If you’ve ever planted a big patch of arugula at the same time you planted the rest of the spring garden, only to watch it shoot up a flower stalk a few weeks later, you’ve already met this week’s topic: heat-sensitive crops.
Heat-sensitive doesn’t always mean a plant can’t survive warm weather. It usually means warm temperatures and lengthening days change the plant’s priorities. Instead of producing the leaves, heads, or tubers we want to harvest, the plant pivots toward flowering and seed production or it keeps growing, but quality drops.
So, today on Just Grow Something we’re talking about the five crops you should plant earlier than you think to avoid this change. And I’m also including an herb that can bolt as fast as you blink. Let’s dig in.
References and Resources:
Ep. 133 - Growing Onions: https://justgrowsomethingpodcast.com/episode/ep-133-growing-onions
Soil Temperature Maps: https://www.greencastonline.com/tools/soil-temperature
Plan Like a Pro Garden Planning Course: https://justgrowsomething.thinkific.com/courses/plan-like-a-pro
Just Grow Something: https://justgrowsomething.com
Just Grow Something Merch and Downloads: https://justgrowsomething.com/shop
Just Grow Something Gardening Friends Facebook Group: https://www.facebook.com/share/g/18YgHveF5P/
Check out how you can become a patron on Patreon: https://www.patreon.com/JustGrowSomething
Bonus content for supporters of the Podcast: https://buymeacoffee.com/justgrowsomething
Amazon storefront: https://www.amazon.com/shop/justgrowsomething
00:00:00
All right, my gardening friends today we are talking about 5
00:00:03
heat sensitive crops that you should plant earlier than you
00:00:07
might think. And when I first started
00:00:10
gardening and I first started to try to grow some of the things
00:00:14
that are on this list today, I most definitely planted them way
00:00:19
too late. And I did not get any kind of a
00:00:22
crop out of them. And if I did, it wasn't a very
00:00:26
good one. And when I say heat sensitive, I
00:00:29
don't just, I mean they don't like summer.
00:00:31
I mean crops where if you wait too long, they literally just
00:00:36
flip a switch and the plant suddenly changes goals.
00:00:40
So instead of making the part that we want to eat, it starts
00:00:42
racing toward flowering and going to seed, or it just
00:00:46
produces a lower quality harvest.
00:00:48
So in practical terms, heat sensitive can look like bolting.
00:00:53
That's when it gets that sudden flower stalk, which also can
00:00:56
cause a very bitter flavor or very tough leaves.
00:01:00
It could look like quality issues.
00:01:02
So maybe your broccoli heads are looser, or you get smaller
00:01:05
onions, or your potato tubers just don't develop.
00:01:09
Or this could look like timing problems, like you plant at the
00:01:12
normal time but the crop matures right as the weather gets too
00:01:17
warm. The big take away today is this,
00:01:20
for these crops, the calendar matters less than the
00:01:26
temperature trend. So if you plant them like when
00:01:29
you usually plant the garden, you may accidentally force them
00:01:33
to do their most important growth during the warm up and
00:01:37
that is when they struggle. Welcome back to Just grow
00:01:42
something. I'm Karen Velez, specialty crop
00:01:44
farmer and all around garden nerd.
00:01:46
This show is here to make gardening feel straightforward.
00:01:49
And today we are covering arugula, broccoli, onions,
00:01:54
potatoes and spinach as our heat sensitive culprits.
00:01:58
And then I've also got a bonus an herb and that is cilantro
00:02:02
because cilantro is basically the poster child for I blinked
00:02:06
and it bolted. Let's dig in.
00:02:10
So one quick note before we start.
00:02:12
I'm going to talk in weeks relative to your average last
00:02:19
frost date. And I will also give air
00:02:22
temperature and soil temperature targets.
00:02:25
And this can actually be very beneficial if you live somewhere
00:02:28
where you don't get a frost, OK, your job is to take your local
00:02:33
frost state and sort of work backwards and then keep an eye
00:02:37
on your forecast. So if your weather is doing
00:02:40
something unusual, you can adjust.
00:02:44
So we're going to start with the fastest growing crop on this
00:02:48
list, and that is arugula. Arugula greens grow very, very
00:02:54
quickly. It makes them a great sort of
00:02:56
beginner crop in that regard because you're going to plant it
00:03:00
and it's going to be harvested very, very soon after you plant
00:03:04
it. But it is a very heat sensitive
00:03:07
plant because it is a cool season, leafy green, and it
00:03:11
tends to bolt very quickly as the temperatures rise,
00:03:15
especially when the days are getting longer.
