I've grown sweet potatoes three times here in Northern Michigan, I'm zone 5. The first year the Georgia Jets I planted did wonderfully. The last two years I've planted Beauregard, Nancy Hall, Georgia Jet and another white skinned sweet potato. My yield has been pretty much zero, in spite of watering, mulching, building up that high "hill" that Steele tells me SPs like. I've given them up, I'll just have to buy them, the slips cost about $20 by the time I pay shipping and SPs are less than 50 cents a pound here in season. Definitely not cost effective, as well as frustrating... I never thought of the night time temps, although I did cover the ground around the plants with black plastic to keep in heat, with no apparent improvement. It's usually in the 50s here at night, even in July and August, and some nights dip into the 40s. Annie

You need a soil test to be certain what's going on with the ground itself. No amount of guessing will help. Tell them what you're trying to grow and they can offer corrections tailor made for specific crops, usually. Generally, you need softer soil so the tubers will be able to expand. Incorporate all the organic matter you can find. Compost is supreme, but chipped leaves are great, manures are good, and if you absolutely have to, try peat moss. Someone suggested sand to me, but I believe that red clay plus sand = concrete and I don't want it to be worse than it is already. I plant about 300 slips per year. I do the same thing every year. I get varying results and still don't know why. Last year, I had a decent crop, but not any huge tubers like in the past. So this March, I hauled in fresh horse manure and dumped it and tilled it in. When I was ready to plant in May when the slips arrived, that had mostly rotted. I use a turn plow to make hilled rows. It digs deep. I go both ways to make one row so it's uniform on both sides. Works for me. Then I'll go back and hand plant 18 to 24 inches apart and firm the soil around them on top of the ridge. I make a depression around them to help catch water. Otherwise, it runs off, not in. Red clay forms a crust in a heart beat. I'll water a few times as is, then I'll go back and poke holes in the hill 6 or 8 inches deep and water again into the holes so water gets into the hill. Usually I have to water 4 to 6 times, once every other day, before it rains enough and the plants look like they will survive on their own. I may go 3 days between if it's overcast and not so hot. Watering is done by hand. I'm not near a spigot. Used to be 2 gallon cans filled from a rubbermaid container and spritz each plant. Now I have a 300 gallon tank on a trailer and a hose. I still walk the rows, but I can give each plant more water at a time without fear of running out so soon. 300 plants means about 500 row feet. last year, I dumped a quart of fish emulsion, a bottle of NOG, and a small bottle of chelated iron (needed magnesium or manganese, I forget) and just for good measure, a handful of 20 mule team borax for boron. They need boron. I added 200 gallons of water. Nice fragrant cocktail. I watered both the sweets and the tomatoes and pepper transplants with it. I had the best pepper production I've ever had. Sweets, not so much. This year, I added fresh manure in March and watered again with the cocktail. I dug sample sweets early last week that were the size of gallon milk jugs. Literally. I'm waiting to dig the rest another week or two. I usually dig them right at the September/October change. I've had rabbit issues this year from what I can tell looking at the patch. But the vines are thick and heavy, the leaves are huge. I'm looking forward to the big dig in another week or two. Next year, I should be using rain water. That's the plan anyway. See if this works. If not, click the link below. This is from two random plants near the end of the rows. Smaller regular size tubers are in the bucket... Here is a link that might be useful:

Dorothy, It has worked for a long time. Maybe for 7 or 8 years now. I've never once had a deer jump it, but on the rare occasion that I've left the gate open at night (OOPS!), I have come outside in the early morning around sunrise and found deer in the garden. Because they saw me (and even though I quickly retreated indoors to avoid frightening them), they wouldn't leave though the gate, and did manage by repeatedly jumping to eventually get over the top of the fence from inside the garden. They did a lot of damage during their mad stampede of running around wildly inside the garden trying repeatedly to jump the fence. I learned a lesson then about double-checking the gate at night to make sure it was closed and firmly latched. Everyone I know here has had success with an 8' fence, but I know that in some parts of the country, it takes a 10' fence. Some years I have had deer loitering just outside the garden fence repeatedly, sometimes even when they could clearly see me inside the garden (Hint: always close the gate behind yourself or you may find a deer coming in through the gate while you're inside the garden, and guess how I know that). I felt like those deer absolutely were planning to jump the 8' fence and I was worried they might succeed, so I tied white Wal-mart bags to the fence at roughly a deer eye level. I think any white material would work, it is just that at that point in time, white Wal-Mart bags were what I had. I tied them every 6' or 8'. They were tied so that they would flutter in the breeze. Because white-tailed deer use their white tails to signal danger to one another, I was hoping white fluttering bags would send a "Danger! Flee!" signal to any deer contemplating jumping the fence. It seemed to work. Those loitering deer went away. I thought that maybe one reason my 8' fence worked in the front garden was because the woodland comes up almost to the fence on two sides (north and west) and the driveway is on the south side, with the barbed wire property line fence just a few feet south of the driveway. I figured that at least on those three sides, deer found it hard to get a running start to leap an 8' fence. The east side had no real obstructions, but it slopes downhill which might discourage jumping the fence from that side. When we built the new back garden three years ago, we put up a sturdier woven wire fence than we have in the front garden. We used landscape timbers for poles and a very heavy gauge woven wire fencing material. That garden has wide-open land on all sides and I was worried deer would jump that fence because several deer trails run though that area. They've never made it over that 8' fence and into the garden, and I've never even seen any sign that they've tried. I've also noticed that the professional game/hunting ranches both here in our county and across the Red River in Montague County, TX, have 8' high fences, so they must find that the 8' high fences keep their deer contained within. However, those game ranches mostly have heavy timber along the fence lines and that might help keep their deer from jumping since the trees are so close to their fences. Dawn

You know what they say about assumptions. ;-) Cracking and splitting can develop at any time, at any stage of growth. But once it happens it's done. That is why consistent soil moisture levels throughout the season is so important regardless of the crop. And it has little to do with how we as people perceive the weather. We often make the mistake of evaluating weather/climate effects in terms of how it affects us - as a person. We're hot, we're dry, we're wet, it's raining on me so the plants are getting watered enough, etc. - when the effects on plants are quite different. The only way we know what is really going on with the plants is with dirty hands deep in the soil. Dave