An inexpensive way to make an outdoor pot that can be watered less frequently or have a reservoir to prevent plant stress when placed in a dry or sunny location. This means less work in the garden and healthier plants.
Step 1: Gather You Materials
You will need:
1.A container with no drainage holes - Large inexpensive plastic containers can be had that are intended to hold drinks and ice in the summer; plastic bins both round and square can be found at dollar stores, and metal containers can be re-purposed or buckets or tubs can be used. For this example, I'm using a white plastic bin that was sold as a storage bin at my local dollar store.
2. Something to poke holes into the pot - What that is depends on what the pot is made of. Usually, I use a power drill, because I have a power drill. If your container is plastic, you can heat a nail and hold it with pliers, or heat an ice pick or awl. If your container is metal, you can use a nail, a hammer, (a scrap of wood behind the nail will help). If you are using a ceramic container, a special drill bit will be needed. Use great care with ceramic, wear eye protection, and don't drill any ceramic whose loss would be devastating. Drilling out ceramic is something that takes plastic..
3.Coarse, light material for the reservoir at the bottom of the container - Here, I use lava rock. I happen to have it left over from another project. I have also used chunks of styrene packing and chunks of pool noodles. It needs to be rigid enough to not compress under the weight of the soil. The plants with the lava rock seem the happiest. I do not recommend stone, as it is quite heavy and inexpensive containers will then possibly lack the structural integrity to be moved.
4. A piece of fabric or batting to cover the lava rock - It should be a few inches larger than the top opening of the container. Here I am using a scrap of quilt batting, again, because I had it on-hand. I doubled it. I have also used an old t shirt.
5.Good potting soil - Use soil designed for pots. I use a commercial brand.
Step 2: Drill Hole for Water Resevoir/drainage
Drill the holes. I put in three or four holes, 1/4 inch each, about 3 inches up from the bottom of the pot. If your pot is proportionally quite tall, make the holes higher. The holes define the top of the water reservoir. This is what makes it "self watering". It will hold from several days to a week's worth of the plant's water needs, allowing you to go away for a weekend or put plants in a hot, sunny area without worrying that they will wilt, grow poorly, or even die. (Sadly, my research into having little elves or the garden gnomes fill the pot reservoir have been thus far unsuccessful!)
Remember, this has to be a container with no traditional drain hole on the bottom. If you wish to use such a container, you will need to plug the drain hole using anything from a wine cork to silicon sealant. Likewise, if it is an upcycled metal container that leaks, you will need to fil any leaking seams with caulk or some such, as the water reservoir needs to, well, hold water.
Step 3: Add Lava Rock Up to Drain Holes
I actually added it slightly above the drain holes, reckoning that the rock would settle a little with time. I think the plants with containers that had lava rock, as opposed to other mediums in the reservoir did better. My educated guess on this is that the porousness of the rock allowed for greater air flow. Plants like some air around their roots, and a reservoir with some air does not smell.
Step 4: Cover the Rock With Fabric
Bit hard to see, as both pot and cloth , in this case, quilt batting, are white. This step insures that the soil does not filter into the water reservoir, clogging it and causing the plant to be water logged and the soil to be leached of nutrients. Tuck the fabric well down around the rock, it doesn't really need to be cut to size, just a few inches larger or so than the rock area it is covering.
Step 5: Add Soil, and Plant!!
Now, add your potting mix to the container and plant as you wish. Water from the top until you see the excess water drain from the reservoir holes on the side of the pot. This tells you that your resevoir is full. Plants that are kept evenly moist grow better and are less prone to disease and pests, This is because they do not have to put energy into recovering from drought and wilt, and put all of their energy into growing,
Even plants that like to dry out between watering will adapt to this set up, I have cactus that are quite happy in this type of pot, I only fill their reservoir once every few months. The thriving plants that you see in commercial buildings are almost all on a self watering system: it is one of the reasons they look so well. (That, and the weekly grooming by commercial plant minions.) I have had nice luck starting seeds in a set up like this, transplanting the seedlings when they are large enough to suit. This is an outdoor pot because of the reservoir overflow simply draining out the holes. I suppose if you were very careful then you could use it indoors, but I don't recommend it.
Thank you for reading along- let me know if you make a self watering planter! I consider this an open source idea, and look forward to the improvements that the gardeners of Instructables suggest!
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