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Resources > Crop Management, Harvesting, and Post Harvest Guidelines

Crop Management, Harvesting, and Post Harvest Guidelines to Maximize Production of High Quality Produce

Anthony Flaccavento, March, 2010

Overview

Most buyers want pretty produce, and as a general rule, they also prefer larger to smaller, uniform to irregular and for fruit, ripe over unripe. They also want produce to last as long as possible, either on their shelves or in their coolers. Maximizing the proportions of this "# 1" produce begins before you plant with varietal selection and continues through to the day of harvest.

It is also important for growers or grower representatives to have a plan to market - or otherwise distribute - your good quality #2 produce, because no matter how much care you take, you will always have a significant proportion of irregular, smaller or otherwise less-than-perfect produce.

Varietal Selection

Choosing a variety involves seeking those that have the highest overall yield, the best proportion of #1's - sometimes referred to as a "high pack out", along with disease resistance, interesting shapes, colors and of course, taste. Once you know your buyers' preferences in terms of size, color and taste, your primary considerations are:

*productivity

*consistent pack out of #1s

*adaptation to your region or farming conditions and

*shelf life.

Shelf life is a particularly important criteria for tomatoes, but must be balanced against flavor and the desire for relatively thin, soft skinned fruit. Among the best tomato choices that balance flavor, productivity, uniformity and moderately good shelf life are: BHN 589 (Seedway), RFT 6153, Big Beef and Fabulous. Mountain Fresh and Mountain Fresh Plus are large, exceptionally productive, with an excellent shelf life; however the flavor is good but not outstanding.

For bell peppers, numerous varieties make excellent green bells, among them King Arthur, Aristotle and Revolution. For red ripening bells, Revolution is outstanding; Red Knight and Socrates are slightly smaller than Revolution, but reach ripeness one week to 10 days earlier.

There are numerous varieties of cantaloupes and other melons with outstanding flavor. However, some are more finicky than others, with more irregular shapes and sizes. Among the best flavored cantaloupes that are also consistently productive and good sized are Aphrodite and Halona (1 week earlier than Aphrodite). Athena is also a consistent producer of large melons, with good flavor, though generally not as sweet as Aphrodite.

Planning for Quality

There are several steps you can take to increase the percentage of high quality fruits and vegetables and minimize the proportion of culls. These include: Spacing, tying and trellising, mulching, weed, insect and disease management, and irrigation.

Spacing - Providing adequate spacing improves quality in several ways: It helps reduce or preclude fungal disease pressure, particularly in tomatoes, mold or rot in lettuce, greens, spinach and similar soft crops. Better air flow and more sunlight on crops speeds ripening which can also reduce damage from insects and disease, compared to longer ripening times.

Proper spacing in melons increases their size somewhat, and can increase the number of marketable fruit per plant. With some varieties, including Aphrodite, a slightly closer spacing - 20 - 22 inches instead of 2' between plants - is desirable to avoid fruit that are too large.

Spacing also includes suckering or pruning in tomatoes. This practice refers to pinching or cutting the small lateral shoot that grows at every node between the stem(s) and branches. Suckering tomatoes to allow no more than 3 - 5 branches per plant increases the average size of the fruit, leading to more #1s. Tomatoes that receive no pruning are likely to produce a high percentage of smaller fruit that is considerably less marketable. The exception to this is cherry tomatoes and roma or San Marzano type tomatoes, which are generally only pruned for the bottom 4 or 5 suckers. With heirlooms or other large "beefsteak" types, it is generally best to prune to only 2 or 3 main stems.

Tying and trellising

Tying is essential for all types of tomatoes, be they indeterminate, determinate, cherry or grape, hybrid or heirloom. The most inexpensive and efficient (and fast!) method for tying is the "weave" method utilizing wooden stakes or metal "T posts" in the center of the row, and a box of tomato twine on the hip of the worker. Care should be taken to minimize contact between the twine and the fruit, although some of this is unavoidable. It should be noted that pruning and tying tomatoes goes hand in hand, as an unsuckered tomato plant is much more difficult to tie.

