Sweet Potato Planting Time

My sweet potato slips arrived yesterday.  By tonight, the garden should be dried enough that I can get them planted.  Yes, I grow sweet potatoes in North Dakota.  I even grow celery here, but that's a topic for another blog.  While Mother Nature only allows us a short growing season, we have daylight and warmth for many hours a day during that short season, so we can grow things that it seems shouldn't be possible.   The trick is getting the soil warmed up before planting and choosing the right varieties for northern climates. 

Sweet potato varieties range from 90 to 150 days to maturity.  Obviously, I want varieties that are closer to the 90 day maturity than those that need 150 days.  There are four varieties that seem to do the best with our season length- Beauregard, Centennial, Georgia Jet, and Varaman. 

Beauregard is a 90 day sweet potato with smooth, light red skin and deep orange flesh.  It is a very high yielding variety and while many of the potatoes are finger-sized when dug, I usually find at least two or three on each plant that are five to six inches long and three inches or so around.  Even the small ones are absolutely delicious, though.

Centennial is another 90 day sweet potato that has coppery colored skin and the deep orange flesh we all recognize as a sweet potato.  Centennial doesn't yield quite as much as Beauregard, but the flesh of the Centennial is a litle bit finer-grained, moister, and in my opinion, tastier.

Georgia Jet is known as the most reliable northern producer and I have had good luck with it in my garden.  Georgia Jet has a deep red skin, moist flesh, and excellent flavor.  It produces nearly as well as Beauregard for me.

Vardaman is a 100 day variety.  This is my first year growing this variety so I don't have a lot to review yet.  It is a bush type sweet potato, so it can be grown in smaller spaces than the other varieties.  It is marketed as a high yield potato with excellent flavor.  Vardaman's foliage is a distinctive purple, so it will be an attractive addition to the garden.

Sweet potatoes are started from slips, not seeds.  You can start your own slips by cutting a potato and soaking it in water.  This takes time and patience, neither of which I am able to find most days, so I order my slips from a reliable grower. 

Sweet potatoes like a loose, well organically amended soil and they don't like to be planted in soil that is less than 55 degrees F.  They will grow well in sand but tend to languish in heavy clay.  My planting area has been amended for many years and has a high organic matter content that the sweets seem to like.  Sweet potatoes are heavy potassium (potash) feeders, so I will work a little organic potash into the soil before planting.  The don't like high nitrogen levels - if the N is too high, the sweets will grow lush, beautiful foliage, but no tubers.  And, while sweet potato leaves are edible and seen as a delicacy in some cultures, I prefer the tubers myself.

I will lay a strip of black landscape fabric in the planting area and make sure it is lying tightly on the soil.  Then I'll cut eight inch long slits about every two feet.  Through each slit, I'll make a small depression in the soil, then dig a hole that will allow me to insert the rooted area of the slip.  I'll cover the rooted area of the slip, leaving a small depression in the soil to capture water.  I cover the exposed leaves of the slips with a wind and sun protector for the first few days.  I use the one gallon pots that perennial plants are purchased in from the garden centers.  I simply cut the bottom from those pots and stick the cut edge about two inches into the soil.  It's a cheap, easy, and at my place, readily available source for plant protection.  After a few days, I'll remove the protectors and store them for next year.

I'll keep the weeds down, which is made much easier by the landscape fabric, and keep the soil uniformly moist throughout the summer.  Then I'll wait for the fall and harvest time. 

Oh, I can just about taste those sweet potatoes already!