High in the Rockies
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Moister measurement

How do you determine if your moister is at its optimum? --- I am putting in automatic watering and building the entire system, including the sensors. I need to calibrate this control mechanism for best plant conditions. (I will be gone several times during the season, sometimes for days) Too wet and too dry are obvious, however is there a simple way to determine that just right range for best plant health? If I find a good way to determine this, then I can calibrate my system to help me out when I'm gone. (New veg. garden)

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rainbowgardener
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Re: Moister measurement

I'm not quite sure I'm understanding the question, but if you are asking about the optimum soil moisture for best plant health, the answer (like most things in gardening) is it depends. It varies widely from one plant to the next.

Some plants like bog/ pond margin things like marsh marigold, milkweed, lobelia/cardinal flower etc thrive in saturated soil. On the other extreme plants like lavender, sage, coreopsis, and cacti and succulents thrive in very dry sandy soil.

What is it you want to grow?
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High in the Rockies
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Re: Moister measurement

Sorry about not being clearer. Typical vegetables. From squash to corn, tomatoes to cucumbers. I would guess there is some variation in optimum needs, however I am looking at general common vegetables. Thanks

JayPoc
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Re: Moister measurement

Sounds like you're trying to design something that isn't needed, and in fact may be bad for your plants. For most things, there isn't a "moisture level" requirement. Many plants might need a lot of water, but they also need time to dry out between waterings. The frequency of the waterings will depend on the size/type of plant, the ambient temp, the ambient relative humidity, soil type, etc. You'll have to do a timed system, with your best guess at amounts of water, interval, etc. depending on the time of year and local weather.

imafan26
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Re: Moister measurement

Watering should always be as needed. Even with a sprinkler system installed at my house, I still have to adjust it for the season and rain. Right now my system is off and I only run it manually if we don't get some rainfall every week.

To mitigate moisture needs of your plants it is best to group your plants according to how much water they need. The ones that want to be evenly moist in one group, another group likes to be dried out between watering and others want to be in a puddle all of the time.

Add compost to your planting site at least 2-4 inches worked into the top 6-8 inches of soil. Compost will help hold on to water and apply a layer of mulch on top to reduce water loss from the surface. To use less water, run your drip irrigation under the mulch.

The type of soil you have, how windy, hot, rain, time of year, water requirements of the plants, and whether the pots are in containers will all make a difference on how much water is required.

The only way to do it is to test. Run your irrigation system till the soil is moist 4-6 inches deep. Dig several test holes to make sure the area is being evenly watered. You may have to adjust or add watering emitters/heads to the dry spots. Dig a test hole daily to determine your watering interval. Water again when your soil three inches deep is almost dry but before your plants start stressing. Some plants like tomatoes will wilt in the heat and others will curl their leaves but that is how they adapt to heat and drought. They should come back by evening. Most container plants will need to be watered daily especially if they are pot bound or have large plants in them. The closer you have planted the sooner you will need to water. Small plants can go longer than large plants with large root systems that are in fruit or flower. As the garden fills with mature plants the watering interval will decrease. During the cooler, wetter months you may be able to water twice a week in a garden that has mostly small plants with lots of organic matter and mulched soil that is more loamy not sandy.
If you have sandy soil, you will still need to water nearly every day.

When the weather gets warmer and the plants size up and start fruiting you may have to water daily or every other day.
The longer and deeper you water, the deeper the roots will go and the longer the plants will be able to tolerate a dry spell. So it is always better to water low and slow rather than quick and shallow.

Even if you automate the system and install a moisture meter. ( they do have it for lawns, it does not work well since the water in the meter does not always dry out at the same rate as the soil), you still need to look at the plants and adjust for conditions that change moisture levels like rain, heat, windy weather, type of soil, size and number of plants per square foot, and individual plant needs.

