Crestone Solar School
Seeds Planting the Self-Watering Container Introducing The EarthBox® A Frost-Free Community Solar Greenhouse
Self-Watering Containers made out of Totes
Make your own Self -Watering Container
out of buckets
by Pat Baumes
Materials for container
A good place to find buckets is at a bakery in a local grocery store. You may be able to get them for free if they are going to put them in the recycle bin. I was able to get 2 sizes, different depths, which worked out great. The shorter used for the plant and the deeper one to hold the water. This makes the water reserve area larger.
1 Styrofoam cup (large - if deep water reservoir, small if shallow) or 1 empty plastic bottle.)
3/4 inch non-PVC plastic pipe (larger if you can find it.)
(You may also use PVC pipe but some people say something bad leaches into the soil from it and can be taken up by the plants. Other people use PVC for everything. I have to look into it further - so for now I am using other tubing.) If using something ridged, a water level gauge may also be made. I will get into that when I expand the article at a later date.
Funnel, (if using 3/4 inch) or make one out of top section of plastic bottle
Black plastic garbage bag or landscape fabric
String or 1 ft. of elastic cording (Found with sewing notions. I like this best.)
A water level gauge may also be made. I will get into that when I expand the article at a later date.
Drill with ¼ inch bit, 1 inch circle bit and 3 inch circle bit (or size of wicking cup)
(No circle bits? Drill small holes for circle and then cut out with utility knife. See foto below.)
Pencil, or something to poke holes if using Styrofoam cup. A nail setter punch works great.
Scissors or tin snips
Hack Saw (depending on type of bottle used)
The Outside Bucket
Put one bucket inside the other and hold them up to the light. Mark the outside bucket where you see the bottom of the inside bucket. This will show you the depth of the combined water\air reserve.
Since you need an air space above the water, make a water level mark about ½ inches below the previous mark. Now measure from the ground up to that mark, and mark the other side of the bucket the same length up.
Drill a ¼ inch hole where the 2 water level marks are on each side of the bucket.
The outside bucket is now complete.
Wicking Cup - 2 styles
1. Styrofoam cup
Put one bucket inside the other and hold a Styrofoam cup against the side to see which cup height would be better. You should try to have it tall enough to go from above the mark for the bottom of the inside bucket down to the bottom of the outside bucket.
Now take a pencil, stylus, nail setter or something pointed and poke holes all over the outside of the Styrofoam cup. Only put holes through the bottom if the cup isn't going to reach the bottom of the water reserve bucket. You would then thread wicking through 2 or more bottom holes.
2. Plastic Bottle
Put one bucket inside the other and hold the plastic bottle against the side. Mark the bottle slightly above the line of the inside bucket bottom. Depending on how hard the plastic is, cut or saw through the bottle. The top section can be used as the funnel if you wish.
If using a hard plastic bottle, drill holes all over the sides using a ¼ inch bit. For soft plastic, poke holes all over sides of bottle.
The Inside Bucket
Turn the inside bucket upside down. Drill a 1 ½ inch hole through bottm near an edge for the watering tube.
Hold the cup upside down with the top edge on the bucket where you want the Styrofoam wicking cup to be and draw around it. Then drill a hole slightly smaller than the circle. When drilled out the cup will fit snugly in. If using a plastic bottle, drill the hole the same diameter.
If you do not have a drill bit large enough, drill 1/4 inch holes just inside your circle as shown on the left, and then cut between holes with your knife. Use a curved rasp to smooth edges. Test the cup inserted and continue rasping until the fit is right.
Drill ¼ inch holes all over the remaining surface of the bucket bottom. These allow air to enter the soil. Sand any rough areas.
Turn bucket upright and place inside the outer bucket. Put the wicking cup in place.
If the cup isn't going to reach the bottom of the water reserve bucket, put in a few holes in the bottom of the cup which will be used for wicking string to be threaded through. Thread the string so it hits the bottom of the bucket and is about 3 inches inside the cup. I ended up using cording. You may use candle wicking, yarn, twine or whatever you have on hand.
