Can a 500 m² backyard grow a year's worth of calories for one person?

Plot Arithmetic

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Can a 500 m² backyard grow a year's worth of calories for one person?<br>A calorie-and-land model using extension yield data, with the assumptions left open to inspection.

Plot Arithmetic<br>Aug 18, 2026

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500 square metres sounds like a lot of garden.<br>So I wanted to reduce the question to something measurable: not whether that much land can grow “a lot of food,” but whether it can grow enough calories for one person for one year.<br>Using 2,000 kcal/day as a reference gives:<br>730,000 kcal/year.<br>That isn’t a dietary recommendation. It’s just a convenient number to test against.<br>And to make the test relatively easy for the garden, I didn’t model a normal backyard full of lettuce, tomatoes and herbs.<br>I gave most of the growing area to two calorie-dense staples:<br>70% potatoes

30% dry beans

This is not supposed to be a sensible diet. It is deliberately biased toward making the smallest possible amount of land look good.<br>If that version struggles, adding lower-calorie vegetables isn’t going to rescue the calorie arithmetic.<br>Start with the yields

Utah State University Extension gives an average potato yield of about 20,000 lb/acre .<br>For dry beans, its home-garden guidance gives roughly 20–25 lb of dry seed per 100 ft of row .<br>Using 22.5 lb and two-foot row spacing gives approximately:<br>Potatoes: 2.24 kg/m²

Dry beans: 0.55 kg/m²

For food energy I used fixed USDA FoodData Central records:<br>Whole raw russet potatoes: 79 kcal/100 g

Dry mature pinto beans: 347 kcal/100 g

That works out to roughly:<br>Potatoes: 1,771 kcal/m²<br>Dry beans: 1,906 kcal/m²<br>With 70% of the growing area in potatoes and 30% in beans:<br>~1,811 kcal per cultivated m² before losses.<br>I then apply a 10% post-harvest-loss assumption.<br>That’s an assumption, not a universal agricultural constant. I left it explicit in the model so it can be changed.<br>After that haircut:<br>~1,630 kcal/m²/year.<br>Divide 730,000 by that and the first answer is:<br>~448 m².<br>At first glance, a 500 m² backyard seems to pass.<br>It doesn’t.<br>500 m² of backyard is not 500 m² of crops

The 448 m² figure is cultivated soil .<br>A real growing area also needs some combination of paths, access, compost, working space, irrigation equipment, storage, shaded edges and other non-producing area.<br>There is no universal percentage, so instead of pretending there is one, I tested several.<br>If productive beds occupy:<br>80% of the site: 448 m² cultivated requires about 560 m² total

60%: about 746 m² total

40%: about 1,119 m² total

I’ll use 60% as the middle scenario below.<br>That isn’t supposed to describe a “typical” backyard. It’s simply one visible assumption that can be changed.<br>A 500 m² total backyard at 60% cultivation gives:<br>300 m² of crops.<br>At the average-yield assumptions:<br>300 × 1,630 ≈ 489,000 kcal/year.<br>That’s about:<br>67% of one person’s annual reference calories.

Not 67% of a family’s calories.<br>Not nutritional self-sufficiency.<br>Just 67% of the 730,000-calorie target for one person.<br>And remember what was planted to get there:<br>70% potatoes and 30% dry beans.<br>The calculation is already trying quite hard to win.<br>Then the harvest gets worse

The average yield is doing a lot of work.<br>Weather, soil, pests, water, cultivar and growing skill all move crop yields around.<br>Utah State also publishes planning values 25% and 50% below its average yields, so I ran those without changing anything else.<br>For the same 500 m² property:<br>Extension-average yield: about 67% of the annual calorie target

25% below average: about 50%

50% below average: about 33.5%

If instead we ask how much total garden footprint is required to reach the full 730,000 calories:<br>Extension average: about 746 m²

25% below average: about 995 m²

50% below average: about 1,493 m²

For four adult-equivalents, those figures become approximately:<br>2,985 m²

3,980 m²

5,970 m²

That’s where the word backyard starts becoming misleading.<br>We’re getting closer to a small agricultural system.<br>But the bean number may actually be too generous

There is another wrinkle.<br>The Utah State home-garden bean figure, when converted using the row spacing above, implies almost 4,900 lb/acre of dry beans.<br>That’s aggressive.<br>University of Minnesota dry-bean guidance uses yield-goal bands extending through roughly 2,900+ lb/acre .<br>They aren’t directly equivalent production systems, so I don’t think it makes sense to quietly replace one number with the other and pretend the result has become more scientific.<br>But it tells us something useful:<br>The main result isn’t being created by choosing a pessimistic bean yield.<br>Quite the opposite.<br>If I substitute 2,900 lb/acre while leaving everything else alone, the middle land requirement moves from roughly:<br>746 m² → 857 m² per person.<br>So the 746 m² result is better thought of as a fairly favorable test than an alarmist one.

Check the model

If you want to inspect the assumptions or replace them with your own local yields and...