Small wicking box experiment

Good point camprn! You wouldn't happen to be able to name a few types of vegetables with more shallow root systems off the top of your head, would you?

I'm thinking for people who do have wicking beds/boxes, they should be conscious of which beds/boxes contain the vegetables with the more shallow root systems, in order to keep a closer eye on the top portion of the soil in case they'd have to sprinkle water from above more often.

One might even want to go as far as designating "deep-root wicking beds" and "shallow-root wicking beds," where instead of using 6 inches of MM in the "shallow-root wicking bed," one could use 4 inches of MM in hopes of a more uniform dispersion of moisture via capillary action/wicking. Does that sound feasible? I'm quite the newbie, so I'm just trying to feel things out a bit, I have no clue as to the validity of my ideas!?

Week 2 update:





The water level in the gravel has dropped to the 3¼ mark.  The MM is bone dry down to 5 inches, and being generous, it's a little dampish at the muslin.  

I haven't added any water to the system.  At this point, I don't see any indication that the water in the gravel is keeping the  MM saturated.  The longest roots are following the water level.

I'm thinking that I'll let the water level drop to 4-5 inches before re-filling the reservoir.  Will a full reservoir drown the roots that are in the gravel?  Will the plants   begin showing signs of nutrient deficiency since the MM is dry?

tumtumsback wrote: I'm thinking for people who do have wicking beds/boxes, they should be conscious of which beds/boxes contain the vegetables with the more shallow root systems, in order to keep a closer eye on the top portion of the soil in case they'd have to sprinkle water from above more often.

One might even want to go as far as designating "deep-root wicking beds" and "shallow-root wicking beds," where instead of using 6 inches of MM in the "shallow-root wicking bed," one could use 4 inches of MM in hopes of a more uniform dispersion of moisture via capillary action/wicking. Does that sound feasible?

Sounds like TMW for me!

Boffer,

Just out of curiosity, why would you let the water drop down so far before refilling? I'm thinking that if your water level has dropped 3 inches in two weeks, that's about a 1/4 inch a day. In a setting like yours, I would probably want to top it off every 4 days, not letting the water level drop lower than an inch from the muslin. The farther away the water gets from the muslin, the harder it would be to initiate the capillary action.

I'm thinking that when I go to do my wicking beds, I am going to want to keep the water level as close to the muslin (or in my case, weed mat) as possible at all times. Since the reservoir in my bed is going to be 4'x4'x9", my volume of water is going to be much greater than yours, which (I think) will make it so I won't have to water as often, plus I think I am going to be using a combination of black corrugated piping with pea gravel, which will make for a much greater volume of water underneath. So much of your water is being displaced by the rocks, which is making your water level disappear much quicker than in a setting with black corrugated piping..

Also, how much MM is there in that box, 5 inches? It seems like more... Also, how moist was the MM to begin with when you put it in the bucket? Also, since my beds are going to be outside, they will see the rain, which will help keep things a bit more moist (especially from the top) than in your experiment.

tumtumsback,

Purpose of this experiment: To observe first hand how water can wick upwards through gravel to keep the growing medium sufficiently damp for the plants in it.

Nominally, there's 6 inches of MM and 6 inches of gravel.  I've read that the gravel filled tub should be no deeper than 200-300 mm.  6 inches≈150mm.  

The MM was nearly saturated when I started.  I'm letting the water level drop in the reservoir to simulate an absentee gardener. If I have to baby-sit this system by keeping the tub topped off, then I'm being less efficient  than using a regular SFG box that is well-mulched, or a wicking box system that uses 'baskets'.

Boffer,   I read the link that Camprn posted here https://squarefoot.forumotion.com/t3068p60-sfg-wicking-boxes#182757
It says that gravel acts as a wicking agent.  So I wonder if the gravel you are using is working as a wicking agent.

Rocks /  gravel can hold a surprising amount of water.  At first glance, they just look solid.

yolos wrote:Boffer,   I read the link that Camprn posted here https://squarefoot.forumotion.com/t3068p60-sfg-wicking-boxes#182757
It says that gravel acts as a wicking agent.  So I wonder if the gravel you are using is working as a wicking agent.

It's definitely not wicking, so I must have defective gravel!   

I'm using what we call 'crushed rock' in the PNW.  I'll try to come up with some pea gravel and then start over.

boffer wrote:

 

It's definitely not wicking, so I must have defective gravel!   

   

boffer wrote:

yolos wrote:Boffer,   I read the link that Camprn posted here https://squarefoot.forumotion.com/t3068p60-sfg-wicking-boxes#182757
It says that gravel acts as a wicking agent.  So I wonder if the gravel you are using is working as a wicking agent.

It's definitely not wicking, so I must have defective gravel!   

I'm using what we call 'crushed rock' in the PNW.  I'll try to come up with some pea gravel and then start over.

Yolos, who said gravel was wicking?

I'm curious why folks that have wicking boxes just don't put actual wicks in them.      

camprn wrote:

boffer wrote:

yolos wrote:Boffer,   I read the link that Camprn posted here https://squarefoot.forumotion.com/t3068p60-sfg-wicking-boxes#182757
It says that gravel acts as a wicking agent.  So I wonder if the gravel you are using is working as a wicking agent.

It's definitely not wicking, so I must have defective gravel!   

I'm using what we call 'crushed rock' in the PNW.  I'll try to come up with some pea gravel and then start over.

Yolos, who said gravel was wicking?

