered at every second watering from spring to July. However, the dosage for cacti is reduced to just 1 ml per liter of irrigation water.

Fertilize cacti in the garden

Outside, coarse horn shavings can be added to the topsoil in the garden or to the substrate in the planter as a basic fertilizer. Nevertheless, you should additionally fertilize from March. In the months of April to June, a 14-day fertilization has proven itself. You can use between 20 and 30 grams of a complete fertilizer (e.g. B. give blue grain. The commercially available liquid fertilizers (usually: 1% nutrient solution) should be watered regularly. In July, it is advisable to only fertilize the plants lightly. It is also advantageous to add a potassium fertilizer (Kalimagnesia 20 g/m²) admit. As a result, the plants harden well and are well prepared for the coming winter.

If you want to know more about caring for your plants, you can find them here 5 best tips for cactus and succulent care.