Harvest Frequency, Yield and Economics of Summer Squash

SUMMARY

During the 2006 growing season in the Treasure Valley of Southwest Idaho, four summer squash varieties were harvested, either daily at a small size or every 2-3 at a larger size. Squash harvested at the larger size yielded about three times more by weight than squash harvested when small, but the plants when harvested more frequently at a small size produced 2-3 times as many squash fruits.

Both squash sizes sold well at the Nampa and Caldwell Idaho Farmers Markets, with fewer small squash than large squash left unsold at the end of market day most weeks. Large patty pan squash were the least popular. Customers preferred to buy squash by numbers rather than weight, even though they paid a premium price; small squash when sold at 5-8 for $1 brought in up to $2.97 per pound and were more profitable than large squash.

Information from a vendor survey helped me formulate an enterprise budget for market squash production in which most costs are multiplied by the percentage of total garden that is planted in squash, or by the percentage of the total income that can be attributed to squash. The enterprise budget demonstrated that a yield of 600+ lbs of mini squash per year should be profitable if sold at farmers market prices for mini squash. Squash growers on small acreages should consider increased production of baby summer squash. To increase the customer base for increased production, we considered offering tastings of grilled squash at the markets.

I wondered if harvesting mini squash is worth the extra effort, and if it can be profitable for a small market gardener. Therefore, the study also included a customer survey at two farmers markets, a vendor survey and development of an enterprise budget for squash production aimed at market gardeners and small farmers.

OBJECTIVES

Our goal was to determine how harvest frequency and harvest size affect the yield and marketability of fruits produced by summer squash plants, Cucurbita pepo.

MATERIALS AND METHODS

I used four summer squash varieties: two zucchini (green, Cash Flow from Johnny’s Selected Seeds; yellow, Butterstick from Territorial Seed Co.) and two patty pans (green, Starship from Territorial Seed Co.; yellow, Sunburst from Territorial Seed Co.). Forty equally spaced hills were created in a sprinkler-irrigated garden plot. Two gallons of commercial composted steer manure were added to each hill before planting.

The hills were randomly assigned a variety and harvest frequency so that there were five hills of each variety and harvest frequency combination. An extra hill of each variety was planted in case some hills were damaged or aberrant. The hills were arranged in five rows of eight or nine hills. Each hill was planted with five seeds of the same variety and thinned to three plants while the plants were young. The hills were planted on July 11 or 12.

Interestingly, the size at which I harvested the squash decreased late in the season as temperatures dropped and day length shortened. When harvesting daily, I picked patty pan varieties at a size that was 40% smaller during the second half of the season as compared with the first half. Green squash picked every 2-3 days decreased much less in size over the season, only 15%.

Yields reached a peak during weeks 3-5. The weather turned cold during the week of September 15-22 and yields declined correspondingly. Note also that overall weekly yield in grams of squash harvested at the larger size was about three times the yield of small squash during peak production. The difference was less as yields declined late in the season.

Although harvesting every 2-3 days at a larger size yielded more grams of squash than harvesting daily at a small size, the daily harvests yielded a greater number of fruits. In the case of yellow patty pans, more than three times more small fruit were produced by the end of the season than large fruits, compensating for the greater yield in weight of harvesting less frequently. However, the other varieties only produced 1.5 to 2 times more fruit when picked small.

RESULTS

Squash were sold at the Nampa Farmers Market on Saturday mornings and the Wednesday afternoon Caldwell Farmers Market. In addition, three large orders of squash were also filled during the season for a local CSA and for Bon Appétit, caterer for Albertson College of Idaho.

At the market, several different pricing schemes were tried. Large squash sold well at 2-4/$1. Small squash sold well at 5-8/$1. The number of small squash for $1 increased as the size of the squash decreased late in the season. Baby squash were sold to Bon Appétit for $1.75 per pound, which is a bargain price compared to the price per pound I got at the farmers market.

Large squash were clearly a better buy for the consumer. For small squash, the zucchini varieties were a better buy than the patty pan varieties. Small squash were a much greater source of income per pound of squash. In most cases the cost per pound increased late in the season as the squash size decreased. However, small zucchini types decreased in price per pound, because their size decreased slightly but the number sold for a dollar increased considerably.

