What type of fertilizer does a cactus need?
This article provides readers with some tips on caring for the multi肉 plant cactus, specifically addressing the question of what fertilizer it needs. Here is a comprehensive introduction to follow.
Many hobbyists wonder what type of fertilizer a cactus requires. All plants need fertilizer, but cacti need so little that their needs are often overlooked.
We have no way of investigating the soil solution composition of all the cactus's native habitats. Based on the long-term cultivation experience of Europe, America, and Japan, the ratio of nitrogen, phosphorus, and potassium that cacti need is roughly 1:2:3. Commercially available chemical fertilizers for cacti are generally designed around this ratio.
Additionally, plants require numerous microelements, but from my observations over the years, I have not noticed where these elements come from or what role they play. The amount contained in various substrates should be sufficient.
What does our soil lack? At the very least, it doesn't lack phosphorus. Although phosphorus is an essential macronutrient for cacti, even without using any phosphorus fertilizer, the coal slag and organic fertilizers we commonly use always contain excessive phosphorus. If you use organic fertilizer, you won't lack nitrogen either. Has your pot ever grown weeds? Cacti require much less nitrogen than weeds. Potassium, on the other hand, is generally deficient.
Simplified Fertilizing Guide:
Now refer to the fifth question. If you are using a soil分离 (separated) substrate, fertilizing is necessary. For common spherical varieties, we recommend using Ogreen A2 slow-release fertilizer or Florduo 11 water-soluble fertilizer. There is no technical skill required for using slow-release fertilizer; just throw it in. Apply once in spring and once in summer. In reality, they decompose much faster than advertised. From the first application in March or April and the second in June (no need for shaping plants), they have already turned into empty shells by the end of summer. In autumn, you can apply potassium nitrate 1-2 times at a concentration of 1/1000. Florduo 11 can be used throughout the growing season at a concentration of 1/1000, alternating between watering with clear water and fertilized water. For mature plants, you can sprinkle it directly into the soil, while for young plants you want to grow quickly, it's best to soak the pot in fertilized water.
If you are using a semi-separated substrate, which includes coal slag, the combined fertilizer should be changed to one without phosphorus, with potassium nitrate being the best option, also at a concentration of 1/1000, and used in the same way as Florduo 11. If potassium nitrate is not available (this stuff can be used to make Qassam rockets in Palestine, so it's not easy to buy), you can purchase "Potassium Plus" from the Long灯 Group, available at agricultural supply stores or on (Taobao).
Soil-fertilizer mixed substrates are not recommended for growing high-end varieties. If you are growing columnar species like the King Cactus or trigonal grafting balls, that's fine, and additional fertilizing can include some homemade organic liquid fertilizer.
The above-specific introduction on the type of fertilizer a cactus needs is provided for readers' reference and learning.