Tying tomatoes improves air flow, increases sunlight for ripening, makes picking easier and keeps fruit off the ground.

In addition to tomatoes, tying peppers, Carmen peppers and eggplant also improves yield of #1s, by keeping fruit off the ground (which tends to create spots or molds on the fruit). Keeping the plants upright by tying them also limits excessive exposure to the sun which will lead to sunscald, which makes the fruit unmarketable.

Weed, insect and disease management

In addition to increasing the overall yield of your crops, minimizing disease, insects and weeds will increase the proportion of high quality, marketable crops. This is true of virtually every vegetable and fruit crop you can grow, particularly when you are selling into markets with higher standards for size and appearance.

Weeds, both in your beds and in the pathways, diminish quality in several ways, most notably by promoting moisture retention and reduction in air flow, which leads to disease problems in tomatoes and peppers, and which promotes various molds and fungi which can damage crops such as leaf lettuce, spinach and greens. Weeds promote molding in beans, which need to dry out quickly in the morning to allow for picking before days become too hot. And weeds - even on the edges of your fields - encourage Stink bugs, which damage tomatoes in particular, ruining otherwise beautiful fruit.

A range of insect pests can do damage both to your plants and fruits. Diseases such as Powdery Mildew in melons, cucumbers and squash, and Early Blight in tomatoes eventually spread from stems and leaves to the fruit, rendering them unmarketable.

The key point here is to plant crops and quantities that you can manage well, or you will find that a high proportion is unmarketable.

Irrigation

Drip irrigation is of course recommended for virtually all fruit and vegetable crops, to increase overall yields, and to improve the quality of your crops. Irrigation, even in a "wet year", can be helpful by equalizing the amount of water your plants receive. This will reduce or eliminate Blossom End Rot, a common problem in tomatoes, and to a lesser degree, peppers and eggplant (Blossom End Rot is not a disease, but rather stems from inadequate calcium. Calcium availability to plants, even when abundant in your soil, is dependent on adequate and even flow of water).

Irrigation also helps sensitive crops like tomatoes grow and ripen more evenly, reducing cracking and splitting which occurs when dry periods are followed by heavy rain. Adequate and even moisture also helps yield uniform zucchini, summer squash and cucumbers.

Beyond the use of irrigation generally to improve crop yields and quality, irrigation can be used to enhance the quality of crops at picking time. Particularly during hotter or drier periods, both leafy crops and fruits will tend to dry out over the course of a day. Often, I irrigate the night before, or very early the morning of picking to ensure that the crop is "full", that is to say robust rather than wilty or shrunken. I find this to be particularly important for lettuce, greens, green beans, and to a lesser degree, cucumbers, eggplant and bell peppers. With tomatoes you do not need additional irrigation just prior to picking, and with cantaloupes, you should substantially reduce water to the plants during the ripening period to maximize sugars.

