Question
Greetings,
this has been my first year with strictly containers. I live in WA, Zone 7 or 8 and have approx. 170+ pots in all shapes and sizes. I now prefer larger pots since they do not have to be watered as frequently. I am using a standard moisture meter and when checking the larger pots, for instance, my mother fern (glazed stone pot) and golden thread (plastic pot), the meter always shows dry, even when the top soil layer feels moist to the touch. That seems kind of odd to me so I did search for a different meter with a longer probe but of no avail. My question is, do you have any idea why the meter shows dry even though the soil is moist and/or do you know of a source where I can obtain a meter with a longer probe, especially for the larger pots 20-24 inch and up? I do not want to over water my precious plants. Any suggestions would be greatly appreciated. Thank you. Liz

Answer
You are doing very well to have 170+ containers in the first year. I plan to answer your question on many levels. The first is from the view of an old pro in the container gardening field. I have so many containers, I am not able to count them. I do not own a water meter. What I read are the plants. I keep a few plants around that wilt. I watch them closely. First sign of droop, and I don't hesitate to water. Plants that I know do not need much water, such as cactus, succulents, and some of the large pots, I will water every other time. I also read the plant. Many plants change color when they are dry. I read the soil. Dig down to see if it is dry, or lift the pot to see if it is light. I also watch the weather. I know that if it is hot, the soil will dry quickly. If the plant is in direct sun, even more quickly. When I water, I don't hurry. I make sure the soil is thoroughly saturated. I fill the pot with water, let it drain, and fill again. The water should run freely out the bottom of the pot. Never let the pot sit in a water dish. Plants that need more water then others, are planted with moisture retaining POLYMERS. They are little crystals that hold the moisture, when the soil dries out. They cut down on plant stress on hot days. To prevent over watering, let the plant dry out. This puts air back into the soil. Plants need that oxygen. If the soil is always wet, the oxygen is replaced by water, and the plant sufficates. So, remember to let the plant breathe, a moment, then water.
Next lets talk about "big pots". I am often ask, "why can't I just plant in a big pot, and not have to plant up all of the time?" The answer has to do with the way that water travels in the soil. In a small pot, the water is concentrated on the roots. In a large pot the water is directed away from the roots, to the outside of the pot. So the soil may feel moist, but the plant is dry. That is the main reason it is important to never plant up to more then one size larger pot.
Now to the "water meter". First, I would test your meter, under the faucet, to see if it is working properly. I would not rely on the reading you get, but also check the soil with your finger. As you have already seen, the meter has not told you what you need to know. Getting a longer probe will not tell you either. I do know of a meter that measures 24 inches and costs $120.00. To see it, go to "Amazon.com" (tools and hardware)- (soil moisture)-
Plants do not need much water in the winter. Just enough to keep them alive. They are dormant. They want to be cool and quiet. Humidity is good, if they are in the house with a forced air furnace. Keep them away from heat ducts,and cold window, and direct sun. I have also needed to learn what temperate zones, each plant can do best in. I have four "zones". The warmest is in the house, then cooler in the solarium, then colder in the green house, and the coldest on the covered deck next to the house.
I hope that I have helped you, with your collection. Have fun. You have picked a great hobby.
bakerplanter