Wednesday, January 22, 2014

How to Grow Organic Potatoes: No. 1 Potato Expert Shares His Best Tips by Joanna Poncavage

How to Grow Organic Potatoes: No. 1 Potato Expert Shares His Best Tips

Interview by Joanna Poncavage

Mother Earth News,  February/March 2014

 In this exclusive interview, professional potato producer Jim Gerritsen gives the full scoop on how to grow organic potatoes, how to store your spuds, and much more.

Jim Gerritsen and family have been growing seed potatoes for 37 years at Wood Prairie Farm in Bridgewater, Maine. Gerritsen, a potato farmer whom many consider the No. 1 organic potato expert in North America, has a lot to say about the benefits of homegrown spuds.

“If you do a good job, you can harvest about 70 to 90 pounds per 100 square feet — that’s a lot of calories and a lot of nutrition,” he says. To get to that point, though, a grower first needs to learn the ins and outs of how to grow organic potatoes on a home-garden scale. Gerritsen agreed to share his potato wisdom with MOTHER EARTH NEWS, and his tips are sure to raise your potato-growing IQ.

Let’s dig in!

What’s the No. 1 most important key to growing organic potatoes?
I would say it’s the seed. Seed is the most important key to growing any organic crop, and that’s especially true for potatoes. There’s a wide variation in seed potato quality, and certified seed potatoes will always do best in terms of yield, storage and overall quality.

How do you grow your seed potatoes?
We start with tissue-cultured, diseasefree mini-tubers that are produced in a greenhouse or hydroponically. We plant them in spring, and after a couple of generations we have enough to sell. Currently, we cultivate two to four generations each of 23 varieties.

Why can’t gardeners just plant potatoes sold in grocery stores?
You can use supermarket spuds, but they won’t grow well because they’re sprayed with chemicals to inhibit sprouting. Some people buy organic potatoes, thinking they haven’t been sprayed, but even these won’t do as well as certified seed potatoes that have been handled properly and are physiologically young. The proof’s in the pudding — or, in your mashed potatoes.

What are ideal growing conditions for potatoes?
The most important thing to remember is that potatoes are a cool-season crop. They simply can’t take a lot of heat and can actually die in temperatures above 95 degrees Fahrenheit.

In what area of the United States are potatoes easiest to grow?
In the northern-tier states, where potatoes can be planted anytime in summer and harvested in fall. In the South, on the other hand, growers need to plant early — either in late winter or early spring — to get the crop to finish growing before the hot weather comes on. Southern growers can also wait for cooler fall weather, planting in July or August and harvesting in October or November.
We have one customer in southern Michigan who plants her crop in fall, putting straw bales over the potatoes to protect them. Then she peels off the straw bales in spring, the plants start growing again, and she has fresh new potatoes in June.

Most growers planting a fall crop live in the southern-tier states, such as California, Arizona, Texas, across the Deep South, and maybe up as far as Virginia. But I say that if a grower can be successfully with fall planting in southern Michigan, then a lot more northerners could be experimenting with it.

What’s the ideal soil for potatoes?
Fertile soil that has good aeration, plenty of organic matter and a granular structure is ideal, such as sandy loam that drains well. Heavy clay soil that holds moisture around a developing tuber will impact that tuber negatively (in such cases, growers can lighten soil with coir or leaves). Potatoes are a heavy-feeding crop, so make sure your soil’s fertility level is high, with good, balanced mineralization. After you have a high level of fertility, you can cut back on amendments. To get to that point, we add 10 to 20 tons of compost per acre, which equates to almost a pound per square foot, and then we scale down.

To read the entire interview,  please click on the link provided below:
Mother Earth News

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