Wednesday, January 1, 2014

Purple Sweet Potato Descriptions and Summary of 2013 Harvest

After growing 3 different purple sweet potato varieties this year, plus an experimental stint with a Stokes Purple sweet potato, I am happy to give a description of each of the purple sweet potato varieties I have grown, along with their growing characteristics.

My son finding an orange sweet potato

Taste Testing to inform descriptions - My children exhibit a lot of potential in taking pictures

All Purple: Long roots are often produced in locations of excess water with tubers often developing deep in the ground. Good yields of mildly sweet potatoes with a consistently purple flesh.

Alabama Purple or Purple Delight: Mostly top setting tubers of variable shape and size. Heavy yields of smooth textured savory tubers with purple flesh.

Dingess Purple: Top setting tubers of very marketable shape and size. Moderate yields of tubers with a rich, complex flavor and dark purple flesh.

Currently, if you live in Tucson and would like to buy any of these sweet potatoes you can contact me through this Craig'slist post. All proceeds go to my garden.

I grew a Stokes Purple Sweet Potato (starting in August or September)

In summary – I would have to say that the Purple Dingess are my all-time favorite, despite the meager 15 pound yield. Harvesting and working with the Dingess Purple Potatoes was much easier than working with the All-Purple or Purple Delight tubers. It would be well worth it to try to cross Dingess purple with another purple variety, such as Alabama, to seek to increase yield.

My Sweet Potato vines in November

Sweet Potato Vines have problems staying on my property

The final results of my 2013 harvest are 165 pounds of mostly purple sweet potatoes from my 7’ by 15’ summer garden bed, meaning the garden produced more than 1 pound of sweet potatoes per square foot, in addition to everything else produced this last summer. That being said, in the long term I am really seeking for quality over quantity. I would much rather have a tasty Delicata squash over a big poor-tasting squash. I am very grateful for such a good harvest, though I will definitely be changing some things this next year. Two of the things I will be changing for next year include planting my slips later in May and applying more EM-1 throughout the season to see how it affects my sweet potato vines.

Purple Sweet Potatoes make great pie.

EM-1: My experience with EM-1 was that it did nothing for any of my garden plants – including the legumes. The exception to this was with my sweet potatoes. EM-1 greatly increased my sweet potato yields. I highly recommend using EM-1 as an inoculant for sweet potato slips to increase yields. It is worth every penny if you are really into growing sweet potatoes. I diluted my EM-1 in purified non-chlorinated water and sprayed it on my young plants until the ground was soaked. The results in both vine and root growth were impressive. In fact, I would warn gardeners that the growth of EM-inoculated sweet potato vines is so vigorous that, in crowded conditions they will grow several feet off the ground.

EM-1 dramatically improves sweet potato growth

I am currently doing some research on culturing my own shelf-stable EM with the same characteristics as the EM-1 that I currently use. I will gladly share any success I experience from my own experience brewing activated EM - as I have time to do so. Another interesting thing is that, from some of the research I found, the Anthocyanins contained in Purple sweet potatoes can better retain their health benefits and color in storage with the presence of lactic acid (7%), which happens to be one of the ingredients in EM-1.

1 comment:

  1. Bonnie from Oregon recently posted the following:
    I live in Portland and just love purple sweet potatoes. I grew some a few years ago and then couldn't get the slips. I tried making them from organic ones from the grocery store but no luck. Now Stokes purples have come on the market and I will try again. How did the stokes compare to your other varieties. We have a long season but cool nights. I have to be creative in keeping these babies warm. I have some good tricks and wish for more hot days than we usually get. Thanks for any comments about stokes purple.

    Dear Bonnie,
    Thank you for contacting me.

    Even in Southern Arizona it can get cold enough to freeze sweet potatoes under the ground. Then if the tubers survive, their quality is diminished by exposure to a frost. Each year in Tucson I would watch the weather until I knew the first light frost would occur (about 32-35 degrees at night). Then I would begin harvesting right around the time of the first frost. The main reason for this is the vines. When the vines are lightly frosted, the sap inside changes so that it does not stain clothes as easily as it does when the vines are alive.

    Stokes Purple are okay and do produce alright, but Dingess Purple has been my go-to for years. The consistency, the texture, the taste along with the adaptability of this cultivar far outdoes Stokes Purple or any other in their class. No other purple variety I know of can be grown in a pot in Northern California and be expected to produce much of anything. But Dingess Purple does. Alabama Purple (or Purple Delight) produces a lot, but the quality is not worth the garden space. Stokes Purple has a good taste and texture (not great) and it is somewhat finicky in its adaptability. I believe it is probably bred more to remain blemish-free and be a specific size at the scheduled time of harvest than it was bred to be adaptable or of a fine texture/taste.

    Since beginning the practice of growing my sweet potato slips in the ground, that is what I always do in order to reduce the time lost by transplant shock. I am still vigilant about removing the mother potato from the ground after initially planting it, as the growing tubers can be negatively affected by it when they grow larger.

    As it goes with the temperature, sweet potatoes will not thrive until the soil temperature is above 70, preferably 75 degrees. Whatever you can do to create radiant heat where you are working to grow sweet potatoes will greatly increase your success during the initial first 2-4 weeks. I'm not talking about cooking them, but I am talking about things like water or milk jugs circled around the plant like a wall-o-water. I hope this helps.

    Wishing you the best with your sweet potatoes.



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