How to Grow Succulents: What Fertilizer to Use for Succulents
Succulents are different from herbaceous flowering plants, so many gardening enthusiasts who grow succulents do not know what fertilizer to use for succulents, or whether succulents need fertilizing at all. There is also quite a bit of information online about succulent fertilizers. This article focuses on analyzing how to fertilize succulents from different angles. Fertilizers can be broadly divided into three major categories: nitrogen, phosphorus and potassium. Their functions are well known, but let us recap: nitrogen fertilizer promotes the growth of leaves and branches, phosphorus fertilizer promotes flowering and fruiting, and potassium fertilizer promotes sturdy roots and stems. So when buying fertilizer, gardeners can take a look at the ratio.
As for what fertilizer to use for succulents, you only need to bury some slow-release flower fertilizer or organic fertilizer at the bottom of the pot, and combined with regular repotting and soil changing, slow-growing succulents hardly need any additional fertilizer supplementation. Because succulents typically grow only a few leaves a year, this results in extremely low consumption. Low consumption naturally means they eat little, and on top of that, there are several months of dormancy during the year. So as for nutrient requirements, what is already present in the soil is more than enough.
As a type of fertilizer, it is added to routine watering to promote plant growth and development. This is similar to the nutrient solution used in soilless cultivation, but slightly different from fertilizing: its concentration should be far lower than the concentration used for fertilizing. In addition, considering the biological effects of plant nutrients, we believe it should mainly supplement phosphorus, potassium and trace elements, and use as little nitrogen as possible. Below is a brief introduction to several commonly used substances:
Potassium dihydrogen phosphate: KH2PO4, a highly effective phosphorus-potassium fertilizer. Its phosphorus-to-potassium ratio is quite suitable for plant growth, and hardly any chemical substance can replace it. This salt hydrolyzes to a slightly acidic solution and is physiologically neutral, making it very suitable for spraying on plant surfaces. It can promote the metabolism and development of epidermal cells, improving ornamental appearance, while also supplementing the phosphorus and potassium elements plants need. In addition, this compound can act as a buffering substance, assisting the absorption of other additives, and it will not damage plant cells. The commonly used spray concentration is 0.01~0.1%; it can also be injected into plant pith as a means of rapidly supplementing a plant's nutrient status. It is very effective, but the solution must be sterilized under high pressure, with a concentration of 0.4 mol/L.
Ferrous sulfate: FeSO4.7H2O, commonly known as green vitriol or black vitriol. It is used as an acid-price regulator, mainly to adjust the pH of water. It is generally not used as a means of supplementing iron, because this substance rapidly oxidizes to ferric iron in aqueous solution, and ferric ions cannot be absorbed by plants and may even be toxic to plant cells. If iron supplementation is needed, chelated iron should be used, such as ferric citrate, EDTA iron, etc., at a concentration of 0.001~0.1%, and it should not be used continuously. In addition, ferrous sulfate is called "black vitriol" because the liquid from fermenting it together with soybeans is black. This is an excellent organic fertilizer and is recommended for use, but it must be fully fermented, otherwise it will cause air pollution and breed pests.