Q and A: sweet potatoes and chicken feed

1. Wow, cptacek!! I was thrilled with my 2 pound sweet potatoes. 8-9 pounders would be wonderful! My kids would be so excited to dig something like that up. :)

2. Thanks Zelda! I’m going to purchase a soil thermometer for this coming season. I’m looking forward to hopefully having my best sweet potato season ever. I’ve always made hills for my sweet potatoes, so I’m going to try a row without a hill to see how that does. Making those 40 ft. long hills is a lot of work, and it would be nice if we can stop doing that.

3. Soil temperature for planting slips needs to be about 65 degrees, especially if you have a clay soil, and where I live, that is usually close to July. Yes, they will grow and produce planted that late if you plant a quick maturing variety. If your soil is sandy and in full sun, 60 degrees should be OK. I put my soil thermometer in the bed in spring and watch the soil warm up. Plastic does help warm the soil more quickly. As Tim said, you can’t give sweet potatoes too much heat, even the cold climate varieties. They just don’t grow well if they get cold. You have to avoid frost pockets, which you can have even if your garden looks level. Watch the frost patterns on the ground in spring to find them, you may be surprised. Some people plant them in hilled rows, I did the first year, but don’t notice enough difference to make the extra work worthwhile. Hilled rows can conserve water. It’s something you can try if your rows are oriented north-south so both sides of the hills get maximum sun. I think planting in plastic is quick and it works and depending on your altitude, the plastic can last 2 to 4 years even if you leave it down year round. If you roll it back you can plant a quick maturing crop like peas, kohlrabi, radishes, lettuce in spring and have that crop out of the ground when the slips go in. Just experiment until you find what works best for your location. If you plant in 2 or 3 different locations next year you will see where they will do best.

4. Thank you very much for all the hints (I’m the original poster). This is just my 3rd year of growing sweet potatoes. The first year was amazing, getting 8-9 lb individual taters out of the ground. The second year I must have planted too early, since I hardly got anything. This year, I planted too late due to personal circumstances and got the garden in really late. There were a lot of individual potatoes from each plant, very long, but only about as big around as 2 large carrots. If they had had another month to grow, the yield would have been amazing. And now they froze the top 2 inches.

   So, plan for next year: Plant 3 times as many when the soil warms up sufficiently, cut back on the winter squash we don’t like so much, water well at first, then taper off, and get them out before the freeze.

5. I read that you dig your potatoes before the temp gets to 50 degrees. At what ground temp would you plant them?

6. My ground might have been cold when I planted them. I need to keep better records, because I’m not sure when I planted them. My family likes sweet potatoes so much that I was planning to plant 200 or more slips next summer. Maybe I don’t need to plant so many but, instead, I need to just make sure to keep them warm. Thanks for the tips!!

7. Again, same experience as Tim except one note about the plastic – I have to use black plastic to warm my soil because of long winters, but scientific studies have shown that clear plastic warms the soil faster and to a higher temp. It’s time this year for another growing experiment! with some slips and clear plastic. I leave the plastic down for the entire growing season to extend the growing season in fall, cutting Xs in it to plant the slips. My soil, even covered with black plastic, starts to cool down in late September, and so far I haven’t been able to extend past that. The sweet potatoes are growing for less than 3 months. Tim is spot on about heat – even the cold tolerant sweet potatoes I grow need lots of heat, and if your crops are small it’s probably lack of heat or planting in soil that is too cold for them. If I were an Extreme Gardener I’d dig up some of my raised beds and put down flexible heating coil, then cover it, plug it in and plant that way. Maybe I’ll do it just because. However, I’m also concerned about the effect on soil microorganisms and worms and other beneficial critters from heating soil. Mine are cool weather critters, and I wonder whether I’m killing them off by using plastic as increasing soil temp is how nematodes, weevils and weeds are controlled or killed. Worms will go deeper in the soil to avoid surface environmental stress, don’t know if the others do. If your growing conditions are uncertain for sweet potatoes I’d suggest setting up growing trials – three or four different methods in separate blocks or sections and monitor soil temp with a soil thermometer. In one growing season you should learn what works best for you.

8. 100 slips should have given you way more potatoes. I’m thinking your ground was probably cold when you planted them. This will ‘stunt’ the taters and they will not recover to be high producers. I throw up a hill in May, then cover it with black plastic. (I’m not big on using plastic, but this is one exception.) Leave that covered hill to heat up. Then, near the end of May of first part of June, depending on heat, we set out the slips. Our favorite, and best producer, is Georgia Jets. We live in the southwest corner of Iowa, but our climate is radical and more like Minneapolis most of the time. Jets do best for us here. Whatever you do, though, keep them warm all the time!

9. That’s a great idea to grow sweet potato to take the place of squash. Squash are iffy for me, too, thanks to the squash vine borer, cucumber beetles, and mildew. But sweet potatoes are one thing that I can grow pretty easily. We planted 100 Beauregard slips this past summer and harvested 5 bushel of sweet potatoes. We plan to double the amount of slips for this coming summer. I appreciate all the tips about watering and soil temp, too. These are things that I didn’t know.

10. When I lived in Kansas in zone 6a, I didn’t plant my potato slips until the end of May, first of June. I dug my sweet potatoes right before the first frost (middle of October). I washed my potatoes off with the garden hose and cured them under the dining room table for a few days in a single layer and then stored them in milk crates that were stacked up. I went through the potatoes every so often and rubbed off any shoots. In the spring I would go through any potatoes that were left and snapped of shoots/slips and placed them in a jug of water in the kitchen window to grow roots. Any potatoes that were left when it was time to dig potatoes again were cooked, mashed, dried in my dehydrator and then powdered in the food processor for thickening soup and instant potatoes. I grew between 80 and 100 pounds every year from about 40 slips. Because growing squash was such an iffy proposition for me I used sweet potato in place of squash in any recipe that called for it and nobody knew the difference. I grew Beauregard and Jewell.

11. I grow sweet potatoes too, and agree with Tim. I keep a soil thermometer in the sweet potato bed all season long and dig mine as he does as soon as the soil temp drops to near 50 degrees. The first year I left them in longer, and they did not store at all well. Brush the dirt off but don’t wash them, then let them cure in a warmish place before storing them. As they dry down in storage they get sweeter, just like a winter squash. Two other growing issues – use a soil thermometer in spring too and do not plant the sllips until the soil is warm, even if that is July. They will grow very quickly in a warm soil. Sweet potatoes planted in a cold or cool soil will not grow or produce well. Too much nitrogen will produce lots of leaves but not many sweet potatoes. They need lots of water the first two weeks, not much after that. They are disease and bug free and require minimal care once they start growing, kind of plant them and forget them until harvest. If you have wind or unexpected cool or cold weather, be prepared to cover your sweet potatoes with a polytunnel to maintain warmth. Sweet potato vines are edible, don’t be shy about cutting them to use as a green vegetable. You won’t believe the difference in taste between home grown and store bought sweet potatoes. You might be able to leave them in the ground if your soil drains well, has full sun all day, your winters are very mild, and you mulch at least a foot deep with hay or straw, but I think it would be iffy even then.

12. Growing sweet potatoes has become one of my favorite gardening hobbies. They do not like any part of anything cold! One important storage point we’ve learned the hard way is this: if you wait until the ground has reached 50F before you dig them, they will not last long in storage. So, monitor the ground temp with an actual thermometer, and when the soil temp gets near that 50F mark, get them out of there. Store them where it is cool, but not cold. We have an old chest of drawers in a 60+ room where we store our ‘taters. Like anything else you grow yourself, the home grown ones are so much better.

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