Indoor Herb Garden With Automatic Watering

Last year I wanted to grow some kitchen herbs indoor, mostly as a fun experiment. My family had planted herbs and vegetables in the garden for several years, and I wanted to try growing something myself but on a smaller scale. I also happen to have some low windows in my living room that get a lot of light during summer which made this place well suited for plants.

This project was done in two parts. First I made the plant boxes and did successfully grow herbs in them last summer. Then more recently I wanted to upgrade with a system that could water the herbs automatically. So in the second part of this instructable I will explain how I made that watering system.

As a side note, I have wanted to make an instructable for a long time but this is my first one. Any feedback on how this or my next instructable can get better is appreciated.

Materials for the basic plant boxes:

• GLES storage boxes from IKEA with lids
• Plastic shelf box (I got it for free) that has room for the smaller boxes in it
• Soil and compost (from the garden, and mixed with equal amounts of each)
• Pebbles to cover waterholes
• Seeds

Tools:

• Sugru for waterproofing the lower box
• Strong knife/Leatherman
• Free chopsticks for making seed holes in the soil

Materials for the automatic watering system:

• 10 liter water container
• Thin flexible plastic tube (around 1 meter), with an outer diameter matching the nozzles inner diameter.
• Small submersible water pump
• Zip ties
• 12 V power adapter for the water pump
• Digital day/week timer with 1 minute as smallest time interval

Tools:

• Hot melt glue gun
• Knife/Leatherman
• Electrical tape

Since I wanted to keep this project cheap I bought the cheapest storage boxes I could find at IKEA, which were the GLES boxes. I was lucky to find a transparent and strong shelf box for free that fit the storage boxes well. I took compost, soil and pebbles from the garden.

When I later wanted to make an automatic watering system I found most of the things I needed at a hardware store called Biltema which is common here in Norway and in Sweden. I already had the zip ties and the power adapter.

The shelf box I had found was not waterproof, so to make it waterproof I sealed the inner edges with a thick layer of Sugru and let it dry for 24 hours. I then filled it with water to make sure it was fully waterproof as I didn't want any leaks on my living room floor.

In the green boxes I cut out holes in the bottom using the knife on my Leatherman. I found that the serrated blade worked well for cutting in plastic as it saws the plastic while cutting. I cut each hole 1-1,5 cm in diameter with a distance of 4-5 cm between each hole. I didn't measure while doing this, as I thought it was more important to have the holes evenly spread out than having exactly the same distance between each hole. On the second picture I have drawn some circles on an unused box to give an idea of how many holes the box can have, but it does not need to have an exact number of holes.

I took pebbles that were just a little bigger than the holes and put one pebble over each hole to allow water to come in through them while avoiding that the soil flows out. I then covered the pebbles with a mix of soil and compost from the garden while making sure that the pebbles covered the holes. I filled the boxes 10 cm deep with soil, as I assumed that would be deep enough for the herbs I had planned to plant.

I used some chopsticks to make holes for the seeds. The packs of seeds I used had instructions on them for how deep they should be planted, and the distance between each hole. I then put one seed in each hole and poured on a lot of water.

Using just one seed in each hole turned out to be a mistake, as nothing grew out of them. Instead, seeds that had been in the soil I used started to grow (see picture 2). This set me back some time, as I had to remove these bad herbs and plant new seeds. This time I made furrows and planted 2-3 seeds at the same place, and then spread out the seeds in lines in the soil. As you can see from picture 3 this gave the result I wanted. I also added small signs to remember where I had planted each type of seeds in the boxes. During the first weeks until the herbs had grown a few centimetres tall I had the transparent lids on the boxes to make a greenhouse under the lids.

With enough light and regular watering in the lower box the herbs may grow fast and be ready to be used in 1-2 months. A good thing with putting water in the lower box instead of pouring it over the herbs is that the soil will absorb the water it needs while the rest of the water can stay in the lower box. But I also watered the herbs from above from time to time to make sure the upper part of the soil would get enough water.