00:03:18
In cooler weather. It's nice and tender and it's
00:03:21
kind of peppery in heat. It starts to get actually spicy,
00:03:27
like hot spicy, to the point where it actually becomes bitter
00:03:31
and it starts to shift into that flowering mode very, very
00:03:34
quickly. The other thing about arugula 2
00:03:38
that is not in relation to like heat is that it just because it
00:03:43
grows very quickly, if you don't keep it cut back and harvest it
00:03:46
very frequently, it's going to bolt anyway.
00:03:49
So it's already a very sort of short lived crop in terms of
00:03:54
harvests. And then you add that heat
00:03:56
sensitivity into it. And I mean, oftentimes you blink
00:03:59
and all of a sudden it's like, Oh my gosh, what?
00:04:01
What happened, right? So if you want arugula in the
00:04:06
spring, the trick is to plant it earlier than you might think.
00:04:13
Arugula grows best with daytime temperatures around 50 to 65°F,
00:04:19
and it can tolerate light freezes so you can actually get
00:04:23
it into the ground earlier than you might expect.
00:04:26
It definitely has to go into the the garden earlier than your
00:04:30
warm season plants would, right? So the easiest way to get
00:04:34
arugula going is to just direct seeded outdoors as early as the
00:04:38
soil can be worked. What does that mean?
00:04:40
We've talked about that before. Basically when the soil is
00:04:44
friable, right? When you can kind of work in it
00:04:47
without it being so wet that it's sticking together and not
00:04:51
so cold that it's not like frozen, right?
00:04:54
You can start arugula indoors if you want to.
00:04:59
Like if you want the earliest possible crop, you can start
00:05:03
transplants about four weeks before you want them outside.
00:05:07
But really the only benefit to this is if you absolutely want
00:05:11
to get the earliest crop possible.
00:05:13
But in my experience, arugula grows so quickly that you really
00:05:17
don't have to wait long after you plant it in order to be able
00:05:20
to harvest it. So it's not something that I
00:05:22
have ever done. I have don't think I have ever
00:05:24
transplanted arugula. I think I have always direct
00:05:27
sown it. Your transplanting time on these
00:05:30
guys is basically as soon as the outdoor conditions are
00:05:33
consistently cool. So again, you know this is, this
00:05:37
is the cooler shoulder seasons. We're not looking at summer
00:05:40
weather. So if you are planning on
00:05:42
transplanting that is when you want to do it.
00:05:44
It is definitely going to be before your last frost date.
00:05:48
The ideal temperature, again, the daytime air temperatures, is
00:05:51
around 50 to 65°F for their growth.
00:05:56
If you're trying to time this based on your soil temperatures,
00:06:02
these can germinate in soil that is as cold as 40°F.
00:06:08
So if it's between 40 and 50°F in the soil, it is OK to go
00:06:13
ahead and start planting your arugula.
00:06:15
Now, germination is going to be a little bit slower at the low
00:06:18
end of those temperatures. They're going to germinate more
00:06:20
quickly the warmer the soil is. But this gives you an idea of
00:06:23
exactly how early we should be planting these so that they
00:06:27
don't hit that sort of heat threshold.
00:06:31
What is that threshold? Well, the temperatures are above
00:06:34
about 85 Fahrenheit, and we're talking about air temperatures.
00:06:38
Arugula is much more likely to bolt.
00:06:41
So shade can actually become your best friend here.
00:06:45
This is one of those crops where if you are looking to inter
00:06:48
plant things, you're trying to figure out where to fit your
00:06:51
sort of high, low, fast, low, right?
00:06:54
Arugula is both fast and low, so you can plant it again beneath,
00:07:03
say, tomatoes, right, If you're trying to get a little bit of a
00:07:06
later crop out of it so that it gets the shade in the afternoon
00:07:10
and maybe it will last a little bit longer for you.
00:07:13
Or you can plant the arugula first and then just plant your
00:07:16
tomatoes into it. And the tomatoes can help to
00:07:19
shade that arugula a little bit. But in reality, once you get to
00:07:24
those temperatures at 85 Fahrenheit or so, the arugula is
00:07:26
not going to last very long. This is why it's kind of a good
00:07:29
split succession, quick succession crop.
00:07:32
You can do it in the spring and you can do it again in the fall,
00:07:34
right? For a baby leaf harvest with
00:07:37
arugula, you're often looking at only about 20 days if, if the,
00:07:43
the, the growth rate is really fast, you know, 40 days on the
00:07:46
slow end, depending on your conditions.
00:07:48
And again, arugula can tolerate light frosts, so don't be too
00:07:54
concerned about getting it planted prior to your last frost
00:07:59
state. Now sustained hard freezes are a
00:08:01
different story. So we're kind of treating it as
00:08:03
cold tolerant, but not necessarily like winter proof
00:08:06
unless you've got some protection available.
00:08:08
But it really is very Hardy and again, it grows very, very
00:08:11
quickly. So I don't see a need for you to
00:08:13
start these indoors and then transplant them outside.
