Garden Yield Calculator

What a yield estimate can and cannot tell you

A yield estimate is a planning tool, not a promise. The numbers below come from average home garden results and university extension trials, and they assume decent soil, full sun, regular water and a normal season for your region. Change any one of those and the harvest moves, sometimes by half. What the estimate gives you is a realistic range to plan around, so you know whether six tomato plants will feed your family or bury it.

The figures are in pounds per plant because that is how most gardeners count. If you think in square feet instead, the calculator also reports the bed area each crop needs, using typical intensive spacing. That makes it easy to compare crops: a plant that gives 8 pounds from 4 square feet is twice as productive per foot as one that gives 4 pounds from the same space.

University extension services publish the underlying trials, and two good references are the University of Illinois extension vegetable guides and the University of Minnesota extension pages. The USDA's People's Garden program also has region-by-region planting advice if you are starting from scratch.

Yield per plant for common vegetables

Average pounds of harvest per plant over a full season, with the space each plant wants and a typical store price for comparison. Prices vary by region and season, so adjust the price field in the calculator to match your store.

Read the table two ways. By weight per plant, tomatoes and zucchini are the heavy hitters. By weight per square foot, pole beans come out on top at about 4 pounds, followed by snap peas and beets, because you can pack them closely into a small bed. If space is tight, plant the crops with the highest pounds per square foot and buy the rest.

Worked example: six tomato plants

The most common garden question is whether a tomato patch is worth it. Here is the arithmetic for six slicing tomato plants at 8 pounds each.

• Yield: 6 × 8 = 48 pounds of tomatoes
• Space needed: 6 × 4 = 24 square feet
• Store value at $2.50 a pound: 48 × $2.50 = $120
• Costs: transplants $5, fertilizer $15, cages or stakes $20 = $40
• First year net: $120 − $40 = $80

The second year looks better, because the cages and stakes carry over. Costs drop to about $20 for transplants and fertilizer, so the same 48 pounds nets $100. If you save seed instead of buying transplants, the second year costs roughly $15.

The catch is the glut. Forty-eight pounds of tomatoes is about 100 medium tomatoes, and a family of four will not eat them fresh before they spoil. The value only holds if you use them, so plan for canning, freezing or sauce. If you will not process the surplus, four plants is a more sensible number and the calculator will show you the smaller harvest.

Worked example: a 4 by 8 foot raised bed

Now plan a single raised bed, 4 feet by 8 feet, which is 32 square feet. A mixed planting makes better use of the space than one crop, so here is a realistic layout.

• 4 tomato plants at 4 sq ft each = 16 sq ft, yielding 32 lb
• 1 zucchini at 9 sq ft = 9 sq ft, yielding 6 lb
• 63 carrot plants at about 10 per sq ft = 6.3 sq ft, yielding 12.6 lb
• Total space: 16 + 9 + 6.3 = 31.3 square feet
• Total harvest: 32 + 6 + 12.6 = 50.6 pounds
• Store value: roughly $104 at the prices above

That is about 1.6 pounds of vegetables per square foot for the season, which is a good target for an intensive bed. Growers who push harder with vertical trellises and succession sowing can reach 2 to 3 pounds per square foot, but the first year is usually lower while the soil settles.

Two details make the difference between the estimate and the reality. Fill the bed with a real soil mix rather than garden dirt, because root crops like carrots fork in heavy clay. And water deeply twice a week rather than lightly every day, which encourages roots to go down and makes the plants far more forgiving of a hot spell.

Getting more pounds out of the same bed

Yield is mostly a function of light, water and spacing, and the last one is the easiest to get wrong. Six habits reliably lift the harvest.

• Plant for the sun. Most fruiting vegetables want 6 to 8 hours of direct light. An hour of extra sun is worth more than any fertilizer.
• Grow up, not out. Trellised cucumbers, pole beans and indeterminate tomatoes use a fraction of the ground space and stay cleaner, which reduces disease.
• Succession sow. Radishes, lettuce and spinach finish in 30 to 45 days. Replanting the same square foot three times a season triples its output.
• Feed the soil, not the plant. Compost worked in each spring does more over three years than a season of liquid fertilizer.
• Water deeply and less often. Shallow daily watering creates shallow roots that fail in the first hot week.
• Harvest on time. Zucchini and cucumbers left on the vine stop the plant producing more. Picking early and often raises total yield.

None of this changes the calculator's per-plant averages, because those already assume reasonable care. What it changes is where you land in the range. A neglected garden might hit half the estimate and a well-run one can beat it by a third, which is a wide enough spread to matter when you are deciding how many plants to set out.

Turning the harvest into a real number

The dollar value in the calculator is only meaningful if you would have bought the vegetables anyway. If you grow 48 pounds of tomatoes and half of them rot on the counter, the saving is 24 pounds, not 48. Be honest about how much your household eats, then grow a little less than the estimate suggests for the first season and add plants once you know your capacity to use or preserve the harvest.

Preserving extends the value in a way the fresh price does not capture. A pint of home-canned tomatoes replaces a $2 can at the store, and 48 pounds of tomatoes makes about 20 pints, which is $40 of shelf-stable food on top of what you eat fresh. Freezing is even easier and needs no special equipment beyond bags and a freezer with room.

Treat everything here as an estimate for planning. Soil, weather and pest pressure swing home garden yields more than any other kind of farming, and the same six plants can give 30 pounds one year and 70 the next. Use the numbers to size your beds and your expectations, then adjust after your first real season. Nothing you type into the calculator leaves your browser.