Monday, October 3, 2011

Growing Sweet Potato Slips for Your Garden

Growing Sweet Potato Slips 
by Robert Mader

Yes. Sweet Potatoes can be beautiful. You can start growing vines right now. Just pick a nice sized Sweet Potato in the grocery store. Set it in a glass of water. Soon within a week or two, you will have "slips" growing from it. If it was spring (warm enough) you could just take that potato out of the water, cut off a slip (eye with a vine starting from it- about the size of a quarter and about as thick and put it into a small pot with potting soil. Let it get nice roots and plant it out in your garden in a nice sunny spot.

Recently, I have had several letters from folks that want to know how to plant their sweet potatoes outside. Either as an Ornamental or in the Garden to grow their own plot of Sweet Potatoes.

A few weeks ago I  started a new Sweet Potato to get better information on "slips" and show their development. From time to time, I will hopefully get some good pictures to illustrate the process all along the way to planting. This may end up with starting more than one potato because they may grow faster than I want! Spring is a long way off here in South Central Kansas! 

I have done some research lately and below is some of the results:

When the sprouts are about 4 to 6 inches long, carefully twist off the sprout from the potato. Strip a few of the lower leaves off. Lay the stem half in a shallow bowl of water (with leaves out in the air). Roots will start to form in a few days.

When the roots are about 1 inch long, you may plant the slips. Pick a cloudy day or plant near the evening . if you can't finish the planting in one day, put the rest in water again or make a mud slurry in a large bowl in the shady place or inside to keep them until the next day or two.

Water well. water every day for the first week and then every other day. Lengthen out the watering period to about once a week. Your plants should be getting about an inch of "rain" a week.

You will want to start your "slip" growing (setting your potato in water) about 9 weeks before planting in spring. The soil should be warm when the slips are planted out. Also loose.

Here is a few pictures that I have recently taken of a new sweet potato put in water just a few weeks ago.

                                                                                                                                                                    Instead of toothpicks, I decided for strength I would try nails. This was a huge Sweet Potato!  So far - no problems have developed. Perhaps it will develop super "Iron Slips"!  It is just now starting to put out slips but has not put out any roots yet. Roots should develop soon at the bottom. "Slips" or stems are just starting.  The container is actually a cottage cheese tub that I cleaned and spray painted green. I think it looks rather nice and I don't have to beg my wife for a quart jar! 

Sweet Potatoes can produce up to 50 or more slips per potato!

 Each one of the "warts" that you can see above produce a "slip" or growing stem with leaves.  At the upper right corner near the right edge, the dark red-ish large perturbance is the beginning of a new slip. Yes, this  potato is an ugly sucker but it has a lot of potential for a lot of kids! Unlike regular potatoes, Sweet Potatoes don’t have eyes – just tiny slits and bumps all over.

 Here near the bottom of the Sweet Potato you can see 2 new "Slips"  or stems forming along with the new leaves which will eventually turn green.

 At the very bottom.  roots will soon form
 but are not yet visible on this Sweet Potato

 Close-up of a "Slip"

When these "slips" reach from 4 to 6 inches long, they can be twisted carefully off at the base where they first come out of the potato and lay in a shallow bowl of water with the leaves out in the air. (Leaves should be stripped off the bottom half rooting end. These slips or stems will soon form roots. Be sure to change the water every few days to molding and rotting. This won't harm the Sweet Potato much at first but it can take the fun out of your project as the weeks progress!

When the roots of these new slips are an inch or so long, you can plant them out in your spring garden -  assuming the soil is warm enough. If it's warm enough for Green Peppers to grow, it’s probably warm enough for this semi-tropical plant.


If the slips have grown into long vines, 10 to 12 inch cuttings from the Tips of the vines can be snipped off to root instead of Slips. Clean a few leaves off the cut end and insert it in water to root. You should see new roots within a few days or so.

 This was just one slip but already it can be divided and made into 2 plants with plenty of roots to spare. 

As you can see, each leaf nodule is putting out new roots. You can see how the leaf has been snipped off with the little short stubs or nodules left. I literally use a small sharp scissors to cut the leafs of and chop the stem into separate starts to put in water.  When cutting the stems always leave one or two leafs at the top to make food from the light until roots come out of the leaf nodules you cut.

This is the same slip cut into 3 seperate pieces . Two - which both had leafs - were set into plain damp potting soil and watered in. The last piece which only has roots was put into a small jar in the light hopefully to generate l leaf or two before planting. 

1.  A whole potato can be cut into 2 or 3 sections or slices. Bottom Half of each section or slice is set down in the water and the Top half stick out into the light and air. Sections or slices will work just as well as a whole Sweet Potato.

2. For best results, plant the slips from 12 to 18 inches apart in rows about 4 feet wide. The soil should be humped into a Ridge and the Ridge should run down the middle of each row and be about 8 inches high to allow good drainage.

3. For best results, Give the plants an inch of rain a week. Sprinklers should fill a soup can set near your plants with one inch of water. Set several cans around to get an idea of how much you are really watering.  See how much time it takes for the sprinkler to fill the can one inch. Each plant should be given this much watering time with the sprinkler at that setting. This will give you very close to a gallon of water per watering - or one inch of rain. In the heat of the summer, you may have to water more than once a week. To keep my plants alive last summer during our 50+ days of above 100 degree heat, I had to water them every day. And the tomato's still turned out little mummified quarter-sized fruit! Go figure....

4.  Fertilize every few weeks with a LOW Nitrogen type all-purpose fertilizer -  5-10-10 is good. Too much nitrogen (the first number) will give you beautiful green leafy plants with little produce! The plants think they are in heaven already - and wont produce fruit! 

Also make a furrow  a few inches ( 6 inches or 12 Centimeters out ) along side the plants and put about a cup of Bone Meal over a length of 20 feet of row. Cover the furrow and water it enough for the soil to be damp down to about about 5 inches. Once a season is enough. Potatoes need Calcium! Do the same with regular potatoes. A box of Bone Meal will cost you a few bucks and will feed a whole garden full of Sweet Potatoes And your "Yukon Gold's" and "Russets" too.

5. The soil should be rich and light so the tubers can grow easily through out the needed growing space.  Here is a good soil mix:

    1 part Potting Soil                          
1 part Compost
   1 part Peat Moss
Mix well

6. Last of all ( or first maybe I should say) start your Sweet Potatoes for your slips in a warm place with a little sunshine - but not right next to the glass of a window to cook! Optimum temperature would be around 80 degrees (25 Celsius) Lower temperatures in the 70's (20's Celsius) will slow down the growing process but they will still grow. Anything lower will probably not produce slips at all and just rot you Sweet Potato.

Copyright Robert Mader 2011
 All Rights Reserved

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Also, please leave a Comment just below this article if you would. We would all like to hear what you think and any new ideas you may have. Until next time.