00:08:17
Now if you garden in a warm climate where I mean it's
00:08:22
naturally just warmer or it's it's warmer earlier in the
00:08:26
season, then often times your arugula sort of season is going
00:08:31
to be the fall through the spring, not late spring into
00:08:36
summer. So plant it when your
00:08:37
temperatures are trending cooler, right?
00:08:40
And you can use afternoon shade or shade cloth if you get some
00:08:43
warm spikes. Now, if you live somewhere where
00:08:45
you have extremely short seasons, arugula is one of the
00:08:48
best things that you can plant because it grows so quickly.
00:08:52
If you really want to get an earlier start, you can use some
00:08:55
row cover to trap a little warmth in your soil and block
00:08:58
the wind and get that arugula planted pretty early.
00:09:01
And then just harvest those baby greens early and often, you
00:09:05
know, because arugula grows so quickly, this is a great one for
00:09:09
succession planting, right? So instead of planting one big
00:09:12
patch, you can plant that really, really early harvest and
00:09:17
then plant some smaller amounts every one or two weeks while the
00:09:20
weather still stays cool. And then you're going to know,
00:09:23
OK, well, when it bolts, then you know that you're kind of
00:09:27
planting window is done for the time being.
00:09:29
And then you might want to go ahead and do this again in the
00:09:31
fall. The second one of these crops is
00:09:35
broccoli, right? And broccoli will absolutely
00:09:40
punish you for getting it in late.
00:09:43
I struggled for years trying to get a spring crop of broccoli
00:09:48
here in West Central Missouri. And the reason for this is
00:09:51
because, you know, when you're first starting out as a gardener
00:09:55
and you're thinking about things that might be a little bit frost
00:09:58
sensitive, broccoli comes to mind because you it doesn't seem
00:10:02
like it would do very well in the frost.
00:10:04
At least it didn't to me. And I was really worried about
00:10:06
it freezing. And so I waited to put it in
00:10:08
until I thought our frosts were pretty much clear.
00:10:11
That was mistake number one. Mistake number 2 was also
00:10:15
planting just sort of your standard varieties, which is
00:10:18
sometimes can take, you know, 65 to 70 days or longer after
00:10:24
transplant to come ready. Well, in that time, you know,
00:10:29
where I am, the temperatures can shoot up very, very quickly in
00:10:33
the spring. We have had years where it
00:10:35
seemed like we didn't have a spring because it got so warm so
00:10:38
fast and broccoli absolutely will not tolerate that.
00:10:42
OK, so these were the things that I struggled with with
00:10:45
broccoli. And you know, if you live in an
00:10:48
area like I am, sometimes it might really just do you better
00:10:52
to actually plant it in the fall.
00:10:54
So broccoli is heat sensitive in a few ways.
00:10:57
It grows best in mild temperatures and heat can
00:11:02
actually reduce the quality of that broccoli.
00:11:05
So if you do get that head to form, it might be just very,
00:11:09
very loose, you know, And if you don't, if you, you can't imagine
00:11:12
what I, what I'm talking about with a loose head.
00:11:14
Think about a head of broccoli that is trying to like really go
00:11:18
to flour. It starts to loosen up a little
00:11:19
bit. Sometimes if it's been hit with
00:11:21
heat, it will never have that nice tight head.
00:11:24
It also can develop a bitter flavor if it's if it's growing
00:11:29
in, in the heat. And I mean, on the other side,
00:11:32
certain stresses can lead to like really weird early head
00:11:36
formation. So you get like this one itty
00:11:38
bitty little floret and then that's all it does in the center
00:11:41
of the broccoli or it bolts immediately, right?
00:11:44
So this is one of those where if you can get away with it, you
00:11:48
really should be starting broccoli transplants indoors.
00:11:51
And you want to give them about 6 to 8 weeks or so before your
00:11:58
expected outdoor planting date. And that is generally about two
00:12:03
to three weeks before your last frost date.
00:12:06
So you got to give yourself some time to get the broccoli started
00:12:10
and also to harden it off and then also get it into the ground
00:12:14
about two to three weeks. I try to aim for three weeks at
00:12:17
least before the last frost date.
00:12:20
I also will make sure that I have some frost cloth on hand
00:12:22
just in case we could start to have something that looks like a
00:12:25
really, really hard freeze. With broccoli, you kind of want
00:12:28
to aim to transplant it when your plants have about four to
00:12:34
six mature leaves on them and a really solid root system.
00:12:40
We we also don't want like really big overgrown transplants
00:12:46
because those are more likely to have issues like getting those
00:12:50
tiny early little heads that don't do anything.
00:12:53
So it is definitely a balancing act with broccoli.
