What does fertilizing succulents actually mean? Read this and you'll understand

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As a stubborn gardening traditionalist (as opposed to a tech-oriented person), Lao Jiang has always upheld the native spirit of China, a great agricultural nation with five thousand years of heritage. I have always believed: "Soil is the only reliable source of plant nutrition; only soil is the necessary medium for plants to take root and grow. Soil has the ability to protect and regulate itself. When pests and diseases appear, plants will die, ultimately depriving pests and diseases of a breeding ground. Once the pests and diseases have starved to death, the soil is still healthy soil. When the soil loses its fertility, plants will not grow until rainwater and air bring nutrients to restore the soil's vitality. A goat grazing on green grass will eventually fall on the green meadow and become nutrients for the grass. The abundant fresh fruit, although it consumes the soil's nutrients, returns everything it received to the soil once it matures. In nature, there are no pesticides and no chemical fertilizers, yet natural soil possesses a powerful force that humans cannot replicate......" Although not religious, Lao Jiang has read the agricultural passages in the Bible several times.

This is not Lao Jiang showing off; the truth is there really isn't much to write about. But since this chapter has already been decided, I still have to pad out the word count somehow. Below I'll briefly share my own understanding of fertilizers and chemicals.

1. The impact of fertilizers on succulents

For plant growth, fertilizer is essential. The "100,000 Whys" tells us that the three essential elements for plant growth were discovered by the British. By burning plants and analyzing the resulting ash, scientists identified large amounts of nitrogen, phosphorus, and potassium, along with trace amounts of other elements. Thus the conclusion was drawn that the three essential elements for plant growth are: nitrogen, phosphorus, and potassium.

Nitrogen is mainly concentrated in the leaves and branches of plants, so supplementing with nitrogen fertilizer can promote the growth of leaves and branches. Lush foliage is the work of nitrogen fertilizer.

Phosphorus is mainly concentrated in the reproductive organs of plants - that is, flowers and fruits. Supplementing with phosphorus fertilizer can promote flower bud differentiation and fruit development. Abundant fruit is the work of phosphorus fertilizer.

Potassium is mainly concentrated in the stem and root tissues of plants. Supplementing with potassium fertilizer can make plant stems thick and strong, roots well-developed, increase resistance to lodging, and increase the ability to withstand external threats. Deep roots are the work of potassium fertilizer.

Apart from the elusive trace elements, the effects of fertilizers roughly come down to the above 3 points. As for whether home-grown succulents need additional nutrients, Lao Jiang has always held reservations. I believe that with proper soil mixing and regular repotting and soil changing, slow-growing succulents hardly need additional fertilizer supplementation. Unlike herbaceous flowers, succulents grow only a few leaves a year, which results in very little consumption. Little consumption naturally means little eating, and on top of that, there are several months of dormancy each year. So for nutrient needs, what's already in the soil is more than enough.

I've never seen succulents suffer from fertilizer deficiency, but I've often encountered root burn from too much fertilizer. As mentioned earlier, the osmotic pressure of succulent roots is mainly discussed in the context of over-fertilization. When Lao Jiang first started growing succulents, he was superstitious about the effects of fertilizer. Unexpectedly, every time he fertilized, the plants rotted. The result was that the fertilizer didn't achieve its effect, but he did gain a lot of experience from repotting and changing soil.

However, nothing is absolute. Constancy is relative, while change is absolute. When there is no need for cross-pollination, fertilizing is superfluous. But if there is a need for cross-pollination, the situation is completely different.

Plants flowering and fruiting requires consuming large amounts of nutrients, not just the phosphorus fertilizer we mentioned earlier. Flowering and fruiting is an important life cycle for plants, so at this time, all of the plant's tissues will coordinate for this important act of reproduction, including: stems will thicken to prevent lodging from the weight of flowers and fruits. Roots will grip deeper to help absorb more nutrients. Some plants will even shed leaves appropriately to avoid blocking insect pollination and fruit exposure to light.

