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Plant of the Month: Spinach

photo johnRimol Greenhouse System's John Wells, who is apart of our sales department for lower Midwest and Werst Coast regions, grows winter spinach in his Rimol, high tunnel greenhouse in New Hampshire. We had the privilege of picking his brain about growing spinach in a high tunnel greenhouse in the winter. Here's some of the conversation:

Tell us a little bit about your past and how you got involved with Rimol Greenhouse Systems?
My whole life has been around farming and growing. During the depression my great grandfather was a farmer and would load up his market wagon and drive to the housing projects and sell vegetables. I remember as a young kid when my great grandfather would dig sweet potatoes (by mule, he never trusted tractors), the whole family community would come and help to get the crop in. My mom would always complain about the red clay ruining my socks.

When I was 8 I had my own watermelon patch. I used IV bottles and tubing to try and boost the size of the melons. I don't think it ever worked though. In college I studied Plant Science. I got my degree in a Plant Science Management; half plant science and half business management. From there I spent the next 10 years as a commercial grower in some the largest and most high tech greenhouses in the country, specializing in plant propagation. After finding an opportunity in Sales, I joined the Rimol Greenhouse Systems team in 2005 to cover sales and service of the New England region.

How long have you had your Rimol Greenhouse? Where is your greenhouse located?
I have a 30 x 72 Nor'easter in my backyard. I have been growing in it for 3 years. Before that I had a different greenhouse for 7 years. I have my house running from East to West. I actually run my rows running across the house instead of running the length. I utilized the truss on each bow to suspend many of the Summer crops, tomatoes, cucumbers, melons, ect.

What kinds of spinach do you maintain in the winter in your greenhouse?
Most types of spinach do well in the greenhouse. Last year I did a trial of 11 different varieties, all did well except for Vitagreen. I would stick to the commercial varieties like Space, Tyee, and the old standard Bloomsdale. I am sure there are other varieties that do well that I am leaving out. I also like Cardinal which has a red stem, great for salads around the holiday season.

Can you briefly walk us through the process of planting and maintaining winter spinach? When do you start the process?
I like to do 5 rows of spinach in a 30 - 32" wide bed. My seed rate is about 1 seed per inch with about 1/4" of soil covered. That is pretty tight spacing so you need to stay on top of how dense the canopy gets so as to discourage disease. For a winter crop, you need to have your spinach planted late August or Early September. If you miss that window and get it in late September, you might get a few salads for yourself over the winter but your yield can dramatically reduced, to the point of not being worth it.

What's one interesting thing about growing winter spinach?
You can increase your yields by using row cover over your crop inside your greenhouse. On the coldest nights your un-heated greenhouse temps will drop within 8 degrees of outside temperatures but under the row covers it will be 10 higher than your greenhouse temps. That's a huge difference to the plants.

The picture is of my wife, Karen Thurber. She has her BS in Horticulture from Cornell.