00:12:57
I don't recommend beginners try broccoli because it can be the
00:13:03
most frustrating thing in the world because they tend to be a
00:13:06
little a little sensitive. Maybe I should start calling
00:13:08
broccoli the diva instead of carrots.
00:13:10
I don't know. They've got carrots have a lock
00:13:12
on that. We'll call broccoli something
00:13:13
else. I don't know yet.
00:13:15
So their optimal growth temperature is roughly between
00:13:19
65 and 70°F, OK. And when I say optimal growth, I
00:13:25
mean this is that's the temperature that they should be
00:13:27
at as they are maturing. So if you can picture when in
00:13:31
spring you're getting to around 65°F during the day, you know
00:13:37
that that's the end of the growing period for your
00:13:40
broccoli. And if you are growing
00:13:42
something, I mean, a lot of homegrown, a home garden
00:13:45
varieties of broccoli already anywhere from, you know, 65 to
00:13:49
90 days after transplanting. So think about how long the
00:13:53
broccoli needs to be in the ground before you have like that
00:13:57
last three weeks of growth where it's really forming those heads
00:14:00
and getting nice and big. And that's when that temperature
00:14:02
should be 65. Well, then how early do you need
00:14:05
to be getting it in the ground, right?
00:14:06
That is the struggle with broccoli.
00:14:08
So your soil temperature at planting A practical target
00:14:13
range for this is around 45 to 50°F, OK, that is when you
00:14:19
should be transplanting. And so you know, don't rely just
00:14:24
on the calendar. If your, if your soils are
00:14:27
warming up to that temperature range, then you probably are OK
00:14:31
to go ahead and plant that, that broccoli.
00:14:33
If you are somebody that has a very, very long spring where
00:14:38
that temperature is not going to get super high, this is the
00:14:40
period where you could actually directly sow broccoli seeds in
00:14:44
the ground. So when it's about 45°F or
00:14:48
slightly warmer, obviously, again, just like anything, the
00:14:52
warmer the soil, the faster it's going to, to germinate.
00:14:56
But we don't want it getting so warm that we know those air
00:14:59
temperatures are getting warm, right.
00:15:01
So this is a good one. You know, again, in the fall, if
00:15:05
your temperatures are cooling off in the fall to be able to do
00:15:08
it that way as well. Broccoli can absolutely handle
00:15:11
the cold, right? It is, it is cool season, sort
00:15:14
of hearty. It's not seriously damaged.
00:15:18
If we get down to around 28°F, that's a that's a pretty good
00:15:23
frost. And you can even handle
00:15:26
temperatures below that, like down into the mid 20s Fahrenheit
00:15:30
for very short periods of time. So again, this is where I
00:15:34
struggled with broccoli. I didn't think I could get it
00:15:36
out there that early. Once I figured that out and
00:15:39
realized, oh it can handle some some really cold temperatures, I
00:15:42
had much, much better luck with that.
00:15:46
If your spring heats up really quickly again, broccoli is often
00:15:51
really good as a fall to winter crop, especially if you just
00:15:56
live in a very warm climate. The goal is to have that head
00:16:00
formation happen in the cool weather.
00:16:03
So smart moves with this are to choose early maturing varieties
00:16:08
so that you can harvest before that heat spikes, or plan your
00:16:12
schedule so the crop matures when those daytime temperatures
00:16:14
are still mild. If you have extreme, extremely
00:16:17
short seasons, your success is going to come from having those
00:16:21
transplants ready to go and making sure that you have some
00:16:24
sort of frost protection on hand.
00:16:27
So you can use a row cover or a low tunnel to buffer those winds
00:16:31
and those frost so that you have the opportunity to get them out
00:16:34
there earlier. I will say that if you struggle
00:16:38
with getting full formed heads of broccoli in your garden,
00:16:42
especially your spring garden, I have actually made the switch to
00:16:46
growing broccolini. You get the same flavor.
00:16:49
The broccolini is actually more tender.
00:16:51
So they've got these really like long stems on them, but it's
00:16:55
fully usable. They're super easy to harvest.
00:16:58
You get to harvest off of that same plant for about four weeks
00:17:02
depending on the variety that you're growing.
00:17:03
And you're not worried about it trying to form a head.
00:17:06
So in the trials that I ran last season, it still did well even
00:17:12
when the heat hit. So if you have tried broccoli
00:17:16
before and you've tried everything that I've already
00:17:18
suggested and it still doesn't work for you, give broccolini a
00:17:21
try. I promise you, you will probably
00:17:23
have much better success. OK #3 on this list is onions.
00:17:28
And the reason that onions make this list is because bulbing
00:17:31
onions need time to build those green leafy tops before they
00:17:38
switch into bulb formation. The more healthy leaf growth
00:17:41
that we have early on, that is going to mean a bigger bulb
00:17:45
later. Each one of those green leaves
00:17:47
on that onion leads to another layer on the bulb and onions can
00:17:53
tolerate those cool conditions when they are getting
00:17:56
established. So we want to give them the
00:17:58
longest time possible to be able to get that good growth.
