How much food can FarmBot grow?

An in-depth analysis based on crop needs and performance

Reading time: 8 minutes

We are often asked questions relating to FarmBot’s yield. “How big of a FarmBot do I need to grow all of my food?” is a common one. While we don’t yet have any empirical data to share with you, we have done an analysis answering this very question. Let’s dive in to see the results.

Gathering Data

We compiled a set of 33 common crops (seen in the table below) that could be compatible with FarmBot in the relative near future. You’ll notice that we did not include tall crops such as sunflowers and corn, and there are no fruit trees or berry bushes (with the exception of strawberries). Additionally, there are no grain crops included because it is unlikely that growing grains would be efficient with FarmBot hardware in comparison to larger scale specialized equipment.

After choosing the crops, we needed to find three pieces of data for each: average yield per harvest (kg/m²/harvest), average days till harvest (days/harvest), and caloric density (calories/kg). We found this information from the USDA and a wide range of other sources online (see below for resources list).

Crunching Numbers

Right off the bat, we made an assumption that FarmBot can increase yield per harvest by about 12% by packing plants in a denser hexagonal packing structure instead of a traditional cubic packing structure. Using this new yield data and the days/harvest values, we calculated daily yield values for each crop in kg/m²/day. Multiplying this figure with the caloric density provided a daily caloric yield for each crop in calories/m²/day.

Crop kg/m²/harvest (cubic packing) kg/m²/harvest (hexagonal packing) Days/harvest kg/m²/day Calories/kg Calories/m²/day
Artichoke 1.23 1.42 120.00 0.0119 470 5.58
Arugula 0.79 0.91 35.00 0.0259 250 6.47
Asparagus 0.49 0.57 360.00 0.0016 200 0.32
Beets 1.57 1.81 60.00 0.0302 430 12.98
Bell Pepper 0.77 0.89 90.00 0.0099 250 2.48
Black Beans 0.16 0.18 85.00 0.0021 3390 7.23
Broccoli 1.18 1.36 65.00 0.0209 340 7.11
Brussel Sprouts 1.79 2.07 110.00 0.0188 430 8.09
Cabbage 3.53 4.08 90.00 0.0453 250 11.32
Carrots 3.36 3.88 70.00 0.0555 410 22.74
Cauliflower 1.35 1.55 80.00 0.0194 250 4.85
Celery 3.59 4.14 180.00 0.0230 160 3.68
Chard 1.68 1.94 50.00 0.0388 190 7.38
Collards 1.82 2.11 40.00 0.0527 320 16.85
Cucumber 1.96 2.27 60.00 0.0378 160 6.04
Eggplant 2.19 2.52 90.00 0.0280 250 7.01
Garlic 0.48 0.56 90.00 0.0062 1490 9.21
Kale 1.82 2.11 50.00 0.0421 490 20.64
Kohlrabi 1.63 1.88 65.00 0.0289 270 7.79
Lettuce 3.03 3.49 55.00 0.0635 150 9.53
Melons 1.68 1.94 90.00 0.0216 320 6.90
Okra 2.55 2.94 60.00 0.0491 330 16.19
Onion 4.32 4.98 110.00 0.0453 400 18.12
Peas 0.45 0.52 70.00 0.0074 810 5.99
Potato 1.92 2.21 110.00 0.0201 770 15.48
Pumpkin 4.48 5.18 110.00 0.0471 260 12.24
Radish 0.84 0.97 60.00 0.0162 160 2.59
Spinach 1.40 1.62 55.00 0.0294 230 6.77
Squash 3.92 4.53 90.00 0.0503 450 22.65
Strawberries 2.48 2.86 360.00 0.0079 330 2.62
Tomato 1.23 1.42 85.00 0.0167 180 3.01
Turnip 4.48 5.18 60.00 0.0863 280 24.16
Zucchini 3.36 3.88 90.00 0.0431 170 7.34

From here, we found out how many calories/day could be produced with each of our FarmBot kits. We calculated these values twice: once by using an average caloric yield of all 33 crops to represent growing them all using an equal amount of area; and once by using an average of the best 10 performing crops as ranked by the calories/m²/day benchmark. The results are in the table below:

 
Calories/day
  Calories/m²/day Express (3.6 m²) Genesis (4.5 m²) Express XL (14.4 m²) Genesis XL (18 m²)
All crops average 9.74 35 44 140 175
Best 10 average 18.21 65 82 262 328

As you know, these calorie counts are very low considering most people eat at least 2,000 calories/day. By this analysis, one would need a huge FarmBot to grow all of their caloric needs. We calculated just how big in the table below, revealing a minimum size of 110 square meters (the size of a small house) in order to provide all 2,000 calories/day for one person.

 
Size of FarmBot needed (m²)
  Calories/m²/Day For a 2,000 calorie diet For a 2,500 calorie diet For 10,000 calories (family of 4-5)
All crops average 9.74 205 257 1,027
Best 10 average 18.21 110 137 549

Cups, Not Calories

But this isn’t a very useful calculation because most people don’t get 100% of their calories from vegetables. Not even close to it, actually. Most people also eat grains, dairy, meats, oils, fruits, etc – all of which are much more calorie dense than veggies. According to My Plate (previously the food pyramid), we’re supposed to eat about 3 cups of veggies a day, and there is no mention of calories of veggies at all.

