I’ve always been interested in gardening. After last season, I’d decided to give it up. Production wasn't the greatest probably due to the crappy soil. And, I didn't want to get the soil test again, till in nutrients, fight insects, etc, etc. Fast forward to now. I came across a few websites dealing with what’s called a double-bucket system also referred to as self-watering containers (SWCs). I found the concept very interesting and really like the benefits these SWCs are supposed to bring: auto-watering techniques, weed prevention, easy soil preparation, and best of all, minimal to no insect control needed.
Since I have a huge deck out back, a perfect spot for SWCs, I decided to take the plunge. I researched the various methods people use on the Internet and decided to make some modifications of my own. For those wanting to construct these yourself, these are just my ideas and you can construct and modify your own to suit your needs. If you are inspired by my SWCs and try 'em out yourself, leave a comment and tell me how they work for you. I'll do more posts in the upcoming months on the subject and let you know how it works out.
The primary part of the SWC is the 5-gallon buckets. You can get these from Home Depot, Lowes, Walmart, and other places. Make sure you get a food-grade bucket. You can tell that by a #2 with a triangle around it and the letters "HPDE" next to it. Most buckets are this, but check the older buckets and if you do use older buckets, know what was in them before. You don't want ones with chemicals or oil products!
In the top bucket, drill holes in the sides and bottom. These are oxygen-providing, draining holes. Also, note the one 1-1/2" hole drilled into the bottom.
In the picture below, you can see where I used a chop saw to cut pieces of PVC. One is a 24" "Water Baton" and the others are 6" spacers. The water baton is where I will fill the bottom bucket. Note the 3 cuts in the water baton. Two are to hold the primary wick and the other is a water outlet so water flows unrestricted into the reservoir (bottom bucket). Each 6" spacer has a hole drilled through both ends.
In the picture below, you can see the wic routed in the water baton. Also, it points out the location of the spacers and how the zip ties are routed. There are 3 spacers on each bucket and their purpose is to lift the top bucket off of the bottom bucket thereby providing a larger water reservoir than if the bucket rested directly on the bottom bucket, a practice most people do who try these SWCs. There are 3 spacers because it offers the best stability with the least amount of spaers/cost. I also show the Rayon cloth (car drying material from Auto Zone) in the picture cut into strips. Some of these are called "Sham Wow." The 100% Rayon cloth wicks water up very effectively and doesn't deteriorate as quickly as cotton. A concern of mine is that this one untried rayon wick will not provide enough water to keep the soil moist as the plants demand more as they grow, so I also purchased a replace mop head from Walmart. It is also Rayon. I separated the strands and tied a knot in 3 of them routing them through 3 of the holes I drilled in the bottom of the top bucket. This is to provide additional wicks. Most people who make these SWCs also do not drill holes in the side of the top bucket. I did because I also fear that the soil could get too wet. Now, with the additional 3 wicks and the holes in the side of the top bucket, I can better control the plant's soil moisture for optimum growth. More to come on how I accomplish this in later posts.
Final assembly consists of installing water baton into hole and putting in landscaping fabric to keep soil from falling down into bottom bucket (reservoir) or out the sides. Also, if you look at the picture below, you can see the handle for the bottom bucket which I removed prior to assembling. I'd forgotten to show this in the pictures above. The bucket assembly only needs the top bucket's handle as they are now securely attached to each other. The reason the landscaping fabric has teeth-looking cutouts is that it is easier to fold and cover the bottom holes than leaving them all. Note the zip tie around the water baton. This is to keep it firmly in place once the baton is routed through the top bucket hole to rest on the bottom of the bottom bucket.
Approximate Cost for 1 Assembled SWC:
1.
Let's begin construction. It takes two buckets to make one SWC. Total: $5.00 (box home store)
2. Hole Saw: $5.00 (box home store)
3. 12' X 1" Thin PVC: ($1.40 Makes 5 Water Batons): $0.28
4. 12' X 3/4" PVC: $1.19 (Makes 6 SWCs): $0.20
5. Walmart Mop Head ($4.00 one will do 30 or more buckets): $0.13
6. 100% Rayon Cloth (one will do 30 or more buckets, $10 guess): $0.30
7. 8" White Zip Ties (various price, but I paid $11 for 500): $0.15
8. Landscaping Fabric (I had this already. A roll will make many, many SWCs) My guess: $0.50
9. Garbage Bag (guess): $0.25
10. Soil: I'll cover later.
Total Per SWC: $7.00. The buckets are $5. If you can get the buckets for free or cheaper, these cost next to nothing to build. I had many already and got some from relatives.
What not shown yet is how I route the white trash bags over the SWC assembly. The trash bag is to retain/control moisture and reflect the heat from the sun. I still have to test the SWCs in different types of soil. More to come!
Number 11 is the bottom of the assembly and goes into the 12' PVC pipe. The zip tie (5) stabilizes the unit in the pipe. Rain flows into #1 through the assembly and out the holes in 9. It will continue to flow into the 12' pipe until the water level reaches #9. At #9, the ping pong ball begins to float upwards with the water level until contact is made with #8. Number 8 has a beveled edge that the ping pong ball seats into which seals the flow. Now, water is cut off from the 12' long pipe and water fills #4 until the level reaches the 2" elbow and flows out. That's it; more to come.
