Making it work at High Meadows Farm

PHOTOS BY VERN GRUBINGER.
Howard Prussack shows off his high-quality greenhouse raspberries.

Howard and Lisa Prussack have been operating High Meadows Farm in Westminster West, Vt., since 1971. The farm was one the of first to be certified organic in the state. Recently, their focus has been primarily on ornamental horticulture. The operation has 18,000 square feet of greenhouses producing potted herbs, hanging baskets, perennials and vegetable starts; there are 3 acres of specialty organic vegetable crops including onions, winter squash and pumpkins. Ninety-five percent of their sales are wholesale; retail sales take place at their farmstand and the Brattleboro Farmers’ Market.

“We were looking for a high-value product that we could add to our mix to fill in a slower sales period just before the mums come in. So, a couple of years ago we added greenhouse raspberries,” says Prussack.

The raspberry crop is grown in a 30-by-100-foot Harnois greenhouse, with top and side vents. “I’m definitely glad I got the top vent, because with the house being so wide the raspberries would have cooked if it only had side vents. I’m also thinking about applying a 10 percent shade paint to limit the small amount of sun scald I did get on the berries. Another reason for this is that it gets so bright in there it’s hard to see the berries when you’re picking them. We do the shady side of the row in the morning and come back in the afternoon to do the other side.”

This 30-by-100-foot Harnois house with ridge vent was put up for raspberry production.

To prepare the soil for planting, Prussack added old potting soil recycled from the ornamentals operation. After testing the soil, he added lime to adjust the pH. That was tilled in, and 3-foot-wide raised beds were formed, 6 feet apart on center. Two lines of drip tape were laid in each bed, and they were covered with 1.1 mil black plastic mulch. Heavy-duty landscape fabric was laid down between the beds. “That does a pretty good job of suppressing weeds and holding moisture in the soil, but if there’s even a tiny hole in it the raspberries will find it and come up through. It creates a good working environment and we can easily sweep it off to keep things clean.”

Plants were set 18 inches apart in the row into the four beds in mid-May. The varieties are Jaclyn, Autumn Britten, Anne (a yellow), Joan (spineless type) and Caroline, purchased from Nourse Farms in western Massachusetts. Irrigation was applied about twice a week, and Prussack dug a small test hole in the rows to see if the soil needed water. To provide ongoing nutrition, an organic fertilizer (Pinnacle 3-1-1 from Daniels Plant Food) was fed through the drip system.

“In the first year, we started harvesting at the beginning of August and we harvested until mid-November. We left quite a bit of fruit on the canes that got frosted at that time. Overall, the first year’s yield was low, which didn’t surprise me because the plants were just getting established and we probably planted a little too late. Plus, the crop got dry once in a while because I was busy,” Prussack explains.

“The following March, we cut all the canes to the ground and topped off the beds with McEnroe compost,” says Prussack. They began irrigating in May, and then “the fruit came in earlier in the second year, starting in July, when we were harvesting an average of two to three dozen half-pints a day.” By the end of July, Prussack noted that production was in full swing and “the yield went up to 60 to 70 half-pints daily; then, it went back down again in October.”

According to Prussack, “We lost about a month of harvest at the end of the second year because the top vent didn’t get closed properly on a really cold night during the third week of October. Normally, the greenhouse would provide plenty of protection down to about 20 degrees because there is so much heat in the ground that radiates up at night. Below that temperature, we can put a heavy row cover over the crop inside of the greenhouse for more protection if wanted.” Prussack considered supplemental heat, but “the math doesn’t work out. I’d only get about [a] dollar of berries for a dollar of heat since the yield goes down so low by the end of the season.”

The farm is selling about two-thirds of its berries wholesale and the other third through farmstand and farmers’ market. “The quality is amazing; they’re bigger than field-grown berries and the shelf life is much better. We pick every day whether it rains or not. It rained for a week late last summer and then we were the only ones with berries. The pickers love it, especially in the fall—the greenhouse is a nice, warm and dry environment to work in.”

As for pricing, Prussack explains: “We can’t get the kind of money for this crop that I read about in some areas, but we were getting $3.50 to $3.95 a half-pint retail, and $3.25 wholesale, most of which goes out of state.”

Spider mites were an issue, but Prussack reports that canola oil and garlic juice spray “worked quite well.” Unlike in the field, the farm did not see any Botrytis problem on the berries because the greenhouse remains drier—“and, of course, we picked every day.” The biggest pest problem, according to Prussack, was honey jackets: “We had quite a few of them, so I had to install traps along the perimeter of the greenhouse. You take empty plastic soda bottles, cut a little hole to install these Fatal Funnel (www.fatal-funnel.com) plastic doors that snap in, then fill the bottles halfway with sugar water and make some vent holes. The doors allow the honey jackets to get in but not out, and they drown in the sugar water.”

You can see the landscape fabric between the rows of raspberries and the lush growth early in the season.

Going into this summer, Prussack plans to thin and top the raspberries, “because the growth was too lush and thick last year. It was hard to get into some of the rows, and the canopy was too thick to easily pick all the berries. I also think that kind of growth suppressed yield. I plan to thin the canes by about a third to improve yield and quality. You have to resist the urge to plant too close together when you start the crop. I planted at about 18-inch spacing in the row, but 2 feet or more would have been fine for the long term since they grow in very fast.”

“I think that greenhouse raspberries make sense, especially if you have the ability to retail, but it’s not a low-maintenance enterprise; you need management time and labor for picking, etc.,” says Prussack. “Any time you add a new item to your operation it diverts you from your other enterprises. The flip side of diversification is watering down your focus, so I tell people to be cautious of that.” However, despite the challenge, Prussack says, “I’m glad we did the greenhouse raspberries; it was a tasty addition to our farm.”

For detailed information on high tunnel raspberry and blackberry production, see the newly revised Cornell guide on that topic at www.fruit.cornell.edu/Berries/bramblepdf/high_tunnel_production_guide.pdf.

The author is vegetable and berry specialist with University of Vermont Extension based at the Brattleboro office and longtime contributor to Moose River Media. Visit www.FarmingForumSite.com to discuss this article!