00:18:02
So if you're starting bulbing onions from seed, then you want
00:18:07
to start them about 10 to 12 weeks before you are ready to
00:18:11
plant them outside. We want them to be about the
00:18:14
size of like a pencil or our pinky finger before we
00:18:18
transplant them. Onion transplants can tolerate
00:18:22
light frosts, and so you're going to want to plant them when
00:18:27
temperatures reach around 50°F. In terms of air temperature, you
00:18:33
know, in terms of the soil temperature, as cold as 45°F is
00:18:38
fine. If you're talking about
00:18:40
germinating them in the soil out in the garden, then 45 is your
00:18:45
absolute minimum. The onion seedlings are going to
00:18:47
tolerate your frost, especially when we are just transplanting
00:18:53
them. So they're brand new in the soil
00:18:55
and they haven't been established yet.
00:18:56
We kind of want to make sure that anything below like 28
00:19:00
Fahrenheit, we might want to give them a little bit of
00:19:03
protection. This is a little bit different
00:19:05
than maybe if we've planted onion sets in the fall like I
00:19:09
do, because even though those sprout, they go through the
00:19:13
entire winter, they've already gotten themselves sort of rooted
00:19:16
in. They can tolerate really, really
00:19:18
cold temperatures. Brand new onion seedlings in the
00:19:21
garden in the spring aren't quite as Hardy because they're
00:19:25
still getting established, so you might want to keep some
00:19:27
frost cloth on hand. Depending on how early you try
00:19:30
to get these in, you would be surprised how early you can put
00:19:34
onions in. I know farmers around here who
00:19:37
have planted as early as the end of February and let me tell you,
00:19:41
we are not planting anything out in our fields at the end of
00:19:45
February. Generally speaking, we are
00:19:47
waiting until March and I can actually, so I'm making making
00:19:50
noise here. I can actually look on my
00:19:52
calendar and tell you that I have my onions marked on the
00:19:58
calendar to go in the ground onions March 15th, OK.
00:20:04
But I have seen farmers get them in three weeks prior to that,
00:20:06
three weeks earlier, OK with with no problem.
00:20:09
So don't underestimate how early you can actually get them into
00:20:13
the ground. The heat stress for onions
00:20:17
really starts to kick in when we hit 90°F for several days in a
00:20:22
row. OK, That's not really what we're
00:20:26
concerned about in terms of why we want to get onions in so
00:20:30
early, because they do grow through the summertime in most
00:20:34
instances in most places, right? We're not harvesting our onions
00:20:38
until June here, but what we are concerned about is the optimum
00:20:44
temperatures for that foliar growth.
00:20:46
We're concerned about those green leafy tops and the optimum
00:20:49
temperatures for that foliar growth is around 65 to 68°F.
00:20:55
So use that as your guide as to when you should be getting your
00:20:59
onions in for transplants. You know, that 50° sort of
00:21:03
benchmark is a useful sort of, hey, it's go time trigger.
00:21:08
If you're direct seating, then you want to plant them as soon
00:21:12
as that soil is workable in the spring because onions vary a lot
00:21:17
by the type of onion and the method of how they're grown.
00:21:21
And, and you know, they can take as as few as 90 days to come to
00:21:25
maturity. They can take as long as 150
00:21:27
days to come to maturity. And we're going to talk a little
00:21:30
bit more about onions and shallots and stuff next week.
00:21:33
But just know, you know that onion seedlings can tolerate
00:21:37
those lice, those light frosts, and you know, some pretty
00:21:42
significant ones. OK, the, the climate sort of
00:21:45
gotcha here is that day length type.
00:21:47
So if you've ever wondered why your onion variety never bulbed,
00:21:50
the day length might be the reason.
00:21:51
So I will link to the onion episodes that I have done.
00:21:55
But essentially onions initiate bulbing in response to day
00:21:59
length. Long day cultivars basically
00:22:02
require, you know, 14 hours or more of daylight to bulb.
00:22:06
Well, short day you're looking at 11:50.
00:22:08
Intermediate day is roughly somewhere in between, between.
00:22:10
So you know, if you're in a warm southern climate, you often do
00:22:14
better with short day onions and often times you might be growing
00:22:17
them through the winter because it gets so hot, right?
00:22:21
Northern climates, typically we're using long day, you know,
00:22:24
types. We're kind of right on the line
00:22:26
here where I am in Missouri. So I can get away with long day
00:22:29
or I can do the intermediate day.
