Of all the things I’ve been looking forward to harvesting this fall, sweet potatoes take the cake. I’ve never had much success growing these aggressive, slightly pernicious tubers, and my early failures didn’t encourage me to try very hard. This past winter I attended a workshop at the organic farming conference in my hometown of Lacrosse, and learned a good deal about how to successfully cultivate this southern delicacy in our decidedly northern locale. With some early results in, we have met the expected yield goal of a little over 1# per foot!
Sweet potatoes are a very involved crop to grow. They are grown from slips; small shoots that form out of the eyes of a mature tuber. While some people grow their own slips in a greenhouse, other have them shipped in from down South when the weather has sufficiently warmed. The slips are planted into plastic mulch, and thoroughly irrigated for several weeks, to help the new plants establish. 100-120 days later, tubers have adequately formed, and we are ready for harvest.
We harvest sweet potatoes using an undercutter. This is a tractor-mounted blade that nose-dives itself as deep as 10” into the soil, and effectively cuts a line underneath the tubers. Harvest with this machine is quite simple, just pick up the plant, remove the tubers, scour through the soil for any loose ones, and done. Sounds really simple right? Well, that’s only the beginning of the process.
To effectively sweeten a sweet potato, 8 weeks of curing must occur immediately after harvest. Stage one of this process is to bring dirty sweet potatoes up to 80 degrees with 90% humidity for 7-10 days. We accomplish this by hanging a tarp in our greenhouse to shorten the square footage needing propane heat, and watering the ground around the crates. This early part of the curing process allows for any wounds, cuts, nicks, or slight bruises on the tuber to heal, so in storage the sweet potatoes do not rot.
Once sufficiently healed up, the potatoes are moved to our 2nd walk-in cooler, where a temperature of 55 degrees must be maintained for 6 weeks. This cool storage is the difference between a sweet potato that is rich, sweet, and complex in flavor, versus one that is not. I’m not sure if it is some complex transformation of starches and complex carbohydrates into sugary deliciousness, or if sweet potato fairies don’t like to wave their wands in temperatures other than 55.7 degrees. Exactly what happens is beyond me, but what’s plain is that the curing process turns somewhat inedible sweet potatoes, into a thing of beauty, and we all know that a thing of beauty is a joy forever!
Based on the curing process then, we should be able to inundate you with very delicious sweet potatoes in time for your Thanksgiving feasts. We also expect to continue to have these curious, challenging, and utterly enjoyable gifts of the south included in the season extender “Bridge” shares. We hope everyone is enjoys them as much as we do.