An easier way I found is to take another cup and cut it through part way down, then insert it into the wicking cup. this gives added height. It all depends on how much height you are missing.
Various filling tube examples:
Measure plastic pipe or combination, so it is about an inch taller than the assembled bucket system.
Make sure bottom edge of pipe is cut on an angle so water has a place to flow out when pipe rests on the bottom of the bucket. (See PEX pipe photo above.)
If the hole is too large in the top bucket for the water tube or wicking cup, the soil mix will fall through. Some people line the bottom of the bucket with shade cloth or coconut fiber so that doesn't happen. I haven't found this neccesary to do.
Planting the Self-Watering Container
It would be good to wear a mask while working with this so you don't breath in the dusty particles.
Buy a good potting mix or make your own.
When buying premixed, check the label. A good mix contains; shredded sphagnum peat, Perlite or vermiculite or both. It may also contain limestone and other ingredients. For self-watering containers avoid mixes containing a wetting agent or water retention material, as these would make your mix waterlogged.. ---- Also avoid; mix with sticks and chunks of soft wood, dusty mix and one that is clumpy.
Make your own
There are many recipes for making your own.
20 lb bag potting mix
20 lb bag high quality compost.
I have made one with:
40 lb bag of Organic Natural Humus
16 dry quarts Perlite
1½ cu. ft. compressed sphagnum peat moss
Mix together well, and add a couple of buckets of water. Stir and let sit several hours or until water is absorbed and mix is moist.
I am using Dr. Earth, 5-7-3.
EarthBox® has a special 7-7-7 plant food which may also be purchased.
Or, use whatever has worked well for you in the past that is granulated, not liquid.
I ran out of Dr. Earth and so am now using Garden-tone, 3-4-4 They both contain microbes. At the end of the season I will decide which worked the best for me.
Next year I would like to mix together my own fertilizer using the recipe found in, Incredible Vegetables from Self-Watering Containers: Using Ed's Amazing POTS System by Edward C. Smith.
You may want to work where the bucket is going to be located, or at least have it in place before adding water to the reservoir. Once planted, the bucket will be heavy.
Important! Once planted, make sure there is always some water in the bottom bucket. If it becomes empty the wicking cup will dry out and then won't wick when more water is added. If that happens, water from the top first to remoisten all of the soil.
9 mixed salad plants or 2 or 3 strawberry plants in one bucket worked well for me. If planting a single plant like a tomato, have plant toward edge of bucket to avoid the fertilizer which is near the tube.
What was going to be a raised bed is now home for my self-watering containers. I first put down landscape fabric to eliminate weeds. More containers will be added.
You may extend the season by moving the containers with tomatoes, etc. into your Sunspace area before the last frost. Check for insects and control, as you don't want to bring these inside. Some plant varieties do better inside than others. Shane Smith discusses this in his book, Greenhouse Gardener's Companion, Revised: Growing Food & Flowers in Your Greenhouse or Sunspace .
End of Season
Depending on where you live, before the snow flies while fall is setting in is the time to clean up your garden and containers. At least those you aren't moving inside.
Remove the old plant, take the funnel out, lift out the top container and dump the soil into a large plastic trash bag. The bag will hold the soil for 3 containers, and the soil will last you many years. Remove roots, etc. I was surprised to find the wicking cup looked brand new! Remove it and after working with all buckets wash everything. Stack the buckets upside down and store the other parts in a few buckets. I am going to either put plastic bags over my stacks of buckets or a tarp. Everything will be stored inside my wooden frame for the winter.
Next spring assembly will be easy. Add fertilizer and plants and ready to go...
If you would like a larger container that can hold more plants, read the directions for making a self-watering container out of Totes. The assembly is a little different. Later I will also show you how to turn the Tote container into a cold frame.
All photos by Pat Baumes
I have found the following books quite helpful.
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