Building a Self-Waterer

Building a self-watering planter is a great way to garden for a number of reasons!

  1. Great for a spot that gets at least 6 hours of sun but you can’t dig, like under a tree

  2. Easier on your knees and back

  3. You have a busy schedule and you can’t babysit your plants when it is hot.

  4. It gives your plants constant water when it is needed

  5. You have the perfect soil and don't have to mess with your clay soil

  6. No weeding

  7. You don’t have to rely on anyone when you are away

Who doesn’t want to make gardening easier and more fun while reaping the benefits of your hard work?

Building a self-watering planter is easy and can be designed to fit anyone's needs. I built mine using an old stock tank. As long as it can hold water, then you can use anything! Since my planter is made out of galvanized metal, it is quick to warm up the soil inside and holds the soil temperature at night--which is perfect for tomatoes but can also be used for other veggies, herbs or flowers.

Self watering pots have been around for decades, and are based on the principle of sub-irrigation, where the water supply sits below the pot that is wicked upward into the container above. My self-waterer uses a wicking system which also serves as the barrier between the soil and water reservoir.

I first made sure that my planter was on a level spot. If it wasn’t level it might wick up too much water or not hold enough water.


I then built my reservoir with a perforated 4 inch pipe and used extra piping that I had laying around as filler so that my reservoir wouldn’t collapse when I put the soil in. I extended the drain pipe on one end to give me a fill tube to fill the reservoir.

I then drilled a overflow hole so when the water level reached 4 inches it would leak out the side. Without the drain hole the water would have nowhere to go and your soil above the reservoir would become a soggy mess. My reservoir holds 4 inches of water. You can make yours however much you want it to hold.


I then laid a cotton landscape fabric over the top of the perforated pipe and tucked the fabric around the sides. The fabric is going to act like a wick and separate the soil on the top from the reservoir on the bottom.

Once that was done I added a good potting soil on the top.

The type of soil that I chose was a compost/peat mix. It had plenty of perlite added so that the roots of the plants could have air. I would not recommend using potting soil that has a lot of fresh bark added to it. Composted bark is great but fresh bark will rob your plants of nutrients to decompose and also create a bog type situation. ( I had that happen before!! Not pretty.) Using straight top soil would get to compact and suffocate the plants.

I filled the planter above the reservoir, almost to the top, leaving a few inches. The idea of the waterer is to water for you, but in the beginning, I had to also top water until the roots went deeper into the soil in search of more water.

Fertilizing

My potting soil that I used had a lot of compost in it, so I probably didn’t need a lot more fertilizer since the compost has enough to start plants. I was growing tomatoes in the containers and tomatoes and peppers are high feeders so I chose to add 3-4 cups of organic fertilizer to the potting mix and mixing it in the top 4 inches of soil. I would eventually add fertilizer through out the season alternating brands and varieties to get the plant to do what I wanted. Early, a lot of nitrogen to get the height, and then others to get them to bloom and produce. I used mainly organic fertilizers not because they are organic but because I wanted slower release and to not push the plant too fast. Every now and then a synthetic to give it a quick boost for a week, either a water soluble added to the reservoir or watered in from the top. Using that much fertilizer throughout the season, I knew would cause salt build up by the end of the year, meaning I'd need to either flush the soil or change or mix for the following year.

By having a constant water and fertilizer system in place I was able to get the return I was looking for and could concentrate on other parts of the yard, making it fun and easier.