00:22:31
If you are in those warm climates, definitely remember to
00:22:34
keep those to treat those bulbing onions as a cool season
00:22:38
crop and match that day length type to your region and plant so
00:22:42
that the major growth happens before your season turns hot.
00:22:46
So this might mean again that you are growing through the
00:22:48
winter time and you are harvesting in the very early
00:22:51
spring because that extended heat can actually reduce the
00:22:54
bulb size. If you live somewhere where you
00:22:56
have extremely short seasons, make sure that you are starting
00:23:00
those onions from seed indoors early on or by your transplants,
00:23:04
and then plant as soon as those conditions allow you to so you
00:23:08
can maximize that leaf growth before the bulbing begins #4 is
00:23:14
potatoes and potatoes are on this list because they are a
00:23:18
cool season crop. They can be planted well before
00:23:22
your last frost as long as you hit your soil temperature target
00:23:25
and manage your frost risk on that emerging foliage.
00:23:31
Generally speaking, the guidelines say you know you want
00:23:34
to plant potatoes up to a couple of weeks before your average
00:23:37
last frost state. You want the soil temperature to
00:23:39
be around 45°F or warmer. Around here, that generally
00:23:45
means Saint Patrick's Day, right?
00:23:47
So March, what is it? 17th, 27th?
00:23:50
See, I got to go back to my calendar again.
00:23:51
I'm telling you guys, you got to have all your stuff on a
00:23:53
calendar so that, you know, potato is March 22nd because
00:23:57
Saint Patrick's Day is the 17th. So yes, I do it the week after.
00:24:01
I'm not as concerned about the possibility of frost damage on
00:24:07
potatoes as you might think #1 you're going to get these tubers
00:24:10
into the ground, is going to take them a little bit to even
00:24:13
start to develop any foliage. And so by the time that foliage
00:24:17
starts to pop up out of the ground after those, you know,
00:24:20
tubers have gotten themselves sort of settled in those those
00:24:24
seed potatoes, you're going to start to see some of that stuff
00:24:28
popping up. Even if you get a frost after
00:24:32
the time that those greens pop out of the soil, in my
00:24:35
experience, it is not going to be a problem.
00:24:37
Those potatoes are going to continue to grow.
00:24:39
So don't let the threat of frost keep you from planting your
00:24:43
potatoes at the right time. So use your soil temperature as
00:24:48
more of a gauge rather than your frosted 45° soil. 40 Fahrenheit,
00:24:53
sorry, is really what you kind of want to aim for.
00:24:57
Up to 50° or so depending on the guideline that you follow.
00:25:00
Soil temperatures above 80° can actually inhibit tuber
00:25:05
development. So that is one of the concerns
00:25:07
that we have when growing potatoes.
00:25:09
If your soil temperature starts to rise very, very quickly, you
00:25:13
very well may not get very many potatoes or those tubers are
00:25:18
going to be very, very small. And a lot of garden potatoes
00:25:21
take, you know, anywhere from 90 to 120 days to mature.
00:25:25
I mean, you can get new potatoes, the smaller ones, a
00:25:27
little bit earlier. But think about that when you
00:25:31
are determining when is a good time to go ahead and get those
00:25:34
potatoes in the ground. They can't handle those lot,
00:25:37
those light frosts, not the Super heavy frost or hard
00:25:40
freezes. But in my experience, that
00:25:42
foliage that dies back comes back anyway.
00:25:45
OK, if you're in a very warm climate, you're definitely want
00:25:49
to try to plant early enough so where that tuber development
00:25:52
happens before the sustained heat sort of kicks in, because
00:25:55
again, those hot soils can really suppress that tuber
00:25:58
formation. Use mulch to help keep your soil
00:26:03
more evenly at a more even temperature.
00:26:06
I'm sorry, and a little bit cooler later into your season if
00:26:10
this has been a problem before. If you are in an extremely short
00:26:13
season area then you definitely want to look for those early
00:26:16
maturing varieties where possible.
00:26:18
And you might even try green sprouting, which is sort of pre
00:26:23
sprouting those seed potatoes to get you a faster start.
00:26:26
Because if your spring is really super cold and wet and your
00:26:30
minimum soil temperature doesn't hit that 45° until really later
00:26:35
on in your season and it doesn't give you a whole lot of time to
00:26:38
get those potatoes grown. If you can sprout them ahead of
00:26:41
time indoors and then transplant them with the sprouts intact,
00:26:46
that might give you a little bit of an advantage #5 on this list
00:26:51
is spinach. So spinach is not just cold
00:26:55
tolerant, it is actually heat avoidance, right?
00:26:58
Spinach can tolerate cold a lot more than people give it credit
00:27:03
for. But the bigger issue is that
00:27:04
it's very quick to bolt when the temperatures rise and the days
00:27:08
start to lengthen, right? That bolting can be triggered
00:27:13
with the combination of both of those things, the warming
00:27:15
temperatures and the longer days.
