sweet potato questions

[kevinrs]

I'm growing sweet potatoes for the first time, got slips from sand hill, as I didn't find any other suppliers that could ship to california.

I do think I might have done better if I'd been able to start a month or 2 earlier, as around here it was basically the heat of summer (mid-late june, consistent 90s) when I planted them, some didn't make it, and most took quite a while to take off.

I'm wondering when to harvest. Looking at temps dropping to highs in the low 60s and lows in low 40s in the next few days(early winter type storm, 70% chance of rain), then going back up to low 80s/low 50s going into next week. There being no obvious sign that they are ready, like with a fruit, and wanting to get them up before frost, need some advice.

Also trying to figure how to cure and store them. Humidity is normally pretty low here.

Was looking at http://www.motherearthnews.com/grow-...b0z10zkon.aspx and it seems to advise letting them get a light frost before digging, though this goes against other instructions I've read. It says cure: "ideally between 85 and 90 degrees Fahrenheit at around 85 percent humidity — for a week to 10 days." and "After curing, move the sweet potatoes to a storage space, such as a root cellar, kept between 55 and 60 degrees with humidity of 75 to 80 percent."

The curing temperature I can maybe manage if I can fit them in a box or container I can fit on my seed starting mat, and use the thermostat, or put the mat in the container. The humidity though... it's more likely to be 10% here than 85%. If I try to add moisture the wrong way, I'm likely to cause a lot of rot and molding I'd think. I've got stuff running through my head about using a plastic bin + heat + fan + humidity source, but that might be too complicated, I might not have time to set it up, and might be completely wrong anyway.

Actually the video linked on that mother earth news page talks about flowers, I haven't seen one yet, I think the combination of getting them late in my season, shipping time, and shipping in heat set me back quite a bit. My plants don't look nearly as full as those in the video.

[kath]

Sweet potatoes need a really long growing season and do love the heat. I've grown them for about 10 years now and use black plastic over the hills to help with that. It also helps to keep the vines from rooting away from the main plant- important because if they do, they'll produce lots of skinny little tubers.

They are super sensitive to frost so cannot safely be set out here until after mid-May without extra protection. I've set them out as late as early June and still had a good crop by the time the first hard frost arrives, which can be any time from about Oct. 10th to November 1 depending upon the year. Since you planted in late June, I'd be surprised if you had much of a crop yet. They bulk up very late, so you want to leave them in the ground as long as possible. A light frost won't harm the tubers but you would want to get them out of the ground if a hard frost was predicted. You can gently dig around the base of the plant to get an idea of the size of the largest tubers but realize that they bruise very easily and you want to leave the skin intact.

When you have to harvest because of the weather, dig and handle them carefully. We usually have our woodstove going by the time I harvest so I have put them in a single layer in trays nearby and covered them with damp towels for moisture. I also have a very small sunroom which really can trap the heat during the day and I've cured them in there with the room closed off and tubs of water for humidity. I read about someone using a spare bathroom with a tub of water and a small space heater providing the necessary conditions. Generally, I cure them for 10-14 days and they always keep until April if we haven't eaten them all by then, and begin to form little sprouts that will become slips for the new year's crop.

I store them wrapped in newspaper and stacked no more than 2 deep in our basement, which averages 55-65 degrees for the time they spend down there. We have a dehumidifier running on "normal" and it doesn't seem to bother them. You'll find a lot of conflicting information about how to grow, harvest and store them, but it seems to me they're quite forgiving so I'd just do the best you can without a lot of hassle and see how it goes.

I've ordered lots of varieties from Sandhill and other places over the years but Beauregard has proven to be the winner for our climate and soil. This year I tried Evangeline, too, since I heard amazing things about it. So far, the vines of both have been rampant and I haven't been tempted to poke around and see what's going on under the soil, so it'll be a surprise, I guess. This year I planted too close to the corner of our garden fence so the vines are being pruned regularly by the deer. I'll try to take a picture and post later.

[kath]

It stopped raining, so I went out with the camera this am.

The first photo shows how nicely the deer are pruning the vines along the fence.We're hoping production doesn't suffer too much as a result.

The second one shows the sea of vines that results after 4 months of growth. There are 2 rows of plants, 4' apart and about 12' long. Ten slips of Beauregard and only 3 of Evangeline "took".

The third shows how the vines take over other plantings- these are in the area where eggplants, onions and butternuts once lived. On the top left you can see how an Evangeline vine decided to climb up a CRW cage.

The fourth shows vines that are now about 11' long and are overtaking the fall brassicas. I move the vines around to try and direct their paths a bit and once a week I lift them up to make sure they're not taking root anywhere they shouldn't.

The fifth is a new shoot on an Evangeline vine- so pretty- really hope they live up to their reputation as even sweeter yet smaller than Beauregard.

Lastly, you inspired me to take a peek and see what's going on under the plastic mesh. This picture was taken at the very end of the Beauregard row. There are some monsters there! This variety gets BIG- almost too big- but we love the flavor and this is the one variety we've found that isn't bothered by disease and gives us loads of potatoes that keep all winter. I've had luck carefully clipping these big ones off of the main plant and pulling them out early, leaving the rest of the plant undisturbed.

[Elizabeth]

I am growing them for the first time this year. I'm near the coast in CA, so I wasn't sure how well they would do - we don't' get a lot of real heat for long periods. So far they are looking very good indeed (I've peeked under the soil in a few places) My main garden is in raised beds, well, large 3.5x3.5 ft x 18" deep containers to be honest.

I planted from slips that I grew from sweet potatoes that sprouted in the pantry. I planted them mid May in the warmest corner of my garden.

