>> Morning, everybody.
Thanks very much for attending
our session on sweet potatoes.
My name is Noel Valdes.
I live in Cambridge.
If you don't know where
Cambridge is, 20 miles due east
of here, get on the Beltline,
it's the first town you will
hit.
I've been growing sweet potatoes
since I moved to Wisconsin in
1986.
it's a very easy crop for home
gardeners to grow.
It's a crop that if you are a
home gardener and you want to
add a good crop to your list of
things, sweet potatoes should be
considered, and I hope I can
give you some good information
on how that can be done
relatively easily.
Most people think of sweet
potatoes as a southern crop, and
there's a good reason for that
because it is, but you can cheat
Mother Nature and grow nice
looking sweet potatoes, healthy
sweet potatoes in your garden
here in Wisconsin.
That's in Cambridge.
You can buy sweet potatoes at
the store, and I often ask
myself why am I doing this when
I can buy them in the store for
two dollars a pound, organic
sweet potatoes at Willy Street.
But we all know that the stuff
you grow yourself is way better
than what you're going to buy in
the store, even the good stores.
So there's a nice little crop of
sweet potatoes that I grew a
couple of years ago.
And getting crops, you can see
very big roots, is not unusual.
So if you're not getting big
roots out of your crops, you're
doing something wrong.
You have to figure out what
you're doing, and hopefully I
can maybe steer you in that
direction as well.
Sweet potatoes, if you didn't
know this, are probably the
healthiest single plant we can
grow as gardeners.
More nutrition and USDA rates it
number one as healthy food for
you to grow.
It's good for people with health
issues.
Diabetics can tolerate it.
It's just got a lot of good
health factors in it.
Low calories, easy to grow, a
lot of ways to prepare it, a lot
of ways to cook it.
I've got a line there that says
high yields in relatively
limited space.
It takes some space.
It's not a very compact plant.
It wants to spread out.
So you do need a little bit of
room.
I grow them in raised beds and
that helps the room issue
tremendously because you can get
a lot more food in a raised bed
than you can planting them
linearly in rows, but I'll show
you again how that works.
They are definitely easy and low
maintenance, especially once you
get the plant started.
It takes a little bit of finesse
to get the plant started, but
once they're started, there's
nothing to do except wait until
it's time to harvest.
And the nice thing, if you use
the right varieties, sweet
potatoes will store at room
temperature, the right
varieties, for one year.
That means you can harvest them
in October; the next October you
can still be eating those sweet
potatoes.
And there's not other crop that
you can do that with, just store
them at room temperature with no
preparation or minimal
preparation, that will last you
a year.
We already talked about that.
A good crop to grow.
And you can grow nice ones
yourself.
Okay, I'm going to give you a
little sweet potato trivia.
If you didn't know, the sweet
potatoes came out of Central and
northern South America.
Probably been cultivated for
close to 4,000 years.
The second line is extremely
interesting.
New Guinea and some of the other
Polynesian nations have been
growing sweet potatoes since
about the year 1,000.
So, guess when the Europeans got
there.
1500, so what happened in that
interim?
How did sweet potatoes get from
South America to Polynesia 500
years before the Europeans?
Most people think that there was
some traffic.
Could be.
They are the seventh
most grown crop in the world.
Corn number one, wheat, and then
whatever.
Most countries, not North
America so much, but Africa,
Asia, Latin America, very heavy
consumers of sweet potatoes.
For the horticulturalist in
there, Ipomoea batatas.
They're a morning glory, and if
you grow them and you're lucky
enough to see some flowers,
undisputedly a morning glory.
That's exactly what they are.
But, unlike the bindweeds and
morning glories that we are used
to growing, they're totally
edible, every part of them.
They won't give you
hallucinations, and they are,
even the leaves and the stems
are non-toxic, and the leaves
and the stems are actually part
of the diet of most of the
people that do use sweet
potatoes in other parts of the
world.
In fact, even down South, sweet
potato greens are a common dish.
So you can eat those leaves.
The most interesting thing about
the sweet potato from a home
grower's point of view is all
parts can be rooted.
The stems can be rooted.
The leaves can be rooted.
The root can be rooted.
Parts of the root can be rooted.
The thing wants to grow.
It's seeking life for whatever
reason, but it's probably the
most easy plant to root for a
vegetable-type crop that's out
there.