00:27:18
So if you're planning on growing, growing spinach in the
00:27:21
spring, those seeds can germinate when the soil is as
00:27:26
cold as 45°F on up to around 68 or so.
00:27:31
And so oftentimes if you look at some of the guidance, you can
00:27:35
actually get these planted around 4 to 8 weeks before your
00:27:40
average last spring frost. So if we do the math on that for
00:27:44
me, like April 20th, I think is our last average frost.
00:27:49
So you're looking at February, the end of February, that you
00:27:52
could potentially get those seeds in the ground.
00:27:55
It is one of those crops that can be seeded in very cold
00:27:59
soils. You can actually plant spinach
00:28:02
seeds in soil that is only 35°F and it will sprout.
00:28:08
This is one of the reasons why spinach is usually direct zone
00:28:11
because you don't have to wait very long to get it into the
00:28:14
ground. As long as your soil can be
00:28:15
worked you can go ahead and direct C.
00:28:16
You can use transplants to get an earlier harvest or to make it
00:28:20
easier to space them out. It doesn't, in my experience,
00:28:23
love being transplanted. It tends to take a little bit of
00:28:27
time to bounce back but I have done it.
00:28:30
Transplants can take about 5 to 6 weeks or so to reach a good
00:28:34
size where you have like 4 to 6 mature leaves on it and a nicely
00:28:39
developed root system before you plant it outside.
00:28:42
So again, make sure that you're hardening them off before you
00:28:45
send them out. Just because they're, you know,
00:28:47
able to tolerate the cold doesn't mean they can be shocked
00:28:49
to their system and and not, you know, take the hit for it.
00:28:52
So once you get it set outside, give it the chance to really
00:28:57
settle in and it can absolutely tolerate those lighter freezes
00:29:02
if they've been transplanted, if they have been direct sewn, it
00:29:06
can tolerate a hard freeze, like it's going to pop up and
00:29:08
immediately be acclimated to it, the surroundings.
00:29:11
And you generally aren't going to have to worry about covering
00:29:14
it. Spinach is one of those crops in
00:29:15
my garden along with kale that I do not have to protect in the
00:29:23
winters here. And we get some very cold
00:29:25
winters. I think -15 is our usual lowest
00:29:30
point. I think maybe that changed when
00:29:32
they changed the zones on us. So it might be -10 now.
00:29:35
But even with that, I have allowed spinach to overwinter
00:29:41
out in my garden and it immediately started growing
00:29:44
again in the spring. No harm, no foul.
00:29:46
And boy did it taste good too. It tastes really good once you
00:29:49
get that kind of cold snap to it.
00:29:50
So spinach varieties are going to vary in terms of how long
00:29:54
they take to get to maturity and whether or not you're harvesting
00:29:58
them. Baby leaf or full size.
00:30:01
Around 45 days is kind of typical for most varieties.
00:30:05
And so this can be one of the very, very first things that you
00:30:10
harvest. You can actually plan for the
00:30:13
spinach by planting it super, super early.
00:30:15
And then when you go ahead and plant that arugula, it's going
00:30:18
to grow fast enough to where you can get yourself a little spicy
00:30:21
green mix with the arugula and the spinach coming ready around
00:30:24
the same time. If you live in a warmer climate,
00:30:27
your spinach season probably is going to fall on fall through
00:30:32
winter and then into the early spring.
00:30:35
So for spring spinach, the goal is definitely like fast growth
00:30:39
in the cool weather and then harvesting it before the heat
00:30:42
arrives. So you might want to be planting
00:30:44
it in the fall and allowing it to winter over and get that
00:30:48
spring growth. And if you love like spinach,
00:30:52
like greens, but your climate is hot, there is New Zealand
00:30:57
spinach and it is sort of a warm season alternative.
00:31:01
It's not a true spinach. I think Malabar spinach is is a
00:31:05
version of this. It's more succulent, but it does
00:31:09
really well in the heat. So if spinach hasn't worked for
00:31:13
you because the area where you are is just too darn warm, then
00:31:17
try New Zealand spinach. It might work out for you.
00:31:20
OK. And then there's that final
00:31:21
little bonus crop. And I say bonus because it's not
00:31:24
a vegetable, it's an herb, right?
00:31:26
But it's one that a lot of gardeners struggle with.
00:31:29
And I get, this is one of the things I get comments about all
00:31:32
the time at the farmers market stand when people come looking
00:31:35
for cilantro, immediately they're saying something like, I
00:31:39
was growing it, but all of a sudden it bolted or all I got
00:31:42
was flowers. And I only had it out there for
00:31:45
like a week or two. It bolts really, really quickly.
