Our Practices

Some observers think that a farm in the midst of a city is an odd sight. But everyone in New Haven eats, and eating, as Wendell Berry once wrote, is an agricultural act.

The Yale Farm is rooted in a long history of vibrant urban agriculture. In the late 1800s and early 1900s, intensive market gardeners developed an efficient gardening system around New York and Philadelphia. The fertility of plots depended on an abundance of organic matter, most in the form of horse manure (which was readily available before widespread automobile use). These market gardeners recycled waste for the city while producing food for its inhabitants. Much like the market gardens of the last century, the Yale Farm bases its fertility on abundant organic matter: Yale’s fall leaves, which are delivered to and composted at the Yale Farm. Without this agricultural use, the leaves would become part of the University’s waste stream.

Closing this loop is an important example of the Yale Farm’s commitment to modeling year-round, sustainable, efficient, small-scale agricultural production. Many of the techniques and tools used at the farm have their origins in traditional market gardening systems. Over the last century, these systems have been modified, adjusted, and improved upon. The Yale Farm busily tests innovative methods and employs new technologies, techniques, and tools. Many of the systems used at the Yale Farm are influenced by the farming, research, writing, and tool design of Eliot Coleman. Eliot and his wife, Barbara Damrosch, run Four Season Farm in Harborside, Maine, and have been friends and advisors to the Yale Sustainable Food Project since its inception. Coleman’s books, as well as the tools he designs, are available from Johnny’s Selected Seeds.

The following sections explain how we manage the Yale Farm.

Soil Fertility

In a natural system, soil fertility is a function of the biological activity of the soil. It is contingent upon the presence of adequate organic matter, diverse mineral content, adequate moisture, and soil organisms like fungi and bacteria. The Yale Farm focuses on supplying these soil organisms with partially decomposed organic matter raw mineral material. Unlike conventional farms, we never micromanage the levels of soluble nitrogen, potassium, and phosphorous available to our crops. By optimizing the conditions for healthy biological activity in the soil, we circumvent the need to measure and manage the flow of soluble nutrients through the soil. We effectively outsource that service to the microorganisms and fungi that are so well adapted to the job.

In practice, this means that we regularly amend the soil with farm-made compost between plantings. We also mulch with raw organic matter—like fall leaves—when dealing with widely spaced crops and when preparing our fields for the winter. In addition, we amend every other year with assorted rock powders to ensure a diverse mineral base in the soil. These include greensand, which is high in potassium and many other minor minerals; azomite, which contains trace amounts of nearly every mineral needed for plant growth; and colloidal rock phosphate, which is rich in phosphorous. Because these sources of minerals are not soluble and their availability is regulated by biological activity in the soil, they cannot do damage if applied too heavily or unevenly.

Our amendments cost next to nothing. They lead to visibly healthy, vibrant soil, with wonderful colloidal structure, high humus content, high water-holding capacity, good drainage, and the ability to produce amazingly healthy, pest- and disease-resistant plants that taste wonderful.

Bed Preparation

The Yale Farm is organized into ten zones, each roughly twenty feet wide and fifty feet long. Each zone is organized into thirty-inch raised beds separated by one-foot-wide paths.

To prepare a bed for planting we generally follow these steps:

Clear the bed of raw organic matter that may inhibit seed germination or get in the way. Generally, this means we pull out past crops and push any remaining mulch into the paths.
Broadfork the bed. This tool, reminiscent of a pitchfork with six tines each five inches apart, does not turn the soil over. Instead it lifts and loosens the dirt to a depth of approximately eighteen inches. This allows oxygen and water to penetrate more deeply, and opens the soil for healthy root growth. The broadfork is easy, pleasant, and fast to use; its action essentially mimics the role that deep perennial roots play over a much longer period of time in a natural ecosystem.
Spread a light layer of compost over the bed. We are not careful measurers, but find that one modestly full wheelbarrow easily covers a twenty-foot-long bed.
Spread rock powders over the compost. We do not need to do this every time we plant, but we aim to have the whole farm amended with rock powders once every two years. Rock powders are pre-mixed in a wheelbarrow and dusted over the beds with a shovel. Again, we do not carefully measure.
Shallowly incorporate the amendments into the soil. One can use a scuffle hoe (also called a stirrup hoe) or a three-tined cultivator. We often use a “tilther,” a recently-invented tool that runs off of a cordless drill, incorporates fine amendments into the top two inches, and leaves a very flat bed behind it. Use of the tilther allows us to skip raking and saves considerable time. Regardless of the tool, we try only to disturb the top two inches of the soil. In this way we maintain a healthy soil structure and avoid bringing weed seeds to the surface. In natural systems, organic matter arrives from above and is gently incorporated into the surface through biological and weather processes. It is hardly ever mixed deeply.
If we have not used the tilther, we rake the bed flat with a grading rake, taking extra care to remove debris and leave the bed smooth and flat. The extra time in preparation is worthwhile, as it allows the use of a pinpoint seeder and makes the harvest of small salad crops and cultivation of other crops more efficient.

Variety Choices

We want the crops we grow to be delicious, a good fit for our focused production system, beautiful, potentially profitable, and interesting. We favor varieties that have extra potential to teach or inspire because of their biology, history, method of cultivation, or use in a given cuisine. We also favor varieties that are delicious, beautiful, or inspiring, but unavailable in most commercial venues because they are obscure or do not ship well. Many of the cultivars we plant are “heirloom.” Others, including some of our favorites like Napoli carrots and Sungold tomatoes, are hybrids. But we do not grow any genetically-engineered crops, and we try to avoid finicky cultivars that require excess special attention.