In summary, plants need more nutrients to support flowering and fruiting. Apart from the earlier accumulation, more importantly, timely external supplementation is needed. Wild Haworthia are not like cultivated ones. Although wild Haworthia will also grow 3 or 4 flower stalks and produce dozens of flowers, not every flower has a chance to be successfully pollinated. On the contrary, this ratio is often even zero. (This is determined by the flower structure of Liliaceae plants.) But home-grown ones are different. The pollination success rate will be much higher, sometimes even a single flower stalk producing over a dozen or twenty seed pods. The situation with Aizoaceae plants is roughly the same. So home-grown succulents, because they need to meet the consumption demands of cross-pollination, require more additional nutrient supplementation.

Flowering fertilizer is mainly phosphorus and potassium fertilizer, with other elements as supplementary. It is best applied in liquid form for rapid effect. You can choose professional flower fertilizers like Huayou or Huaduoduo, or directly apply monopotassium phosphate. The application ratio should be controlled at about 1:2000, that is, 1 gram of fertilizer to 2 kg of water. It should be noted again here that some experts may think a 1:1000 ratio is more appropriate, but that is under greenhouse and conservatory cultivation conditions where plants are growing vigorously, so this concentration can be used. In a home environment, the rate at which plants absorb nutrients is far slower than in greenhouses and conservatories, so dilute as much as possible.

The timing of fertilization is during the flowering period, that is, starting from when the flower stalk emerges, once every half month, applied together with watering. Continue until the seed pods mature. For individuals whose flowering period needs to be controlled or flowering time coordinated, you can apply less or not at all.

That's all Lao Jiang knows about fertilizers. Any more and it would just be nonsense, so I'll stop here. Now let's talk about chemicals.

2. The impact of chemicals on succulents (excluding growth-regulating chemicals)

Succulents rarely suffer from pests and diseases, even if they come from South Africa. The harsh environment of the African continent has given succulents strong adaptability. Probably because they are exotic species, home-grown Haworthia and Aizoaceae give me the overall impression of being ignored by chickens and ducks alike. Common red spider mites and scale insects are nowhere to be seen. Occasionally a small black fly emerges from the soil, but it's harmless.

However, I have heard about pest and disease problems from some flower enthusiasts' blogs, mainly about the larvae of flying insects like fungus gnats harming seedling roots. Although I have never experienced this myself, I suspect it may be related to the soil properties these enthusiasts use. These enthusiasts add natural ingredients like leaf mold and coal cinder to their medium, or even use these materials entirely. Natural things are indeed environmentally friendly, but it's hard to avoid insect eggs and pathogens lingering in them. Over time, it's only natural that bugs appear.

Lao Jiang doesn't have much experience with using chemicals. Many times, when one or two plants show symptoms of rot or disease, Lao Jiang prefers to use surgical methods to completely eliminate the affected area. In hindsight, prevention should still be the priority. Technology is so advanced now; not making good use of the power of technology and instead constantly cutting away with a scalpel is a bit too bloody...... So for a period of time, Lao Jiang also put effort into doing some superficial research on chemical use. Below I'll briefly share what I learned.

For ordinary gardening enthusiasts, the most commonly used garden chemicals are broad-spectrum fungicides like carbendazim, thiophanate-methyl, and chlorothalonil, as well as expired pesticides like carbofuran (carbofuran has been banned by the state due to its high toxicity and high residue). For home cultivation, the above chemicals are already sufficient to handle common pests and diseases, but which specific chemical to use and how to use it involves some subtle points.

Common diseases of general garden plants include leaf rot, root rot, and a series of harms caused by fungal infections. If each condition is not treated promptly, it will lead to the rotting of some plant organs or even the death of the entire plant. But for South African succulents, bacterial leaf rot and root rot rarely occur (except when wounds from physical damage are not treated promptly). The only thing that poses the greatest threat to succulents is infection caused by fungi, specifically manifested as large-scale fungal infection after poor ventilation, humidity, and inadequate sterilization of the growing medium, which is what we commonly call "fuzz." The probability of outbreak is highest especially at the seedling stage.