It's not hard to start your own
plants.
Those are roots.
I was told by a professor friend
who taught me a lot about sweet
potatoes that those are not
tubers, they are roots.
So don't call them tubers.
They are roots.
And they are not yams.
There's a reason sweet potatoes
are called yams.
When all the Africans came to
North and South America to the
Americas, there was a plant that
they ate in Africa that they
referred to as a yam.
And so sweet potatoes looked
like yams, and naturally the
Africa word for yams made them
yams in the nomenclature.
But it's a misnomer.
And they're two totally
different plants.
And now the USDA requires sweet
potato growers to call them
sweet potatoes on the package
even though they're the guys
that contributed to part of the
problem because they used to
call them Louisiana yams or
North Carolina yams in their
marketing.
But those are yams.
And those are yams.
And if you go to the Asian
markets around Madison or in any
town, you'll see yams.
Yams taste more like a potato.
They're starchier.
They're usually larger.
They usually require a much
longer growing season.
Nobody grows yams in Wisconsin,
but they are yams.
And it's crazy because even some
of the sweet potato varieties
out there are called yams.
There's a very popular sweet
potato variety called red yam,
but they are not yams.
Okay, I'm going to talk a lot
about starting and how to get
your own starts and various ways
to do that, but it's already
middle of February and some
people are going to say, hey,
I'm not going to go out and try
to get starts.
I just want to buy some plants
and get them in the ground.
You can do that.
And a lot of the catalogs and
some of the garden centers will
cell you the starts.
They're referred to as sweet
potato slips.
So if you want to shop for them,
shop for sweet potato slips.
And a lot of the catalogs will
carry them, and that makes your
life easy.
You get your sweet potato slips
around Memorial Day, you get
your garden ready, you go plant
your slips, and you're good to
go.
The disadvantages to slips are
primarily cost.
They're very expensive.
A sweet potato slip from a
catalog is going to cost you
$1.25 to $3 for a single plant,
and you can get 50 plants off of
a single sweet potato.
So you can see that if you can
start your own starts, you're
going to save a lot of money,
but I'm not discouraging you, if
you want to try sweet potatoes,
to just go out and buy some
slips and do it.
You can grow your own starts
from roots, shoots, or vines.
And remember, this is a root.
So that root will root numerous
ways, as we will show you as we
go forward here.
And sprouts will form on a root,
if you just leave it out in the
air, if you put it in the
ground, or if you put it in
water.
In any one of those of cases,
it'll start throwing out shoots
and start throwing out sprouts,
and I'll tell you which sweet
potatoes you should kind of use.
I think a lot of you have seen
this.
Starting you sweet potatoes in a
glass of water.
If you're going to do that,
we're kind of getting a little
late this year to make a crop
happen.
You can try it, but I would,
normally if I were going to
start them in water, I'd start
them in early January.
You can try it now with February
half way through, but whether
you'll get enough good shoots
and sprouts in time to get them
into the ground at the end of
May, it's dicey.
You may make it, and you may
not.
So I'll just say that.
But it's a very easy way to
start your starts.
That's a sweet potato that was
in storage and wrapped up in a
newspaper.
And those are the sprouts.
They're the same thing you see
here, but you can see they're
white because they weren't
getting any sunlight.
But each one of those little
sprouts, as you see here, can be
rooted, and any little section
of that vine or leaf that has at
least a nodule where there's
some growth coming out, any one
of those can be put in water or
put in a potting soil and be
rooted.
The method you choose is up to
you.
Starting in water is usually the
easiest for beginners, but I
think after you've grown them
for a while and it becomes part
of your garden repertoire, then
starting from vine cuttings or
starting from rootings from an
old plant is a lot easier and
you can wait longer before you
have to worry about getting your
plant started.
So there's what happens if you
put a sweet potato in water.
And each one of those little
shoots coming out can be snipped
off, stuck either in another
glass of water to form roots, or
stuck directly into potting
soil, a nice warm, deep potting
soil, and those will all form a
plant that you can stick in the
ground and grow a sweet potato
plant.
But, as I said, it's easier to
do it off of a sprouted root or
a vine cutting that you have.
There's a harvest where I've,
there we go, that's the vine
from a sweet potato.
