Post-Harvest Handling Decision Tool > Crop Groups > Tender Crops

As a category, tender crops cover a wide variety of produce. Specifically included here are peppers, winter squash, and cucumbers. Tomatoes, zucchini, and summer squash, as crops that require very gentle and very specialized handling, were specifically excluded.

On large, commercial operations, a water dump (submersing crop in water) seems to be the most common method for removing dirt and dust, and, in the case of cucumbers, any remaining blossoms. In regions where contamination from wet soil does not present a problem for crop quality, field packing is a common practice. Hydrocooling is not normally a consideration for these crops, all of which perform better when storage temperatures are above 40°F.

Small-scale Upper Midwest market farms will handle these crops using a water dump, although a number of techniques and tools can increase the speed of this operation. Large operations in the Upper Midwest typically invest in a brush washer. The tools surrounding the infeed and outfeed operation of the brush washer typically expand the functionality and capacity of that tool on larger farms.

Removing excess moisture from the surface of these fruiting crops is extremely important to prevent decay. Where fruits touch each other in storage, water will not evaporate and will provide a point for fungal germination and bacterial growth.

Manual Handling

Manual handling typically relies on some sort of water dump to remove dirt and dust. The most basic tool is a water tank. Workers on various farms use a selection of clean cloths, burlap sacks, and cotton gloves to increase the speed of scrubbing, if necessary.

Mesh bags provide a mechanism on small farms to batch process crops such as peppers and cucumbers. The bags also provide a way to increase agitation for the removal of mud from crops. Workers hold one top corner of the bag in each hand, submerge the produce, and shake and swish the bag in the water to scrub the vegetables against each other. The entire bag is then removed and dumped onto a sorting table or drying screen.

Submerging peppers provides an opportunity to sort and cull for corn borer damage, considered by Upper Midwest market farmers to be the most common blemish that renders the fruit unusable. Damaged peppers take on water and sink to the bottom of the tank.

Winter squash must be handled more gently to avoid damage. At Spring Hill Community Farm, workers clean the squash in the field using a burlap sack to removed dried-on dirt. Other manual cleaning methods include dunking individual fruits into a bucket or tank of water, scrubbing with a cloth or cotton glove to remove soil, then drying with a towel to prevent decay.

The Brush Washer

“If you have two crops to put through a brush washer, then as soon as you can afford it, buy one, regardless of the scale of your operation.” – Linda Halley, Gardens of Eagan

A brush washer, as part of a vegetable wash line, is perhaps the most versatile and most widely-used piece of post-harvest handling equipment on small vegetable farms in the Upper Midwest. A series of ten rotating brushes move produce through a water spray, scrubbing and rinsing dirt away from the product.

A vegetable wash line can include multiple components, in addition to the basic washing unit. An in-feed belt provides a space to dump totes or large bins of produce and pre-sort any obvious culls before they are conveyed into the brush washer; neither Gardens of Eagan nor Hog’s Back Farm uses this addition, instead feeding produce into the brush washer by hand. Hog’s Back Farm has a dedicated table for staging produce totes of produce, while Gardens of Eagan uses overturned plastic totes. Gardens of Eagan had purchased an in-feed belt when they acquired the brush washer, but no longer uses it.

After product has been cleaned by the washer, it proceeds to the out-feed system. Most commonly, the first step is a series of foam “donut” rollers, referred to as an “absorber,” that squeegee water off of the produce, removing surface moisture that can promote fungal and bacterial growth. A kicker brush moves the produce on to the next piece of equipment in the line. Hog’s Back Farm did not have an absorber, but planned to make that investment in the near future.

From the donuts, produce may move onto optional sizers. Belt sizers are three feet long and grades one size onto a side packing table or side conveyor for packaging. A punched conveyor belt moves the produce from one sizer to the next, allowing produce that fits through the sizer to fall through to the side packing area. One or more sizers may be in use. Produce not captured by the sizers moves to the main packing table.

The packing table may be a homemade tray slanting away from the brush washer. Models sold with the wash line are round and have a rotating table to move produce out of the way of further produce coming off the line, as well as to move product in front of multiple packers. A low rail keeps produce from falling off of the packing table.

A single motor normally powers the in-feed belt, the washer, the absorber, and the sizing belts. The round sorting table is powered by its own motor. Mid-sized machines use about 1½ gallons of water per minute.

In addition to tender crops, Upper Midwest market growers use brush washers to clean round root crops, tomatoes, and potatoes. Brush washers can also be used on fruit crops such as apples.

Speed of handling is generally increased by using more people on the line. At Gardens of Eagan, one person feeding the machine can keep up with two workers packing; at Hog’s Back Farm, one worker feeds while a single worker packs. While even the smallest machines are rated at 100 bushels per hour, growers in this project reported speeds of around 20 bushels per labor hour with two or three workers operating the machine.

Used machines are available, but not recommended as brush washers tend to show wear quickly.

Scale and Costs

1 bushel of peppers = 25 lbs
1 bushel of squash = 35 lbs
1 bushel cucumbers = 48 lbs

Up to 10 bushels per day:
2 100-gallon Rubbermaid-style livestock watering tanks - $150
5 mesh bags for gentle agitation - $25

Over 10 bushels per day:
16-inch brush washer - $1200
Absorber - $741
5-ft rotary packing table - $870
(optional) 4-ft in-feed belt - $548