Excerpted from Sustainable Market Farming by Pam Dawling
Which crops to grow
Some crops require more skill or are less dependable. If your climate is marginal for okra, avoid relying on it for a large part of your summer income. Gardening When it Counts by Steve Solomon has a table of “Vegetables by level of care needed.” His “Highly-Demanding Crops” list includes some greens that bolt easily in spring, crops which quickly go “over the top,” and some which are plain old persnickety, requiring near perfect soil and conditions to perform well. He and I agree on the challenges of brussels sprouts, cauliflower, celeriac and bulb onions. Steve’s list also includes asparagus, Chinese cabbage, early cabbage, cantaloupe, leeks, large fruited peppers, spring turnips and spinach. While those ones are easy here, challenges in our climate include rutabagas, drying beans and shelling peas.
Some crops offer high yields or high market value for a small space. Do you have a lot of labor or a lot of land? In terms of yield per unit area, the best include carrots, summer squash, onions, potatoes, sweet potatoes and tomatoes. Peas, sweet corn, radishes and bush beans are among the worst. But in terms of tonnage per hour worked (“efficiency”) the best crops are sweet corn, potatoes, cucumbers, cabbage, summer squash, peas and peppers. The worst include pole beans, radishes, onions, carrots, bush beans and lettuce.
Neither high retail price nor high yield is the same as most profitable. See Richard Wiswall’s Organic Farmer’s Business Handbook for twenty-five sample crop enterprise budgets that you can use to make a comparison of costs, sales and profit from each vegetable. This is a book about number crunching that’s accessible and inspiring. (One of the author’s main goals is to help create less stressed-out farmers.) Beware of preconceived notions on what is most profitable — get real numbers. His highest to lowest net profit per bed are: greenhouse tomatoes, parsley, basil, kale, field tomatoes, cilantro, dill, peppers, carrots, parsnips, celeriac, spinach, beets, lettuce, summer squash, bulb onions, cabbage, potatoes, cucumbers, broccoli, winter squash. Peas, beans and sweet corn all ran at a loss. Remember — your results may vary! One lesson from this list is the ability of long- season crops such as kale with an extended harvest to provide high yields for the time put into soil preparation, planting and cultivation. Another lesson is that while bunched herbs can bring a good profit, people will only use a certain amount, and a diversity of crops is needed to keep customers returning.
What the market wants and what it can take
Many CSAs, including Roxbury Farm, post the contents of their shares. Sometimes you will want to grow certain crops even if they are not the highest money-earners because they enhance what you have to offer. Perhaps they round out your market display, or your CSA boxes. Perhaps you’ll grow a crop because it is extra early, or eye-catching. If you are growing for farmers’ markets you can choose to only grow high-value crops, but if you are doing a CSA, your customers may expect to receive some of everything and you will need to grow some low-value crops. But don’t be afraid to say no to growing a crop such as sweet corn or shelling peas that just doesn’t work for your farm. A CSA has the advantage of money upfront and guaranteed customers, as well as avoiding the costs associated with going to market. On the other hand, a farmers’ market booth can take a flexible range of produce, and so is easier if plans go awry.
Flow of decision-making on how much to grow
Producing crops when you want them and in the right quantities is a complex task, and the grower does not control all of the variables. However, to get the best chance of success, take decisions in a logical sequence. Once you’ve decided which crops you want to grow, here is a step-by-step process
to determine how much to plant:
1. Figure out how much of each crop you’d like to harvest, how often and over what length of time;
2. Calculate how many plants you will need. This depends on the yield per plant and how long the crop will stand in the field;
3. Add a percentage (perhaps 10%) to allow for culls;
4. Decide the dates for the sowings to meet the harvest date goals.
Charts of possible crop yields are available in the Roxbury Farm’s Field Planting and Seeding Schedule and their Greenhouse Schedule. Some seed companies have tables of likely yields in their catalogs, although these are sometimes more for the home gardener than for market growers. The Center for Agroecology and Sustainable Food Systems at the University of California, Santa Cruz has a lot of useful information including a thirty-page Crop Plan for a hundred-member CSA, with planting requirements including total bed length for a range of thirty-six crops in its Unit 4.5 CSA Crop Planning. Their Appendix 9 includes the area requirements translated into fractions of an acre. A further source of this kind of information is Sharing the Harvest by Elizabeth Henderson and Robyn Van En. A two-page table includes yield per hundred row feet.
How much to grow
If the average person needs 160–200 pounds (72–90 kg) of vegetables per year and the average household (= 1 CSA share) is 2.5 people, then one share will be 400–600 lbs (180–270kg) per year, roughly ten pounds (4.5 kg) per week for a full year. The table below lists forty-eight crops, along with likely yield; quantity required for a hundred CSA shares; and length of row needed to grow this amount. This fictional CSA (a blend of information gleaned from the various sources I’ve mentioned) runs for twenty-six weeks and has shares sized for two and a half “standardized” people. For comparison, I have included how much of those crops we grow at Twin Oaks Community for fifty-two weeks for a hundred specific people. My point in including both is that every group is different, and no one else’s table will reflect your group of customers exactly.
If all people were the same, the Twin Oaks list would total about the same amounts (twice as many weeks, less than half the number of people). You’ll see some of our preferences come into play: we don’t grow arugula in any quantity worth recording, and celery and mustard greens are not very popular. Even though we freeze and pickled green beans, corn, eggplant and okra, they’re not as good as fresh crops, so we eat less than the fictional 250 people have fresh. On the other hand, beets and garlic store well, so we have more than Fiction Farm shareholders, as CSAs often don’t supply for winter needs. Chinese cabbage, mizuna and pak choy bolt too readily to be worthwhile at Twin Oaks in the spring, so we only grow them in the fall, and most of that in a hoophouse, where yields outstrip those grown outdoors. Fiction Farm probably has cooler summers than we do! Kale, leeks and spinach overwinter outdoors here, so we grow lots more than a CSA supplying only in the warmer half of the year. I have to wonder how many of the hot peppers supplied by Fiction Farm get used? We make lots of salsa for winter use, but only plant 71 feet (22 m). Do your customers want attractive foods they might not actually eat? Maybe they do! Other differences are a matter of scale, and will be relevant to growers supplying institutions. For example, it’s hard work to prepare scallions for a meal for a hundred, whereas a hundred separate cooks might enjoy adding them to the small meals they prepare. I wonder why the amounts of butternut squash and sweet potatoes are so much lower at Twin Oaks than Fiction Farm? Ours last through to May, quite long enough! I notice that we grow lots of paste tomatoes and fewer regular fresh eating ones. That might be because our quality standards can be lower because our tomatoes don’t commute to market, and we’re not so picky about looks!
Deciding sowing dates
It might be hard to orchestrate your annual startup so that you have a generous bounty. It’s OK to tell your CSA subscribers that the beginning-of-season boxes will be less full and the summer ones more bountiful. Johnny’s Seeds website has a Harvest Date Calculator which you can copy and use to calculate sowing dates to meet a target date (e.g., first market of the year).
You may also enjoy these excerpts from Sustainable Market Farming:
This excerpt has been reprinted with permission from Sustainable Market Farming by Pam Dawling and published by New Society, 2013.