? about Balancing Fish and Plant Ratios:

(From student after the March Abundance Foundation workshop)

Rachel:

1. For my outdoor system (even my indoor system) I STILL can’t figure out the ratio thing…meaning HOW do you know you can grow 3 heads of lettuce to 1 lb fish and 1 tomato plant to 6 fish.

What I am trying to figure out is that I want to grow peppers, lettuce, tomatoes, snap peas, broccoli (for example) and I have two grow beds 4ft X 4ft (16 square ft ) and 12inches deep (16 cubic feet= 119 gallons)…attached to a 200 gallon tank. Help?

Dear M,  remember to use the rule of 1lb fish/sq ft of planting area (derived from Rakocy's feeding ratio of 60-100 g feed/m2/day)

1st determine # of fish needed to maintain the desired plant bed size.

How?

1lb fish/square ft : if 16 square ft then 16 lbs of fish required

Fish density?: 16lbs of fish/200 gallon tank = a density of 1lb fish/ 12.5 gallons

Notice your plant bed:fish tank volume ratio is ~1:2 (119:200) which will work well with media beds and in fact this is a great fish density to start with since it will be easy to maintain at this low density

2nd determine # of plants based on max planting density:

How?

if 16 square ft= then ~45 heads of lettuce can be planted (max. planting density= 2.8 heads/sq ft)

or 3 tomato plants (planting density- 1 tomato/6 sq ft)

[note 45 heads/16lb fish = 3 heads/fish & 3 tomato plants/16 lb fish= 1 tomato plant/ 6 fish]

You can do any combination of lettuce or tomato plants in the 16 square ft, just make sure you plant them at their max density.

Question 2. I am still unsure how to figure out how I can grow 6 heads of lettuce, 1 tomato plant, 2 bean plants and 4 heads of broccoli… Because I don’t know how to figure out how many fish I need for bean plants and how many fish I need for broccoli…does that make sense? Even Strawberries, how many fish do I need for strawberries…