DIY Auto-Pumping Drain Bucket

Automatic Drainage Systems, Automatic pumping drain bucket catchment solution for cannabis grow

Auto-Pumping Drain Bucket

An automatic pumping drain bucket is the final piece to complete an automatic drainage system. This bucket will sit inside the tent and receive the run-off water from the self-draining saucers. Water enters the auto-pumping drain bucket only 2 inches from the floor of the tent. This prevents you from having to raise your plants. The pump inside the bucket is activated on a float switch and turns on when the water level is less than 2 inches high. The pump will send the water out of the grow tent and into a separate bucket or catchment that can hold more water and be emptied with ease.

Automatic Drainage Systems for Grow Tents

In drain to waste fertigation, each watering should produce run-off which must be removed from the plant. We suggest using self-draining saucers and provide a complete tutorial to build your own. However, the saucers need to drain to someplace. If you can raise your plants, perhaps raise the whole tent, then you can simply use gravity to drain into a bucket. Preferably the catchment bucket will sit outside the tent or grow space to reduce humidity.

If you want to maximize the space for growing, then you want to limit the height that you raise the plants inside the tent. Rather than raising the plants to use gravity, the auto-pumping drain bucket is designed to receive the water at only 2” from the floor of the tent. This means that the 3.5” height of the self-draining saucers is sufficient to fully drain each saucer at each event. This keeps plants close to the floor and maintains the vertical growing space needed for your plants.

Supplies for an Automatic Pumping Drain Bucket

5-Gallon Bucket with Lid
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You need two buckets for this automatic drainage system. One sits in the tent and holds the pump. It is the "Auto-Pumping Drain Bucket". The other sits outside the tent and is the final catchment. The Auto-pumping drain bucket only needs to be large enough to hold the pump. I use a 5-gallon bucket because I have the space for that in my tent, but you could use a smaller bucket. The bucket should be large enough to hold the pump and have a lid. The Final Catchment Bucket can be as large as you like. A 5-gallon final catchment is adequate for several days with my 4x4 tent.

Shallow Pan Condensate Pump
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This is a pump that is designed to sit in a tray (or bucket) and turn on automatically when the water reaches a certain height. This is the “shallow pan” model, which turns on in only 1.75” of water and shuts off again when water is about 1”.

The pump is expensive but be careful about cutting corners here. I did a lot of research and if this is your problem, this pump is an excellent solution. I have owned this pump for over a year and used in on 4 different grows. It is one part of my grow that I can simply forget about because it always does its job.

1/2" Rubber Grommets
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You drill holes in the bucket to allow the drain lines from the saucers to enter the bucket. These grommets hold the drain lines in place.

Drain Line: ½” Vinyl Tubing
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You may already have this for your drip system. This is the outflow line and can be run to another bucket that sits outside the tent.

Assembling the Automatic Pumping Drain Bucket

Step 1: Prepare the Bucket

You need to cut holes in the edge of the bucket for the drain lines to enter. My self-draining saucers have 1/2” (outer diameter) drain lines. The grommets that will hold these lines require a hole that is 3/4”.

Measure 2” from the bottom of the INSIDE of the bucket and mark the midpoint height to drill the holes. The height of 2” from the bottom of the inside of the bucket ensures that the pump will activate before the water level rises to the height of the drain lines. It also ensures that the water enters the bucket low enough that gravity will successfully drain the saucers.

Drill a 3/4" hole for each drain line that needs to enter. Insert a grommet into each hole.

Step 2: Install the Pump

The vinyl tubing attaches to the outflow fitting on the pump. You can run this tubing out of the tent and into a separate bucket or catchment that can be emptied or drained.

The pump itself simply sits in the bottom of the bucket. There is no need to attach or fasten it. You simply set it down and plug it in.

You need to cut a hole in the lid of the bucket to run the power cord for the pump and the outflow water vinyl tubing.

Step 3: Install the Auto-Pumping Drain Bucket

Bring the bucket into the tent and set it in a convenient location. Run each drain line into the auto-pumping drain bucket through a grommet hole. Trim excess length from the drain lines but be sure you have the positions of everything correct first.

The outflow tubing can run out of the tent through a convenient port. It does not matter if this line goes up or down as the pump is powerful enough for any reasonable application.

Step 4: The Final Catchment Bucket

I use another 5-gallon bucket for my final catchment. It sits just outside the tent and I attach the end of the vinyl drain line to the lid. This holds the drain line out of the water and prevents any possible back-flow. When the bucket fills up I simply swap buckets and move the lid.

This system has run perfectly for me for over a year and across several grows. The only potential run-off risk is overflowing the final catchment bucket.

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Author: Dr Coco

I am a university professor and have taught courses in horticulture. I am coco for cannabis and I hope you are coco for cannabis too :) Grower Love!