Tips for Harvest

  1. Pick in the morning, the earlier the better. This is particularly true for the more succulent crops (lettuce, greens, bok choi, etc) , but also for green beans, broccoli and cauliflower (to reduce field heat). If you cannot pick in the morning, try to pick late evening.
  1. Use a sharp knife and make clean cuts when you are harvesting fruits with a stem - lettuce (any full sized head), asparagus, bell peppers, Carmen peppers, zucchini and summer squash, butternut and winter squash, broccoli and cauliflower. A ragged cut, which results from just breaking the fruit off, or from using a dull knife, will very quickly become brown and soft and often will lead to rejection of the fruit by buyers. Most buyers also want a stem of ½ to 1 inch, so be sure not to cut too close to the fruit.
  2. With tomatoes, some varieties hold on to the stem tenaciously. In those cases, you'll need to put a finger on the stem while you pull the fruit off, to avoid either damage to the plant (you can rip the plant if the stem does not come free) or too much pressure on the fruit.
  3. Cantaloupes are usually picked at "half slip" for any market other than the farmers market. First, you will see a change in color on the outer skin, in most cases from green to a buff or yellowish/golden color. At this point the melons are within a day or so of being ready (can be the same day in very hot weather). Half slip means that with a modest amount of pressure applied to the stem, the fruit will easily slip off cleanly. Never harvest a cantaloupe wherein you must break the stem to get it from the plant, as it will not be ripe or sweet.
  4. Picking containers: for many items - beans, bell or Carmen peppers, eggplant, cucs, leaf lettuce heads - a 1 1/9 bushel waxed box works great. It will hold about 12 - 15 heads of lettuce, 20 - 25 pounds of peppers or eggplant, and nearly 30 lbs of beans. A full box will hold almost 50 lbs of cucs, so you may not want to fill it fully. But all of these crops can be stacked up without damage. Zucchini, golden zucchini and especially yellow summer squash are considerably more delicate and easily bruise or cut, so it is better to use smaller containers for harvesting these, such as a ½ or ¾ bushel waxed box. You can pick in other containers, such as a peach basket, but then you will have to handle them again when you transfer to the box to take to the drop off, so it is better to pick directly into that container. Note: If conditions are muddy or otherwise messy, you will need to take care not to get your picking container dirty, as buyers don't like muddy, messy, torn boxes, no matter how pretty the produce is inside of them. Thus, at some times, you may need to pick in one set of boxes (that can be reused many times) and then transfer the produce to the clean shipping boxes.
  5. For tomatoes, it is best to pick into a 20 lb tomato box, which is wider and not as tall as the older boxes, if you can get them. For heirloom tomatoes, pack one layer only. For red slicers, put a piece of cardboard over top of the first layer and then put a second layer on top. Always place tomatoes in the boxes blossom end up, as this is the part that ripens first and bruises most easily. Depending on your buyer, and how quickly the tomatoes are going to market, you will want to pick between the "blushing" stage - when the blossom end begin to turn color - and the light pink stage, rather than letting the fruit ripen completely.

Post Harvest Handling

Once you have picked, it is critical to get the produce into the cool as quickly as possible. The best temperatures for produce vary considerably, from just above freezing to 60 degrees. This fine tuning is beyond what most growers are able to achieve. To simplify things somewhat, growers should think in terms of three categories, all related to perishability and field heat:

  • Must be refrigerated asap : All berries; broccoli, cauliflower, cabbage; asparagus.
  • Cool - 40 -50 degrees: Peppers, cucs, eggplant, zucchini and summer squash, beans and peas, leaf lettuce, spinach and greens, cantaloupes and watermelons, most other produce (NOTE: The lower end of this temperature spectrum is better, but you can generally get by with the higher end, if you pick early morning and only store short term at these temperatures).
  • Moderate temperature - upper 50's to low 60's: Tomatoes. Depending on the ripeness at which you pick, this temperature range will hold tomatoes well for a few days. Don't go below 55 degrees for tomatoes as this will diminish their flavor and texture.

Regardless of your cooling capability, it is best to deliver your produce to the packing house, where proper cooling is available, as quickly and frequently as you feasibly can.

It is critical to send produce that is clean and free of dirt. At times, you will thus need to clean the fruit before packing it in a box. Whether you are rinsing, dunking or simply wiping with a wet cloth, you must use clean, potable water. If you have access to municipal water, you should use if for this task. If you have well or spring water, be sure to test it for biological contaminants (Virginia Tech can do this, perhaps other labs closer to you) before you use it as a wash.

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Anthony Flaccavento:

Anthony Flaccavento

Anthony Flaccavento has 25 years of hands-on experience in sustainable community development, along with a BS degree in Agriculture and Environmental Science and a Masters degree in Economic and Social Development.

Anthony has been a certified organic produce farmer for the past 15 years during which time he also founded and directed Appalachian Sustainable Development. He is the author of “Healthy Food Systems: A Tool Kit for building Value Chains” and over 100 published articles.

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