Soil Moisture

[SeniorCitizen]

What soil moisture does your vegetable garden plants like. I've found a 25% moisture by weight is suitable for most of my common vegetable garden plants.

 

[Chuck]

I haven't used that particular meter but I have yet to find any of them to be more accurate than my finger. I am convinced it is just a scam. Most of them only go to about 6 inches or so. In container plants the lower few inches will be wet while the top 4 - 6 inches will say "needs moisture". NOTHING tells you when a plant needs water other than the plant itself and that happens in the AM hours, not in the heat of the afternoon. And in most garden soil, roots are below 6 inches. Most seedlings are planted about 3 inches deep and as they grow the roots go deeper. And how will you determine with that particular meter? Dig up the soil around the plant and damage the roots or dig a foot away and miss the root zone altogether?

 

[SeniorCitizen]

That's exactly how it's done, with a core sample. It just doesn't get any better.

 

[Chuck]

That's exactly how it's done, with a core sample. It just doesn't get any better.

This is something new that I haven't seen before. Core samples taken at different depths could be a game changer. Glad you showed us. What is the name of this product and exactly how does it work?

 

[NigelJ]

Can't quite see how its going to work, the picture shows a form of balance, scale pan on the left, pivot on the left of the cast? piece then on the right of that what could be a spring or indicator (it's a really small, blurry picture so detail is hard to make out)
So I presume use would be to take sample using soil corer, place on pan and read then dry in oven at x° for n hours and take a second reading, difference is weight of moisture in soil sample.

 

[SeniorCitizen]

Can't quite see how its going to work, the picture shows a form of balance, scale pan on the left, pivot on the left of the cast? piece then on the right of that what could be a spring or indicator (it's a really small, blurry picture so detail is hard to make out)
So I presume use would be to take sample using soil corer, place on pan and read then dry in oven at x° for n hours and take a second reading, difference is weight of moisture in soil sample.

The scale was actually developed for gun powder weights many years ago but i use it because it weighs in grains and the sample can be dried in minutes in a microwave if a person is impatient. I also find it useful to determine MC of wood. For drying wood samples it's recommended to keep the °F or °C below water boiling point so i follow thet suggestion for dirt. When the sample ceases to loose weight it is said the MC is 0.0 % moisture. Some scientists will probably NIT-PICK and disagree but what the hell, we're drying dirt.

Most any scale will be satisfactory if time allows, even a food scale, being the result is determined mathematically.

 

[Chuck]

So, how do you take a core sample in the root zone of a tomato plant 6 inches deep?

 

[SeniorCitizen]

So, how do you take a core sample in the root zone of a tomato plant 6 inches deep?

I'm not understanding a need to take the sample within the root zone of a plant to check soil moisture, but regardless of where someone wants to take their sample I've pictured the 3/8" sharpened stainless tubing I've made to accomplish several tasks here at the ranch.

 

[Chuck]

I'm not understanding a need to take the sample within the root zone of a plant to check soil moisture, but regardless of where someone wants to take their sample I've pictured the 3/8" sharpened stainless tubing I've made to accomplish several tasks here at the ranch.

I can see how this can work. I'll see if I can scrounge up a piece of pipe and something to push the dirt out with. I have a bunch of different vegs growing in containers, some root bound, some not, I think. This can give me a better understanding of what is going on out of sight in the soil plus tell me how much moisture is there.

 

[NigelJ]

I must admit I hadn't thought of special scales for weighing gunpowder. For UK and other metric users 1 grain = 0.065 grams.
How big a soil sample do you take?

 

[SeniorCitizen]

I must admit I hadn't thought of special scales for weighing gunpowder. For UK and other metric users 1 grain = 0.065 grams.
How big a soil sample do you take?

That on the scale, original weight was 60 grains, dried weight 48 grains.

I'm kinda old and don't have much time to watch dirt dry so i'm into the micro thing. lol