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.

2013 All Purple Harvest

In early April, when Tucson’s average high temperature rose above 80 degrees, I put out my All Purple Sweet Potatoes to start growing slips.

 

A few All Purple Slips I transplanted though I will probably not transplant next year.

 

With some EM-1 my slips really took off by mid-may

 

 

Slips can take a long time to start – especially if being grown indoors. That is why I have been working on a new way to start my slips outdoors. Though I have greatly improved my method for growing sweet potato slips, I believe that my sweet potatoes do much better when I wait until May 1^st to start growing out slips.



 

My second harvest of sweet potatoes required a flashlight to procure

 

When the time finally came to harvest my All Purple sweet potatoes from the garden, I had to do so a little at a time. It is difficult to harvest a sweet potato that can mature over a foot below the ground, and doing so requires loose soil and some dedicated time to feel through the soil by hand.

 

 

Some of my first harvest of All-Purple Sweet Potatoes

 

 

Some of my second All-Purple Sweet Potato Harvest

 

 

One of my larger All-Purple Sweet Potatoes

 

 

Another large All-Purple Sweet Potato.

 

 

By the end of my harvest I felt both good and bad. It seems that the quality of this variety of sweet potatoes decreased from going into the ground so early. A few of the larger sweet potatoes did not exhibit the color or texture I would have expected from this variety. On the other hand the harvest of 95 pounds was a nice way to finish my summer garden harvest.



Some of my second All Purple Sweet Potato Harvest. Can you find the nickle?

Mail Order Sweet Potato Slips and EM-1

Last May I received a long-awaited package from a company headquartered in the East. The package contained two small bundles of very small-looking sweet potato slips.



Amazingly, the slips came out of a dented package out unharmed!



In the past, I had always produced sweet potato slips myself from sweet potatoes, and knowing that the daytime temperatures were already topping above 95 degrees Fahrenheit I thought it wise to start some of my plants in pots or vases indoors before planting them out in the garden. This was a type of experiment to see what method of planting would work best. The three different methods I tried were slip to garden, slip to pot to garden, and slip to vase to garden.



How my package arrived in the mail.

The package got a little dented. I'm grateful the slips made it.



General Sweet Potato Background: Sweet potatoes like a lot of light. By a lot of light I mean full sun in very hot, sunny places. Established plants do not require shade and are able to endure brutally hot environments. What sweet potatoes do have difficulty with is a lack of light. Any kind of environment in which plants are not receiving direct sun will make the plants dither or at least grow slowly.

The plants in the pots did not fare as well as those put directly in the garden

Though I put my indoor plants directly under windows, they had difficulty growing very well because they did not receive enough full sun. Most of the slips that I put in pots had difficulty establishing themselves indoors and did worse than those put out in the garden. Slips I put in vases did exhibit more root growth, which was helpful when it came to transplanting them in the garden. The constant sterile water supply was helpful, though a lack of direct sunlight was not. Slips that were put directly in the garden exhibited significant wilting over the first 10 days but did better after about 14 days. Filtered shading from a shade cloth helped minimize wilting until the plants could establish themselves well.



Initial placement of slip in vase.



The slip grew more roots but plant suffers from a lack of light

Recommendations: Based on my experience with mail order sweet potatoes I would recommend that the gardener either allow sweet potato slips to establish themselves in a vase that receives an abundance of direct sun or put the slips in the garden with filtered shade, such as shadecloth, until the plants become established. As filtered sun could decrease plant growth, and possibly yield, I would think that any shadecloth or filtered sun provides only a temporary benefit to the sweet potato slips as they are becoming established.

Shading Slips helps them become established without extreme wilting

One additional thought: Previously I had posted about a microbial product that is supposed to increase plant growth in the garden. The name of the Product is EM-1 and it is produced by Teraganix. The initial application of EM-1 seemed to have no impact on my garden. After two weeks of application no signs of increased growth or plant vigor were noticed. However, after 6 weeks of the initial application the sweet potato slips that were growing exhibited a dramatic increase in growth. The increase in plant growth was not imagined, but is very real. Though previous sweet potato growth did not move several feet past my garden, my current sweet potato vines have grown at least 10 feet past the confines of my garden. Neighbors are probably wondering why I have what looks like ivy growing out into my alley. My experience with EM-1 has taught me that it is an incredibly effective inoculant in growing sweet potatoes. I will be sure to continue to use this product for this purpose, in the future!