As you can see, the parsley in particular grew into big plants. So I cut it down to give the basil next to it some more light. I found that the parsley grew fast, so it was not a problem to cut some off and let it grow again.

Now in January I decided to take this project one step further by adding a system that could water the herbs regularly for some time without any input. I decided to go for a simple system with a submersible pump in a water container, and connect the pump to a digital day/week timer to program how often the plants would be watered.

As I wanted to limit the water flow out of the pump as much as possible
I took a small ruler with me to the shop and measured the inner diameter of the pump nozzle instead of the outer diameter and then chose a tube with an outer diameter as close as possible to the inner diameter of the pump nozzle (see picture 1). When testing the pump later I found that the flow of water was around 1 liter / minute, while the specifications of the pump say it can pump 7,5 liter / minute. This means that I can get choose how much water I want to get out of the pump by adjusting the time of the timer.

To make it easy to refill the container with water and also attach the pump to the container I cut out an opening on top of the container just big enough to fit my hand through it (picture 2 and 3). I also cut out a smaller opening for the water tube and power cable for the pump (picture 4). I then tested out the pump inside the container.

My first plan was to just attach the pump inside the container with Sugru. So I put a good amount of Sugru on the pump and pressed it against the inner wall of the container. However, after a few hours it came loose, and I had to choose another solution. it can be due to the surface of the plastic container, or because the Sugru I have is somewhat old. I then found that the Sugru makes for a good flat surface on the pump that keeps it better in place against the container side.

I chose to use zip ties to attach the pump, with the zip ties attached permanently to the container but not the pump. In this way the pump can be removed for servicing or replacement if it should fail in the future. While holding the pump in place I made some marks to remember where to place the zip ties. I cut out some holes just big enough for the zip ties and fed them through the holes. I glued one end of the zip ties against the container side with a hot melt glue gun, then put the water pump inside the container and tightened the zip ties with the other end. After making sure that the pump sits well in place but can still be taken out I put a good amount of hot melt glue on top of the holes to make the container fully waterproof. I then finally tested the container for leaks by filling with a few litres of water.

The picture show the watering system ready for use. The power adapter plugs into the timer that can be programmed in any way with 1 minute as the shortest time interval. So I can the system water the plants as often as I need. Since the pump outputs around 1 litre / minute this is the lowest amount of water I can get at a time. But this is fine for me as the big box the herb boxes are standing in can fit up to 5 litres of water with the plant boxes in it.The end of the water tube can be attached to the inside of the bigger box, or be used for another plant in the future.

When using the automatic watering system I quickly found out that it did not work fully as planned. The reason for that was that I had not taken into consideration the siphon effect. When the water tank was filled with water and standing on the floor next to the garden boxes the water would flow through the tube into the garden box by itself until the water in the tank and garden box had the same level. This happened outside of the programmed watering time, but luckily I only had 2-3 liters of water in the tank otherwise the garden box would have overflowed onto the floor. So I realised the garden boxes had to be higher than the water tank to avoid this effect.

So for this I built a simple bench using one 4,5 x 2,5 cm piece of pinewood. I tried to keep it simple so I only used this plank of wood for the whole bench. I don't have more instructions for this bench than the photos, but it should be relatively simple to make. I first glued and screwed together the frame using four pieces of wood, then added the legs and finally the angled reinforcement pieces. This bench also has the added benefits of simplifying cleaning around the garden boxes, getting a better work height and it gets the garden boxes up to window height. A low table or a normal table with a shelf underneath it for the watering system would also work.

In the second year of using the garden boxes I grew tomatoes (normal and cherry tomatoes). The plants ended up being around 3 meters tall! For this (3rd year) I will try to grow carrots in them. With that I hope you liked this instructable, and again I'm happy to get any feedback on how this or my next instructable can get better.