Sunday, August 22, 2010

A New Wicking Bed

Now that we have started harvesting from the lettuce and rocket in some earlier established wicking beds, they will need to be replaced in the near future. Another bed has been set up to plant some more lettuce and rocket.

 
In this post I will outline the process that I have used for this new wicking bed.

 
I used a foam "brocolli" box for this new bed. It was one that was just begging to be used after sitting empty for a few weeks.

 
First I made 2 holes in each side of the box, about 30cm down from the top of the box. This will allow for about 30cm of compost/soil to be established above the reservoir of water at the bottom of the box. (more about that later).

 

 
 
 
Next prepare the material to used as the reservoir to hold the water that will be stored in the bottom of the bed. I used several plastic water bottle. I cut tops and bottoms of all the ones to be laid on the bottom of the box, so they fit together to make a long tube, the length of the bed. If the ends of the tube are closed, any water added will seep more slowly along the length of the box and be stored at the base of the bed to be taken up the soil above it. But once again I am getting ahead of my self.
 
In one end of the tube, cut a hole to allow another plastic bottle to be fitted at right angles above the tube you have made. See the photo below.
 

 
 
 
Next, collect some stone, rocks or building rubble to pack around the tube made in the step above. This will keep the tube in place and also allow water to be stored among the packing.
 

 
Collect compost to build up the soil for planting. Put this over the tube and rubble packing that were added in the previous step. I add approximately 25 to 30cm of compost, which becomes the growing medium for the plants to grow in. Sometimes I also add some commercial potting mix to get the best consistency in soil.
 
 
To help the wicking bed to perform effectively I also add some worms. These come from my compost heap, and at this time of year they are easy to collect from there.
 

 
Next, plant the seeds (or if using seedlings, plant them out now). And add water.
 
 
 
 
 
The wicking bed is now set up. All that needs to be done now is to monitor progress and occasionally top up up the water when necessary. This can be checked by looking into the bottle used  for filling. 
 
And finally, here is one that I prepared earlier. 
 
 
Finished and operating Wicking Bed, with Rocket and Lettuce.
How does a Wicking Bed work.
 
If you have seen the "self-watering " pots that you can buy at your local nursery, or even at the supermarket, then you have seen an example of a wicking bed.

I believe that it works like this:

  • The bed is set up with the capability of keeping a reservoir of water in the base.
  • This water can be topped up by having a pipe at the end that be used to add when when the level gets low.
  • The soil above is prevented from a falling into this reservoir by the pipe(s) laid along the base, but some of it comes into contact with water that spills from the reservoir into the packing materials.
  • Capillary action (similar to the way in which a candle wick takes up melted wax) makes the water work its way up the soil. This makes the soil damp, but for the plants I have chosen in my beds, not too wet.
  • Water is thus conserved and put to good use as there is less evaporation and leeching out of the bottom of pots.
  • This keeps beds (pots) moist and requires minimal watering. In fact I have not needed to water my beds once established. All that is needed is an occasional top of the reservoir.
I have used Wicking Beds for small scale vegetable growing, but I believe that it is also possible to this on a much larger scale, with great benefits in water conservation.

Good luck with your own Wicking Bed experiences. Let me know how you go. 
  
 

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