We are lazy gardeners. To find a self watering system for our raised beds were important to us. We investigated several possible systems, but decided to let the capillary force do all the work for us. After a few hours on Google – we had enough input to do a minature proof of concept with a flower box and some PET-bottles. The prinicple seemed to work just fine – so we felt ready to scale it. You can do this in several ways. This is a guide to how you can do it your self. We did like this:
1. We started by lining the inside of our raised beds. You can use pond lining, but we decided to go with the cheaper option and use regular building plastics that we already had at home.
2. Placed drainage pipes in the beds. (They don’t have to be connected to each other, but ours are.)
3. We did a hole in one of the pipes, and connected a regular PVC-pipe. The PVC-pipe is supposed to go through the soil and will be used to fill the wicking bed with water.
4. Cover the pipes with cloth to prevent the gravel to clog the system later.
5. We almost forgot to construct the drainage, so it was done last minute. We simply drilled a hole and stuck a small piece from a garden hose through the wood, and sealed the gap around the garden hose with silicone. A bit “MacGyvery” method, but saved us a trip to the store. We had a bit of problems with the drainage being clogged later in the summer – so I would recommend a more solid solution to this. (We will probably revisit it next year.) Importat that you place the drainage on the same height as the gravel will end and the soil will start. That makes is possible for the water tank to be full, and excessive water to drain.
6. Next step is to fill with gravel – we used macadam, but you can basically use anything that has OK wicking qualitys. We took the same macadam that we had used around the raised bed when we constructed them. Fill about 40 centimeters high.
7. Then fill with water. Make sure that the drainage is working when the water reserve is full.
8. Cover the macadam/gravel with a cloth. This is to prevent the soil from leaking into the macadam/gravel water reserve.
9. Last step is to fill with soil. In one of the benches we went for 50% compost and 50% soil. This proved to be the winning concept – so to recommend.
Wicking bed update
Sharing some more pictures on building these Raised Beds, and the veggies that was growing in them during the first season. On some pictures you can see the Pergola that we built 2 months after we built the Raised Beds.