How do you determine your soil's water saturation level? I feel fairly competent to measure this in the summer, outside, but am concerned about watering through the winter dormancy. I am planning to take my deciduous trees to the garage for the winter. The trees will experience freezing level temperatures but won't be exposed to frost. So, I'm anticipating the soil to freeze. How do you go about water plants in this phase?

bmrscreamr wrote:

How do you go about water plants in this phase?

Well, usually they need almost no water during dormancy.
Like once every two or three weeks, if you are in a cold region.
The plant is not growing and photosynthesis is not occurring (so it doesn't use water), and water in the soil is not being lost due to evaporation (winter, rain, snow...)

My trees stay outside throughout winter. Only deep frost, say, colder then -5 means plants get sheltered. I do not water them, except for after frost, as longer frist reduces water availability. Normally, you should water when the soil gets really dry. how to tell.. dunno. Look at the plant. If the first cm is dry, it needs water.

Having been a technology freak for decades I usually look for a technology solution. There really ought to be something to stick in a pot to report humidity levels and red flag when a plant needs water. I have looked for something like this in Amazon but haven't found it. Anybody know of anything that measues water level? Right now I stick a finger in the dirt, which is low tech and gets my finger dirty.

Ivan wrote:

Having been a technology freak for decades I usually look for a technology solution. There really ought to be something to stick in a pot to report humidity levels and red flag when a plant needs water. I have looked for something like this in Amazon but haven't found it. Anybody know of anything that measues water level? Right now I stick a finger in the dirt, which is low tech and gets my finger dirty.

You can control water levels electronically in hydroponics, but I doubt it have any reliable apparatus for pots and soil on Bonsai, or at least on a worthy price.

Ivan wrote:

Having been a technology freak for decades I usually look for a technology solution. There really ought to be something to stick in a pot to report humidity levels and red flag when a plant needs water. I have looked for something like this in Amazon but haven't found it. Anybody know of anything that measues water level? Right now I stick a finger in the dirt, which is low tech and gets my finger dirty.

I love to go tech. So, we are looking for a hydrometer basically. Unfortunately, most are designed for measuring in a medium different than soil. But, then I found one at Home Depot! I might get one of these and start taking measurements for baselines in different types of soil. Fun tech stuff!

Correction. What we are talking about is a hygrometer, not a hydrometer.

A hygrometer measures humidity, the amount of water vapor in air. A hydrometer, on the other hand, measures the density or specific gravity (SG) of a liquid by floating in the liquid.

Either way, I gotta get me one of those.

Ryan Neil has a free instructional video on winter preparation and the effects of winter on trees. I included the link below. One of the things that struck me was he said the number one reason a tree didn't leaf out in spring is that it likely died of dehydration over winter. Trees being dormant doesn't mean they don't lose water to the air. Conifers constantly lose water through their foliage, just at a slower rate in winter. Deciduous can also be affected by this because of their thin twigs.

live.bonsaimirai.com/archive/video/winter-preparation

Shermanator wrote:

Ryan Neil has a free instructional video on winter preparation and the effects of winter on trees. I included the link below. One of the things that struck me was he said the number one reason a tree didn't leaf out in spring is that it likely died of dehydration over winter.

Exactly. This and other causes i once put together too: www.growingbonsai.net/what-kills-bonsai-in-winter/

It is actually quite simple (in my opinion).
Once the substrate is frozen - you don´t water nor stick anything in it ... cause its frozen.
Once defrosted due to warm spell, substrate tends to stay wet much longer than in spring or summer.
You just got to check on your trees daily.
Once you´ve got a feeling when you touch the substrate that it is getting dry - you water.
I would never let the substrate get really dry nevermind the species of the tree
When you get snow in winter, you shovel it onto the substrate and cover the pots with it.
And when overwintering in cold garage for example - as I do with my ulmuses, berberises, wisterias, blackthorns etc ... you just check if the substrate is frozen/wet daily or maybe every 2-3 days might be enough.
That is my experience that works for me.