To Wick or not to Wick

17 years ago

IÂve been reading so much on the subject of container mixes, self watering containers, water wicking, wicking to lower the pwtÂÂ.So much that I think my brain needs a wick to absorb all of this information. This year IÂll be using for the first time 2 purchased Earthboxes, a few home made self watering containers, and many "regular" containers from past years. IÂm all set with the EB and self watering methods but have questions and or just looking for confirmation on my understanding on the use of regular containers. I very much understand there are many strong opinions on many topics on this forum so ultimately most decisions are your own after doing your homework. Anyway here goes.

Using regular containers with AlsÂs recommended mix ingredients:

1. The mix allows for good drainage so more frequent watering will be necessary, is top watering okay or would wick watering be the preferred method?

2. If wick watering: just place a good wick about half way up the container and have the bottom end lay in a water source that needs to be kept full. Correct or not?

3. To lower the perched water table place a good wick a few inches up in the soil via one of the drainage hole, can the end be touching the ground as long as itÂs not in a puddle or saturated area, or must it be completely free of the surface.

Using regular containers with good commercial mix:

4. Top watering is less appropriate so wick watering is best???

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Comments (4)

justaguy2
17 years ago
To top water or bottom water really doesn't much matter for a typical container garden. Where it matters is in terms of efficiency and how long the plants will be in the container.

Think of a commercial operation with thousands of containers needing at least daily watering. Clearly having all containers in trays that could be bottom watered would be a huge benefit.

The next issue is build up of salts from the water supply and nutrients. Bottom watering, if it doesn't keep the media constantly wet, results in salts forming on the media. This is bad. A good top watering can flush much of the salts out, but in a commerical operation where the plants spend only a limited time in a bottom watering situation before being shipped out is not important.

The perched water table may or may not matter to you. If you have a 12" deep container with a 2" perched water table you have 10" of vertical growing room before encountering a constantly wet area. What's the difference between a 10" tall container with no perched water table and a 12" deep container with a 2" perched water table? Nothing much other than the 10" deep container needs to be watered more often.

Since you are using some self watering containers you are deliberately (if not knowingly) relying upon the same physical principles that create a perched water table to keep your plants irrigated.

Question 2 is correct.

Question 3 it doesn't much matter. As long as the wick isn't in contact with a wet surface evaporation will occur. If you want to speed up the draining of the PWT, put the bottom of the wick in contact with something that absorbs water.
richdelmo
Original Author
17 years ago
Thank you for the explanations:

To top water or bottom water really doesn't much matter for a typical container garden. Where it matters is in terms of efficiency and how long the plants will be in the container.

Everything will be annuals if that matters any.

The perched water table may or may not matter to you. If you have a 12" deep container with a 2" perched water table you have 10" of vertical growing room before encountering a constantly wet area.

How would I know where the pwt is on a particular container 10" 12" or otherwise. Are you saying it is generally 10 inches from the top of the container?
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justaguy2
17 years ago
The perched water table will vary from one media to the next and will be the same height regardless of container height. It is simply the point where the downward force of gravity equals the upward force of capillary action.

I can't say where it will be in any of your containers.
tapla (mid-Michigan, USDA z5b-6a)
17 years ago
Well, it should be at the bottom. ;o) Unless you're using a layer of large material hoping it will help drainage, in which case it should be immediately above that layer.

You can easily tell how tall a perched water table is in any soil with a simple process. Fill a Styrofoam cup with a hole in the bottom (cover the hole with a screen) and completely saturate the soil. If the soil glistens at the top with water that is not draining, the perched water table is higher than the cup is deep - discard the soil. ;o) If it drains so that the soil is simply wet, begin removing some of the soil, spritzing the soil occasionally, until you see water glistening at the top surface of the soil after water has stopped draining from the bottom. Measure the depth of soil in the cup & it will tell you the depth of the PWT in any container with THAT particular soil.

Al

To Wick or not to Wick

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justaguy2

richdelmo
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To Wick or not to Wick

Comments (4)

justaguy2

richdelmoOriginal Author

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justaguy2

tapla (mid-Michigan, USDA z5b-6a)

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Original Author