I planted my purple sweet potato slips a couple of days ago and I thought I’ll share the process with you here. I will start by apologizing for the lack of photos. This is the first time that I am planting purple sweet potatoes in my garden and I wasn’t sure I will even get to the slips planting stage so I didn’t take many photos in the beginning of the process. Also, take into consideration that this is the first year that I am attempting to grow sweet potatoes so this is all experimental for me.
Anyway, I did some research about potatoes as in general and learned that there is a rule of thumb in regards to this crop: you grow English (Irish) potato in the winter and sweet potatoes in the summer. The first like cool weather and the second hot weather. This means that I can grow three cycles of potatoes in my garden:
1. Plant English potatoes in the beginning of March – will be ready for harvest in the middle of June.
2. Plant sweet potatoes in the middle of May (when temperatures stay relatively hot day and night here in the south) – those should be ready for harvest by September (it takes them about four month).
3. Plant English potatoes in the beginning of September – will be ready sometime in December (I will probably need to cover the plants in November to protect them from the frost).
With this plan in mind I started by purchasing seed English potatoes. The bag cost me $4 and there were 8 seed potatoes in it. I planted them in the beginning of March.
This is my end-of-June harvest. We will eat the big potatoes during the summer and save the little ones as seed potatoes for planting in the fall. It might take the small potatoes longer than the summer to start sprouting, if that happens I will purchase some more seed potatoes for fall planting and keep those for planting next March.
Step one complete.
Right after I planted the English potatoes I started to prepare to the sweet potato planting which is different than the English potato planting. With sweet potato, you don’t plant the actual potato but the slips; the vines which grow from the top of the potato.
I searched online for slips and found seed companies who sale them in batches of 16 or 18 for almost a dollar each. I really don’t have room for so many plants and the price was too high for me so I decided to grow my own slips.
I started with regular orange sweet potato. I placed it in a water container at the end of March (I later learned that it’s better to use a glass jar. Also, use filtered water and replace the water every 3-4 days) just like in the picture above; one half of the potato is covered with water and the potato is held in the middle of the container by tooth picks. This also holds the potato about an inch from the bottom of the container.
Roots did develop nicely, but something went wrong… I think that (maybe) the wrong end was down in the water and the potato rotted before it started sprouting. Based on this experience I would say that if your potato doesn’t start sprouting within a week and a half or so, turn it so that the other end is in the water and see what happens.
After my first potato rotted I decided to try again with some purple sweet potatoes I purchased from the farmers market some three month earlier. They were sitting in a basket in my pantry and started sprouting. Because they were already sprouting I knew which end needs to go in the water (the not-sprouting end).
Do you see the difference between the orange and purple potato? The orange one is a bit rounder than the purple. The purple potato is kind of brown from the outside but if you open it up it’s dark purple inside. It is as sweet as the orange potato but a bit harder. You may need to cook it longer than the orange one to get it soft, but I think that it is holding better (longer) in storage.
Those little purple vines in the picture above grew very very fast once rots developed on the other side of the potato (the side that is in the water).
I am missing a picture here (sorry). Basically what happened is that a month and a half after I placed those two potatoes in the water They grew a bunch of white roots on the end that is in the water and slips, with green leaves from the upper end. You need to wait until the splits are at least 8 inches long before you cut them off of the potato and place them in their own water jar.
Here are my slips… They are way longer than 8 inches. When they were about four inches long we flew to Israel for a three week trip to visit family and friends. When we cam back we had this crazy growth on our potatoes. I just took a kitchen knife and cut the slips as close to the potato as I could, then placed 4 or 5 of them in each jar and filled it with filtered water.
Within 4 days or so they developed roots of their own. You can leave them even longer in the water if you want, but because June is almost over and sweet potatoes need about four, hot month in the ground, I decided to go ahead and plant them in the garden.
Planting Purple Sweet Potato Slips
All I did was take the slips out of the jars and plant them 7 or 8 inches deep in the ground so that the roots are completely covered. I spaced them about a foot from each other and watered them in.
Sweet potatoes are ground covers so they supposed to spread and cover the whole bed. I think that I planted about 12 slips in this bed. It’s probably too many for the space… but I didn’t know two potatoes will give me so many slips and I didn’t want to just get rid of some, so I ended up planting them all. We’ll see what happens.
A day after I planted the splits they wilted. I was devastated and thought I lost them, but my husband saved the day by covering the ground with straw.
The young plants just couldn’t handle the heat, the direct sun and the new soil all at once. Covering the ground with straw (or wood chips, dry leaves, etc.) helps to keep the moisture in the ground and to shade the slips a bit.
They came back to life within a couple of hours and are still doing very good. My watering system works in the morning and evening for 15 minutes each session. To help the slips root I water them one more time in the middle of the day.
Another thing I learned in my research is that it is recommended to cut the plant back if it grows too big, so I will cut whatever vines start growing outside of the bed once the plant starts to spread. The interesting thing is that as long as you cut the vines when their leaves are still young, you can eat the leaves just like you will eat spinach. I am curious to taste those young leaves.
I am anxious to see how the slips are going to develop. I hope this is helpful information for some of you. I will keep updating this post as the plants develop. Hopefully with some good harvest pictures in four month or so.
If you have any experience growing sweet potatoes and have a suggestion for me I’d love to hear it.