If I can keep those alive,
that's in October, if I can keep
those alive until next spring,
just bring them in the house and
keep them alive, treat them like
a house plant, then I can cut
those all up and make starts out
of them and put them in the
ground and get sweet potato
plants.
It's crazy.
They want to live.
So that's kind of what you're
seeing here.
Those can be cut up into
multiple pieces.
And that long one there, I'd
really cut that one into about
three pieces and pot off all
three of them, as you see here.
They will root very easily if
you give it a couple of
considerations.
You can transfer them to water
and let them root in water, and
then go to a potting soil
medium.
Or you can go directly to
potting soil, but if you're
going directly to potting soil,
the soil needs to be deep, warm,
and relatively rich.
Once you get your potatoes in
the garden, the soil doesn't
have to be so rich, but your
potting soil should be fairly
nutritious.
So that almost dead looking
thing in no time will start to
look like that.
It'll become alive again.
It'll start throwing roots down
below, and if you are going to
pot them off, they don't like
shallow soil.
So you can't put them in a
shallow flat.
You want to put them in a deeper
box or at least eight inches
deep.
And that's what will happen.
And you can see I've got them in
a box there, and I've got my
starts coming along very, very
nicely.
That's what they look like in a
relatively deep box.
As I said before, starting from
the whole root in water, late
January is about the latest
you're going to easily get away
with it.
If you're starting roots in soil
where you're just going to put
the whole root in soil, any time
in February you can get away
with it.
From cuttings, you can go as
late as the first of May and
still get some root out there
and still get them in the
ground.
You just need enough root to get
the plant to start when it gets
into your garden, but they have
to be hardened off.
Now, I'm going to have to, I
know a lot of you know what
hardening off is, but some
people do not know what
hardening off is.
Hardening off is exposing your
plants, and it doesn't matter,
sweet potatoes, whatever it is
you're going to put in your
garden, I don't care if it's
your tomatoes, you do it with
your tomatoes, exposing them to
weather gradually, a little bit
at a time, from the indoor
temperature to the outside
temperature so they get
acclimatized or used to that
outside temperature, the outside
wind, the outside sun, and it's
not a shock when they get
transplanted in the garden
because you'll kill sweet
potatoes if you shock them.
So you have to be a little
careful.
And we'll have time for
questions This won't take a
whole hour.
So I'll have plenty of time for
questions.
People have asked that we hold
questions off until the
presentation is done, but if you
have questions on any of these
things, save them up and we'll
have time to answer them.
I do this with my sweet potatoes
in the house.
I make a little mini greenhouse.
That's a south-facing window.
And you can see Wisconsin,
that's out my backyard there,
typical snow.
But that'll keep the temperature
up over 70-75 degrees even if
your room temperature in your
house isn't that hot.
That works great to give the
sweet potatoes a climate that
they will enjoy in the house.
Just make a little mini
greenhouse inside the house.
So I'm assuming everybody's got
their starts under control,
whether they're from slips or
your own cuttings or rootings in
water or rootings from vines,
whatever it is, but we're good
to go now.
We're ready to get into the
garden.
You've got your plants hardened
off.
I always shoot for Memorial Day
weekend or the last week in May
to get them in the ground.
If you get them in before the
15th of May, you're taking way
too big a risk.
I will go through this again,
but sweet potatoes will tolerate
zero frost.
They will tolerate zero frost.
Don't try to cheat.
You'll lose.
They do not like frost.
They're a Central America plant,
so you have to keep them in a
warm condition.
You have to both get them in the
ground after the last hard
frost, and you have to harvest
them before the first hard
freeze.
I use what are called open
raised beds, which you can see
here.
These are about 20 feet long.
The length doesn't matter, but
three feet across the top of
growing space.
The nice thing about raised beds
for growing sweet potatoes are
that you can get a lot more
plants in a smaller space, they
warm up faster, and it's easier
to achieve softer soil using
raised beds.
But if you don't have raised
beds, you can easily grow sweet
potatoes.
There's not problem at all.
Just take your garden area that
you want to grow in and make a
ridge.
So, essentially, what you're
doing is just having that fall
right down on the other side,
and you have a ridge of soil at
least a foot tall.
But if you can get about 15-18
inches of soft soil below the
top of that ridge, that's good.
They're going to want softer
soil as opposed to harder soil.
