Published Aug 14, 2014

Field Day Recap: Moveable high tunnel field day draws big crowd – and lots of questions

By Tomoko Ogawa

It was a hot and vibrant day packed with information at the Rolling Acres Farm field day on Sunday, Aug. 3. Close to 80 people gathered at the beautiful farm of Denise O’Brien and Larry Harris in Atlantic, Iowa – including nearly 35 cross-country climate campaigners who made an overnight stop at the farm for some relaxation (and an unexpected learning opportunity!) as part of their eight-month-long trek from California to Washington D.C.

Denise and Larry have owned and operated Rolling Acres Farm – a 17-acre farm with 5 acres in production – since 1976, growing food organically. Standing by the farm’s new movable high tunnel, guests were so eager to ask questions and learn that they didn’t even seem to notice the hot sun. Along with Denise and Larry, 2014 farm crew members Jordan Foster, Amber Mohr and Annie Glawe also spoke to the crowd and answered questions on topics ranging from pest control to soil amendments. Here are some of the topics covered during the field day:

High tunnel

Building and using the movable high tunnel has been an incredible learning experience for Denise and Larry, and they say they had to learn a lot to go from a small tunnel to a big one. They ordered the structure for their movable high tunnel from Four Season Tools in Kansas City, Mo., a company that has led some PFI hands-on field days in the past. Their high tunnel is 30 feet wide and 70 feet long. The inside has 30-inch beds with 12-inch walkways and irrigation with deep wells.

Last year, Denise spent about 30 hours at classes on high tunnels at Practical Farmers’ annual conference and MOSES’ Organic Farming Conference. She has also done a lot of reading and online research. When putting up a high tunnel, Denise and Larry recommend that you get someone experienced to help you, and also suggest that you organize a group to help put the plastic together. Another important point: Before installing a tunnel, go over the manual and do an inventory to make sure you have all the bolts and screws needed ready and organized.

One field day attendee asked about high tunnels on skids. Denise said Four Season Tools also offers tunnels designed on skids. In fact, she thought Eric Colman – high tunnel guru—started with a tunnel on skids.

This year, the Rolling Acres Farm crew planted spinach in October 2013 and harvested in March 2014 in the high tunnel. Spinach harvest was strong through the spring, and Denise said it had such sweet flavor with the cool spring that people are still asking about it. Following the end of spring spinach season, Denise and Larry moved the tunnel off the winter crops on April 12and planted kale and other spring crops the next day on April 13. The high tunnel showed its amazing ability as they started harvesting these spring crops on May 10!

So far, to their surprise, kale has been the most profitable crop in the high tunnel. They sell four cases of kale per week ($70 worth) to HyVee in Atlantic. Tomatoes and cucumbers are closely following the kale. With the cool season, everyone has been having problems with tomatoes, but the high tunnel has been helping a lot. On the day of the field day, we saw tomatoes, basil, eggplant, kale and chard in the high tunnel, with plastic side walls rolled up.  One thing Denise and Larry said they would change for next year: allowing more space between plants; this year, they planted things a bit too close together.

While they love the movable high tunnel, Denise says, “If we are to put up the second high tunnel, it will be a stationary one because the movable tunnel is too costly.” Denise cautioned, however, that with a stationary high tunnel you won’t be giving soil a rest, and soil salinity may become a problem because it can keep the rain from flushing nutrients and salts out of the soil.

Cover crops

Denise and Larry use several cover crops on their farm, including radish, field pea, oats, rye and buckwheat. “We love buckwheat because it is good for pollinators,” Denise says. As if to emphasize the point, as we chatted with Denise we saw a beautiful Monarch butterfly flutter gracefully past us. These long-distance migrants have seen steep population declines in recent years – but you wouldn’t know it when visiting Rolling Acres Farm: Denise said they’ve seen several this year.

Soil amendments

The soil type at Rolling Acres Farm is Marshall, a well-drained, silty clay loam formed in loess. In terms of taking care of soil in the movable high tunnel, crop rotation – just as in the field – is the key. Denise and Larry commented that they need to be careful with soil compaction issues on walkways. They have been applying homemade compost (poultry manure and vegetables with worm tea) as a soil amendment. Larry and Denise warned the audience to be careful about herbicide residues that could be in the compost: Compost made with yard waste has tested high for chemicals. Someone from the audience mentioned a local compost company called OmaGro, which has been tested fine.

Squash bugs and other pests

Jordan, one of the farm crew who spoke, said he sprayed some neem oil that morning to control squash bugs. However, the farm hasn’t had many squash bugs yet this year, fortunately, so the team can’t yet tell if it will be successful. He also described a concoction of sugar, vinegar and banana peel the farm crew made for a moth trap they hang in the high tunnel. So far, however, the trap has not seemed to be very effective.

Jordan has also sprayed neem oil for troubles with grass hoppers. Other pest controls they have tried include Bacillus thuringiensis (Bt) spray, soap, fish oil and worm casting tea.  Worm casting tea is supposed to increase bacterial activity and release chemicals. They’ve also been planting Hubbard squash as a trap crop to effectively attract bugs away from their summer squash. Denise recommended to look up some studies done by Dr. Mark Gleason at ISU– he has done many studies on squash bugs (row covers, etc.).

As for controlling raccoons, possums and deer? Brandy, Denise and Larry’s golden retriever, takes care of them!

Denise left field day attendees with this closing thought: “The challenge and joy of farming is to use your wit. Go to field days, workshop, classes and keep learning as much as you can!”

There are still lots more field days left this year where you can learn about a range of farming enterprises and practices. Make sure to check out the Practical Farmers 2014 Field Day Guide!