I'm curious why folks that have wicking boxes just don't put actual wicks in them.      

Camprn, in the quote box is a link to a thread about wicking boxes.  In that thread you referred to this link -




http://www.resilience.org/stories/2011-05-31/bottom-diy-guide-wicking-beds

In this link the article mentioned gravel as a wicking agent.  At least that is how I interpreted the article.  Here is an excerpt from the article.

Reservoirs with Media
Most of the DIY sites for wicking beds focus on building beds that use media, a layer in between the soil and the water reservoir, as their wick. This is an easy and cheap way of supporting the soil on top of the reservoir. Gravel is the most common medium, but there are a number of materials that do the trick. Here's a good DIY blog on media wicking beds.


I am not sure why they are not using wicks but I think it is because of the size of the beds and if gravel really does wick it is spread evenly throughout the box and supports the soil.  More contact with the soil ???    

Thanks for finding the details for me yolos! I 'preciate it, a lot!!!!! 
Hey Boffer, if you're interested, would you make a bucket with a few actual wicks and see how that does with the 6" of MM?

Very interesting experiment. I would also think that an effective wicking box needs an effective wick. I have 4 wicking boxes (2- 2x12, 2- 2x6) and found that the various materials I used as wicks (mostly old shirts and blankets stuffed inside plastic coffee cans with holes) work well when the cistern box is at least 1/2 full but need to be kept very full during dry times or the plants show stress. At one point, my heavy feeders (corn and sunflowers) roots had completely taken over the wicking basket and became very hard to pry up at the end of the season. Last year, I installed an effective gavity fed watering grid from a large IBC tote for my 2x12 beds and this made a big difference. At least this way, any water that is not used right away is stored in the bottom cisterns and I can add more consistent moisture. Another reason I opted for the water grid was to help keep the roots more shallow growing.

On a big FYI for anyone considering a wicking bed, my worst problem has been the SLUGS!    When the cistern would overflow, I would have tons of slugs come pouring out of the overflow hole. I will be attempting to battle them w/ essential oils diluted and poured into the cisterns to get them under control this year. I did have a lot of success with Sluggo last year.

I'm concluding this experiment because I'm seeing no wicking action whatsoever, and I want chard for dinner.    

The magenta chard is getting thirsty.


When I disassembled the bucket, the MM and muslin were totally dry, and here you can see that the top one inch of gravel is dry too.

Water Usage Chart:

Experiment Conclusion: I've found one method that doesn't work.  
But I don't know for sure why it doesn't.

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camprn wrote:....Hey Boffer, if you're interested, would you  make a bucket with a few actual wicks and see how that does with the 6" of MM?

  Can do!

I dumped the bucket.  Stuck in 3 strips of terrycloth.


Filled it back up.  Added 2 chard seedlings.



I left the cloth ends exposed intentionally.  I'm thinking they'll dry out quickly in the heat and fan breeze, and that will encourage more wicking action.

Boffer, I like your new experiment.

Boffer, thank you for sharing.

Update using wicks in gravel:

Plants are looking healthy.



Although the reservoir is nearly empty, the plants' roots are finding sufficient water in the MM.

Water Usage Chart:

Using 'wicks' is working good so far.

Excellent!!!  

GG

Nice! This morning I was wondering about this experiment. Thanks for the update!

  hey this is great BOFFER!

im wondering then if we could use this idea when we make a few more self watering containers......instead of using plastic cups at the bottom for the reservoir, we could use stones/rocks with something like you used as the wicking ....and then MM on top

did you use the ....I think it was a cloth?......just between the rocks and MM or is the wicking cloth on the sides as well?

happy gardening
rose

oops....just looked back and found the answer....the terry cloth is on the sides as well

Bob, what a neat experiment.  Thanks for doing it and for sharing.

Would you have reduced moisture loss if you have put a plastic cover over the soil and then cut a hole and put chard in the soil?  Like an Earthbox?

squaredeal wrote:Would you have reduced moisture loss if you have put a plastic cover over the soil and then cut a hole and put chard in the soil?  Like an Earthbox?

I would guess that a plastic mulch would inhibit evaporation but it also encourages nice breeding ground for molds and fungus......
BOffer remind me please. The fabric wicks went up the sides of the bucket, yes?

I question the whole idea of adding black plastic to the top of a planter bucket.  I know the arguments of "prevents rainwater from overwatering", "prevents evaporation" and even "keeps weeds out."  Any SFG'er already knows that top-weeds are very minimal and easy to pull.  To me it seems that the baking of the summer sun (in the south, especially) would heat the container too much.  I like the idea of just using a natural mulch, which would allow for some breathing of the soil, while retaining moisture.

That makes sense, mapspringer. Pots getting very hot in the summer is already a common problem, even when they're not covered.

squaredeal wrote:Would you have reduced moisture loss if you have put a plastic cover over the soil and then cut a hole and put chard in the soil?  Like an Earthbox?

I'm sure that it would.  

Indoors, I'm very careful about providing air circulation to prevent problems like camp suggested.  I mentioned that I left the top of the wicks exposed to increase evaporation to see faster wicking.  The cloth is getting a slight green tinge even with good ventilation across the top of the bucket.

Outdoors, I'd be willing to try it.  I know that my TT's are typically 5-8° cooler than boxes on the ground due to our cool nights  most of the summer.  

camprn wrote:...BOffer remind me please. The fabric wicks went up the sides of the bucket, yes?

Yes, just as a convenience when refilling the bucket.