Why do your plants often get sick?

The answer lies in a particular feature of natural ecosystems known to professionals as the "Curse of Dimensionality." Here's the deal. If the state of an ecosystem as a whole depends on many parameters at once, then the optimal niche for a specific flower within the system becomes exceedingly small. And the more independent factors influencing the system, the smaller this comfort zone becomes.
In simple terms, the more external parameters, the harder it is to hit the optimum. In practice, the optimum in a multi-parameter system is not even the "bullseye" of the target, but a small point at the center of the "bullseye" that is almost impossible to hit.

Let me try to illustrate this with an example. (If you're not a fan of long explanations, skip to the conclusions at the end of the article)

So, let's start by estimating how many independent parameters need to be optimized to create ideal conditions for a plant.
At the very least, we will need:

1. Average minimum temperature in the coldest month
2. Average summer temperature
3. Daily temperature fluctuation in summer
4. Level of precipitation over 4 seasons
5. Light exposure during the warm season
6. Soil acidity
7. Soil's ability to retain moisture
8. Content of at least the basic 5 elements in the soil
9. Air humidity

So, considering the multiplicity of items 4 and 8, we end up with no less than 16. This will be the dimensionality of our "configuration space." For simplicity, let's normalize the axes so that the entire range of life-sustaining conditions along any axis fits within the range from 0 to 1. Let's use the standard Euclidean metric (this is, of course, a very, very rough simplification, but it will do for illustration).

Now, again for simplicity, let's assume we need to find a planting spot for a flower whose life optimum is at the origin, where the "green" zone is no further than 0.33 from the origin, the red zone is beyond 0.66, and the yellow zone is in between.
Mathematically speaking, we have three 16-dimensional spheres before us.
Let's say we are very lucky and found a spot in the garden where all the listed parameters fall within the green zone: from 0.15 to 0.25. On average, 0.2. Where will our flower with these parameters end up?
In other words, at what distance from the origin will the point in our 16-dimensional space with coordinates 0.2 along all axes be? The correct answer is √(16×0.2²)=0.8 (check it yourself).
So, it ends up far in the red zone.At first glance, N-dimensional spaces with the Euclidean metric may seem very similar to the familiar 3D to us. In many ways, that's true. But there are nuances. In particular, as the dimensionality increases, the main volume of the sphere rapidly shifts towards the periphery. For a sphere of radius 2, for example, with N=2, 1/4 of the volume lies at a distance of less than 1 from the center.
For N=3, it's already 1/8, for N=10—less than 0.1%!!
And for N=16, the ratio is even more extreme.
This is essentially what the article is about.
Note that when randomly selecting initial parameters, the probability of hitting the zone of optimal growth with N>10 is practically zero. This is one of the reasons why a professional, who makes a conscious choice, will quickly outperform an amateur who essentially rolls the dice when making decisions.

What does this look like in practice? Quite simple: a little less watering, a bit more shade, plus overly acidic soil and a lack of phosphorus— and your plant no longer has the strength to resist infection.

Conclusions

When the effectiveness of a system depends on many parameters, even a relatively small deterioration in each of them can throw the system far into the red zone relative to the optimum. This is the "Curse of Dimensionality."

This happens quite often with plants.
Formally, everything seems fine with the parameters, the soil, water, and fertilizers, yet the end result is barely passing. You waste time, money, and all in vain.

By the way, celebrities are somewhat similar. A clone may look very much like the original, but slight deviations immediately throw it out of fans' interest zone along many parameters.

But why do weeds grow so well then?
The thing is, nature is a great experimenter. For thousands of years, it has been trying thousands of variations (only the strongest survive!) and eventually gets as close as possible to the center of the multidimensional target. And you end up with an indestructible weed.

How to Overcome the "Curse of Dimensionality" in Practice?

Main advice: observe. Observe and experiment. Look for the species that thrive in your specific conditions and support them. Think twice before planting something you're not 100% sure about. Then your garden will bring you health with minimal maintenance costs.

And of course, use microclimate sensors. They won't solve all your problems, but they will prevent major mistakes. And that's already 80% of success.

Here are a few simple examples:
— a basic sensor measuring soil temperature in real-time will save you from pondering what and when to plant; just glance at the graph
— a soil moisture sensor will help you see not only the water available to plants but also determine the rate of its loss per hour, a key indicator of how quickly the soil moves out of the comfort zone after watering
— if you know the light intensity and temperature precisely at the north wall of your house, you won't make a mistake planting a plant there that is specific to these parameters

and so on. Trust me, it's worth it!