In the last four years we have tested over three-hundred varieties of crops at the Farm, constantly searching for new varieties to test and regularly culling varieties and crops that do not fit well into our system. We do not value variety for variety’s sake. Rather, we are working toward a balanced crop list that features the best-suited varieties for our production system.

Direct Seeding

We direct seed crops using one of three methods:

Widely spaced, large-seeded crops (melons, watermelons, summer and winter squash) are seeded by hand.
Large-seeded crops that are spaced close together (peas, favas, beans) are seeded using a single-row Earthway Seeder. This device has various plates that work with different seed sizes. It digs a furrow at a depth determined by the operator, drops the seed into the furrow, and covers the seed.
Small- and medium-seeded crops that are spaced relatively close together and planted in multiple rows per bed are seeded using a six-row pinpoint seeder. Many of our crops are seeded with twelve rows to the thirty-inch bed. This tool can seed all twelve rows in two passes. The depth, seed spacing, and number of rows are all adjustable by the operator.

Transplants

Seedlings are started on site in soil blocks. These blocks are made by pressing a metal mold into moist potting soil, and then popping the blocks out with a lever. These blocks allow us to avoid using plastic trays and pots, and they enable extremely healthy root development. Certain slow-growing spring and summer crops begin life in the heated greenhouses at Marsh Botanical Gardens.

We transplant seedlings out into beds on a grid pattern, by hand, using a trowel. We mark the proper rows with a rake, a length of string, or a section of metal conduit, being careful to keep them straight, evenly spaced, and at right angles.

Irrigation

The Farm boasts six frost-resistant spigots that can be used even in the coldest months. From these taps, crops are irrigated by one of two methods:

Drip tape—tubes of thin plastic punctured at even intervals—focuses water directly in the root zone of the crop. It uses water efficiently, and it is very effective in irrigating fungus-prone crops. We use drip tape for squash, peas, tomatoes, eggplants, and peppers.
We prefer overhead irrigation, and use chains of small sprinklers to perfectly cover our zones. Overhead irrigation leads to less plastic waste (drip tape seldom lasts more than a season), keeps all the soil biologically active, and mimics rain in the way that it cleans and livens plant leaves. In addition, overhead irrigation gives the low levels of chlorine that are present in New Haven water a chance to evaporate before sinking into the soil. Overhead irrigation is the only way to effectively irrigate the closely spaced rows that we use for the majority of our crops.

Pests and Disease

We see all problems in the garden as indicators of our own imperfect practices. To deal with pests and disease we focus on growing healthy, resistant plants. This is achieved through creating healthy soil, timing plantings to optimize plant health, and practicing stress-reducing methods like mulching. We also focus on creating an environment that is inhospitable to pests and diseases: certain plantings lure the natural predators of common pests, and proper irrigation and spacing minimize fungal disease.

Pest problems are almost always related to soil or ecosystem imbalance. As our soil has become healthier, higher in organic matter, richer in micronutrients and humus, our plants have become more and more resistant to pest problems. Rather than study plant diseases and pests, we study plant health. Our pest and disease management practices are essentially preventive measures that rely on inexpensive, safe, ecologically sound tools.

Weeds

Weeds often indicate a problem in our practices and in our soil’s health. At the Yale Farm, we focus on reducing deep tillage (which can replenish the weed-seed bank by drawing buried seeds to the surface) and preventing weeds from going to seed.

Additionally, we rely on shallow cultivation to kill weed seedlings before they are firmly established. Light, long-handled hoes (particularly collinear hoes) are very effective at this job. We often cultivate with collinear hoes before weeds are even visible above the ground, but after they have germinated below the soil (this is called the “white hair stage,” as all that is visible upon cultivation is the first white root hairs). Clear, dry days offer the best weather for cultivation, as the weed seedlings desiccate in that weather and do not reseat themselves. By cultivating early and often, we avoid the need to hoe established weeds, or pull them one at a time by hand. This saves time and our backs.

Paths are cultivated with stirrup hoes. Cultivation, a lack of deep tillage, and never letting weeds go to seed have all led to the steady decline of weed pressure at the Yale Farm.

Harvest and Post-Harvest Handling

Our harvest is generally done the day before our farmers’ market. We harvest by hand, and rely on small, serrated Victorinox knives for nearly all of our harvesting. These knives are incredibly sharp and must be handled with extreme care. Tomatoes, peppers, melons, and cucumbers are harvested without any knives.

All leaf crops go directly into cold, potable water, where they are washed and chilled. Cut salad greens, spinach, and chard are drained and dried in an industrial-sized salad spinner, then bagged for market. Heads of lettuce, chicory, and cabbage drip dry. Roots are hosed off under pressure, and then drain as they are bunched. All crops except for tomatoes are then put into trays, bagged to prevent dehydration, and refrigerated until market. Herbs, flowers, and squash blossoms are picked on the morning of the market.

Greenhouses

We have three unheated greenhouses at the farm. Two enclose planting zones, and one covers a produce-washing area and an area for growing seedlings; each is covered by a roll of medium-gauge plastic. In the winter, this plastic can heat the inside to summer temperatures in the day and preserve a climate roughly five degrees above ambient temperature all night. In the summer months, we remove the end-walls and use the greenhouses to grow crops that are especially heat-loving: tomatoes, eggplants, peppers, and melons. When their season draws to a close, we replant the beds with winter-hardy salad crops and put the end-walls back up.