My Sweet Potato vines in Early August - The bottom half are from the slips!





EM·1 Microbial Inoculant

Back in December 2011 I attended a Tucson Organic Gardener (TOG) meeting with a presenter from Terra Ganix. During this meeting, the gentleman presenting highlighted the incredible properties of their EM·1 Microbial Inoculant. He noted that its multiple anaerobic microbes were able to naturally “heal” gardens and bring the beneficial microbes in a garden into balance. I thought very little of this presentation until this last spring when I decided to give the EM·1 stuff a try. I contacted the company and found the location (on West Grant, in Tucson) where I could pick up a bottle from a vendor without having to pay shipping.

EM·1 Microbial Inoculant

With some amount of hope, I took my EM·1 home and diluted it in water – making sure to apply it in the evening. As luck would have it, I applied it on the only cloudy day in April.  Instead of using tap water, which is full of chlorine and other possible antibacterial substances, I just used filtered water that had been sitting out for a day – just to make sure. I also applied more water afterwards – to ensure that the EM·1 penatrated deep into the soil.

So – does EM·1 Microbial Inoculant really work? What happened when I applied this miracle cure to my garden? Nothing really. All of my plants miraculously grew at the exact same rate that they had been growing. The plants that were doing poorly continued to do poorly and those that were doing well just kept on doing well. I would like to say that EM·1 is some kind of miracle item but I really cannot. One would hope that this means that I have plenty of good microbes in my garden already. Perhaps, in the future, I will get better results by applying diluted kefir to my garden

EM·1 Update: Even though the EM·1 did nothing for the rest of my garden it helped my sweet potatoes grow and produce much more than they would have otherwise produced. If you grow a lot of sweet potatoes I would highly recommend this product. I have more information on my more recent experiences with EM·1 posted here.

No noticable change in my Garden after applying EM·1 

My experience was not a total waste of money. To be able to compost more of my kitchen scraps – including bones, meat, and dairy I plan on using my EM·1 to make some Bokashi. Bokashi is a substance that uses a substrate (such as wheat bran) to pickle your compost in a way so that it does not stink. You can think of Bokashi as a compost pre-digester. EM·1 can be activated to make more EM·1 and make lots of  Bokashi – so you can compost more food without having the negative pests and smell associated with composting. You can find out more about this process on Terra Ganix’s website.

Does Soil Inoculant really work?

When I have problems with digestion I often benefit from eating yogurt that contains the Acidophilus bacteria. There are products that can help a plant’s roots, like yogurt can help a person’s stomach. These products are often made out of nitrogen-fixing bacteria (rhizomes) and are touted as helping legumes get good head-start. Products in this class are often loosely referred to as “soil inoculants”.

Yogurt contains beneficial bacteria.

At first I thought that rhizomic soil inoculant was some kind of propaganda marketed by gardening companies to lure gullible gardeners into spending more money on their products. However, a recent experience has taught me otherwise. A while ago I had been given a gift certificate from a family member to a large seed company. I could not find too many open-pollinated seeds in their catalogue so I chose to add soil inoculant to my purchase. I didn’t think the inoculant did too much the first time I tried it and I had nothing to compare it to. In hindsight though, my first crop of peas was better than any other crop I have had since.

Soil Inoculant contains beneficial bacteria.

I have been growing Chinese Long Beans the last few years and have noticed that they often take a while to sprout. Recently I tried soaking my Chinese Long Beans overnight, then draining the water and rolling the seeds in soil inoculant. Within a few days half of the seeds began sprouting. They continued to sprout again and again. I have never seen such high germination in this seed variety and can only attribute it to the soil inoculant. Since then the beans have continued to grow at an accelerated rate in comparison with growing them in years past. I don’t believe that using soil inoculant for legumes is the only thing legumes need, though I do believe the inoculant helps germination rates, increase plant vigor, and speed up the time between sowing bean seeds and reaping a crop.

Step 1: Soak Beans overnight

Step 2: Put soil inoculant in a container.

Step 3: Rinse out beans

Step 4: Mix inoculant with beans

Step 5: Plant beans with inoculant

Step 6: Watch your plants grow!

There are a variety of soil inoculants out there and I cannot speak to the effectiveness of any other variety than the one I used. Some have a few good bacteria varieties while others contain a host of beneficial organisms. One farmer even conducted an unbiased comparison of the affect of using inoculants (and some other things) in his soil. Given my recent success with soil inoculant I will definitely consider investing in these bacteria in the future.