Home from CFSA, Superstorm Sandy

Beauregard sweet potato
Photo Southern Exposure Seed Exchange

Superstorm Sandy didn’t do us much damage, luckily. It’s been raining for 40 hours, but we’ve only got 2.8 inches so far and it looks like it’s going to clear up later today. Despite my worries about the broken hoophouse windows blowing in and us losing our newly re-plasticked hoophouse, it didn’t happen. We didn’t have any really high winds, and we didn’t even lose power, but of course we did all the prep work.

Georgia Jet
Photo Southern Exposure Seed Exchange

Yesterday we re-stacked our sweet potatoes which had finished curing (the skins don’t rub off any more). We moved them into a wire rodent-proof cage, and close-stacked them, taking away all the sticks that spaced the boxes during curing. I haven’t got numbers for the total yield yet, but it comes to 96 boxes. The Georgia Jet produced 42 boxes and the Beauregard only 32 from the same length row. Our two heirloom varieties produced three boxes each. We don’t expect many of them, but we are keeping the varieties alive, because genetic diversity is important and who knows what secret virtues these varieties have?

We also bravely spent time in the rain, digging drainage ditches to reduce the impact of the hurricane. They seem to have worked quite well. And we draped the soggy rowcovers over the frost tender crops, in anticipation of freezing conditions.

While I was away at the CFSA Conference, the crew harvested the white potatoes. We got a good yield (also no numbers yet), but we got a disappointingly large number of greened potatoes. (Green from being exposed to the light.) I think the reason is that our new experimental tractor-mounted furrow-making disks don’t make furrows as deep as we need. The walk-behind BCS furrower on the rototiller made adequate furrows, but not as good as the old Troybilt furrower. This flags a need to research better gear before March.

I had a great time at the CFSA Conference. I think there were about 700 people there. About 70 came to my workshop Growing Great Garlic, on Saturday afternoon. They were very appreciative, and I managed OK without my notes! It’s not as bad as it sounds – I had a slideshow and had practiced quite a few times, and knew it better than I would have guessed. Somehow I couldn’t get my notes on the laptop screen without them also appearing on the big screen along with lots of clutter. This flags a need to find out before my three workshops at the Southern Sustainable Agriculture Working Group conference in Little Rock, Arkansas, January 23-26. Busy, busy.

The conference was very well organized and the food was spectacular – mostly local and sustainably grown. I had the chance to attend several workshops by other people. Tony Keinath, the vegetable pathologist at Clemson University, talked on Sustainable and Organic Approaches to Managing Cucurbit and Tomato Diseases – a very well-prepared and information-packed session. I feel in a better place to tackle next year’s plagues now. I was struck by the fact that he had seen NO benefits of using Oxidate, the hydrogen peroxide disease control product.

A workshop I found particularly valuable was Laura Lengnick‘s presentation “Is Your Farm Climate Ready?”  She is doing valuable work to help farmers get ready for climate variability. She is one of the main authors of a USDA ARS report Climate Change and Agriculture: Effect and Adaptation. Its publication date is November 14 2012. She also spoke at the August 2012 symposium of the Ecological Society of America, Climate change impacts on agricultural systems:

She suggests viewing climate change as yet another production risk to assess and prepare for. The vulnerability of your farm has two components: exposure and adaptive capacity. As far as vulnerability, the most immediate key exposure is water issues (too much and too little). Rising air temperatures, including night temperatures, more extreme temperatures provide threats and some opportunities. Increasing CO2 levels will provide some positive effects such as faster crop growth. As far as adaptive capacity, the main feature of that aspect is our personal capacity to respond and plan. Laura Lengnick says “Greater attention to climate as critical for decision-making is expected by future generations of producers.” We need to start with ourselves.

Baby ginger, ready to be eaten, pickled, candied, frozen.
Photo East Branch Ginger

Next I attended a workshop by Susan Anderson of East Branch Ginger, and learned so much about how to do the best by this crop, that I am looking forward to an even bigger harvest next year. This year we harvested 165 pounds, and saved 65 pounds as seed stock, so we can plant a bigger patch in next year’s hoophouse.

Harvested baby ginger, about 6 months old
Photo East Branch Ginger

Meanwhile I’ve finished my next article for Growing for Market. My working title is Knowing When to Take Action. It’s the third part of my series on being a resilient farmer. This article includes scouting and monitoring for pests and diseases; using pest and disease forecast services; and being prepared for the effects of extreme high and low temperatures. When is it time to cut your losses? A big part of the article is a table of soil temperatures to help when deciding planting and harvesting dates.