I have RKN in most of my beds so I went looking for resistant varieties online. I found a company that looks like they ship to California - Steele Plant Company. I have never used them, but most of the reviews on Dave's Garden Watchdog are positive. I plan on using them for next year's plants.

When I set them out it was quite warm so I shaded them for a few days. The leaves are a bit ratty now from this and that, but in general the plants are quite healthy and I haven't had to do anything special to them. They have put on a burst of growth in the last month - it was warm here in September, and the roots have really sized up in the late few weeks. Until a couple of weeks ago I wasn't sure if this little experiment was going to work out, but now I'm looking forward to growing them each year.

I'm going to give them at least a couple more weeks in the ground, maybe until the end of October to let as many get large as possible before the harvest. Everything I have read about timing the harvest says to just keep checking for size, but whatever you do, harvest before frost.

I had some extra slips after I planted so I but them in some really large pots (24") I have by the front door. The lovely cascading vines look quite nice and decorative. I will harvest those at the same time as the main garden ones.

edit: The photos show them the day of planting, and today. I was in error. It looks like I planted them mid-June based on the timestamp on the photo. I intended to plant them mid May

[kevinrs]

I'm kind of surprised that there don't seem to be any suppliers for non commercial in California. From what I read, much of California would be ideal for sweet potatoes, including the miles of farms around here that are used for alfalfa, onions for export, carrots and other crops, that would use less water and fertilizer.
I looked up Steele Plant company, while they don't have the huge selection of sand hill, getting them at least a month and a half earlier looks like a good thing. Really, everything I planted I had random results this year, one tomato plant grows to 8 feet, while the one next to it dies without producing for example. Even the 8 foot one I've just pulled, it was running ahead of whatever was killing the foliage all this time, so it was green on top and no leaves on the bottom, but whatever it was finally killed the tips. The sweet potatoes the same, I have a few plants that are moderately large, though nothing like people's pictures, and others that are still pretty small. Even within the same variety.

[Elizabeth]

Ummmmm.......nevermind. What I wrote in this space a few minutes ago was a bad reply - I totally misread your post and neglected to notice you were the OP to boot..

Ahem, so, anyway....... going back to your first post, the flowers are subtle and short lived. Mine are sort of a light pink with a magenta center. I have been getting them off and on for the last couple of months - I don't think it means much when they flower, as I understand it they aren't like Irish potatoes in that way. I have seen some sites say that when the flowers appear and the plants die back it's time to harvest - I think they are confusing Irish and sweet potatoes since the most reliable ag sites say to check for size as there aren't other indicators. The main sites also advise to not let them freeze in the field. If you do get a freeze you are supposed to cut off all the vines immediately (I think the damaged tops will wreck the roots somehow) and harvest.

If you are having hit and miss on your plants of the same type that are near to each other you may have an irrigation problem like blocked emitters or possibly a root knot nematode problem, since that can be very localized. It could also be something like gophers nibbling away at the roots of some plants. Those little buggers can wreck havoc unseen. Usually if it's a blight of some sort all your plants of the same type will succumb close in time if they are near each other. There are some diseases transmitted by insects, so I suppose that could be it too. You might want to check the UC IPM site to see if you can find some visual matches to your plant problems.

[kevinrs]

What I was saying was surprising, was that there aren't consumer level suppliers growing slips here, they'd be able to ship just about anywhere with little restriction, as they'd already be within the most restricted state. Most of the big name catalogs that list sweet potatoes get them drop shipped from a few southern growers that cannot ship to California. They are grown commercially here, mostly in central California.

[Elizabeth]

I agree - it does seem odd - it sure would make it easier for us here in California

[Elizabeth]

I'm wracking my brain for a name - I know there used to be a company in N Calif that shipped slips, but it was a good 10 years ago that I saw it. I was going to buy some and then we ended up moving and gardening was back burnered for a few years until we got into our permanent home.

[kevinrs]

On the hit and miss, I'm growing the same selection of plants in 2 locations, about 8 miles apart. One has fine sandy loam, not much organic material, I've added what compost I had last year and this, probably not enough, probably lacking iron, just from the color. I know there are gophers or similar there. The soil texture should be ideal for root crops as it's well drained sandy that goes down quite deep, and the only gravel was added during house construction. The same soil type has for years been used for many acres of alfalfa, onions, and more recently carrots.
The other, new garden this year, should be similar or have more coarse sand and/or iron, from looking at soilweb map and roadside dirt, but I think it has fill dirt from somewhere else. I added 3 inches of commercial compost. No gophers there, but lots of earwigs, doubtful anything can be done with them as they live in everyone around's lawns I think. Trying to reduce them is like trying to get rid of ants by stepping on the ones you see.

Anyway, I need some soil tests, and haven't found anything other than sending it out of state to test.
Both locations have had the hit and miss problems. Broccoli was the only thing that did real well, though I had to get some BT for the caterpillars that like it so much. The cauliflower next to the broccoli I got nothing from. Tomatoes, tomatillos, peppers, squash, cucumbers, watermelons, cantaloupe, all had issues where one plant did drastically worse than another next to it.

[kevinrs]

Originally Posted by Elizabeth

I'm wracking my brain for a name - I know there used to be a company in N Calif that shipped slips, but it was a good 10 years ago that I saw it. I was going to buy some and then we ended up moving and gardening was back burnered for a few years until we got into our permanent home.

If it's mericlone labs, they seem to have lost their website last year, and not gotten it back or made a new one. I've not found a reference to anyone else besides commercial suppliers.