They will grow in hard clay, but
if they have room to spread out
and softer soil, fine.
If you're in sandy soil, you
won't have any issues.
So, no raised beds, do exactly
what I'm telling you except just
do it in ridged hills as opposed
to beds.
I work in a little compost to
soften up the soil.
They don't need or want rich
soil, so don't go adding a lot
of nitrogen-rich material.
Don't go adding a lot of
fertilizers.
Once they're rooted in the
ground, they're actually better
off in just pretty plain soil.
You don't want too much nitrogen
in there.
I cover my sweet potatoes with a
plastic mulch, as almost every
northern grower does.
Some people use the clear mulch.
I've seen some people recommend
it, but most people use a black
plastic mulch.
It's the thicker mulch, I think,
is what they sell.
And you can get plastic sheeting
extremely cheaply at places like
Menards and Home Depot and the
other construction stores.
They sell it as protection for
construction, and they got the
size you need.
Ag stores will sell it as well,
but you can usually go to a home
store, a home improvement store,
and get it cheaper and easier.
Spacing on you sweet potatoes,
they need room to spread out.
You'll have problems if you grow
them too close together.
You'll get stringy roots.
You won't get nice, big, fat
roots.
They've got to have some room to
spread out.
Your spacing between plants
should be at least 18 inches.
I'm actually shooting more now
for like two feet between each
plant minimum spacing.
There's the black plastic that
I've laid down.
It's totally covering that bed
that I showed you earlier.
I've got holes cut into the
plastic, and then I use a little
plastic protector, which I'll
talk about in just a minute.
I wrap the edges of the plastic
in long boards so that it's held
down securely.
And that's what it takes.
So lay that down before you're
ready to plant your plants.
And then it's just a matter of
taking your starts and literally
just sticking them into the
holes that you set up to plant
your plants in.
If you buy slips or you're doing
your own starts, this is the
most fragile time for that
plant.
When it gets from your house or
from the nursery or wherever it
is into the ground.
This is the only time where you
really have to baby the plants
and take care of them to make
sure that they're going to
survive.
So you have to protect them.
You have to keep, make sure you
keep them moist, not let them
dry out.
The wind will try to beat them
up.
If you're not careful with how
you have your plastic holes cut,
that plastic can blow over them.
So that's why I use those little
protector rings.
And that's most likely the time
that the animals are going to
find them the most delicate and
delicious as well.
I make little protector rings.
That's a core of a shipping
tape.
That's just PVC,
three-and-a-half-inch PVC that
I've cut down to two-inch
things.
You can do whatever works for
you, but I just put a little box
around the sweet potatoes to
give them some protection when
they're first taking off.
And there you can see they're in
the little holes there and just
starting to pop out.
But once the vines start to
sprout, once they start to leaf
out, you're pretty much home
free until harvest time.
Very little has to be done from
this point on.
Once you get that far, it's
going to happen.
Now, as far as irrigation goes,
most years in Wisconsin I don't
even have to irrigate my sweet
potatoes.
I don't even have to water them.
There's enough natural rainfall.
They don't need an excessive
amount of water.
I do put little slits in the
plastic here and there to make
sure that the water just doesn't
run off, but it does drain down
into the beds.
Obviously, it's going to pick up
moisture from the holes in the
plants themselves, and it's
going to pick up some moisture
from the edges of the bed.
But it's rare that I've had to
irrigate my sweet potatoes.
And the leaves will tell you.
They'll show a little distress
if they need water.
If you see a little
inward curl and you
know you're watering the other
rest of the garden heavily, then
you might want to water them,
but normally they don't need a
lot of irrigation.
So if you've done everything
right, around the end of summer,
that's what your sweet potato
bed is going to look like.
And the vines are very, very
prolific.
In fact, a lot of years I have a
problem with too much vine.
I just end up, I don't cut them
off because I want all of that
nutrition from the vine to go
down to the root.
I just wrap them around and
throw them back in there.
But you can see vines are very
prolific on the amount of vine
that they put out.
The things that are going to
give you trouble in a home
garden here in Wisconsin,
primarily, voles can be the most
destructive.
If you're familiar with voles,
they're a little mouse.
They're like a field mouse.
You'll mistake them for a mouse
if you see them in the garden.
They look just like a mouse.