It should be noted here: the "fuzz" on the soil surface is a fungal infection, a pathological manifestation, while the mycelium inside the medium is an inevitable phenomenon of soil organic matter decomposition, a normal phenomenon. Fungal infection uses the plant's tissue cells as a nutrient source, ultimately causing the plant's tissues to rot. The mycelium inside the medium, however, is a saprophytic fungus, a probiotic that decomposes organic matter in the medium to help plants absorb nutrients, and will not harm the living plant body. (Except for the heat generated during bacterial reproduction.) These two need to be treated differently; do not lump them together.

Through the above analysis, we also need to be selective in using antibacterial chemicals. We all know that carbendazim and thiophanate-methyl are broad-spectrum antibacterial drugs, mainly targeting bacterial infections. Chlorothalonil, on the other hand, mainly targets fungal elimination. In the process of home cultivation of succulents, since the main focus is on resisting fungal infections, preventive application should use chlorothalonil as the main chemical. To avoid the development of drug resistance, carbendazim and thiophanate-methyl can be used alternately as a supplement. For wound treatment after pruning and shaping, carbendazim and thiophanate-methyl should be the main choices, and the effect of chlorothalonil will be much worse by comparison. Chemical use should follow the 16-character formula: "prevention first, alternate use, increase concentration, reduce frequency."

Prevention first means nipping problems in the bud, controlling before signs appear. Don't wait until you see the lesion before using chemicals; by then, even if you get it under control, it will affect the plant's appearance and even its future health. Generally, the period of seasonal transition is a key point for preventive chemical application.

Alternate use means preventing the development of drug resistance in fungi. The same chemical should be used continuously at most 3 times before switching to another. Otherwise, once resistance develops, applying the chemical is like watering - completely ineffective. And because you have one less alternative chemical available, the frequency of using other chemicals will increase, causing those other chemicals to also become ineffective due to resistance.

Increase concentration - this is a chemical application strategy that applies to both animals and plants. For routine diseases and explosive acute infections, increasing the concentration by 30-50% above the label concentration can achieve good results in a short time, allowing the infected individual, in the sterile environment created by the high-concentration chemical, to improve its own resistance through strengthened management and follow-up care, and recover health sooner.

Reduce frequency - this is relative to increasing concentration. As mentioned above, there are probiotics in the soil. Sterilizing chemicals, while treating the problem, will also indiscriminately kill probiotics. Probiotics are beneficial for improving soil quality and preventing compaction. So this factor must be considered when using chemicals; do not use them too frequently. Give probiotics appropriate space to grow. In addition, reducing the frequency of chemical use can also avoid the development of drug resistance. It is recommended that the interval for preventive application be 2 months, and it can be appropriately increased during seasonal transitions.

Finally, 2 tips:

1. After sowing, if there is continuous rainy weather and the potting soil is too moist, fungi can easily break out in the pot, and at this time chemicals must be applied. However, since the potting soil is already in a very moist state, applying conventional chemicals will undoubtedly add more water to the already moist environment, which is very unfavorable for seed germination. At this time, you can directly and evenly sprinkle the dry powder of the chemical on the pot surface, without needing to dilute it with water and spray.

2. Conventional sterilizing chemicals are powders that use talc as a carrier (the white powder we see is actually talc, and the actual active ingredient of the chemical is invisible). After dilution and spraying, it will form white spots on the plant surface, affecting the plant's appearance and photosynthesis, and is very difficult to remove. It is recommended to let the diluted chemical sit for 2 hours, and after the talc has settled, use only the supernatant liquid for spraying (that is, the active ingredient of the chemical), which can avoid the above contamination.

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