Do Cheap Soil Moisture Meters Work?

I have always been very good at judging when to water a plant, but lately I'm having a tougher time on some of my plants (Mostly Hoyas). One reason for difficulty is when the plant canopy is so tight, you can't get your finger into the soil to check for dampness. Another reason is using a new soil media that you are unfamiliar with and or combined with heavy pottery (when you are used to light weight plastic pots) so that it is difficult to judge by weight whether the plant needs water or not.

My question is do these cheap soil moisture meters that use no batteries, and are available everywhere, work or not. It is not much money, but I don't want to buy one if they are worthless. They do sell expensive ones, but they sound too complicated - requiring calibration and batteries. What is the best way to go when you really need to know if your plant needs water.

I think I may have just found the answer to my own question. I researched them on Amazon and the feedback pretty much indicated they were junk. Does anyone have experience with the more expensive meters ($35-$100)?

I've been using one for over a year now. It works better than my finger did. I also lift up the plants to see if they are heavy or light. I think I only paid $12.00 or some where close to that.

Don't waste your money. Get some bamboo stakes and stick one down in the soil and pull it out. Is it damp? Don't water! Dry? Water! Also learn how to water by the weight of the pot/container.

ooooo...I like the bamboo stakes idea.....good one...kinda like testing the doneness of a cake!!!

I'm going to try the stakes idea too. Maybe shishkabob skewers? I'm sure that has got to be spelled wrong:)

I know that I am overwatering my hoyas...........because i just assume that if everything else on the front porch needs water, they do, too!!!!!!!!!! They don't!!!!!!!!!! There are way too many plants to water by hand unless I am feeding them...................

Hoya,
Sure they'll work, anything that lets you see moistness of the stick or skewer.

Ive been using inexpensive moisture meters for over 20 years now - wouldnt be without one! Think they cost me something like $10 Cdn.

Cheapo moisture meters are next to useless at telling you how wet/dry your plant's soil is. They measure EC (Electrical Conductivity) and are far better at telling you how much salt is in the soil than how wet it is. If you doubt - try probing a glass of deionized (distilled) water. The meter will read dry. Sprinkle in some table salt & the meter will change. You'll get wildly varying results based on the ratio of salts to water.

Al

Al,

Thanks for that information. It is pretty much as I thought.

Doug

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This message was edited May 11, 2011 10:58 PM

WC2 - Since you made it clear that price isn't the object, I'm just wondering how you can make that statement - never having tried the new model? No need to answer - it's a rhetorical question.

Al

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This message was edited May 11, 2011 10:58 PM

Actually it can hurt--if the plant was already wet enough and you water it anyway, it can make the roots rot.

I've found the moisture meters are useful for telling if a plant is still pretty wet or if it's all dried out, I would never use it how they suggest on the box where they tell you for certain types of plants what level the moisture meter should be at for you to water the plant again, I just don't think it's that sensitive. But for a gross measurement of is the plant wet or dry, it works OK.

.

This message was edited May 11, 2011 10:57 PM

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This message was edited May 11, 2011 10:59 PM

Hmmm ...
WC2 - Expecting us to guess that the guage was hard to read would be like me saying, "I'll never walk out my front door again!" - and expecting readers to know that yesterday, a mudslide took the front yard and there's nothing but a 100 foot shear cliff where the porch was. ;o) You left out some pretty important stuff that allowed readers to believe you found great comparative value between the two meters. Your response seems reasonable enough after explaining though, since we now see how you arrived at B from A and it had nothing to do with the value of the meter.

Quantitative analysis? I'm up for the discussion. ;o) Perhaps we should say though, that it's a moot point. Plants absorb water in the presence of air and when soil particulate moisture content is around 30-33% (for peat and bark). So how much water the soil is capable of holding, or is holding at any one particular time is unimportant. What is important is the ratio of air to water in the soil and how the water is distributed. The meter will not tell you that, either. Even if your meter could tell you the soil is too saturated, or too dry, the plant would already be stressed or strained under those conditions.

Finally, plants are only able to absorb moisture when the EC (electrical conductivity) of the soil moisture is within a certain set of limits for that plant. Depending on the meter, it may be able to tell you that, but you need to note that it will not tell you if there is too much moisture and not enough air in the soil for plants to absorb water and nutrients - only if the EC is conducive to water/nutrient uptake.

Al

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This message was edited Feb 10, 2008 5:47 PM

This message was edited May 11, 2011 10:59 PM

Apology accepted.

Al

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This message was edited May 12, 2011 6:03 AM

I'm loose as a goose, & I'd already let it go and accepted the apology. No problem on this end, & no need to perpetuate things. ;o)

Al