Measuring Yields in the Vegetable Garden

Two years ago, one of my fellow speakers at an organic farming conference shared his research on calculating the profitability of growing different vegetables, and carrots were on the chopping block. Time spent watering, thinning and weeding pushed up labor costs, planting more than 12 plants per square foot reduced yields, and then there was price competition from commercially-grown carrots from California. Instead of carrots, the professor suggested going big on fingerling potatoes.

I get where he was coming from, and his goal was to educate farmers, not gardeners. As a carrot-loving gardener, I have other questions. How do you measure the vibrant flavor from a freshly pulled carrot? If the carrots came from your garden and you know everyone who touched them, isn’t that worth something, too?

These and other subjective questions show the weakness of the profitability model in the vegetable garden, but that doesn’t mean we should not watch yields and use productivity as a major factor in deciding what to grow.

Measuring Vegetable Yields

In 2012, a team of horticultural experts at the Rutgers New Jersey Agricultural Experiment Station computed yields per square foot for numerous vegetables and small fruits, and their chart can serve as a useful reference for those who wish to count or weigh their harvested produce. These are straightforward numbers – half a pound (227g) of bush snap beans per square foot, or 1.5 pounds (680g) of potatoes, but they tell only part of the story.

The next factor is how long the crop stays in the ground, which affects whether another vegetable can be grown in the same spot in the same season. For example, tomatoes and peppers stay put in the same place from spring to fall, so their space is spoken for all season. But most other garden vegetables use only part of the growing season, so the space can be used twice. In many places you can grow fall greens after early potatoes, or bush beans after spring carrots. This is called succession cropping or multi-cropping, and things get complicated fast when vegetables are planted in sequence or interplanted, for instance allowing pumpkin vines to run among sweet corn.

Should you weigh or count your produce to get baseline numbers? I tried this a time or two, and quickly gave it up. After impressing myself with the size of my cabbages, I changed my focus to how much garden food was making it to the table, which is perhaps the best measure of garden productivity.

Tracking Kitchen Usage

If you want to see maximum monetary returns when measuring yields in the vegetable garden, you will be astounded by what you learn from keeping a food diary for a few weeks during gardening season. Granted, having a garden bursting with produce influences what you eat, but money not spent on main-dish salads and vegetable casseroles adds up fast when you eat from your garden every day. A food diary also allows you to factor in the use of fresh herbs, which are easy to grow and preserve yet expensive to buy.

There is also added value in home grown vegetables that are easy to store, like the garlic in my pantry and the butternuts in the basement. There are still a few carrots and beets in the fridge, and when they’re gone I have frozen, dried and canned veggies to add to winter meals. The convenience of having at least some garden vegetables on hand is noteworthy in normal times, and priceless in a pandemic.

Using the Garden Planner and Journal to Improve Productivity

Those of you who are using our free Garden Journal can record your harvests by weight and quantity so you can track your garden’s progression from year to year. You can add notes and photos too, which makes it really easy to see what has worked well and what was less successful.

The Garden Planner’s Succession Planting feature helps you to make the most of multiple planting opportunities. Double-clicking on a plant in your plan and setting its in-ground dates enables you to then view your plan month-by-month, so you can quickly see where gaps will appear and plan to fill them, ensuring no part of your garden ever languishes unproductively.