They will tunnel into your sweet
potatoes, and they can ravage a
crop in very short order.
There's a worm called a
wireworm.
It's a little segmented gold
worm.
You'll see them a lot in carrots
and turnips.
That same worm will get into
sweet potatoes and tunnel into
sweet potatoes.
As far as under the ground
damage, those are probably the
only two things you really have
to worry about.
Wireworms will go away if you
rotate your crops consistently
and your garden soil is
relatively healthy.
The wireworms will pretty
much diminish over time.
The voles, that's your best vole
protector right there.
[LAUGHTER] But you can see what
happened to Boots over there.
She got into the catnip and went
to sleep one year.
[LAUGHTER] And so I did have one
year I had bad vole damage, but
normally those guys do their job
and I don't have much vole
damage.
You can see the sweet potatoes
there are covered under a cloth,
and I've got fencing around
here.
That cloth is called
agricultural fabric.
I'll explain it in a minute.
[LAUGHTER]
That was in my
backyard, and they love sweet
potato vines.
They love them, love them, love
them.
They'll eat the over anything
else in your garden.
They'll go for the sweet
potatoes vines number one.
So you have to worry about these
guys, and I don't know where you
live, but where I live, they're
a big problem.
So covering with that fabric
that I showed you keeps these
guys off of them.
They won't try to figure out how
to get through them.
So I've had good luck protecting
from deer with a cloth over the
sweet potatoes or fence it or
whatever it is you need to do
for deer protection.
These guys, Japanese beetles,
they weren't even around in
Wisconsin 10 years ago, but now
they're becoming a problem.
They're actually diminishing
now.
They're not as bad as they were
three or four years ago because
natural predators are showing
up.
But they will do a good number
on the sweet potato leaves.
They like sweet potato leaves.
Obviously they like grape leaves
and rose leaves and other things
better, but they can do a number
on you sweet potato leaves as
well.
And, again, that cover, that
fabric over your sweet potatoes
will help.
Okay, so we made it to the end
of the year.
This is already October.
You can see I'm already pulling
out some squash out of the
garden I'm ready to harvest.
This is imperative.
Don't let your sweet potatoes
stand through a hard freeze.
You'll lose your crop.
You will absolutely lose your
crop.
What will happen is the leaves
and the stems first will start
to turn brown and black, and
then if that blackness works its
way down to the root, that root
will spoil.
You can harvest after your
leaves have been damaged by
frost, but you better harvest
right away and not let that
frost damage work its way back
to the root.
So usually about the second week
of October is about as late as
you can get unless you've really
got a nice hoop house system or
something like that.
But I try to cheat.
I do what I can.
I've done this, covering it with
polyethylene and things like
that, but they're super frost
sensitive.
And there where I've pulled that
poly, you can see there already
the leaves are turning black
there.
So I'm right on the borderline
of where I have to get those
things out of the ground.
I use pruning loppers, the same
thing I prune my apple trees
with, to cut the vines and
separate the vines from the
plant.
Super easy.
Super fast.
Cuts the work way, way down
because they're tough vines and
you got to cut them.
A little hand secateurs
is much harder work than using
a big pruning loppers that
you can get both hands on.
So there you can see, there's my
loppers, there I've cut all of
the vine off the plastic, I peel
the plastic back, and I'm going
to tell you this about the
plastic too, I know that black
polyethylene isn't the most
environmentally friendly thing
we can use out there, but it's
cheap and I can get three years
out of them.
Okay, I'll take that off, rinse
it off with the hose, let it dry
out, fold it up, and I'll use
the same cover again next year.
So three years, I'm doing my
part.
So there we are.
We've got it all cleaned off.
I'll pull the boards out of the
plastic that were holding the
boards down, roll the plastic
back, and that's what you'll
see.
And if you're very lucky, you'll
see that they're popping out of
the ground, and I know I'm going
to get a big lunker out of that
one.
It's already showing.
But there you can see where I've
cut the vines off with the
pruning loppers.
And you can see, you can do it
by hand with hand pruners, but
it's so much easier with a heavy
duty pair of pruning loppers.
When your sweet potatoes are in
the ground at harvest
time, they're
going to be super fragile.
They're going to be very, very,
very delicate.
If you cut the skin, they'll
exude a little white sappy
juice.
They'll snap and break very
easily.
