41. DIY Self Watering Tray
Instructions for making a capillary tray.
I created a prototype for a cheap DIY self-watering tray. Here is what you need:
Product List
Gardzen (Amazon) seed trays with lids, 10-pack ($31) — optional
Gardzen (Amazon) trays, 10-pack ($17)
Playground Sand (free - we have a pile in the yard)
16 ounce (U-line) Banjo Sauce bottles ($57 for 36)
Cost Per Tray
The total cost of each tray is $6.38, which is about a third of an off the shelf system.
Tray Design
I tested out a few designs before landing on this Capillary Tray Design:
Step 1
Gather your store bought materials: trays and bottle.
Step 2
Cut out hole for bottle location in your multi-cell tray.
Step 3
Drill 1/4” hole in the bottle cap and fill the bottle with water.
Step 4
Collect medium for the tray — I used sand from our yard, but probably any well draining medium would work.
Step 5
Compact the medium to create a level surface.
Step 6
Create a hole for the water bottle; I used a section of PVC.
Step 7
Saturate the medium with water, until water barely shows up at the surface; this photo was taken just after I poured the water, it was mostly absorbed before I went on to the next step.
Step 8
Take your bottle — full of water and with the holey cap on it — and place it upside down into the tray. You may see a few small bubbles, but it should quickly stabilize.
Note: If you are looking for a basic self-water tray, you can stop here! You are all set to put your pots with drainage holes on top of this tray.
Step 9
Add your multi-cell tray with drainage holes on top of the bed. I had to wiggle the bottle a little bit to get it to fit. This caused some bubbles in my water bottle and mixing of the sand and water, but that is just cosmetic.
Step 10
Fill your tray with your preferred seeds or cuttings and enjoy easy watering. Refill the bottle whenever it runs dry.
Storage
Locate your tray in a green house, cold frame, garage or window sill. I am still not expert about light levels and temperatures, so I suppose ask your plants what they would prefer. For me, I am planning to have 30 of these self watering trays located on shelves in my green house (technically a cold frame since there is no supplemental heating or humidity control).
My next step is to test our some lupine seeds in my trays. I am quite excited!