How to grow succulents? Fertilizing methods and care tips

  Many friends ask how to fertilize succulents and how to mix soil when repotting. Actually, succulents themselves do not really need fertilizer. So if you do want to fertilize, how should you do it? The following summary should be useful to everyone:

  1. Potassium fertilizer is very important. Most commercially available compound fertilizers are not suitable for cacti and succulents. Phosphorus fertilizer comes second, especially when flowering and fruiting. With compound granular fertilizers, it is sometimes really impossible to say exactly what they contain. Traditional chemical fertilizers are still more reliable.

  2. Potassium chloride can be used temporarily in small amounts; the main issue is that it leaves chloride ions in the soil. Likewise, potassium sulfate should not be used much either.

  3. Chemical fertilizers that can be mixed together: potassium nitrate, monopotassium phosphate, plant ash, potassium chloride, etc. Among them, potassium nitrate and potassium chloride are neutral.

  4. Acidic pesticides and fertilizers all carry a warning: prohibited from being mixed with alkaline pesticides and fertilizers. Acidic fertilizers refer to salts that show acidity when dissolved in water, mainly ammonium salts of strong acids such as ammonium nitrate, ammonium sulfate and ammonium chloride, and acid salts such as monopotassium phosphate and superphosphate (whose main component is monocalcium phosphate). They cannot be mixed with alkaline pesticides and fertilizers because: ammonium salts decompose into ammonia gas when they meet alkali, and superphosphate reacts with alkali to form calcium phosphate, which is extremely insoluble in water. Monopotassium phosphate should not be included in this category, because when monopotassium phosphate is neutralized by alkali, the products dipotassium phosphate and potassium phosphate are both soluble in water.

  Conclusion: monopotassium phosphate should be able to be mixed with plant ash.

  5. Calcium is very important for some cactus globes, especially for those such as Ariocarpus (living rock cacti) that originate from limestone soils. Gypsum can be used, and it is best to use raw mineral gypsum. If you do not have it, then use superphosphate. Note that at this time alkaline substances such as plant ash must not be mixed in; for the reason, see 4… I feel that using peeled eggshells is also very good, provided the soil is on the acidic side.

  6. Regarding nitrogen, globe-shaped cacti generally do not need urea; its fertility is too strong and hard to control, and the small amount of nitrogen in potassium nitrate is enough. Everyone must pay attention to this: too much nitrogen fertilizer will make the globes burst. This includes types such as Astrophytum and Frailea; once you apply a handful of urea, the globes will crack within a few days… Ammonium nitrogen fertilizer lasts longer in the soil than nitrate nitrogen fertilizer, because nitrate easily washes out through the bottom of the pot with water. Ammonium salts, being cations, bind to soil particles and are more lasting. If the soil is on the acidic side, using a little ammonium dihydrogen phosphate, or a few granules of urea, will act over a longer period. Note: just a little urea.

  Summary:

  Formula 1: Use monopotassium phosphate + potassium nitrate as a top dressing, at very low concentration. Mix gypsum or superphosphate or eggshells into the soil. Then everything is fine.