00:31:50
You would think because we use cilantro in things like salsa,
00:31:55
which is alongside warm season plants like tomatoes and
00:32:00
Peppers, that cilantro would be something that tolerates the
00:32:04
heat. That was the impression that I
00:32:06
had when I first started growing it.
00:32:07
I thought, oh shoot, OK, I'm going to grow it right alongside
00:32:10
my tomatoes and my Peppers because that's what goes in
00:32:13
salsa and wrong. It does not like the heat.
00:32:17
Cilantro is typically direct sewn.
00:32:19
You can transplant it, but it does have a little bit of a
00:32:23
taproot, so it sometimes can be difficult to transplant.
00:32:26
Or if you do, it will sort of, you know, look a little weepy,
00:32:29
weepy at 1st and then it will bounce back.
00:32:31
Generally speaking, it does best around 50°F and it tends to bolt
00:32:38
when temperatures start to exceed about 85°F.
00:32:42
We're talking about air temperatures here.
00:32:44
So the optimal conditions are a little bit on that cooler side,
00:32:48
the 50°, the typical, I think cilantro days to maturity is
00:32:53
around 40 to 45 days. This is another one that is a
00:32:57
really good one for succession planting.
00:32:59
If you want to sow a small patch every two to four weeks, then
00:33:03
you'll always have young plants coming on behind the ones that
00:33:06
bolt because it's very similar to arugula in that way.
00:33:11
You just look away and all of a sudden you look back and you
00:33:13
have flowers. Now, if you leave those flowers
00:33:16
there, those flowers will eventually turn into seed.
00:33:19
And that seed, if you collect it, is coriander.
00:33:23
So coriander is the seed of the cilantro plant if you didn't
00:33:27
know that. So the flowers are beautiful and
00:33:28
they definitely attract pollinators and it will self
00:33:31
seed itself as well. So if you do have a spring crop
00:33:35
that bolts of your cilantro, feel free to let it drop those
00:33:38
seeds because you very well may get a fall crop in the exact
00:33:42
same space. I do this all the time and then
00:33:44
I will just continue to plant more successions of the cilantro
00:33:48
around it. If you're in a warm client,
00:33:50
cilantro actually performs really well as a winter crop.
00:33:54
So you know, a winter sort of harvest window is a really good
00:33:57
idea if it always fails for you in the summer.
00:34:00
This may not be a you problem as a gardener, it just may be a
00:34:03
timing problem because of where you live.
00:34:06
So try to grow it through the winter time if you can.
00:34:08
Cilantro is fast. It's a fairly fast grower.
00:34:12
So this is another one where if you have short seasons, you can
00:34:16
plant it early. You can do some succession
00:34:18
plantings and harvest it really frequently.
00:34:21
And then once it starts to sort of elongate and it changes that
00:34:24
leaf shape, it's telling you that it's getting ready to
00:34:27
change up its growth habit. It's getting ready to bolt.
00:34:30
So keep an eye on that and either decide to let it go to
00:34:34
seed or cut it back and try again in the next season.
00:34:38
So I'm going to leave a link in the show notes to a website that
00:34:43
I use that actually tracks the average soil temperatures for my
00:34:48
area. You can enter in your zip code
00:34:51
and it will do the same thing for you.
00:34:52
It will show you the historical data for like the last 10 years
00:34:56
and the last five years and then last year specifically.
00:34:59
And that will also show you the up to date current information.
00:35:02
So if you don't want to be running out into your garden,
00:35:04
you know, every other day with your soil thermometer checking
00:35:08
to see what the temperature of your soil is to see if it's time
00:35:11
for you to plant any of these things, You can use this website
00:35:14
to give yourself a general idea of when it should be the proper
00:35:17
temperature. And then you can time going out
00:35:19
there and checking the soil to see whether or not it's time to
00:35:23
get some of these things in the ground.
00:35:25
As always with anything that we're planting super early on, I
00:35:28
do recommend having some sort of frost cloth available and ready
00:35:32
to cover in case you have any extreme winter changes.
00:35:35
Just because winter changes, weather changes, sorry, Just
00:35:39
because these crops are all tolerant of frost doesn't mean
00:35:44
that if you have an extended hard freeze, they're going to
00:35:47
survive. So it's always better safe than
00:35:49
sorry. So always make sure that you
00:35:50
have that on hand. If you found this episode
00:35:54
helpful, will you share it with a gardening friend, especially
00:35:57
the one who keeps planting spinach like in May and then is
00:36:00
personally offended by it when it bolts?
00:36:03
It's a great way for us to be able to get word out to new
00:36:06
gardeners, beginning gardeners, or gardeners who just need a
00:36:08
little refresher is by sharing this episode.
00:36:11
I truly appreciate it. Until next time, my gardening
00:36:13
friends, keep on cultivating that dream garden, and we'll
00:36:15
talk again soon.