You have to be careful with
them.
This is where you want to get
them out of the ground and
they're not ready to eat when
you pull them out of the ground.
They need to be cured for a
couple of weeks, and I'll go
through that in just a second.
So you have to be careful.
If you damage them, don't worry
about then.
You can still use the sweet
potato and everything's okay,
but obviously the less damage
you do, the better.
So I get a fork underneath them,
a big fork, and then I'll clean
them out as carefully as I can.
And you can see with that stray
root how far that is from the
mother stem, and that's why I
said they like to spread out.
But that's all one plant there.
Dig them out, and there you go.
And there's the one I broke off.
No problem.
But that's about eight pounds of
sweet potatoes out of one plant.
And that's what they look like
out of the ground.
Now the big boys,
when they grow sweet
potatoes for money, the average
yield in the United States is
well less than three pounds.
In fact, it's just over two
pounds per plant is what they
get out of a plant.
Home grower can easily get four
or five pounds a plant,
sometimes even eight, 10, and 12
pounds out of a single plant.
So you can beat what the big ag
guys are doing growing them in
your own backyard.
That's 80 pounds of usable sweet
potatoes out of one 20-foot long
bed.
So your yields are huge if you
do it right, OK.
The book says that you should
cure your sweet potatoes at 85
degrees.
Well, none of us have 85-degree
environments in our house.
I've had totally successful luck
bringing the plants in, brushing
the dirt off, you don't want to
wash them if you don't have to,
just brushing the dirt off, I
lay newspapers down on the
floor, put them under the
kitchen table, and just leave
them there for a couple of weeks
before I put them into storage.
It's at 70 degrees, and I've
never had a problem.
So you can cure them at 70, but
the growers, they'll have a
special room, and they'll cure
them at 85 degrees.
If you don't cure your sweet
potatoes, they don't store as
well.
If they're fresh out of the
ground, they don't have any
flavor.
They develop sugars and
longevity by being kept in
storage.
I wrap each individual root in a
sheet of newspaper.
Just like any other plant, you
use the lesser quality ones up
first, the smaller ones, the
stringier ones, the damaged
ones, use those up.
The nice, big roots that you're
really proud of, wrap those up
in a single sheet of newspaper,
put them in an open box, and you
will get long, long storage out
of your plant.
The variety of sweet potato that
has worked best for me in my
garden is called Jewel.
They spell it both ways with two
Ls and with one L. you'll find
these a lot in the stores
because they're a common variety
grown by the commercial growers.
There's a handout that I've
referenced on my handout, a
handout of a handout.
A professor of agriculture at
the University of Illinois in
Champaign-Urbana named Chuck
Voigt, who also runs the
Illinois State Master Gardener
program, is probably the North's
expert on sweet potatoes in the
whole United States.
He knows more about sweet
potatoes than any man walking.
He has a handout that you can
search through the handout that
I gave you.
It'll be a UI Master Gardener
handout.
You got to scroll down.
And he will give you a bunch of
varieties that will do well in
northern climates because a lot
of varieties and a lot of reason
people have problems with sweet
potatoes is they're growing
varieties that should be grown
in Louisiana shouldn't be grown
in Wisconsin, and they're just
not going to do well here.
You need a shorter season, a lot
of different things.
So he's gone through all these
trials.
He's trialed over 400 different
kinds of sweet potatoes, and
he's got them listed.
So I definitely recommend if you
say what variety should I grow,
look at that.
The other thing I would look at
is if you go to the markets and
the farmers market and it's a
Wisconsin grown sweet potato,
pick one up.
Pick a couple up and you can use
those for rooting.
If the farmers in Wisconsin are
growing them, so can you, and
they're going to do well here.
That's a Jewel.
That is two of them.
One year old.
All right?
Unwrap them a year after we
harvested them, and they're
great.
Delicious.
After a year, they'll start to
deteriorate, and that's what
will happen.
Okay, they'll start to throw out
shoot, and they'll start to get
shrivelly.
They'll start to feed the shoots
and things like that.
But you can easily get a year
out of the right variety.
Not every variety, some
varieties store less than
others.
And, again, that University of
Illinois handout that I showed
you will give you the best ones
to try out.
And there's our man.
Okay, so that's the end of the
slide presentation, and now we
can take questions.
[APPLAUSE]