A Short Post on an Ebb and Flow Idea

A Short Post on an Ebb and Flow Idea

 

Someone recently on the Reddit r/Hydroponics group put up a photo of a five-gallon bucket with a PVC “T” mounted in the bottom and extending out the base. We wondered what it was, and I speculated it might have been part of a Dutch Bucket system. It seemed an awkward way to approach Ebb and Flow, but after sleeping on it, I realized that it wasn’t a crazy idea and that with some tweaks, it could be a very workable way to do an Ebb and Flow system with individual growing buckets.

Individual buckets of course allow mixing buckets with different media. I sat down to try to design such a system, and this post is about what I came up with. I’ve done some searching and have not found Ebb and Flow done quite this way.

It does have a lot in common with the “poor man’s” Ebb and Flow setup, which is two buckets connected by tubing that enters each near the bottom. One holds the medium and plant. The other holds the nutrient, just the right amount to fill the growing bucket sufficiently. Put the nutrient bucket on a chair or table to make it drain in the growing bucket on the floor. At the end of the flood cycle time, set the nutrient bucket on the floor and the growing bucket on the chair to recover the nutrient for the ebb cycle.

Indeed, there is at least one multi-bucket Ebb and Flow system marketed. It pumps nutrient into buckets and then pumps it back out, all controlled by a timer.

I wanted something a little less demanding and more easily constructed by a grower. A typical commercial bucket line Ebb and Flow uses a controller bucket, the bucket to which the pump directs nutrient from the reservoir and from which is later pumps is back. A float valve in the controller bucket determines the nutrient level at flood. Nutrient seeking its own level flows among all the growing buckets through connecting tubes near the bottom of the buckets, so all experience the same nutrient rise. The system requires two pumps or a reversible pump.

My design works very like that. Here is my schematic.

 

In place of a controller bucket, I have the riser on the left. During flood cycle, the pump runs continuously. Nutrient in the system is always flowing, so it cannot at any point be higher than the bottom of the horizontal leg of the inverted “U” of the riser. Because water always seeks its own level, the nutrient is at the same height in the buckets as in the riser. As flooding begins, the nutrient levels in the riser and the buckets will all be equal. Rapidity of flooding will depend on the capacity of the pump. The pump must have sufficient excess head rating to handle the maximum nutrient height, so a ten-foot head rating would be the least I would want.

When the pump stops, nutrient drains back through the pump into the reservoir, as it does in most Ebb and Flow systems. I have added ball valves at each bucket so that any bucket can be disabled when idle. It’s pretty failsafe. If a pump hangs on, it just flows through to the reservoir. If a pump fails, there’s a bit of nutrient remaining in the buckets, and like all ebb and flow, roots continue to get their air from the atmosphere.

Note that I had to skew the perspective to show everything. The buckets and their valve-controlled feeds can be on the same level, so long as it’s all above the highest reservoir nutrient level. Some things could not be shown, like the fact that screens fine enough to block the size of the smallest medium used should be placed over the ends of the pipes inside the buckets. Alternately, the medium in a bucket can be contained in a mesh bag.

It’s hardly a major advance in hydroponics or even in Ebb and Flow systems, but I find it attractive, in that I could use different media in different buckets to suit different plants. Or no media at all. There’s no practical limit to the number of buckets.