Growing for Market, Sweet potato propagation and yields

The April issue of Growing for Market is out! For those of you growing sweet potatoes, Andrew Schwerin from NW Arkansas has written an interesting article. I’ve written about starting sweet potato slips before and I have a slideshow that includes three methods of  starting your own slips.  He and his wife Madeleine grow 1500 feet of sweet potatoes each year, a third of their growing area.

I was interested to note their reasons for growing so many sweet potatoes (apart from the obvious fact that they can sell that many). Sweet potatoes are not a big moneymaker in terms of the space occupied. Here at Twin Oaks we pondered similar issues this winter when deciding which crops to grow.  We worked down a list of 25 factors, deciding which were important to use. We chose our top handful of factors and then worked down a list of crops we might grow, awarding points (or not!) for each factor for each crop. This helped us narrow down what to focus on this year. And yes, we are growing sweet potatoes! I wrote about this in Growing for Market in February 2017.

These growers listed the following factors as their reasons to grow sweet potatoes:

  • Sweet potatoes produce well in our soil

  • They aren’t troubled by intense summer heat

  • Extensive vines will smother most weeds

  • Few pest or disease issues

  • Most of the labor is in early October, between intensive harvests of summer and fall crops

  • They store long-term for steady sales through the winter

Sweet Potato harvest at Twin Oaks. Photo McCune Porter

They like Beauregard, and wanted to try using the single node cutting method, as advocated by Anthony and Caroline Boutard – see my Sweet Potato slideshow for details. Initially they were excited about the single node cutting process, as their roots produced exponentially more growing shoots each week. OK, maybe exponential is a bit of an exaggeration, but it gives the sense of it. Because they had so much propagation material, they started making 5-node slips, rooting clusters of cuttings in pots of compost, 3 nodes in the soil for roots, 2 nodes above ground.

Some of their single node cuttings failed to thrive, both in the trays and in the field, so they developed a 2-node cutting system instead, and also used their five-node slips. And so they had a trial of three sweet potato cutting methods, with plants in different 100 ft beds. In the past (using the regular slips method) they have averaged yields of 500-600 lbs of sweet potatoes per 100 ft bed, with a range from a poor 250 lbs to a few successes with 1000 lbs/bed. Of course, yield is not the only important feature of a market crop, although understandably it has a high profile for those growing 1500 row feet for sale.

At harvest, they found that their single-node sweet potato plants were producing a couple of hundred pounds per 100 ft bed. The 2-node beds produced about 500 pounds per bed, of relatively few, very large (6 – 20 lb) sweet potatoes. The plants with 3+ nodes in the soil gave more reasonable sized potatoes. They tend to get jumbos, so they have started planting closer (10″) to tackle this – not many customers want jumbos.

In his article in Growing for Market,  Anthony Boutard pointed out that single-node cuttings do produce fewer tubers which are larger and better formed. This is a big advantage for growers in the north, but less so in the south. The Arkansas growers have found that the 2-node cuttings are even better at this tendency in their location, which is much further south than Anthony Boutard’s farm.

Beauregard sweet potatoes saved for seed stock.
Photo Nina Gentle

Other articles in this month’s Growing for Market include Managing a cash crisis
How to climb out of the hole by Julia Shanks, the author of The Farmer’s
Office. Farmers deal with a very seasonal cash flow, and may well have gone into farming with good farming skills but not good business skills. Julia writes about four rules for getting out of a financial hole.

  1. Quit digging (don’t incur any more inessential expenses).
  2. Keep the dogs at bay (communicate with your creditors about how you plan to pay, and how you plan to keep producing the goods).
  3. Climb out (increase revenue in as many ways as possible).
  4. Get your head out of the sand (don’t panic, face realities, be proactive).

She goes on to list 10 ways to protect yourself from getting in such a hole again.

Sam Hitchcock Tilton has an article about cultivating with walk-behind tractors, ie, weeding and hoeing with special attachments. There are some amazing walk-behind
weeding machines (manufactured and homemade) throughout the world. There
is an entire style of vegetable farming and scale of tools that have been forgotten, in between tractor work and hand growing – the scale of the walk-behind tractor. The author explains how commercially available tools can be adapted to work with a BCS or a carefully used antique walk-behind tractor.

Mike Appel and Emily Oakley contributed Every farm is unique, define success your own way. Money is not the only measure. Quality of life, family time, and personal well-being are up there too, as are wider community achievements. Farming is equal parts job and lifestyle, and the authors recommend having a strategic plan for yourself and the farm, which you update every couple of years to pinpoint goals and the steps you need to take to reach them.

Cossack Pineapple Ground Cherry
Photo Southern Exposure Seed Exchange

Liz Martin writes about husk cherries (ground cherries) and how to improve production of them, to make a commercial crop viable. Who would have guessed that hillling the beds before planting can make harvest so much easier, because the fruits roll down the sides?

Judson Reid and Cordelia Machanoff wrotea short piece: Fertility tips and foliar testing to maximize high tunnel crops, and Gretel Adams wrote about  Scaling up the flower farm. Many of the ideas also apply to vegetable farms.

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