Tomatoville® Gardening Forums


Member discussion regarding the methods, varieties and merits of growing tomatoes.

Thread Tools Display Modes
Old September 30, 2007   #1
Thawley's Avatar
Join Date: May 2007
Location: SoCal - Zone 10
Posts: 106
Default Moisture Meter: Ideal Reading for Tomatoes???

I'm on my second crop and am taking it a little more seriously than the first. My neighbor and I planted the last crop on the same day, with the same plants from the same source. We have similar soil, though I tilled in some organic mulch. He did not. His crop was phenomenal. Mine just short of a disaster. Mike is botany major, now turned commercial landscape executive. He's got the feel for plants that I have always lacked.

The Moisture Meter seems to me to be a simple tool and something that might be an aid to the ignorant like me. You have a target or idea moisture range in mind and adjust watering to reach it, right? I'm using a drip irrigation system (now covered with paper mulch) that would seem to give me a fairly fine degree of fine tuning, so this should be a cinch. Shouldn't it?

My question is this: Is there one ideal moisture number? If so, what? Are there other variables that would make my ideal moisture level different than the nieghbor's?

The meter's instructions don't list an ideal level for Tomatoes. The lady I got the plants from mentioned such a low number that I was sure I'd never forget, but did. Most of the books suggest some level of restraint about watering. Yet the neighbor's outstanding crop got a thorough soaking 2-3 times a week that was FAR in excess of what I did and measured around 8-9 in my bed...

I am so confused.
Thawley is offline   Reply With Quote
Old September 30, 2007   #2
Join Date: Jan 2007
Location: PNW
Posts: 4,750

I would aim for 5-6 most of the time, right in the middle
of the range on the meter. Figure it is going to be pegged
at the high end right after you water. The important question
is, how long does it take to get below 4?

One way to find out an ideal reading would be to find
someone with an earthbox with a healthy looking tomato
plant in it, wait until after they fill up the water reservoir,
then test it with the moisture meter when the water reservoir
in the earthbox is about half-full. Whatever it is, that is
probably perfect.
dice is offline   Reply With Quote
Old September 30, 2007   #3
dcarch's Avatar
Join Date: Jun 2006
Location: NY
Posts: 2,619

Moisture meter is highly inaccurate.

It depends on how deep into the soil you measure, where you measure, how compact/loose is your soil, how fresh is your meter's batteries, and salt/chemical contain of your soil.

It's much better just stick your figure into the soil and feel it.

tomatomatomatomatomatomatomatomatomatomatomatomato matomato
tomatomatomatomatomatomatomatomatomatomatomatomato matomato
tomatomatomatomatomatomatomatomatomatomatomatomato matomato
dcarch is offline   Reply With Quote
Old September 30, 2007   #4
Ruth_10's Avatar
Join Date: Feb 2006
Location: MO z6a near St. Louis
Posts: 1,349

If you can dig down an inch or so and feel moist soil, you're probably watering enough. In general, more damage is done by too much water than not enough.

Have you considered other factors? Were there other differences like amount of sunlight, windscreens, nearby lawn/trees/concrete sidewalks, etc.?

It might take some trial and error, but you WILL get yourself a good crop of tomatoes one day soon.

Some say the glass half-full. Others say the glass is half-empty. To an engineer, it’s twice as big as it needs to be.
Ruth_10 is offline   Reply With Quote
Old October 1, 2007   #5
Tomatovator's Avatar
Join Date: Aug 2006
Location: Pennsylvania Zone 6
Posts: 461

I agree with DC. I got one of those meters last year and quickly discarded it. I could move it around and get whatever reading I wanted. I'm still not sure how to know when to water but the meter I bought did no good for me.
Tomatovator is offline   Reply With Quote
Old October 1, 2007   #6
Join Date: Jan 2007
Location: PNW
Posts: 4,750

I've used them on potted plants for years. No problems.

But there is an easy alternative: dig down about a shovel's
depth, take a handful of soil, and ball it up in your hand.
If it crumbles when you open your hand, plants need water.
If it sticks together, they don't need water yet.

This works best if your soil is of consistent composition for
a couple of feet deep. If you have a foot of loose sandy
loam above heavy clay loam, for example, a test on the
water content of the sandy loam does not tell you how wet the
heavy clay soil is down below.
dice is offline   Reply With Quote
Old October 5, 2007   #7
Mantis's Avatar
Join Date: Jan 2006
Location: Oz
Posts: 1,241

this is why earthboxes work so well, the mix wicks up the moisture it needs and the aeration holes allow air movement. So I think that having a soil that allows for air to be drawn down after rain is perfect. Hard to do when you have a hard clay base like I have :-(
This is why I grow 95% of my plants in pots, SWT's etc.
Mantis is offline   Reply With Quote
Old July 22, 2015   #8
Join Date: Jun 2015
Location: Huntington Beach
Posts: 1

The problem may be in the meter that you are using. Some of the really cheap meters are known to have a lot of inaccuracy. For example, many will corrode quickly over time, and as a result, will give a false reading. Another issue is that many of the cheap meters are affected by salinity (i.e. fertilizer). In this case, the salinity will also give inaccurate readings, saying that your soil is more wet than it really is. Now this doesn't mean that all meters are bad. Essentially, you get what you pay for. I am currently using this soil moisture meter and it has worked very well for me. Rather than giving an obscure number, it displays moisture as a percentage, with 0 being no moisture at all. It also doesn't corrode and isn't affected by salinity (which for me is a huge plus). Although it cost more expensive than the cheap ones, I have been extremely happy with it for the 3 years I have had it.

If you don't want to put down the money for a better sensor, here are some alternative options:

1. Stick a finger or piece of bamboo in the soil. If it comes up dry with no soil stuck, it needs water.
2. In the case of potted plants, you can either kick the pot or lift it. You will get a feel of how heavy it should be when watered.

Whatever you happen to do, hope you found this helpful!
RGrandall is offline   Reply With Quote
Old July 23, 2015   #9
Gardeneer's Avatar
Join Date: Feb 2015
Location: NC - zone 8a - heat zone 7
Posts: 4,683

I have a cheapo pH meter that has a moisture indicator option.
I'll have to find it and test. @ 15 bucks it is a good deal just as moisture indicatore.

NOTE: The probes need to be cleaned a soft/old Scotch Brite , once in a while.
Gardeneer is offline   Reply With Quote

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump

All times are GMT -4. The time now is 11:40 AM.

★ Tomatoville® is a registered trademark of Commerce Holdings, LLC ★ All Content ©2017 Commerce Holdings, LLC ★