We kept track of the numbers of squash left over at the end of the Saturday market, and compared that with the number of squash that were harvested during the week. We found that we sold all but about 6% of the small squash that we harvested with green squash slightly more popular than yellow. An average of 17% of our large zucchini squash did not sell. Least popular were the large patty pan types; 28% did not sell. People frequently asked what to do with them. Most people bought other squash varieties if they were available, even when we offered recipes.

To get more information about customer preferences, we did three customer surveys during the season. Two were conducted at the Saturday market and one at the Wednesday market. For the survey, we hired a friend to grill squash so customers could taste the cooked squash before filling out the survey.

A total of 75 people filled out our market surveys from the three days combined. Overall, customers were equally willing to purchase baby squash compared with “medium” sized squash. Very few were interested in “huge” squash. Most preferred to buy squash by numbers (5-6 baby, 2-4 medium) than by the pound. When asked how much they would pay per pound for squash, most chose $1 or less, and many said they would not pay as much for baby squash per pound as for medium squash. This response is surprising, given that those who purchased squash paid $2 or more per pound for them.

Six producer vendors who sell summer squash at the Nampa Farmers Market filled out questionnaires concerning their cultural practices on August 5, 2006. All of these vendors sell a diversity of produce, so squash is only a portion of their sales.

In summary, the vendors who sell squash at farmers markets have small plots of squash, generally only a row or two, 60 or fewer plants or hills. Most prepare the soil with a tiller rather than a plow, most plant by hand, use compost or other organic supplements as fertilizer, and use minimal pesticides. Most harvest two to five times a week. Daily harvests are rare, though harvesting takes only 15 to 20 minutes for most vendors. Only two vendors reported selling baby squash. The other vendor who sold baby squash did not sell much at farmers markets, but sold it to restaurants. The most that vendors reported bringing to market was 75 lbs of squash. Most vendors sell out of squash at the market or sell most of what they bring, with vendors doing better at the Capitol City Public Market than at the Nampa Farmers Market.

OBSERVATIONS AND RECOMMENDATIONS

1) The extra effort to grow baby squash was justified. If baby squash is sold for 5-8/$1, the price per pound ($3) was considerably better than could be achieved with the sale of larger squash. This study suggests that squash growers on small acreage should consider increased production of baby summer squash.

2) My Enterprise Budget indicates that my income from squash covered variable costs of production and marketing in 2007, but not fixed costs or unpaid labor. Planting earlier in the season so that I can sell at more markets and increase total squash yield would increase my profits.

3) In 2006, I found that mini squash would sell at close to $3/pound, especially late in the season. If I can build a clientele to purchase squash at this price throughout the season, and double my production of squash, I should be able to not only pay my expenses, but also make a profit with mini squash.

4) One trade-off is that problems from squash bug pests were avoided by planting late. I saw only one adult squash bug during the entire season. Pest managements can be achieved by late planting.

5) Selling by numbers rather than weight was preferable for baby squash and preferred by customers for all summer squash. Large patty pan squash sold poorly; growers who plant these varieties are especially encouraged to harvest small fruits.

6) Grilling squash was not only productive in that our squash sold out completely the day we tried it, but we also had great fun and customers loved it. We are considering getting a temporary food establishment license and selling grilled squash and other vegetables routinely at the market as well as fresh produce. Growers should consider offering samples and/or selling grilled squash at farmers markets to increase profits.

OUTREACH

January 2007, we discussed the squash research at the University of Idaho’s Living on the Land Course in Parma, ID.

April-May 2007, copies of my January 2007 preliminary report were shared with the market growers at the beginning of the Nampa Farmers’ Market. During the 2007 season, I noticed that more growers at the Nampa market brought small squash for sale.

July 2007, I started a blog to keep track of my time and costs, as well observations of my 2007 squash patch.

November 29, 2007, I discussed the squash project with “Cultivating Success” class taught by grower Mary Rohlfing at the Ada Co. Library.

January 2008, I contacted researchers at the University of Florida and Pennsylvania State University who have studied squash production and the ecology of squash respectively to discuss my squash research.

February 2008, I discussed the squash project at a workshop run by Rural Roots, referred growers to the web site for further information.

March 2008, I was invited to present a poster on the project at the National SARE Conference in Kansas City, MO.