Sweet potato harvest – all in!

Our sweet potato harvest well underway.
Photo credit Wren Vile

           

Usually sweet potatoes are harvested the week the first frost typically occurs. In anticipation of frosts (that didn’t happen) on Sunday and Monday nights, we harvested this week. Contrary to myth, there is no toxin that moves from frozen leaves down into the roots. On the other hand, cold injury can ruin the crop, and roots without leaf cover are exposed to cold air temperatures, and have lost their method of pulling water up out of the soil. Cold wet soil can quickly rot sweet potatoes (I know, it’s happened here).

To harvest, we first remove the vines from the area to be harvested that day. There is usually 3 afternoons’ digging for ours, and we want to leave live vines to protect the rest of the crop overnight. We use pruners to snip the vines where they emerge from the soil, leaving stumps to show where to dig. We roll the vines into the spaces between the rows.           Using digging forks, we carefully dig up the roots, which grow in the ground in a bunch-of-bananas shape. We want to select good potatoes for seed, and we grow several different kinds (Georgia Jet, Beauregard, and a couple of heritage varieties whose names we don’t know), so we make sure not to mix potatoes from different rows. As we dig, we set the potatoes out beside the spot where they’ve grown, one clump per plant, so it’s easy to identify the most productive plants.

It’s important not to bruise the roots, or to leave them exposed to temperatures higher than 90°F (32°C) for more than half an hour, or they will get sun-scald. Below 55°F (13°C), they’ll get chilling injury. We also avoid any abrasion of the skin, which is very fragile at this stage. We leave the sweet potatoes to dry on the ground for 1-2 hours, unless the weather is unsuitable. This year we had ideal weather, not too hot, not too cold; breezy enough to dry the skins, sunny.

We want to grow our own slips (baby plants) next year, so we save at least 1 root per 5 slips wanted.  (1 good slip every 16″.) So to plant 800 row feet, (600 slips), we save 100 each of our two main varieties and 20 each of the two heirlooms. That should be plenty. Some will shrivel or rot, so we allow a margin. We don’t save for seed any roots that look diseased. We choose plants with a high yield and no string (rat-tail) roots. From these plants, we choose small-medium sized potatoes with typical shape and color.

When grading and crating the roots in the field, we first choose the seed potatoes, and then sort storable from “Use First” roots. Large open broken surfaces will cure and can be stored, but any roots with soft wet damaged areas or deep holes (whether from voles, bugs or fork tines) will not store, and should be graded out, for composting or immediate use. We sort into 4″ deep wood flats or 5″ plastic crates for curing, and buckets for the “Use First” category.

Immediately after harvest, we took the boxes of sweet potatoes into a warm damp basement below the dining hall, to cure. This allows the skin to thicken, cuts to heal over and some of the starches to convert to sugars. Uncured “green” sweet potatoes are not very sweet at all, and are better used in dishes where they combine with other foods. A baked uncured sweet potato is a sad disappointment.

We stack our boxes of roots on pallets, and put wooden spacer sticks between boxes in each stack, to ensure air flow. We get quite good temperatures, but keeping humidity up is difficult for us. We cover the flats with newspaper to hold in some moisture. The best result seems to come from splashing water on the concrete floor several times each day. We use box fans to improve the airflow, and the basement already has some natural ventilation.

Ideal conditions for curing are 85-90°F (29-32°C), and 80-95% humidity for 4-7 days, with some airflow and ventilation. Curing takes longer if conditions are less then perfect. The length of the curing period also varies with the dryness of the soil just prior to harvest. We usually reckon on 10-14 days. During that time, we’ll be taking turns to stoke the stove in the basement to keep the temperature up.

So – how did we do this year? Middle of the road, I’d say. Decent yields, but not a bumper crop – we still had empty boxes left over. The deer were regularly eating our vines until quite recently. Last year we had a dog to chase the deer off, but he met with a road accident. His replacement was old, and she just wanted to be a pet, so we had deer again. We used drip irrigation and biodegradable plastic mulch this year, and did a good job of weeding, so I put the lower yields down to deer damage.

Last year’s (weedier!) sweet potato field.
Photo credit Kathryn Simmons

Now the harvest is complete, we will disk the area and sow cover crops. It’s too late in the year for oats. We can sow wheat, winter rye and Austrian winter peas up till 10/31. We prefer winter wheat after the sweet potatoes,  because we’ll use that area next year for spring white potatoes in mid-March, and rye takes too long to break down early in the spring.