The Green Thumb - It's a myth

Pictured flower is Iris 'Air of Mystery"

"I don't have a green thumb."

The best example of this statement that I have heard comes from my own mother who, while I was growing up, would occasionally use the phrase, "I can't even keep a cactus alive."

Many people fantasize that to garden you have some inherent innate ability to just "get it", that this magic secret gardening tool is already inside you - or your hands.

They would say that you have it or... you don't.

Well, for someone who grew up like me with no family members who garden, no indoor plants that survived and virtually no experience with plants whatsoever, I have simply learned how to garden and for this reason I know that the inherent green thumb is in fact a myth.

Gardening is a skill that is learned akin to something like cooking. There are many tricks to many plant types but the most common root cause of failure is found in one of the most basic steps and if you fancy yourself having a green thumb, you already know the answer.

Get ready....

It's water.

The secret to almost all plant problems and all plants that thrive is found inside the dirt. It is the water content. And the quickest method for someone to learn how to gauge and understand the water content is just to get your hands in the dirt!

Below I will show you some diagrams for visual reference of water content.

(However, should you want to tackle this learning curve yourself to really understand this essential tool, I would urge you to try starting some seeds indoors! Young seedlings require a great deal of water and it is an accelerated cycle of learning that will take place as you watch new growth come to life!)

Allow me show you a diagram:

Soil Hydration Diagram

50% Hydration means that the soil is mixed with 50% water and 50% air pockets. Plant roots are like fish! They still need to breathe the oxygen trapped in the soil.

Happy plants live in a soil that has roughly 50% hydration. This goes for nearly every plant out there in my experience! The main difference is that each plant drinks at a 'different speed' and the hydration level dips much faster in some plants than in others. So inevitable the hydration level is always moving up and then down the scale!

Where people go wrong:

The main mistake of watering is to OVER-WATER and take the hydration up to 95%.

The most ideal range for watering is:

Water to 50% hydration and let dry to 20% before watering again.

The only time I water to 70% is:

Watering young seedlings. In a single day in a small 2" diameter pot, hydration levels for fast growing seedlings can go from 70% down to zero sometimes even before the following morning! But still with these fast drinking plants I never water to 95%.

Each extreme of this scale can result in a dead plant but it is infinitely more common that plants die at 95% than they do at zero. And some plants (like cactus!) are happy at zero for a time before needing to be watered again. But almost no plants can survive at 95%. They will drown!

The most common method I use for checking soil hydration:

It is known as the 1 inch rule. An inch below the surface of the soil is the real measure of maintained moisture levels. The top inch can easily dry out because of the sun or open air.

The Method:

Stick your finger into your soil about an inch. Cool temperature is an indication of water content and only time and experience will help you to gauge the hydration level by touch. However, following the general range of 20-50% is an excellent tool to help you learn about each plant that you care for and to watch how quickly it is able to drink the water!

What to watch for:

A key plant tell is to watch after watering for the bottom leaves turning yellow. This is the tell-tale sign of overwatering and can even happen to sensitive plants who prefer less that 50% hydration levels.