This means that the question we are asking and answering should instead be: “How big of a FarmBot would I need to grow the recommended cups/day of veggies I need?” Let’s see how this changes things.

If you chose to eat 3 cups of Black Beans every day, that would be over 1,500 calories, and require about 250 square meters to grow. This is a huge amount of area needed to satisfy our 3 cups goal. If you chose to eat 3 cups of Arugula every day (a crop with similar calorie/kg value to Black Beans), that would be less than 20 calories, and only require about 3 square meters to grow. This is a much smaller amount of area needed because our new goal is cups, not calories. So while both crops perform similarly according to the calorie benchmark, they perform extremely different under the cups benchmark.

Promising Results

Looking back out our table of 33 crops, with new columns for cups/m²/day, and FarmBot is looking quite a bit more feasible for satisfying our needs.

Crop kg/m²/harvest (cubic packing) kg/m²/harvest (hexagonal packing) Days/harvest kg/m²/day cups/kg cups/m²/day
Artichoke 1.23 1.42 120.00 0.0119 7.46 0.09
Arugula 0.79 0.91 35.00 0.0259 50.00 1.29
Asparagus 0.49 0.57 360.00 0.0016 7.46 0.01
Beets 1.57 1.81 60.00 0.0302 7.35 0.22
Bell Pepper 0.77 0.89 90.00 0.0099 8.33 0.08
Black Beans 0.16 0.18 85.00 0.0021 5.43 0.01
Broccoli 1.18 1.36 65.00 0.0209 10.99 0.23
Brussel Sprouts 1.79 2.07 110.00 0.0188 11.36 0.21
Cabbage 3.53 4.08 90.00 0.0453 14.29 0.65
Carrots 3.36 3.88 70.00 0.0555 8.70 0.48
Cauliflower 1.35 1.55 80.00 0.0194 9.35 0.18
Celery 3.59 4.14 180.00 0.0230 9.90 0.23
Chard 1.68 1.94 50.00 0.0388 27.78 1.08
Collards 1.82 2.11 40.00 0.0527 27.78 1.46
Cucumber 1.96 2.27 60.00 0.0378 9.62 0.36
Eggplant 2.19 2.52 90.00 0.0280 12.20 0.34
Garlic 0.48 0.56 90.00 0.0062 7.35 0.05
Kale 1.82 2.11 50.00 0.0421 14.93 0.63
Kohlrabi 1.63 1.88 65.00 0.0289 7.41 0.21
Lettuce 3.03 3.49 55.00 0.0635 27.78 1.76
Melons 1.68 1.94 90.00 0.0216 5.88 0.13
Okra 2.55 2.94 60.00 0.0491 10.00 0.49
Onion 4.32 4.98 110.00 0.0453 6.25 0.28
Peas 0.45 0.52 70.00 0.0074 6.90 0.05
Potato 1.92 2.21 110.00 0.0201 6.67 0.13
Pumpkin 4.48 5.18 110.00 0.0471 8.62 0.41
Radish 0.84 0.97 60.00 0.0162 8.62 0.14
Spinach 1.40 1.62 55.00 0.0294 33.33 0.98
Squash 3.92 4.53 90.00 0.0503 8.06 0.41
Strawberries 2.48 2.86 360.00 0.0079 6.94 0.06
Tomato 1.23 1.42 85.00 0.0167 5.56 0.09
Turnip 4.48 5.18 60.00 0.0863 7.69 0.66
Zucchini 3.36 3.88 90.00 0.0431 8.06 0.35

Using the average yield for our 33 crops, and an assumption that they will all be grown in equal quantities, one only needs about 7 square meters of space to grow the daily recommended servings of veggies for one person. If one decides to grow only the top 10 performers (by the cups/m²/day benchmark), then they will only need 3 square meters to grow all of their daily veggies.

This indicates that both FarmBot Express and FarmBot Genesis could produce all of the veggies needed for one person every day

Meanwhile, Express XL and Genesis XL could produce enough veggies for a family of four to five every day. See the table below for the numbers:

 
Cups/day
  cups/m²/day Express (3.6 m²) Genesis (4.5 m²) Express XL (14.4 m²) Genesis XL (18 m²)
All crops average 0.42 1.5 1.9 6.0 7.6
Best 10 average 1.00 3.6 4.5 14.4 18.0

Yield Hacking

The analysis above is just a start. There are many ways in which you might be able to produce substantially more with a single FarmBot. For example, you might select crops or varieties that perform even better than the ones we decided to look at. Additionally, by placing vining and other indeterminate crops near the ends of the bed and training them outwards, you can easily double or triple the area your plants can utilize while still being maintained by the FarmBot.

To conclude, your FarmBot will not be able to produce all of your calories. However, it will be able to produce enough cups of vegetables to satisfy you and your family's daily needs. We look forward to seeing what (and how much) you grow with your FarmBot!

References

Caloric density: 
ndb.nal.usda.gov

Days to harvest: 
iastate.edu 
harvesttotable.com

Recommended vegetable intake: 
choosemyplate.gov