Monday, May 2, 2011

Dollar Store Bucket SIPs

On a recent trip to my local dollar store, I came across these buckets. They cost, you guessed it, a dollar each. Now, they’re not too heavy duty, but I didn’t need them to be. They hold about two gallons of water, but I don’t want them to just hold water. I want to grow things in them.

Cheap, $1 2-gallon bucket
The first thing I did was wash them thoroughly. I don’t know what kind of mold release agents the manufacturer used, what kinds of oils may have built up on these things in their processing and handling and shipping from point of manufacture to here. So I washed them off.
Ummmm, clean bucket.
Next, I measured the length of PVC pipe I needed to be the fill tube for the water reservoir. I did this in the most scientific manner I could. I stuck the pipe into the bucket and market where it stuck up over the top. I added a couple inches to that and voila! A fill tube.

Since I was making 5 of these at once, I cut 5 tubes the same length. I cut one end of each one at a 45-degree bevel so that the water would have an outlet into the reservoir. Then I set them aside.

The next step involved making the soil/water interface area, also known as the wicking cup. I made these by measuring 3 ½” from the bottom of several two-liter soda bottles. I marked these with a marker so that I could see where I was going to cut them.  Then I used a drill to put about 20 holes in this area of the bottle, spaced evenly in four rows of 5 holes. I don’t think that the number of holes is particularly significant; a few more or a few less won’t change the function.
Finished Soil Wicking Cup
Then I drilled two more holes about a half inch below the marked cut line directly opposite each other. These will be used to attach the cup to the soil shelf.  Then, I cut along the line with a pair of scissors. I tried to keep it as level as possible so that it will fit snuggly against the soil shelf bottom.  I did this to all five of the soda bottles and ended up with 5 cups.

The next step involved marking and cutting out the soil shelves. Since I was making five at once, I wanted to have a template for the round. I didn’t want to have to measure more than once to make the shelf. I don’t draw circles very well.

I measured up about 4 inches from the bottom of the bucket and measured the diameter of it. Then I traced the bottom of the bucket on my shelf material. I used hollow core campaign signs from a recent election. I believe in recycling both plastics and politicians (because they can be quite plastic sometimes). This is a good, strong material that will support the weight of the dirt and the plant without weakening in the presence of water. (I wish the politicians would remain strong without weakening in the presence of money. The signs are made of tougher stuff sometimes.) I cut this one out with a knife and checked it against the bucket and trimmed and snipped until it rested on the cup without binding on the walls. I used this one as a pattern to cut out the other four.
Using the first one as a template
After I had them all cut out, I stacked them together to drill the weeping holes around the edge. This is a way for excessive water to drain into the water reservoir and out through the drain hole if they get caught in the rain. You don’t want your roots standing in a muddy bath all day. The lack of oxygen will kill the little guys.
All the shelves cut and ready for drilling
I drilled holes around the circumference of the disks with a power drill. I simply left them stacked together and drilled about every inch or so around the perimeter.  This gives us enough holes to effectively drain the growing medium and allows us to hold the water below until the plant needs it.
Drilling the weep holes. You could also use a
soldering iron to melt holes in this stuff.
 The next step involved marking where the fill tube will pass through the soil shelf. I did this by tracing around the pipe pieces with a marker with the pipe held fairly close to the edge. Since the pipe will stay close to the edge of the bucket, the hole should also.
Weep holes with fill tube hole drawn, ready to cut.
Then I used a roll of tape to mark a circle in the center for the soil cup. I made this just a little smaller than the diameter of the soil cup because I want the cup to help hold up the soil shelf.
Fill tube hole cut and the wicking hole roughly marked out for cutting.
 After I cut these center holes, I stacked all five of the discs together again and drilled two more holes through each of them about a half inch from the center hole and directly opposite each other. These are for the zip ties that I will use to fasten the cup to the shelf. It may not be necessary to fasten the cup to the shelf, but I do it to avoid the cup slipping to a side and upsetting the soil and the plant.

I attached the cup with the zip ties. Don’t tighten them too much; this stuff can’t take a lot of torque. Cut off the excess zip tie. I don’t think it will interfere with the plant, it just looks messy. (Yes, I know it will be covered with dirt and nobody will see it. But I will know that it is still there and it will bug me all growing season.)

Then drop the assembled cup/shelf system into the bucket. Slide one of the fill tubes down into the hole, bevel cut down. Hold the fill tube to the side of the bucket and drill two more holes, one on each side of the tube. Use another zip tie to keep the fill tube in place.

The last step is to locate a point on the opposite side of the fill tube about a half inch below the soil shelf. Drill a hole here to serve as your overflow. This will allow oxygen to get in below the shelf so the roots will have access to it and will allow for water to escape if your bucket is out in the rain. When I’m watering, I water through the tube until it comes out the overflow, then I know it’s full. The purpose of the cup is to provide a place for the water and the potting mix to come into contact with each other. When the dirt in the cup is wet, capillary action will raise the water through the soil to where the roots of the plants can get to it. It keeps the soil moist without saturating it and allows for oxygen transfer also. The plants have access to water when they need it and not when I can get to it.

When you fill the bucket, make sure that your soil mix is moist. You don’t want to have your plants die waiting for the water to wick up through the soil into the bed. If it is moist going in, it will stay moist as long as you have water in the reservoir. Fill the soil cup first and make sure that it is pressed down firmly. Add your soil mix and then your seeds or seedlings.
Internal view of a finished SIP. Total cost is $1.00 for the bucket,
everything else was free on hand.

I strongly recommend a mulch of some kind. Although using these types of growing containers will reduce your water usage by up to 90%, you must make sure that you are not losing water through evaporation from the top of the soil mix. You can use plastic or aluminum foil or even a piece of cardboard cut to fit the top with holes for the plant and the fill tube. You can even plant a second plant below the first if you plant a tall or vining plant in the middle. The leaves of the second plant can act as a mulch for the system.

You can use the bucket sides to attach stakes and poles or cages to support high-growing or vining plants. Put them perpendicular to the fill-tube-drain hole line and anchor them to the sides with zip ties like the fill tube.

These are not as large nor as heavy-duty as when you use a 5-gallon bucket but the cost is great and they work.

Have fun!


  1. That's so cool! I had no idea you were so creative!

  2. Sounds like a lot of work. Let me know if something delicious grows out of them.


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