In the beginning it does take a while to get a hang of it, but after a while, you will be able to look at the plants and the top of the soil and tell if they need more or less water. If you are going on vacation and it is only for a week, and you have been watering twice a week, you can probably keep that same schedule, even if it rains while you are gone. Just make sure the water timer and batteries are working.
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High in the Rockies
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Re: Moister measurement

It appears that I did not make myself clear. I am at about 7700 feet in CO. It can be raining, and an hour latter it can be 90 in the shade with humidity at 5 percent, and don't forget the wind. The sun at this height, and far south, is very potent. No way can I get away with watering a couple times a week. Nor can a repeatable timer get the job done. We can get an inch of rain in a couple of hours, and I don't want to add to the flood. When I am gone for more than a week, the only way I see is to have some type of monitoring.

imafan26
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Re: Moister measurement

The temperature and wind will determine how quickly the plants will transpire to lose water, but the soil should dry out at a different rate even with rain.

Doing a percolation test might help to determine how quickly your soil drains. If your soil is rocky or sandy and drains very fast, adding organic matter will still help to hold on to water longer. If your soil drains quickly rain would have to be torrential and long to stick around. Short bursts of rain even heavy rain, that runs down the street before it has a chance to soak in really doesn't count for much. What will count is long, slow rain that allows the soil to soak it up not run down the hill. Soil percolation tests are usually done when installing a septic field but it is also useful in determining how well your soil holds on to water.

https://www.todayshomeowner.com/diy-soil ... your-yard/

If you are looking specifically for field moisture sensors, this is one site. It is designed more for commercial use.
https://www.specmeters.com/soil-moisture/
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Rairdog
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Re: Moister measurement

If too wet/dry is that much of a problem you could build wicking beds which are just a raised beds with a reservoir. Then you could tie it into the hose or downspout with a float valve to automatically fill. An overflow keeps it from getting swamped and you have ideal moisture.

High in the Rockies
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Re: Moister measurement

I appreciate all the feedback and comebacks, however this has gotten clear off topic. I will repeat my question, which is the first sentence, "How do you determine if your moister is at its optimum?" ( Just noticed my spelling. Spell checks are great, however you have to keep one eye on what they do. )

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brooksms
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Re: Moister measurement

Just to make sure I understand, you have some kind of technology to monitor the moisture level but you need to tell the sensor when the moisture is at a preferred level so it will maintain? You will be growing different types of vegetables but need to choose an average moisture level to work for all of them, right? I'm not an expert by any means, but I really don't think there is a trick besides making sure it isn't overly wet or dry. Follow the method below to make it the proper consistency, calibrate the sensors and be done with it. It won't be perfect because of the varying plant watering preferences but there is only so much you can do when going out of town.

"To determine if your soil has a moist consistency, versus dry or overly wet, pick up a small amount of soil and roll it between your palms or your thumb and forefinger. You will find that moist soils sticks together when rolled together, but loose soil falls apart when pressed. This indicates a loose, well-draining, moist soil consistency, which is perfect for many garden plants. On the other hand, wet soil performs differently under this test. Wet soil is sticky when rolled between the thumb and forefinger, while it has a plasticlike consistency when rolled in the palm of your hands. Soils that are too dry do not stick together and have a dusty consistency."

JayPoc
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Re: Moister measurement

High in the Rockies wrote:I appreciate all the feedback and comebacks, however this has gotten clear off topic. I will repeat my question, which is the first sentence, "How do you determine if your moister is at its optimum?" ( Just noticed my spelling. Spell checks are great, however you have to keep one eye on what they do. )
No...the thread hasn't gotten off topic. you're asking an inherently unanswerable question. For most garden veggies, there is no such thing as an "optimum soil moisture level". It really should be though more as available VOLUME of water, per period of time. And that is dependent on the type of plant.

Again, I'll use a tomato plant as an example. If you kept a tomato plant at some certain percentage of moisture 24/7, it won't do well. It needs a heavy watering every so often with time to dry out between.

Just my two cents...

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