DIY Self-Watering Transplant Tray

comments (4) July 31st, 2011

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yourownvictorygarden Greg Holdsworth, contributor
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Click To Enlarge Photo: Greg Holdsworth (all photos)

One of the most critical tasks in growing your own transplants is making sure they have consistent moisture. This can be time-consuming if you're growing a lot of them. Not to mention occasions where one might not be able to water them as often as they would like, be on vacation, etc. For the most part this problem is now solved!

This transplant tray is almost totally self-watering and self maintaining. Here's how it works once it is set up and timed correctly:

DIY Trellis
  Photo A
  DIY Trellis
  Photo B
  DIY Trellis
  Photo C
  DIY Trellis
  Photo D
  DIY Trellis
  Photo E

At a set time, water is pumped from the bottom reservoir into the top tray, providing a high-enough water level to wick some of the water into the transplant containers, watering them. Holes drilled at the four corners prevent this water level from rising too high.

The water continues to be pumped into the tray for a set time until it is shut off by the timer. By then, the transplants have received enough water to moisten the soil media that they're in. But, it's not a favorable condition for the transplant's soil to be constantly moist, as their roots need to "breathe". Holes drilled into the bottom of the top tray allow the water to quickly drain out, thereby allowing the soil to (at least partially) dry out.

Yes, I know... nothing can be totally self-watering and self-maintaining. This setup does require occasional maintenance, such as replacing fresh water lost in evaporation, or that's gotten dirty. But for the most part, this is a "set it and forget it" setup.

The list of things you'll need:

• 1 - 25 quart (24 liter) clear plastic storage container

• 1 - 51 quart (48 liter) clear plastic storage container (photo A)

• 2 ft. - 1/4" or 3/8" clear plastic tubing (photo B)

• 1 - low-volume fountain or other water pump. I used a 70 gph unit (photo C)

• Electric timer (preferably 3-prong)

• Electrical extension or power cord

• Drill & drill bits

• Knife or small saw

• Permanent marker

• Two-to-three-prong electrical plug adapter (only if needed).

Note: The two plastic containers need to be the same width and length, and the shorter container has to fit inside the taller one.

Skill Level:



1. Place the smaller storage container inside the larger one and mark on the outside of the larger container it where it ends. You'll need that later.

2. Fill the top storage container with enough water to completely cover the bottom of it. Depending on the container, the depth of the water at this point shouldn't be more than a half inch. This is going to be the highest point at which the water will rise above the bottoms of the transplant containers (photo D).

3. Put a mark at each of the four corners, right at the top of the water level. This is an important measurement, as it will become the overflow points. That way, if something goes awry, they won't be overwatered (photo E).

After you try it, show it off to other members in the
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posted in: seed-starting, Projects, watering, transplants

Comments (4)

toasties_post writes: Can you tell me what brand of pump you used?
Posted: 5:05 pm on January 10th
veggielover53 writes: Can someone tell me if it is ok to use non food grade plastic containers for this?
I have no idea.
But the water comes into contact with the plastic for quite a while.
Does it leach anything out of the plastic?
Posted: 1:13 pm on October 11th
Alvinbass21 writes: incredible
Posted: 5:10 am on July 15th
Dwiggit writes: Wow...great design! I may try something like that as I begin sowing my winter crops...a couple of weeks from now. I can tell you are a pretty creative guy. I know you folks are having some terribly hot weather as we are in Abilene. Ready for some rain and lower temps!
Posted: 9:58 pm on August 4th
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